Browse Topic: Fuel control

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SAE Truck & Off-Highway Engineering: June 202626TOFHP066/11/2026
Hitting the road in the all-new VNR Volvo Trucks' revised VNR brings updated safety tech, improved fuel economy and driver comfort features to the regional haul segment. In fuel control How to ensure off-highway combustion systems operate with sufficient control to meet tightening emissions standards and evolving fuel landscapes without sacrificing reliability. Keeping industrial vehicles secure in a digital landscape OEMs, integrators and suppliers must continuously process, assess and identify platform vulnerabilities to prioritize and implement updates that protect systems from cyberattacks and data breaches. Editorial Diversification key for sustainable fleets ACT 2026: Uncertainty still exists over EPA 2027 NOx limit ZF bets big on hybrid transmissions Moog simplifies off-highway electrification Bosch shows off its first U.S. electrolyzer Microvision fast-tracks adoption of Luminar tech; eyes defense, industrial sectors Future-ready, customizable connectivity powers precision agriculture Kenworth's new C580 clocks in for work Harbinger extends its range of medium-duty EVs Kubota's SVL110-3 brings new tech and service features to CTL segment Product Briefs SPOTLIGHTS: Diesel Engines & Subsystems; Manufacturing Tools & Materials; Motors, Inverters & Gearboxes Q&A Volvo turns attention to vocational trucks
IN FUEL CONTROL26TOFHP06_026/1/2026
How to ensure off-highway combustion systems operate with sufficient control to meet tightening emissions standards and evolving fuel landscapes without sacrificing reliability. Off-highway equipment is being asked to do more with less. Less margin for emissions, less tolerance for downtime and less room for inefficiency, while operating under some of the most demanding duty cycles in the transport sector. Tier 4 and Tier 5 emissions standards have reshaped engine calibration strategies. Renewable diesel and biodiesel blends are entering worksites and farms at scale. At the same time, construction, mining and agricultural machines are expected to run for 20-25 years, often at sustained high load and far from service infrastructure. In this environment, combustion systems are far from being phased out.
Anderson, Todd
Mitigating Air Flow Sensor Signal Variability to Optimize Engine Operation in Passenger Cars2026-26-05121/16/2026
In order to control the engine performance which is driven by the strict emission regulations and customer request for the improved fuel economy, precise air intake measurement and fuel control system are essential. In the modern engines, the mass air flow sensor (MAF) acts an important role which provides a precise estimation of air flow from the clean side ducting of air intake system to engine control unit module (ECU). The hot wire mass air flow sensor are mounted on the clean side of the air intake system in order to protect the sensing element from the contamination and to extend their lifespan as well as maintain its accuracy. It is essential to maintain a steady and a uniform airflow at the sensing element of the MAF sensor for reliable sensor reading at different engine speeds and varying engine load. However, the physical limitations of engine packaging inside the engine bay, limits the sensor placement. Incorrect sensor mounting can lead to errors in the airflow estimation which in turn adversely affect engine thermal performance and emissions. During the development of a new passenger vehicle, it was observed that the unpredicted engine torque oscillations were detected and that too in various operating conditions. When the root cause of these oscillation were studied, it was linked with the oscillations and fluctuations in the MAF sensor’s output signal. In order to address the issue, a number of clean side ducting as well as air filter assembly top cap geometry and configuration were modified and studied. These design iterations were tested on the dynamometer in order to identify their effect on the sensor signal and corresponding engine torque variation. The current paper presents the investigation and evaluation of the different clean side ducts geometries and sensor mounting strategies. This would ensure that there will be minimum signal disturbance which would further improve the mass air flow measurement accuracy. The final air intake clean side design have reduced sensor signal pulsations and oscillations significantly. This has further lead to a smoother and more stable engine torque output.
Sonone, Sagar Dinesh, Zope, Mahesh, Kale, Vishal, Padmawar, Harshad, Sridhar, S, Kolhe, Vivek M, Panwar, Anupam
Optimization of CI Engine Operation with DME on an FTP Cycle2025-01-039410/7/2025
Fuels that can be produced in a sustainable manner are of high interest because they can provide an essential step toward net zero emissions vehicles. This study examines the combustion of one such fuel, Dimethyl Ether (DME), in a compression ignition, 4-cylinder, 2.2L engine. Testing was conducted using the Federal Test Procedure (FTP) certification cycle from the US Environmental Protection Agency (EPA). Different sets of calibration maps were designed to target low-NOx (30-50ppm) by using high EGR and intake throttle and high-NOx (approximately 1000ppm) using no EGR. An intermediate, mid-NOx calibration was also evaluated. Varying calibration approaches yielded total integrated engine out emissions ranging from 118 to 145gCO2/km, all below the 191gCO2/km from the baseline diesel. The corresponding NOx+UHC and CO emissions were also evaluated. The mid-NOx calibration was overall more favorable, as it met TIER 3-Bin 20 emissions requirements with the current efficiencies of the base engine diesel aftertreatment system. This paper reviews the transient behavior with three different calibrations, noting the effect of air-to-fuel ratios where the engine combustion efficiency deteriorates. It also highlights the impact of improved air and fuel controls, and the application of real time combustion feedback to enhance the combustion stability of the engine and the reduction of CO2 emissions. The paper explores the impact of renewable DME, and its carbon index, on the CO2 emissions for the low-NOx calibration. While a 5% renewable DME content can reduce the CO2 to the target level, the fuel consumption remains high due to the poor combustion efficiency and corresponding high HC and CO during transient operation.
De Ojeda, William, Wu, Simon (Haibao), Harrison, Christopher, Hall, Carrie, Arslan, Elaheh, Pulpeiro Gonzalez, Jorge
Aircraft Fuel System and Component Icing TestARP1401C (Current)6/27/2025
This SAE Aerospace Recommended Practice (ARP) covers a brief discussion of the icing problem in aircraft fuel systems and the different means that have been used to test for icing. Fuel preparation and icing test procedures for aircraft fuel systems and components are proposed herein as a recommended practice to be used for fixed wing and rotary-wing aircraft within their operational environment. This ARP mostly addresses aircraft fuel system level testing and provides a means to address the requirements of FAR 14 CFR § 23.951(c), § 25.951(c), § 27.951(c), and § 29.951(c). In the context of this ARP, the engine and the auxiliary power unit (APU) are not considered to be components of the aircraft fuel system. However, some of the methods described in this document can be applied to the engine, APU, and other aircraft (system or component level) icing tests. This revision does not completely address new developments in ice accretion and release resulting from internal flow in tubing (see 2.3.6). This will be addressed in a different document when more experimental data is available.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Prediction of Combustion Process Based on Physics-Informed Data-Driven Model2025-01-70341/31/2025
Predicting the ignition and heat release patterns during diesel combustion processes is of great significance for improving engine efficiency, reducing emissions, and enabling future low-carbon and zero-carbon flexible fuel control. However, traditional Wiebe physical models face challenges in handling the highly nonlinear nature and variable operating conditions of diesel combustion, failing to achieve accurate real-time prediction. Pure data-driven models demand large amounts of data and lack physical interpretability, while physical models based on parameter learning have restricted fitting accuracy due to structural and parameter constraints. To address these issues, this paper proposes a novel Physics-Informed Data-Driven Model. It defines data loss as the deviation between neural network predictions and measured data, and physical loss as the deviation between neural network derivatives and the differential form of the physical model. By minimizing the combined loss, which is a weighted fusion of these two loss terms through back propagation, the model effectively integrates physical and data-driven approaches to estimate the heat release rate and combustion phase instantaneously. Experimental results showcase the remarkable performance of this model with a high CA50 prediction coefficient (R2 = 0.9779), surpassing physical models based on parameter learning in accuracy and demonstrating stronger generalization capability than pure data-driven models, thus holding great promise for advancing diesel engine technology and contributing to the broader goals of sustainable energy use and environmental protection.
Zheng, Jiaao, Song, Kang, Xie, Hui, Zhou, Shengkai, Sang, Hailang, He, Guanzhang
UCF’s Hypersonic Technology AdvancesTBMG-5219612/1/2024
Hypersonic propulsion would allow for air travel at speeds of Mach 6 to 17, or more than 4,600 to 13,000 miles per hour, and has applications in commercial and space travel.
Estimating Light-Duty Vehicle Gaseous Emissions Using a Data-Driven Approach in Off-Cycle Measurements2024-01-27054/9/2024
As global regulations on automotive tailpipe emissions become increasingly stringent, developing precise tailpipe emissions models has garnered significant attention to fulfill onboard monitoring requirements without some drawbacks associated with traditional sensor-based systems. Within the European Union, there is consideration of mandating real-time measurement of emission constituents to enable driver warnings in cases where constituent standards are exceeded. Presently, available technology renders this approach cost-prohibitive and technologically challenging, with most sensor suppliers either unable to meet the demand or unwilling to justify the development costs associated with sensor commercialization. Efforts to circumvent the sensor-based approach through first principle models, incorporating thermokinetics, have proven to be both computationally expensive and lacking in accuracy during transient operations. We propose a data-driven solution based on DL (deep learning) to create virtual sensors capable of accurately estimating instantaneous emissions comparable to fast gas analyzers as an alternative to these approaches. To construct such DL models, a highly accurate dataset is essential for training, validation, and testing. This level of precision was achieved by utilizing a PEMS (portable emissions measurement system) to analyze real-world exhaust stream constituents, complemented by the logging of critical powertrain variables. The data recorded by the PEMS comprises a comprehensive inventory of THC (total hydrocarbons), CO (carbon monoxide), and NO (nitrogen oxide) concentrations in the tailpipe, correlated with engine speed, air intake charge, ignition timing, catalyst temperatures, and other key powertrain signals. During the collection of emissions and powertrain characteristics, test vehicles were driven over diverse city and highway routes, encompassing various ambient conditions, to create an extensive dataset conducive to training. The generated datasets exclude cold-start events, which are subject to rigorous scrutiny in vehicle certification efforts. Furthermore, the model relies on the closed-loop operation of the fuel control system, which is often not the case during cold start conditions. The trained networks exhibit good accuracy, as R2 and error metrics demonstrate. The resulting data-driven model can be integrated into production vehicles as an independent virtual measuring module or with OBM (onboard monitoring).
Hashemi, Ashton, Schlingmann, Dean
Revision of Modeling Scenario for Hydrogen Fueling Protocol under MC-MM2023-01-04894/11/2023
A new hydrogen fueling protocol called MC Multi Map (MC-MM) was developed to reduce hydrogen station operating costs. With the MC-MM, the number of fueling control maps has increased from before and precise switching among them according to circumstances has achieved relaxation of precooling temperatures. Fueling control maps for hydrogen stations are created in accordance with Society of Automotive Engineers (SAE) protocol, but with the MC-MM, greater accuracy of mapping is necessary, so steps were taken to revise the boundary conditions prescribed by the SAE. The creation of fueling control maps for a hydrogen fueling protocol used to require outsourcing of map analysis. However, the National Renewable Energy Laboratory research institute in the US has made a hydrogen fueling simulation called H2FillS publicly available on the Web so that analysis of fueling control maps can now be performed by anyone. Therefore, revision of the SAE boundary conditions was examined on the assumption that analysis would be performed using H2FillS. With regard to the fueling control maps newly added with the MC-MM, since the boundary conditions are not indicated by the SAE, those conditions were specified independently in this research. The fueling control maps created for use with the MC-MM were compared with the fueling control maps of existing protocols to confirm the influence from revising boundary conditions and switching to H2FillS as the analysis tool. Finally, the accuracy of the fueling control map created in this research was verified by conducting fueling tests in accordance with the MC-MM protocol using that fueling control map.
Yamaguchi, Shigehiro, Handa, Kiyoshi
Helicopter Power AssuranceAIR4083A (Current)1/20/2023
This SAE Aerospace Information Report (AIR) defines helicopter turboshaft engine power assurance theory and methods. Several inflight power assurance example procedures are presented. These procedures vary from a very simple method used on some normal category civil helicopters, to the more complex methods involving trend monitoring and rolling average techniques. The latter method can be used by small operators but is generally better suited to the larger operator with computerized maintenance record capability.
S-12 Powered Lift Propulsion Committee
Aircraft Turbine Engine Fuel System Component Endurance Test Procedure (Room Temperature Contaminated Fuel)MAP749C (Current)5/2/2022
This SAE Aerospace Recommended Practice describes a method for conducting room temperature, contaminated fuel, endurance testing when the applicable specification requires nonrecirculation of the contaminants. The objective of the test is to determine the resistance of engine fuel system components to wear or damage caused by contaminated fuel operation. It is not intended as a test for verification of the component's filter performance and service life. ARP1827 is recommended for filter performance evaluation.
AE-5B Aircraft and Engine Fuel and Lubricant Sys Components
A Methodology for the Design Optimization of Fuel Control Unit Bracket and Fuel Pump Housing Integration and Achieving the System Targets2022-01-06363/29/2022
The increasing demand for higher specific power and the need for weight reduction and decrease of emissions have become the driving factors of product development in the automotive market today. Substitution of high-density materials and more precise adjustment of material parameters help in significant weight decrease, but it is accompanied by undesirable cost increase and manufacturing complexity. One of the approaches to optimize the design is through the process of integration which involves integrating the functional elements of two or more components into one and achieving a reduction in weight and cost without impacting required performance. This paper explains a similar approach followed as a part of the Design and Development of 1.5 L, 3 Cylinder CRDI Diesel Engine for a new vehicle platform, developed for automotive passenger car application. Two components of the fuel injection system - the Fuel Injection Pump (FIP) housing and the Fuel Control Unit (FCU) bracket are integrated into one component. The paper discusses the design methodology, integration of classical methods, and verified through CAE simulation to ensure the required targets of modal analysis and strength analysis are met. Simulation results and actual measurement results are discussed in detail to show the effectiveness of an integrated approach used in this development program. Tools like DFMEA, DFMA,etc. are used along with value engineering concepts to make an efficient and cost-effective product to the end customer with minimum iterations in reduced cycle time.
Vinaya Murthy, Vijayendra, Rengaraj, Chandrasekaran, Dharan R, Bharani, Boita, Dhananjayarao
Challenges Overwhelmed to Meet BSVI Emissions with SPFI Fuel System for Heavy-Duty CNG Engine Application2021-26-01029/22/2021
As competent and low-pollution alternative fuel, CNG has revealed its excellence over engine performance and emissions. In recent years, CNG is considered as the diesel engine alternative fuel for heavy-duty engine applications due to its lower emissions and cost effective after-treatment systems. Due to the implementation of stricter emission norms over the years, the evolution of the fuel supply system has become more robust and electronically controlled. In the case of CNG engines, most of the engines were equipped with MPFI fuel system, for its precise fuel control abilities and controlling emission parameters. However, this MPFI system encompasses severe design changes in the intake manifold and is cost worthy to OEMs over the SPFI fuel system. MPFI system adds on the overall cost of the engine unit and its maintenance when compared to SPFI system. SPFI fuel system had proved its robustness to achieve BSIV emission norms but, due to challenging test methods and stringent emission limits, BSVI development with this fuel system seems cumbersome with limited control parameters. This paper presents the research work conducted on a heavy-duty CNG engine with a SPFI fuel system. The challenges involved for achieving the BSVI emissions through engine calibration, without major engine hardware change along with engine performance is incorporated in this work.
bandyopadhyay, Debjyoti, Sutar, Prasanna S, Sonawane, Shailesh Balkrishna, Rairikar, S D, Kavathekar, Kishorkumar, Thipse, Sukrut S, Kshirsagar, Chinmay, Kale, Samir
Fuel Level Control Valves and SystemsAIR1660C (Current)4/23/2021
A fuel level control valve/system controls the quantity of fuel in a tank being filled or emptied on the aircraft. This document provides a general familiarization with these mechanisms (e.g., forms they take, functions, system design considerations). This document provides the aircraft fuel system designer with information about these mechanisms/devices, so that he can prescribe the types of level control valves/systems which are best suited for his particular fuel system configuration. The scope has been expanded as different aircraft manufacturers may use different type of fuel system architectures. Their refueling and defueling systems may take different configurations, may require different types of fuel control valves and may require different types of interface with the onboard Fuel Measurement System. They must also limit pressure surges and be compatible with ground refueling equipment which have varying surge potentials and create surges.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Controls and Hardware Development of Multi-Level Miller Cycle Dynamic Skip Fire (mDSF) Technology2021-01-04464/6/2021
mDSF is a novel cylinder deactivation technology developed at Tula Technology, which combines the torque control of Dynamic Skip Fire (DSF) with Miller cycle engines to optimize fuel efficiency at minimal cost. mDSF employs a valvetrain with variable valve lift plus deactivation and novel control algorithms founded on Tula’s proven DSF technology. This allows cylinders to dynamically alternate among 3 potential states designated as: High Fire, Low Fire, and Skip (deactivation). The Low Fire state is achieved through an aggressive Miller cycle with Early Intake Valve Closing (EIVC). The three operating states in mDSF can be used to simultaneously optimize engine efficiency and driveline vibrations. Acceleration performance is retained using the all-cylinder, High Fire mode. mDSF can be implemented cost-effectively using an asymmetric intake valve lift strategy, with one high-flow power charging port and one high-efficiency Miller port. Prototype mDSF cylinder heads were based on the EA888 Gen 3B engine by retrofitting the valvetrain with asymmetric intake cams, deactivatable roller finger followers and two oil control valves per cylinder. Event-based engine controls were developed to enable for each cylinder dynamic selection of the three mDSF operating modes: High Fire, Low Fire and Skip. Appropriate air estimation, fuel control and ignition control techniques were employed to ensure acceptable torque delivery and tailpipe emissions. Engine dynamometer tests showed a 23% reduction in engine fuel consumption at 1500 rpm, 2 bar NMEP. Maximum torque and power from the baseline production engine up to 5000 rpm were also achieved. mDSF vehicle tests on the WLTC demonstrated a 6% reduction in CO2 from Miller 2-step. Euro 6d compliant emissions were also reported. Further improvements in fuel economy, drivability and NVH may be possible by leveraging mixed firing densities more extensively.
Ortiz-Soto, Elliott, Yang, Xiaojian, Van Ess, Joel, Owlia, Shahaboddin, Joshi, Abhishek, Younkins, Matthew
Fuel Level Point SensingAIR6325 (Current)11/30/2020
This report is intended to identify the various existing technologies used for a fuel level sensing system. In addition to sensing technologies, it describes the basic architecture of fuel level sensing systems and their association with fuel gauging system to increase integrity of fuel measurement and management. As the fuel level sensing system is generally based on electrical components within fuel tanks, a specific focus is made on fuel tank explosion safety protection. An overview of the capacitive fuel gauging operation can be found in AIR5691.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Acceptance Test Procedures and Standards to Ensure Clean Fuel System ComponentsARP1953B (Current)10/1/2020
To describe general guidelines for achieving selected levels of cleanliness in gas turbine engine fuel system components and to describe laboratory methods for measuring and reporting the contamination level of the wetted portion of fuel system components. As in SAE J1227 (covering hydraulic components) this practice includes guidelines for levels of acceptance but does not attempt to set those levels.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Considerations on Ice Formation in Aircraft and Engine Fuel SystemsAIR790D (Current)9/18/2020
Ice formation in aircraft fuel systems results from the presence of dissolved and undissolved water in the fuel. Dissolved water or water in solution with hydrocarbon fuels constitutes a relatively small part of the total water potential in a particular system with the quantity dissolved being primarily dependent on the fuel temperature and the water solubility characteristics of the fuel. One condition of undissolved water is entrained water, such as water particles suspended in the fuel as a result of mechanical agitation of free water or conversion of dissolved water through temperature reduction. This can be considered as analogous to an emulsion state. Another condition of undissolved water is free water which may be introduced as a result of refueling or the settling of entrained water which collects at the bottom of a fuel tank in easily detectable quantities separated by a continuous interface from the fuel above. Water may also be introduced as a result of condensation from air entering a fuel tank through the vent system. Assuming good quality of uplifted fuel, vapor passing through the aircraft vent system is a significant water introduction mechanism. Entrained water will settle out in time under static conditions and may or may not be drained, depending on the rate at which it is converted to free water. In general, it is not likely that all entrained water can ever be separated from fuel under field conditions. The settling rate depends on a series of factors including temperature, quiescence, and droplet size. The droplet size will vary depending upon the mechanics of formation. Usually the particles are so small as to be invisible to the naked eye, but in extreme cases can cause a slight haziness in the fuel. Free water can be drained from a fuel tank if low point drain provisions are adequate and recommended maintenance actions are followed. Water in solution cannot be removed except by dehydration or by converting it, through temperature reduction, to entrained, then to free water. Water strictly in solution is not a serious problem in aviation fuel so long as it remains in solution. Entrained and free water are the most problematic because of the potential of freezing on the surfaces of the fuel system. Further, entrained water will freeze in cold fuel and tend to stay in solution longer since the specific gravity of ice is approximately the same as that of hydrocarbon fuels. The elimination of undissolved water, to the extent it is practical, in fuel storage, handling, and delivery systems, as well as in aircraft fuel systems, can reduce or eliminate the potential for icing problems. Appropriate testing of fuel systems, subsystems, and components under controlled icing conditions can establish confidence in the safe operation of the aircraft fuel system in such icing conditions. The objective of testing is not necessarily to demonstrate that no icing will occur but rather that the effects of the icing will not create a hazardous condition. Considerations for these measures to control potential icing problems are addressed herein.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Water Load Determination Approach in Two Wheeler Exhaust System2018-32-007510/30/2018
Future emission norms in India (BS6) necessitates the 2 wheeler industry to work towards emission optimization measures. Engine operation at stoichiometric Air-Fuel Ratio (AFR) would result in a good performance, durability and least emissions. To keep the AFR close to stoichiometric condition, an Oxygen sensor is placed in the exhaust system, which detects if air-fuel mixture is rich (λ<1) or lean (λ>1) and provides feedback to fuel injection system for suitable fuel control. O2 sensor has a ceramic element, which needs to be heated to a working temperature for its functioning. The ceramic element would break (thermal shock) if water in liquid form comes in contact with it when the element is hot. To counter this, oxygen sensor is either fully heated only when all the water in the exhaust system is evaporated, which results in delayed closed loop control, or is capable to withstand higher amount of water in the exhaust system by for example being applied with thermal shock protection and a protective tube. It’s a challenge to control the HC emissions during first 100 seconds of engine start, as the catalyst is not functioning during this duration. Also, the system runs in open loop for first 50 seconds, as the lambda sensor is not functioning. Hence, determining the amount of water present in exhaust and having a protective layer for lambda sensor against water would enable early start of sensor functioning. The present paper explains an approach to determine the maximum water droplet size and water flow rate using a special Liquid sensor mounted in the exhaust pipe. Test cases are defined at various engine and exhaust gas temperatures to determine an appropriate set up and methodology for measurement on a 2Wheeler. The test cases are repeated on various 2wheelers available in the Indian market and influence of different exhaust configurations, mounting location of the Lambda sensor are analysed. The information of water droplet size and water flow rate are driving factors for the design and application of lambda sensor. With thermal shock protection over lambda sensor a full heater voltage can be applied to sensor even before all the water has evaporated in the exhaust system. An early sensor readiness results in a quick closed loop control of the fuel mixture thus reducing emissions.
Meena, Ranjana Kumari, Krusch, Andrea, Meister, Konrad, Holzknecht, Christopher
LEVER ENDS - FUEL AND POWER CONTROLAS56D (Current)9/19/2018
E-25 General Standards for Aerospace and Propulsion Systems
Operating Instructions for Aircraft Engines (Preparation of)AS177C (Current)9/11/2018
This specification covers the requirements for format and outline of contents of operating instructions in published form or in manuscript form suitable for publication.
E-25 General Standards for Aerospace and Propulsion Systems
Fuel Control and Spark Optimization of a Propane Fuel System for an Engine-Generator System2018-01-11414/3/2018
As climate change drives the exploration into new and alternative fuels, biodiesel has emerged as a promising alternative to traditional diesel fuel. To further increase the viability of biodiesel, a unique system at the University of Kansas utilizes glycerin, the primary byproduct of biodiesel production, for power generation. This system converts glycerin into a hydrogen-rich gas (syngas) that is sent to an engine-generator system in one continuous flow process. The current setup allows for running the engine-generator system on pure propane, reformed propane, or reformed glycerin, with each fuel serving a unique purpose. This paper discusses upgrades in pure propane operation that serves the intent of preheating the engine prior to syngas operation and establishing the baseline energy requirement for fueling the system. The current upgrade to the fuel system incorporates an Electric Fuel Valve (EFV) as a replacement for a gaseous propane carburetor, providing the ability for Air-to-Fuel Ratio (AFR) adjustment of the engine at different generator loads. The use of EFV in a continuous fuel additive manner provides a solution to the carburetor’s inherent disadvantage: maintaining a constant AFR. Hence, this upgrade allows the system to adjust more accurately to different engine operating conditions and other unique fuels to be potentially tested (e.g., natural gas and biogas). Moreover, spark timing optimization accompanies the new fuel control in order to enhance engine performance and maximize fuel economy. Finally, in-cylinder pressure traces and associated performance parameters are reviewed and discussed in order to analyze the operation of the new EFV-based system.
AlZeeby, Khalaf, Depcik, Christopher
Vehicle Exhaust Emission Control-Dynamic Signature Measurement and Analysis - A Method to Detect Emission Testing Irregularities2018-01-06504/3/2018
To meet US EPA light-duty vehicle emission standards, the vehicle powertrain has to be optimally controlled in addition to maintaining very high catalyst system efficiency. If vehicles are operated outside the bounds of a standard laboratory exhaust emission test (e.g., on-road or off-cycle) the operating control strategy may shift to optimize other desirable parameters such as fuel economy and drivability. Under these circumstances. The engine control system could be operating in a different state space from an emission control stand point. This control state-space can be observed based on four principal parameters: NOx, Lambda and exhaust temperature (measured at the tailpipe) and vehicle acceleration. These vehicle emission control patterns can be characterized by their corresponding emission control signatures, such as cold start, transient fuel control, and high speed/high load open loop. These emission control signatures are unique to a variety of engine technologies as well. Recognizing these signatures during vehicle operation can identify engine control state space and could estimate NOx mass flow by utilizing an ANN (artificial neural network) for pattern recognition. This could assist in detecting emission testing irregularities that might indicate a malfunctioning emission control system. One advantage to this approach is the equipment overhead to acquire this information is much less compared to other conventional methods such as PEMS (portable emission measurement system). US EPA is investigating this approach, recording the vehicle emission control dynamic signatures during normal dynamometer testing and on-road/off-cycle. Optimized data sets of emission control signatures are currently being used for training an artificial neural network to estimate NOx mass-based calculations and distinguish between well-controlled and uncontrolled systems. This non-intrusive testing method may be used to detect catalyst early failure and monitor emission test irregularities.
Tang, Xiaoguo, Caldwell, Walter, McBryde, Dan
The Impact of Intake Valve Dynamics on Knock Propensity in a Dual-Fuel SI Engine2017-01-223610/8/2017
In this study, the impact of the intake valve timing on knock propensity is investigated on a dual-fuel engine which leverages a low octane fuel and a high octane fuel to adjust the fuel mixture’s research octane rating (RON) based on operating point. Variations in the intake valve timing have a direct impact on residual gas concentrations due to valve overlap, and also affect the compression pressure and temperature by altering the effective compression ratio (eCR). In this study, it is shown that the fuel RON requirement for a non-knocking condition at a fixed operating point can vary significantly solely due to variations of the intake valve timing. At 2000 rpm and 6 bar IMEP, the fuel RON requirement ranges from 80 to 90 as a function of the intake valve timing, and the valve timing can change the RON requirement from 98 to 104 at 2000 rpm and 14 bar IMEP. These significant changes in the required fuel RON are attributed to increases in the charge temperature due to high residual concentration as well as increased cyclic variability in combustion phasing. Due to the wide range of fuel RON requirements with respect to the valve timing, a more sophisticated fueling control strategy is required in order to ensure that knock is properly suppressed despite varying valve timing. The impacts of valve dynamics are investigated in this study to evaluate the effect of response lag in which there is a mismatch between the commanded and actual valve position. The simulation of a WLTC drive cycle is used to illustrate the resulting effect on fuel consumption, which shows a 6% excess consumption of the high octane fuel during valve mismatch periods of the cycle.
Kassa, Mateos, Hall, Carrie, Vidal-Naquet, Fabien, Leroy, Thomas
Contaminants for Aircraft Turbine Engine Fuel System Component TestingAIR4246D (Historical)9/27/2017
This SAE Aerospace Information Report (AIR) is intended as a guide toward standardization of descriptions and specifications of fluid contamination products.
AE-5B Aircraft and Engine Fuel and Lubricant Sys Components
Achieving Performance Advantages in Unmanned Systems16AERP10_0110/1/2016
Unmanned Vehicle Systems (UVS) are reaching new levels of functionality and performance, and it's not just for air vehicles either. Unmanned Vehicle Systems (UVS) are reaching new levels of functionality and performance, and it's not just for air vehicles either. Ground and underwater UVS programs are all taking advantage of the higher-performance computing platforms that are using highly integrated, multicore processors; faster and larger DDR and flash memory; as well as integrated I/O. Additionally, remote I/O subsystems are being implemented to distribute the processing power closer to the sensors and use packetized message passing - with multiple levels of security (MLS) - back to a smaller central vehicle and mission management computer. Traditional vehicle platforms had split the vehicle management computing functions (flight surfaces, engine and fuel controls, etc.) and mission management computers due to the overall expense of the computing hardware platforms and the costs to develop the software. Today, however, these hardware functions are being combined and then redistributed around the vehicle, significantly reducing size, weight, power, and cost (SWAPC), due to the density and performance improvements in the underlying processing technology (Figure 1).
Beyond Euro VI - Development of A Next Generation Fuel Injector for Commercial Vehicles2014-01-14354/1/2014
Delphi Diesel Systems (DDS) - Heavy Duty Business is developing a new range of Ultra High Pressure Common Rail Fuel Injectors with the functionality to allow the combustion heat release to be heavily adapted during operation. This allows the injector performance to be simultaneously optimised across a broad range of engine conditions, removing the constraints of having to select a single rate shape type for all operating conditions. This new technology range builds on the performance of Delphi's 2700 bar Fuel Systems of F2E, F2P and F2R, whilst adding in new levels of injector control, beyond what is available in the current market. In addition to this new functionality, Delphi's new Heavy Duty Injector range also demonstrates greatly reduced leakage and improved accuracy of fuel control. This paper reviews the benefits and possibilities of this new injector technology.
Graham, Mark S., Crossley, Stephen, Harcombe, Tony, Keeler, Nathan, Williams, Tony
Individual Cylinder Fuel Control for a Turbocharged Engine2014-01-11674/1/2014
This paper discusses on-engine results achieved in applying an algorithm-based Individual Cylinder Fuel Control (ICFC) to turbocharged four-cylinder engines. ICFC is a software algorithm which permits the detection and closed-loop correction of air/fuel imbalances on a cylinder-by-cylinder basis, which is not possible with typical bank-wide closed loop fuel control systems. Cylinder-to-cylinder air/fuel imbalances can be the result of a number of combined sources. The potential sources include fuel injector variation (both new and aged) as well as maldistribution of fresh air airflow, evaporative emissions purge flow, or exhaust gas recirculation flow. The ICFC algorithm requires no additional hardware beyond the typical sensor set already present on modern automotive spark-ignition engines, including oxygen sensor(s) and engine controller. While the ICFC algorithm has been employed in production programs since 2009, to date these have all been naturally-aspirated engines using switching oxygen sensors. With increasingly stringent worldwide emissions and fuel economy standards, the demand for both turbocharging and WRAF (wide-range air/fuel) oxygen sensor technologies in the light-duty passenger vehicle market has grown. In this investigation, the ICFC algorithm was applied to and verified on two different turbocharged engines, one with switching oxygen sensor feedback, and the other with WRAF oxygen sensor feedback; in both cases the oxygen sensor was located downstream of the turbine outlet. It was demonstrated on these engines that the ICFC logic is capable of correcting cylinder-to-cylinder air/fuel imbalances through adaptive learning, despite the potentially disruptive effects of the turbine in the exhaust stream, and with either type of oxygen sensor.
Burkhard, James F.
Dual-Fuel Effects on HCCI Operating Range: Experiments with Primary Reference Fuels2013-01-16734/8/2013
Results from a large set of HCCI experiments performed on a single-cylinder research engine fueled with different mixtures of iso-octane and n-heptane are presented and discussed in this paper. The experiments are designed to scrutinize fuel reactivity effects on the operating range of an HCCI engine. The fuel effects on upper and lower operating limits are measured respectively by the maximum pressure rise rate inside the cylinder and the stability of engine operation as determined by cycle-to-cycle variations in IMEP. Another set of experiments that examine the intake air heating effects on HCCI engine performance, exhaust emissions and operating envelopes is also presented. The effects of fuel reactivity and intake air heating on the HCCI ranges are demonstrated by constructing the operating envelopes for the different test fuels and intake temperatures. The paper discusses, in the light of the results, how the nonlinearity in fuel effects makes the dual fuel control approach less effective in extending the lower end of the HCCI load range. It also discusses how intake air heating affects the engine operation stability at low loads, and how varying fuel reactivity and intake heating can complement each other as an integrated control approach to extend both ends of the HCCI load range.
Aldawood, Ali, Mosbach, Sebastian, Kraft, Markus, Amer, Amer
Development of an Improved Residuals Estimation Model for Dual Independent Cam Phasing Spark-Ignition Engines2013-01-03124/8/2013
Estimating internal residual during engine operation is essential to robust control during startup, steady state, and transient operation. Internal residual has a significant effect on combustion flame propagation, combustion stability and emissions. Accurate residual estimate also provides a better foundation for optimizing open loop fuel control during startup, while providing a basis for reducing emissions during closed loop control. In this paper we develop an improved model to estimate residual gas fraction by means of isolation and characterization of the physical processes in the gas exchange. Examining existing residuals model as the base, we address their deficiencies making changes to appropriate terms to the model. Existing models do not work well under wide angle dual independent cam phasing. The improved residual estimation model is not limited by the initial data set used for its calibration and does not need cylinder pressure data. The model can work with different valve lift profiles and compression ratios. The model is calibrated by using two datasets, a single cylinder engine simulation dataset comprising of a range of speeds from 180 to 6000 rpm and loads from an existing validated model; and simulation dataset from a validated multi-cylinder engine model. Simplified real-time ECU implementation is also discussed.
Kale, Vaibhav, Yeliana, Yeliana, Worm, Jeremy, Naber, Jeffrey
Numerical and Experimental Investigation of Catalyst Flow and Air/Fuel Control2013-01-15774/8/2013
Recent regulatory requirements have introduced, for the first time, catalyst exhaust systems with closed loop air/fuel control into the severe environment of stern-drive and inboard-powered pleasure marine vessels. These engines often maintain consistently high power levels due to vessel drag. Sea water used to cool the engine and exhaust is corrosive, and the engine experiences high g-loads when the planing vessel is used in wavy sea conditions. Engineers must face these challenges in order to develop a durable, efficient, clean-operating, and affordable marine engine. Computational fluid dynamics (CFD) has become a key tool to drive the design optimization of catalyst exhaust systems for marine applicatons. CFD models are used to simulate the unsteady exhaust gas flow of a fired engine. In particular, CFD is used to develop an exhaust system which will promote efficiency, low emissions, and robust closed-loop air fuel control. Increased gas residence time via catalyst flow uniformity and balanced cylinder flow streams at the oxygen sensors are required to achieve an optimal design. A recent study was conducted in order to establish a correlation between unsteady exhaust flow CFD and physical testing for catalyst flow uniformity and oxygen sensor placement. This was done with prototype marine catalyst exhaust systems running on an eight cylinder gasoline engine. The desire was to prove that the CFD method provides accurate design direction to the team responsible for optimizing the exhaust system. The strong agreement established in this paper provided the confidence necessary to employ CFD in the development of future marine catalyst exhaust systems.
Morton, Scott, Hall, Ronald, Radavich, Paul
The Potential of Fuel Metering Control for Optimising Unburned Hydrocarbon Emissions in Diesel Low Temperature Combustion2013-01-08944/8/2013
Low temperature combustion (LTC) in diesel engines offers attractive benefits through simultaneous reduction of nitrogen oxides and soot. However, it is known that the in-cylinder conditions typical of LTC operation tend to produce high emissions of unburned hydrocarbons (UHC) and carbon monoxide (CO), reducing combustion efficiency. The present study develops from the hypothesis that this characteristic poor combustion efficiency is due to in-cylinder mixture preparation strategies that are non-optimally matched to the requirements of the LTC combustion mode. In this work, the effects of three key fuel path parameters - injection fuel quantity ratio, dwell and injection timing - on CO and HC emissions were examined using a Central Composite Design (CCD) Design of Experiments (DOE) method. The experiments were performed on a single-cylinder diesel research engine operating in a high-EGR mixing-controlled LTC mode (EGR ~ 62%, intake O₂ = 8.5%) with a split fuel injection for all conditions. The experiments identified the potential of fuel metering control for optimizing HC emissions in LTC by showing the effects of fuel control parameters on fuel mixing quality and emission formation mechanisms. The experimental results at this high-EGR operating condition were shown to be highly sensitive to the intake oxygen level. Accordingly, the use of DOE methods was found to be essential to this study. The detailed statistical analysis enabled by the experimental design was able to model and correct for the substantial effects of normal variability in the input oxygen mass fraction noted under these high EGR conditions; thus, permitting a reliable comparison of results.
Sogbesan, Oluwasujibomi M., Davy, Martin H., Garner, Colin P.
Operating Instructions for Aircraft Engines (Preparation of)AS177B (Historical)11/1/2012
This specification covers the requirements for format and outline of contents of operating instructions in published form or in manuscript form suitable for publication.
E-25 General Standards for Aerospace and Propulsion Systems
Aircraft Fuel System and Component Icing TestARP1401B (Historical)6/6/2012
This Aerospace Recommended Practice (ARP) covers a brief discussion of the icing problem in aircraft fuel systems and different means that have been used to test for icing. Fuel preparation procedures and icing tests for aircraft fuel systems and components are proposed herein as a recommended practice to be used in the aircraft industry for fixed wing aircraft and their operational environment only. In the context of this ARP, the engine (and APU) is not considered to be a component of the aircraft fuel system, for the engine fuel system is subjected to icing tests by the engine/APU manufacturer for commercial and specific military applications. This ARP is written mostly to address fuel system level testing. It also provides a means to address the requirements of 14 CFR 23.951(c) and 25.951(c). Some of the methods described in this document can be applied to engine and APU level testing or components of those application domains. This revision does not completely address new developments in ice accretion resulting from internal flow in tubing. This will be addressed in a future revision when more experimental data is available. Some background information on the topic is planned to be available in AIR790.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
A move to ‘more electric’ engines12EVSD0418_024/18/2012
Researchers detail a motor control design for the fuel system of a more electric aero engine, focusing on the necessary safety and reliability aspects. Reducing fuel consumption is a key area of aviation technology, and improvements in aircraft engine design to enhance environmental performance have been ongoing for many years. The more electric aero engine (MEE) is an innovative control architecture for aircraft engines that introduces electric motor-driven accessories in place of the conventional accessory gearbox (AGB)-driven pumps or hydraulic actuators. The MEE is a highly effective approach, capable of improving engine efficiency and reducing fuel burn and CO2 emissions. Conventional AGB-driven fuel pumps are generally fixed displacement pumps (e.g., gear pumps). The speed of this fuel pump is proportional to core engine speed; the pump is designed to provide much greater flow than the actual engine burn flow. The fuel system must bypass the excess fuel flow to return to the fuel pump inlet. This flow of excess fuel can sometimes be several times greater than engine burn flow, and recirculating this excess flow can result in fuel system inefficiencies and increase fuel temperatures.
Control Strategy for Electro-Mechanical Actuators Versus Hydraulic Actuation Systems for Aerospace Applications2010-01-174711/2/2010
Actuators are critical engine and flight control components used in aerospace applications for motion and fuel controls. All aircraft today contain three primary types of actuators; electro-mechanical actuators (EMA), electro-hydraulic actuators (EHA), hydraulic actuators. Actuators control thrust vectoring of the main engines during powered ascent, movement of the aerodynamic control surfaces, and the positioning of propulsion system geometry and fuel/air control valves. EMAs consist of an electric motor and gear-train to reduce speed, translate motion, and provide appropriate load torque. Electro-hydraulic actuators are self contained systems that combine the benefits of an electric system with the benefits of hydraulic systems. EHAs use an electric motor to drive a hydraulic pump which develops hydraulic pressure to act on a cylinder to provide the mechanical actuation energy. Hydraulic actuators use a centralized hydraulic pump that supplies the required pressure. EHAs avoid the operability issues associated with a central hydraulic supply and distribution system. They also have weight and integration benefits. Aerospace actuation has historically been dominated by hydraulic and fluid power systems. Sales of hydraulic actuation systems today accounts for more than several billion dollars per year of business for the major vendors. These systems comprise about 19% of the cost of a commercial aircraft. However, as entrenched as hydraulics are in flight applications, the emergence and maturation of electrical actuation promises to encroach significantly on hydraulic technology over the next several decades. This paper focuses on the potential of EMAs for aerospace applications and compares their qualities and benefits with hydra-mechanical actuators (HMA) and hydraulic actuators. Emerging industry trends have demanded compact, accurate, actuation for turbine fuel and geometry control. The EMA provides these benefits for applications where high-precision rapid actuation is desired. EMAs maintain the same high performance capability as hydraulic actuators and the potential for enhanced reliability and controllability in a compact package. The EMA will lend itself to high levels of diagnostics and fault prediction capability using algorithms in the engine/aircraft control system. Adaptive engines of the future will demand a variety of actuation solutions which may be a combination of EMAs, EHAs, and others. Their use requires careful system considerations to achieve optimal integration in the engine and air vehicle.
Behbahani, Alireza R., Semega, Kenneth J.
Individual Cylinder Fuel Control Application with a Switching Oxygen Sensor2010-36-002810/6/2010
In this paper we discuss in detail an algorithm that addresses cylinder-to-cylinder imbalance issues. Maintaining even equivalence-ratio (θ) control across all the cylinders of an engine is confounded by imbalances which include fuel-injector flow variations, fresh-air intake maldistribution and uneven distribution of Exhaust Gas Recirculation (EGR). Moreover, in markets that are growing increasingly cost conscious, with ever tightening emissions regulations, correcting for such mismatches must not only be done, but done with no additional cost. To address this challenge, we developed an Individual Cylinder Fuel Control (ICFC) algorithm that estimates each cylinder's individual θ and then compensates to correct for any imbalance using only existing production hardware. In our production-bound algorithm, modeling and control of the cylinders' dynamic θ was performed using a single switching oxygen sensor. Our ICFC algorithm was developed on a 2.4-l four-cylinder DOHC engine and it is in production at 2010 Multifuel engines 1.0, 1.4 and 1.8L four-cylinders SOHC selling a volume of 90 k/year. It meets internally defined performance requirements and NLEV emissions. Other important contributions in this work include an analysis of exhaust gas transport and mixing phenomenon, and an analysis of digitally acquiring and post processing oxygen sensor data.
Krenus, Roberto G., Costa, Herbert L.
Contaminants for Aircraft Turbine Engine Fuel System Component TestingAIR4246C (Historical)8/5/2010
This document discusses descriptions of fluid contamination products. These contaminants are used for design evaluation and formal component qualification/certification testing. Such tests are routinely performed on candidate aircraft engine fuel and pneumatic system components. Typical of these components are fuel pumps, fuel filters, fuel controls, pressurizing valves, flow dividers, selector valves, and combustor nozzles. The purpose of this document is to recommend standard descriptions to be used by specification writers.
AE-5B Aircraft and Engine Fuel and Lubricant Sys Components
Lost-Motion VVA Systems for Enabling Next Generation Diesel Engine Efficiency and After-Treatment Optimization2010-01-11894/12/2010
The primary variable valve actuation strategies for diesel engines are variable late or early intake valve closing for control of effective compression ratio for Miller cycle and part-time HCCI, PCCI, or LTC; variable early exhaust valve opening for exhaust temperature control for after-treatment regeneration and improved engine transient response; on/off control of intake pre-bump and/or exhaust post-bump for IEGR and control of residual fraction; and on/off control of compression release and brake gas recirculation events for engine braking. Lost-motion hydraulic VVA is well suited to diesel engines due to the capability of on-off control of secondary events for IEGR and engine braking, high load capacity for early exhaust opening and engine braking, and inherent protection against valve-to-piston contact. Production requirements for VVA systems include proven reliability/durability, cost effectiveness, compact packaging, cold start capability, acceptable valve seating velocity over the full operating range, and convenient lash setting. Several production-intent lost-motion VVA systems are described for variable late intake valve closing and IEGR intake pre-bump and for early exhaust valve opening and engine braking. Features include a lost-motion cam profile, a collapsing tappet located either between the rocker and the bridge or between the push-tube and the rocker, and a hydraulic circuit with a high-speed solenoid valve. Partial main event lift is provided with the tappet collapsed for failsafe operation and cold start. A valve catch to control valve seating during early intake valve closing is incorporated in the tappet assembly. A valve control unit, communicating with the fuel control, actuates the high-speed solenoid valves. The variable valve lift capabilities of several VVA systems and the valve-train parasitic loss over the range of operation are discussed, showing both simulation and test.
Schwoerer, John A., Kumar, Krishna, Ruggiero, Brian, Swanbon, Bruce
Individual Cylinder Fuel Control for Imbalance Diagnosis2010-01-01574/12/2010
This paper identifies a select method for performing cylinder imbalance measurement, correction and diagnosis. The impetus is to address new U.S. Federal regulations that require the detection of excessive cylinder air-fuel ratio (AFR) imbalance, and doing so requires the foundational ability to measure and preferably remove cylinder imbalance via active closed-loop control. This function is called Individual Cylinder Fuel Control (ICFC). ICFC starts by extracting cylinder-imbalance information from the front oxygen sensor, and that information comes in the form a of continuous data stream. That stream is then parsed to create virtual sensors- one for each cylinder. Each virtual sensor acts as an imbalance or error signal which ICFC uses to correct and learn via feedback and feed-forward control for each cylinder. The cylinder imbalance diagnostic is enabled by the presence of ICFC. The diagnostic continuously monitors to determine if ICFC is operating within its control authority, or if sufficient imbalance may exist to exceed a multiple of the applicable FTP emissions standard. Implementation of the diagnostic adds a subcategory to our existing Fuel System Diagnostic structure and reuses the common function-calling and accounting mechanisms to satisfy all of the fuel system monitoring requirements.
Smith, James C., Schulte, Charles, Cabush, David
Development of Bi-fuel CNG Engine based passenger vehicle and Field Trials study in Indian condition2009-28-001912/13/2009
Compressed natural gas (CNG) is being explored as a sustainable renewable fuel for vehicles in India due to mounting foreign exchange expenditure to import crude petroleum. Impending emissions regulations for diesel engines, specifically exhaust particulate emissions have caused engine manufacturers to once again examine the potential of alternative fuels. Much interest has centered on compressed natural gas (CNG) due to its potential for low particulate and hydrocarbon based emissions. Natural gas engine development projects have tended toward the use of current gasoline engine technology (stoichiometric mixtures, closed-loop fuel control and exhaust catalysts). Significant amount of research and development work is being undertaken in India to investigate various aspects of CNG utilization in different types of engines. This paper discusses about the development of the bi-fuel CNG engine for passenger vehicular application. The impact of using CNG was studied in terms of cold start ability, drive-ability, acceleration, max speed, grade ability, fuel economy and exhaust emissions. The field trial of the CNG vehicle had been made to study the impact of CNG used on the engine parts and vehicle emission.
Agarwal, Sunny, Singh, Jasbir, Kulshrestha, Gaurav
Road Traffic Control by Regulating Street Noise Propagation in an Urban Area2009-01-279511/2/2009
Recently, the control of traffic flow has been proposed using several types of criteria (e.g. minimum-time control, minimum fuel control and so on). Most recently, an environmental noise pollution problem caused by the road traffic is being aggravated more and more by the consolidation and expansion of roadway system particularly in urban areas. However, the objective of this paper is to control road traffic flow by regulating traffic noise propagation in an urban area in Cairo city. The results of traffic noise prediction obtained by trending of the experimental data collecting by systematic noise measurement and the evaluation of the traffic noise which is in close connection with physical parameters of traffic flow and noise propagation characteristics is presented. The analysis of road traffic flow noise control is based on the mixed integer non-linear programming technique, where the optimal control strategy is used. The results indicate that significant information gained for controlling road traffic in urban areas.
Khalil, Mohamed, Mettwaly, Sameh, Mohamed, Eid, Abouel-Seoud, Shawki
Analysis of Oil Sump Contamination with Ethanol in Flex Fuel Engines after Crank and Warm-up2009-36-011710/6/2009
A flex fuel engine which operates with high ethanol content fuel can show a significant level of oil sump contamination with ethanol depending on startup coolant temperature and driving behavior. In general, the lower the coolant and the more aggressive the driving pattern the higher the oil sump contamination. As the engine warms up and the oil temperature increases, the liquid ethanol mixed in oil sump evaporates (boil-off phenomenon) and returns into the induction system through the engine venting system. Oil contamination and boil-off phenomena have to be properly considered by the engine management controller so that closed loop fuel control, fuel trim diagnosis and ethanol learning are not fooled by the extra fuel coming by blow-by. This paper presents the results of an analysis conducted in a GMPT 1.4L Flex Fuel engine running with E85 and E100 fuels. A method for quantifying the different levels of oil contamination is proposed based on measured exhaust air-fuel ratio during oil decontamination. A correlation is developed between the unburned fuel during cold engine operation and the vaporized ethanol during boil-off. It is shown that warm-up driving mode is more important for oil sump contamination than the engine crank. Therefore, an oil contamination algorithm should be capable of identifying the differences in driving behavior in order to provide a consistent contamination index and prepare the fuel injection management system for the corrective actions that should be taken during boil-off.
Engler-Pinto, Claudio M., de Nadai, Leandro, Martins, Erico
Demonstration of Advanced Emission Controls for Nonroad SI Class II Engines2009-01-18996/15/2009
The U.S. Environmental Protection Agency has completed a program to demonstrate the feasibility of using low-cost engine management systems and modern, high-efficiency exhaust catalysts for nonroad spark ignition gasoline Class II engines (sub-19 kW, greater than 225 cc). Low-cost electronic engine management and fuel injection systems originally developed for motor-scooter and small motorcycle applications were installed on two 500cc single-cylinder spark-ignition lawn-and-garden engines. Integrated catalyst-muffler systems were developed for both engines and fuel control was calibrated to achieve emission control goals while maintaining or improving fuel consumption, engine durability and performance. NOx+HC emissions were reduced approximately 75% and brake-specific fuel-consumption improved by 6 to 12%. .
McDonald, Joseph, Olson, Brian, Murawski, Marc
Linearization of the GenHel S-76D Model with Engine and Fuel Control ModelsVFS-F65-0002805/27/2009
The Sikorsky S-76D™ helicopter was to incorporate a new automatic flight control system (AFCS). Linear flight dynamics models were needed to support design of the AFCS. The linear models were derived from the GenHel S-76D model. A requirement existed for governed rotor speed dynamics to be incorporated into the linear models used for AFCS design. Consequently, the process of incorporating the governed rotor speed dynamics into the linear models had to be developed. In this paper, the method used for incorporating these additional degrees of freedom into a linear model derived from the GenHel S-76D model will be discussed. In addition, the impact of these additional degrees of freedom on aircraft flight dynamics pertaining to AFCS design will be examined.
Quiding, Chris
The All New AJV82009-01-10604/20/2009
This paper describes the design and function of the all new AJV8 engine. The engine is deployed in both naturally aspirated and supercharged form. The 90 degree four valve per cylinder V8, is of all aluminum design and employs a new spray guided direct injection combustion system, with the injectors located centrally within the chamber for more precise fuel control. Intake and exhaust valve timing is varied via four cam torque actuated variable cam timing units. The naturally aspirated derivative employs both two stage inlet valve lift control and two stage inlet manifold tuning to provide excellent low speed torque. This results in superior vehicle dynamic response and fuel economy. The supercharged derivative uses Twin Vortex supercharging technology in combination with the optimized high pressure die cast, deep skirt block structure to deliver a class leading balance of performance and refinement.
Sandford, Malcolm, Page, Graham, Crawford, Paul
SI Engine Hardware and Software Design for High Power, Low Emission Applications2009-01-06174/20/2009
High technology, spark ignition direct injection (SIDI), engines are currently capable of achieving optimum horsepower and ULEV emissions levels. However, to meet the requirements of modern automotive powertrains, the task of increasing power density, improving fuel economy and reaching SULEV2 emissions is much more challenging. To achieve this, direct injection (DI) fuel systems offer the greatest precision and flexibility for engine fuel control. Features like high pressure start and improved catalyst heating, through multiple injections per combustion cycle, produce low engine-out emissions without the need for a secondary air injection system. This paper describes the analytical and experimental work done to achieve SULEV emissions levels for a twin-turbocharged derivative of General Motors (GM) high feature V6 engine.
Brdarski, Adrian, Kern, Justin, Woldring, David, Yilmaz, Hakan, Christie, Mark, Müller-Haas, Klaus
Low-Cost Air Estimation2009-01-05904/20/2009
The focus of this paper is an air charge estimator for engine control system applications which do not feature a mass air flow (MAF) sensor. The proposed approach, beyond its independency of a MAF sensor, is designed to be compatible with the confines of a typical production control system configuration. The air charge estimation algorithm is based on mean-value models for the manifold pressure dynamics and the gas flows through the throttle and valve orifices. It involves nominal static models for the volumetric efficiency of the engine and for the throttle discharge coefficient. The static models for those parameters are complemented with correction factors that are adjusted on-line. The update of the volumetric efficiency correction is implemented in the form of a Kalman-filter which uses the difference between the measured and the modeled manifold pressure as an error metric. The discharge coefficient correction, on the other hand, is implemented in the form of an adjustable correction look-up table. The adjustment of the correction table evolves as a function of the operating condition and is based on an error metric which is derived from the value of the closed-loop fuel control correction factor. The performance of the algorithm is tested on the basis of various realistic driving maneuvers, i.e., maneuvers that include the first 18 cycles of the FTP test schedule and the US06 driving schedule. The experimental tests confirm that the algorithm meets typical performance requirements and that the overall system performance is indeed even comparable to the performance of MAF sensor based systems. The proposed approach is certainly a prime candidate for deployment in markets with moderate emission standards. However, in light of its cost effectiveness and especially its adaptive capabilities, which make up for many of the long-term detriments commonly seen among MAF-sensor-less low-cost solutions, the approach may even have potential in markets with more stringent emission standards.
Turin, Raymond, Dagci, Oguz, Chang, Man-Feng
Study of Heated Exhaust Gas Oxygen sensor downstream of the catalyst as an emissions calibration tool2008-36-031910/7/2008
Vehicle emissions development is a costly and time-consuming process, with numerous iterations in emissions laboratory. Besides the high cost of such tests, the limitation on the availability of that resource may be a serious obstacle to development timing. The objective of this study is to perform statistical comparisons between the second-by-second modal analysis of emissions laboratory analyzers, and the voltage signal of a heated exhaust gas oxygen sensor placed downstream of the catalyst, in order to assess the usage of such sensor as an auxiliary tool to calibrate closed loop fuel control, aiming NOx tailpipe emissions, out of the laboratory.
Miyashita, Eduardo Mizuho, Ruivo, Manuel Dimitri, Higa, Robson
Improvements on the Start Performance of Diesel Engine by Fuel Control Strategy Optimization and Heating Measures2008-01-16466/23/2008
The incomplete combustion and misfire of diesel engine during starting result in unwanted white smoke. The histories of combustion and emission in different phases under different start conditions were studied in this paper. The optimization of the fuel injection control strategy under start conditions was performed. When the diesel engine is started under low temperature, the control strategy adapted to start the engine with a certain constant fuel mass injected per cycle, there may be misfire cycles in the initial period or in the transitional process, which is mainly caused by the mismatch between the fuel mass injected per cycle and the instantaneous engine speed. Therefore, an optimized control strategy was put forward, namely, the engine starts with high fuel mass injection in the first several cycles and then decreases step by step during the transitional period until it operates at idle condition. This strategy was validated to decrease significantly the misfire cycles. When the start conditions are improved by preheating intake air or coolant, the misfire and incomplete combustion which easily occur during the transitional period may be eliminated.
Su, Yan, Liu, Zhongchang, Han, Yongqiang, Guo, Liang, Li, Jun
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