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Influence of port water injection on the combustion characteristics and exhaust emissions in a spark-ignition direct-injection engine

Shanghai Jiao Tong University-Yadong Fan, Tianbao Wu, Xuesong Li, Min Xu, David Hung
  • Technical Paper
  • 2020-01-0294
To be published on 2020-04-14 by SAE International in United States
It is well known that spark-ignition direct-injection (SIDI) gasoline engines have a huge advantage in fuel economy due to their good anti-knock performance compared to port fuel injection engines. However, higher particle number (PN) emissions associated with fuel impingement make the SIDI engines have additional difficulties to meet the upcoming China VI emission standards. In this study, the port water injection (PWI) techniques on a 1.0-L turbocharged, three cylinder, SIDI engine were investigated. PWI strategies were optimized to quantify port water injection as a means of mitigating the knock and improving the combustion performance by sweeping water-fuel mass ratios and PWI timing at different operating conditions. Measurements indicate that regardless of engine load, PWI induced a worsening of the maximum in-cylinder pressure (P-Max) and cycle-to-cycle variations (IMEPN-COV ) , which mainly due to the effects of water dilution and slower burning velocities. But by the advance of spark timing with knock mitigation, we find that the improvement of combustion phasing finally makes it possible to eliminate fuel enrichment, which bring the potential advantages on the…
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Real-Time Embedded Models for Simulation and Control of Clean and Fuel-Efficient Heavy-Duty Diesel Engines

Daimler Trucks North America-Marc Allain, Siddharth Mahesh
University of Michigan-Saravanan Duraiarasan, Rasoul Salehi, Fucong Wang, Anna Stefanopoulou
  • Technical Paper
  • 2020-01-0257
To be published on 2020-04-14 by SAE International in United States
The ever increasing demand for fuel economy and stringent emission norms drives researchers to continuously innovate and improve engine modes to implement adaptive algorithms, where the engine states are continuously monitored and the control variables are manipulated to operate the engine at the most efficient regime. This paper presents a virtual engine developed by modeling a modern diesel engine and aftertreatment which can be used in real-time on a control unit to predict critical diesel engine variables such as fuel consumption and feed gas conditions including emissions, flow and temperature. A physics-based approach is followed in order to capture vital transient airpath and emission dynamics encountered during real driving condition. A minimal realization of the airpath model is coupled with a cycle averaged NOx emissions predictor to estimate transient feed gas NOx during steady state and transient conditions. The complete airpath and NOx emission model was implemented on a rapid prototyping controller and experimentally validated over steady state and transient emission cycles. The overall performance of the reduced order model was comparable to that of…
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MIMO Control of a Turbogenerator for Energy Recovery

Loughborough Univ.-Simon Petrovich, Kambiz Ebrahimi, Nikolaos Kalantzis, Antonios Pezouvanis
  • Technical Paper
  • 2020-01-0261
To be published on 2020-04-14 by SAE International in United States
Market trends for increased engine power and more electrical energy on the powergrid (3kW+), along University of Loughborough for fuel consumption improvements and emissions reduction, are driving requirements for component electrification, including turbochargers. GTDI engines waste significant exhaust enthalpy; even at moderate loads the WG (Wastegate) starts to open to regulate the turbine power. This action is required to reduce EBP (Exhaust Back Pressure). Another factor is catalyst protection, where the emissions device is placed downstream turbine. Lambda enrichment or overfuelling is used to perform this. However, the turbine has a temperature drop across it when used for energy recovery. Since catalyst performance is critical for emissions, the only reasonable location for an additional device is downstream of it. This is a challenge for any additional energy recovery, but a smaller turbine is a design requirement, optimised to operate at lower pressure ratios. A WAVE model of the 2.0L GTDI engine was adapted to include a TG (Turbogenerator) and TBV (Turbine Bypass Valve) with the TG in a mechanical turbocompounding configuration, calibrated with steady state…
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Hybrid Powertrain Choices for Emerging Engine Technologies

Aramco Research Center-Vincent Costanzo
Argonne National Laboratory-Ram Vijayagopal, Daniela Nieto Prada
  • Technical Paper
  • 2020-01-0440
To be published on 2020-04-14 by SAE International in United States
US department of energy estimates the peak efficiency of a modern spark ignited naturally aspirated Otto cycle engine to be 36%. Atkinson cycle engines are estimated to get 40% peak efficiency. Most engines can achieve this peak efficiency only for a limited operating region. Hybrid powertrains enable engine to operate in this efficiently. Overall efficiency is improved by shutting down engine during idle events and by adjusting the operating speed and load on the engine using electric machines. The choice of the powertrain and component sizes depends on the engine characteristics, drive cycles and vehicle technical requirements. This study examines what type of powertrains will be suitable for more efficient engines that are likely to be available in the near future. Some of these technologies achieve higher efficiency with a trade off on power or by accepting a more restrictive operating region. An appropriate powertrain choice can still enable such an engine to be a viable option for an automobile. Using simulation tools, 14 different engine technologies are evaluated in this paper for their fuel…
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Investigation of Diesel/Natural Gas RCCI Combustion Using Multiple Reaction Mechanisms at Various Engine Operating Conditions

FEV North America Inc.-Mufaddel Dahodwala, Satyum Joshi, Erik Koehler, Michael Franke, Dean Tomazic
Michigan Technological University-Jeffrey Naber
  • Technical Paper
  • 2020-01-0801
To be published on 2020-04-14 by SAE International in United States
Past experimental studies conducted by the current authors on a 13 liter 16.7:1 compression ratio heavy-duty diesel engine have shown that diesel /natural gas Reactivity Controlled Compression Ignition (RCCI) combustion targeting low NOx emissions becomes progressively difficult to control as the engine load is increased due to difficulty in controlling reactivity levels at higher loads. For the current study, CFD investigations were conducted using the SAGE combustion solver in Converge with the application of Rahimi mechanism. Studies were conducted at a load of 5 bar BMEP to validate the simulation results against RCCI test data. In the low load study, it was found that the Rahimi mechanism was not able to predict the RCCI combustion behavior for diesel injection timings advanced beyond 30bTDC. This behavior was found at multiple engine speed and load points. To resolve this, multiple reaction mechanisms were evaluated and a new reaction mechanism that combines the GRI Mech 3.0 mechanism with the Chalmers mechanism was proposed. This mechanism was found to accurately predict the ignition delay and combustion behavior with early…
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Fuel consumption on different drive cycles: A unified approach based on average power/weight

Ford Motor Company-Patrick Phlips, William Ruona, Thomas Megli, Mrudula Orpe
  • Technical Paper
  • 2020-01-1278
To be published on 2020-04-14 by SAE International in United States
In previous work we have shown that fuel consumption on a particular drive cycle is proportional to traction work, with an offset for powertrain losses. The finding applies to different drive cycles, but with different offsets. Following Soltic (2011), it is shown that if fuel usage and traction work are both expressed in terms of cycle average power, a wide range of drive cycles collapse to a single transfer function. Data for vehicles of different weights further collapses when normalized for weight, i.e. by working in power/weight (P/W). The fuel P/W is primarily a function of traction P/W, and secondarily of displacement/weight. The useful work or power definition is then expanded beyond the traction power to include electrical power for customer functions, and power to drive the air conditioning. With this expanded definition the linear powertrain transfer function can be applied not only to strictly defined regulatory drive cycles and procedures, but also to ‘real driving’ conditions that cover a much broader range of situations. When applied to hybrid electric vehicles, the method clearly shows…
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Effects of a Probability-Based Green Light Optimized Speed Advisory on Dilemma Zone Exposure

Indiana Department of Transportation-James Sturdevant
Purdue University-Enrique Saldivar-Carranza, Howell Li, Woosung Kim, Jijo Mathew, Darcy Bullock
  • Technical Paper
  • 2020-01-0116
To be published on 2020-04-14 by SAE International in United States
Green Light Optimized Speed Advisory (GLOSA) systems have the objective of providing a recommended speed to arrive at a traffic signal during the green phase of the cycle. GLOSA has been shown to decrease travel time, fuel consumption, and carbon emissions; simultaneously, it has been demonstrated to increase driver and passenger comfort. Few studies have been conducted using historical cycle-by-cycle phase probabilities to assess the performance of a speed advisory capable of recommending a speed for various traffic signal operating modes (fixed-time, semi-actuated, and fully-actuated). In this study, a GLOSA system based on phase probability is proposed. The probability is calculated prior to each trip from a previous week’s, same time-of-day (TOD) and day-of-week (DOW) period, traffic signal controller high-resolution event data. By utilizing this advisory method, real-time communications from the vehicle to infrastructure (V2I) become unnecessary, eliminating data-loss related issues. The effects of three different advice approaches (conservative, balanced, and aggressive) on dilemma zone exposure are analyzed. Proof of concept is carried out by virtually driving through a test-route composed of an arterial that…
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Modeling, Validation and Control Strategy Development of a Hybrid Super Sport Car based on Lithium Ion Capacitors

Automobili Lamborghini Spa-Riccardo Parenti, Maurizio Reggiani
University of Bologna-Alessandro Franceschi, Nicolo Cavina, Enrico Corti
  • Technical Paper
  • 2020-01-0442
To be published on 2020-04-14 by SAE International in United States
Today, the contribution of the transportation sector on greenhouse gases is evident. The fast consumption of fossil fuels and its impact on the environment have given a strong impetus to the development of vehicles with better fuel economy. Hybrid electric vehicles fit into this context with different targets, starting from the reduction of emissions and fuel consumption, but also for performance and comfort enhancement. Lamborghini has recently invested in the development of a hybrid super sport car, due to performance and comfort reasons. Aventador series gearbox is an Independent Shift Rod gearbox with a single clutch and during gear shifts, as all the single clutch gearbox do, it generates a torque gap. To avoid the additional weight of a Dual Clutch Transmission, a 48V Electric Motor has been connected to the wheels, in a P3 configuration, to fill the torque gap, and to habilitate regenerative braking and electric boost functions. This paper discusses the usage of a control-oriented vehicle and powertrain model to analyze the performance of the first Lithium Ion Capacitor-based hybrid V12 by…
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Impact of Engine Oil Detergent on Low Speed Pre-Ignition (LSPI) and Fuel Economy Performance

Afton Chemical Corp.-Ashutosh Gupta, Mark Devlin
  • Technical Paper
  • 2020-01-1424
To be published on 2020-04-14 by SAE International in United States
Low Speed Pre-Ignition (LSPI), also referred to as Stochastic Pre-Ignition (SPI), Superknock or Megaknock is an undesirable combustion phenomenon that limits the fuel economy, drivability, emissions and durability performance of modern turbocharged gasoline engines. Numerous studies have previously reported that the frequency of LSPI is sensitive to engine oil composition. One of these drivers is the concentration of Calcium, which is usually delivered in the form of a detergent in the additive package. Switching to completely all-Magnesium detergent and/or severely limiting the concentration of Ca in the engine oil have recently been proposed as potential means to reduce LSPI. In this work, we evaluate the impact of detergent type on LSPI performance as well as on other performance that the modern engine oil needs to deliver. Particularly the impact of detergent type on Fuel Economy performance is evaluated. To ensure a rigorous and high precision measurement of the impact of engine oil on fuel economy, representative of real-world conditions, under well-controlled conditions, the ASTM D8114 test (Sequence VIE) was used to quantify fuel economy performance…
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Validation of Road-Preview-Based Predictive Gear Selection on Heavy-Duty Vehicle Transmission Control Unit

AVL-Zhen Zhang, Bernhard Knauder, Martin Ackerl, Johannes Pell
  • Technical Paper
  • 2020-01-0962
To be published on 2020-04-14 by SAE International in United States
The eHorizon unit enables the possibility, to get information of the road ahead in a defined prediction horizon. This data, like road gradient, curve radius, velocity limitation and road class, can be used by the on-board transmission control unit (TCU) via Controller Area Network (CAN) bus. This obtained predictive road information combined with the actual driving conditions are used to optimize the shifting strategy by a nonlinear model predictive control (NMPC) algorithm which intends to reduce the fuel consumption. The optimization problem in the PGS strategy is solved by a nonlinear optimization based dynamic programming. In this paper, the predictive gear selection (PGS) strategy will be compared to a conventional automatic gear shifting strategy in a simulation environment and validated on road by implementing it a heavy-duty truck with a 16-speed automated manual transmission (AMT). At last, this strategy consumes in total around 20kb RAM which can be handled by modern SOP TCU.