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Advanced Exergy Analysis of an Air Craft Gas Turbine Engine at Different Power Loading Operations.

Alok Kumar Mohapatra
  • Technical Paper
  • 2019-01-1863
To be published on 2019-09-16 by SAE International in United States
The innovations in aircraft propulsion have been identified as the key parameter towards the progress in transportation. Continuous advancement in the performance and efficiency of propulsion has enabled aircraft to travel over larger distances with higher speed. Aviation is also responsible for approximately 2% of total greenhouse gases emission and is expected to grow around 3% by 2050. The present study aims to use the exergetic analysis of a turboprop engine which should be helpful in designing of such engines and also helps these engine users to regulate and select the operation modes. A gas turbine with film air cooling of turbine blades has been proposed to be the turboprop engine. The engine is analyzed on exergy point of view at different power loading operation modes and the performance is studied. Selected exergetic measures under consideration are Exergy Efficiency, Fuel Exergy Depletion Ratio, Relative Exergy Consumption Ratio, Exergetic Improvement potential and Productivity Lack ratio. The total fuel exergy depletion ratio of the turboprop engine is estimated to be around 44%. . Also, among the identified…
 

Modelling and control of a novel clutchless multiple-speed transmission for electric vehicles

Mecaprom SRL-Mauro Grandone, Alberto Lega, Michele Pennese
University of Salerno-Ludovica Malafronte, Cesare Pianese
  • Technical Paper
  • 2019-24-0063
To be published on 2019-08-15 by SAE International in United States
Conventional electric vehicles adopt either single-speed transmissions or direct drive architecture in order to reduce cost, losses and mass. However, the integration of optimized multiple-speed transmissions is considered as a feasible method to enhance EVs performances, (i.e. top speed, acceleration and grade climbing), improving powertrain efficiency, saving battery energy and reducing customer costs. Perfectly in line with these objectives, this paper presents a patented fully integrated electric traction system, as scalable solution for electrifying light duty passenger and commercial vehicles (1.5-4.2 tons), with a focus on minibuses (<20 seats). The adoption of high-speed motor coupled to multiple-speed transmission offers the possibility of a relevant efficiency improvement, a 50% volume reduction with respect to a traditional transmission, superior output torque and power density. The proposed clutchless four-speed transmission is specifically conceived and designed to have the good matching with the traction electric motor. Indeed, clutches and synchronizers are not required thanks to the small inertia of the traction motor and its fast regulation in both torque and speed mode (torque modulation process). Therefore, an advanced shifting…
 

A Review of Spark-Assisted Compression Ignition (SACI) Research in the Context of Realizing a Production SACI Strategy

Clemson Univ-Robert Prucka
Clemson Univ.-Dennis Robertson
  • Technical Paper
  • 2019-24-0027
To be published on 2019-08-15 by SAE International in United States
Low temperature combustion (LTC) strategies have been a keen interest in the automotive industry for over four decades since they offer improved fuel efficiency compared to conventional spark-ignition (SI) engines. LTC strategies use high dilution to keep combustion temperatures below about 2000 K to reduce heat transfer losses while avoiding locally rich in-cylinder regions that produce high soot. High dilution also enables an efficiency improvement from reduced pumping work and improved thermodynamic properties, though it requires high ignition energy. Combustion can be achieved by triggering autoignition from compression energy. High compression ratios are typically required to produce this level of ignition energy, which further improves fuel efficiency. The timing of the autoignition event is influenced by fuel properties and mixture composition, and is exponentially sensitive to temperature. Control of autoignition timing is difficult without a direct actuator, and has been a significant obstacle for realizing LTC in production. Spark-assisted compression ignition (SACI) addresses this challenge by using a spark plug to initiate chemical reactions that trigger autoignition. The combustion chamber is slightly stratified to promote…
 

Design and Development of Different Regenerative Braking Systems for a Commercial Electric Bus

Delhi Technological University-Lalit Kumar Choudhary, Kunal Mathur, Aditya Natu
  • Technical Paper
  • 2019-24-0208
To be published on 2019-08-15 by SAE International in United States
In today’s world, energy saving has become a crucial need for day to day operations. It is because of this need for development and enhancement of energy efficient technology, various industries and organizations are researching on ways to improve the energy savings, which would not only be holistic but also increase their own brand value in the market. A similar such method that can have an immense positive impact on conservation of energy is “Regenerative Braking”, which is now being implemented by various OEMs. With the help of this concept, a decelerating vehicle’s kinetic energy is harvested and stored for utilization at a later stage; instead of dissipating this useful energy as heat such as in the conventional braking system. Such a concept of extracting and storing energy can be utilized by the emerging electric vehicles to generate electric current that can be used for recharging the battery, powering the onboard appliances and increasing the range of these vehicles. The following paper describes the detailed study of a unique flywheel based regenerative braking system (f-RBS)…
 

Oil Cooler Removal from Light duty Diesel Engines for Cost Reduction purpose.

Tata Technologies Ltd-Aashish Bhargava
Tata Technologies, Ltd.-Shirish Madan Deshpande
  • Technical Paper
  • 2019-24-0175
To be published on 2019-08-15 by SAE International in United States
Automotive industry is going through phase where Energy efficiency and Cost is major differentiator in market. Taking up these considerations, development has been taken to improve thermal management of engine while optimizing the cost of engine. One of the important area in thermal management of Engine is Engine Lubrication system. This consist of Engine oil and oil cooler, which play vital role in thermal management as well as optimization of frictional losses by ensuring proper lubrication and cooling of engine components. For better thermal management of engine, a lubrication system is designed without Oil cooler, proto type made and tested. This paper deals with evaluation of various engine performance parameter & Thermal management with respect to modification carried out. Further solution of Oil cooler removal is validated at vehicle level to understand real world behaviour of the system. Finally test results were compared for further optimization in lubrication system. It was concluded that Oil cooler can be removed from the engine by doing optimization in thermal management of the engine.
 

Diesel Vehicle with ultra-low NOx emissions in the city

AECC-Joachim Demuynck, Cecile Favre, Dirk Bosteels
IAV-Andreas Kuhrt, Joachim Spitta, Frank Bunar
  • Technical Paper
  • 2019-24-0145
To be published on 2019-08-15 by SAE International in United States
The paper discusses the technical approach to meet Euro 6d Real-Driving Emissions (RDE) requirements and beyond, with a particular focus on reducing diesel NOx emissions in urban driving situations. Novel technology aspects of the diesel powertrain are an RDE-optimized catalyst system layout to improve both low- and high-load DeNOx performance and a 48V P0-hybrid system. A key element of the powertrain concept is the advanced model based DeNOx control strategy. The optimized exhaust aftertreatment layout combines lean NOx Trap (LNT) and Selective Catalytic Reduction (SCR) technologies. For maximum low load DeNOx performance, the close-coupled SCR, consisting of an additional slice upstream of an SCR coated on filter, is assisted by an LNT. High load conditions are covered by a 2-stage SCR system with twin AdBlue® dosing. The P0 48V electric motor supports the NOx control in addition to ensuring good driving performance and fuel efficiency. A smart and advanced control strategy is implemented to ensure optimal interaction between all components. The first part of the proposed paper provides a brief summary of Euro 6d and…
 

A proposed diesel powertrain to meet future emission standards and achieve high engine efficiency

FPT Motorenforschung AG-Konstantinos Priftis, Apostolos Karvountzis Kontakiotis, Wolfgang Gstrein PhD, Christoph Schuette
  • Technical Paper
  • 2019-24-0191
To be published on 2019-08-15 by SAE International in United States
Nowadays, powertrain development activity is performed on the base of fulfilling the stricter emission standards under real driving conditions (RDE). However, the pressure on automotive industry to reduce CO2 emissions in high efficient diesel applications results in lower exhaust gas temperatures. Therefore, it is highly needed to develop advanced vehicle thermal management methods to both fulfil the targets of emission standards and high thermal efficiency, without increasing dramatically the powertrain cost. The aim of this work is to experimentally demonstrate that by utilising advanced engine and ATS control methods and revising the engine hardware and subsystems can lead to significant improvement on the fuel efficiency and emissions of the conventional diesel powertrain. The revised engine includes an improved combustion system, completely revised turbocharging and air handling system whilst being heavily reworked with respect to FMEP reduction. The aftertreatment employs a closed coupled electrically heated DOC, SCR on filter, NH3 slip catalyst followed by an underfloor SCR and NH3 slip catalyst. The urea dosing system is utilising double urea injection to maximise the overall performance. The…
 

Quantification and Analyses of Knock in Gasoline Engines

Ford Research and Advanced Engineering-Maziar Khosravi
Ford-Werke GmbH-Albert Breuer
  • Technical Paper
  • 2019-24-0089
To be published on 2019-08-15 by SAE International in United States
The continuously increasing demand for improved fuel efficiency, low-emissions and high performance in gasoline engines has led to down-sizing and down-speeding. This promising and broadly applied concept, which necessitates ever higher Break Mean Effective Pressure (BMEP), is impeded at high loads by knock, stochastic Low Speed Pre-ignition (LSPI), and mega-knock. Significant research has been conducted in recent years in the field of abnormal combustion phenomena in gasoline engines and the impacts of potential mitigation concepts by using various simulation tools. In the present study, a knock analysis methodology has been developed to investigate knock in Gasoline Engines. The strategy employs multiple techniques to quantify knock tendency and severity as well as identify outlier cycles for frequency analysis. By incorporating a Continuous Wavelet Transform in addition to conventional Fast Fourier Transform the amplitude, frequency, and temporal location of the oscillations can be analyzed simultaneously. The analysis led to the detection of numerous peculiar cycles with high peak oscillation amplitudes but negligible resonance. A low amplitude oscillation with a frequency of 24 kHz likely caused by the…
 

HCCI with Wet Ethanol: Investigating the Charge Cooling Effect of a High Latent Heat of Vaporization Fuel.

Stony Brook Univ.-Brian Gainey, James Gohn, Ziming Yan, Khurram Malik, Mozhgan Rahimi Boldaji, Benjamin Lawler
  • Technical Paper
  • 2019-24-0024
To be published on 2019-08-15 by SAE International in United States
The combustion phasing of Homogeneous Charge Compression Ignition combustion is incredibly sensitive to intake temperature. Controlling the intake temperature on a cycle-to-cycle basis is one-way control combustion phasing, however accomplishing this with an intake air heater/intercooler is unfeasible. One possible way to control the intake temperature is through the direct injection of fuel. The direct injection of fuel during the intake stroke cools the charge via evaporative cooling. Some heat is absorbed from the incoming air, lowering the in-cylinder temperature, while some heat is absorbed from the piston/cylinder walls if the spray reaches the walls. The amount of heat that is absorbed from the air vs. the walls depends on the injection timing during the intake. Therefore, if a high latent heat of vaporization fuel is used, the intake temperature will become very sensitive to injection timing, allowing for cycle-to-cycle control of combustion phasing. Ethanol is a fuel with a high latent heat of vaporization and therefore possesses a large charge cooling potential. Wet ethanol, a mixture of ethanol and water, offers an even higher…
 

One-Dimensional Modeling of a Thermochemical Recuperation Scheme for Improving Spark-Ignition Range Extender Engine Efficiency

Univ of Minnesota-Twin Cities-Darrick Zarling
Univ. of Minnesota-Twin Cities-William F. Northrop
  • Technical Paper
  • 2019-24-0066
To be published on 2019-08-15 by SAE International in United States
Vehicle electrification has accelerated as global fuel efficiency standards have become more stringent and battery costs have decreased. Although full electrification, i.e.; battery electric vehicles, may be appropriate for some light-duty vehicle applications, many vehicles will still require an engine to overcome range limitations. Range extender (REx) engine generators can be used to charge vehicle batteries as needed to meet driver demands. One advantage of REx engines is that they do not have a direct mechanical connection to the wheels and can frequently within the most efficient speed and load ranges. Therefore, REx engines provide an opportunity to implement advanced engine technologies that are more difficult to apply in conventional engine-powered vehicles. Thermochemical recuperation (TCR) schemes use exhaust waste heat to catalytically convert a portion of the fuel into a gas that has increased heating value. TCR schemes are ideal for REx architectures because they yield the most benefit at relatively high engine load and because they do not respond well to rapid transients. This paper explores a TCR scheme for a 2-cylinder BMW spark-ignition…