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Optimization of Compression Ratio for Direct-Injection Diesel Engine for better fuel economy.

Tata Technologies Ltd-Sujit Vithoba Gavade, Aashish Bhargava, Chandrakant Deshmukh, Gaurav Soni
  • Technical Paper
  • 2019-24-0165
To be published on 2019-08-15 by SAE International in United States
Fuel economy is becoming one of the key parameter as it not only accounts for the profitability of commercial vehicle owner but also has impact of environment. Fuel economy gets the benefitted from optimum compression ratio in modern engines. Increasing of compression ratio of any vehicle results in improvement of emission levels and performance. This paper evaluates the optimization of Compression ratio and study its effect on Engine performance. The parameters investigated in this paper includes include; combustion bowl volume in Piston, Cylinder head gasket thickness & Piston topping as these are major contributing factors affecting clearance volume and in turn the compression ratio of engine. Based on the calculation results, an optimum Compression Ratio for the engine is selected for further Verification.

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…

Optimal Engine Re-Start Strategy on a Mild Hybrid Powertrain by Means of Up-Front Modelling

Ford Werke GmbH-Harald Stoffels, Shan-An Kao, Michael Frenken
  • Technical Paper
  • 2019-24-0206
To be published on 2019-08-15 by SAE International in United States
The ability to switch off the internal combustion engine (ICE) during vehicle operation is a key functionality in hybrid powertrains to achieve low fuel economy. However, this can affect driveability, namely acceleration response when an ICE re-engagement due to a driver initiated torque demand is required. The ICE re-start as well as the speed and load synchronisation with the driveline and corresponding vehicle speed can lead to high response times. To avoid this issue, the operational range where the ICE can be switched off is often compromised, in turn sacrificing fuel economy. Based on a 48V off-axis P2 hybrid powertrain comprising a lay-shaft transmission we present an up-front simulation methodology that considers the relevant parameters of the ICE like air-path, turbocharger, friction, as well as the relevant mechanical and electrical parameters on the hybrid drive side, including a simplified multi-body approach to reflect the relevant vehicle and powertrain dynamics. Applying different ICE re-start strategies at different speeds and gears, the driveability of the ICE re-engagement was evaluated using a commercialized driveability evaluation tool. The objective…

Replacing twin electric fan radiator with Single fan radiator Abstract.

Engine Design & Testing-Tushar Warkhade
Tata Technologies Ltd-Aashish Bhargava
  • Technical Paper
  • 2019-24-0181
To be published on 2019-08-15 by SAE International in United States
Downsizing is one of the crucial activities being performed by every automotive engineering organisation. The main aim is to reduce – Weight, CO2 emissions and achieve cost benefit. All this is done without any compromise on performance requirement or rather with optimization of system performance. This paper evaluate one such optimization, where-in radiator assembly with two electric fan is targeted for downsizing for small commercial vehicle application. The present two fan radiator is redesigned with thinner core and use of single fan motor assembly. The performance of the heat exchange is tested for similar conditions back to back on vehicle and optimized to get the balanced benefit in terms of weight, cooling performance and importantly cost. This all is done without any modification in vehicle interface components except electrical connector for fan. The side members and brackets design is also simplified to achieve maximum weight reduction. Further Cooling system performance of engine is evaluated along with Fuel efficiency; results are compared with present configuration.

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…

Sensitivity Analysis of the Combustion Parameters in a Stratified HCCI Engine with Regard to Performance and Emission

mahboud Armin
Mazandaran university of science and tec-Mohsen Pourfallah
  • Technical Paper
  • 2019-24-0114
To be published on 2019-08-15 by SAE International in United States
Homogeneous charge compression ignition (HCCI) is a promised solution to environmental and fuel economy concerns for IC engines. Engine application for HCCI engine depends on an array of parameters such as fuel type, mixture composition, intake condition and engine specification, meaning that controlling an HCCI engine can only be done through the adjustment of these parameters. In this numerical study which is driven from an experimental work, thermal and charge stratification is used to control HCCI combustion. The effect of intake temperature, compression ratio, intake pressure, EGR, reformer gas (CO-H2 mixture) and glow plug temperature on engine performance and emission was investigated using a 3D model on AVL-FIRE parallel with 1D model on GT-Power software. Then AHP model as a multiple Attribute Decision making method has been used to analyze the sensitivity of these parameters on performance and emission. Results indicate that increasing intake temperature causes the operating condition approaches knock which results in a narrower operating region. Increasing EGR ratio makes possible the expanding of operating range rich limit since it causes delayed combustion…

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 of Linear Approximation Error for Model Predictive Control of Spark Ignited Turbocharged Engines

Rohit Koli
Clemson Univ-Daniel Egan
  • Technical Paper
  • 2019-24-0014
To be published on 2019-08-15 by SAE International in United States
Modern turbocharged spark-ignition engines are being equipped with an increasing number of control actuators to simultaneously meet fuel economy, emissions and performance targets. The response time variations between a given set of engine control actuators tends to be significant during transients and necessitate highly complex actuator scheduling routines. Model Predictive Control (MPC) algorithms have the potential to significantly reduce calibration and control tuning efforts as compared to current methodologies that are designed around integration of multiple single-input single-output sub-system controllers. MPC systems simultaneously generate all actuator responses by using a combination of current engine conditions and optimization of a control-oriented plant model. To achieve real-time control the engine model and optimization processes must be computationally efficient without sacrificing effectiveness. Most MPC systems intended for real-time control utilize a linearized model that can be quickly evaluated using a sub-optimal optimization methodology. Online linearization of the engine model is computationally expensive so it should be performed as infrequently as possible. Since engine dynamics are non-linear, a local linearity approximation error occurs during this process. This research presents…

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…

Synergistic effect of millerization, electric supercharging and 48V mild hybrid system

Continental Automotive Systems-Hanyong Park, Jongsuk Lim, Dowan Kim
Hyundai Motor Company-Heechang Oh, Jonghyeok Lee, Seungwoo Hong, Donghee Han
  • Technical Paper
  • 2019-24-0195
To be published on 2019-08-15 by SAE International in United States
The hybridization of the powertrain will be indispensable concerning the CO2 emission targets of 2020 and beyond. Moreover, 48V mild hybrid systems is regarded to be the prospecting near term solution due to its cost-effective fuel consumption reduction with the minimum system change for production acceptance. In this study, the potential of fuel consumption reduction in a natural aspirated MPI engine with 48V electric super charger and other synergistic technologies was evaluated to investigate the optimized gasoline engine concept for the 48V mild hybrid vehicle. The compression ratio was increased to for thermal efficiency enhancement. Tumble ratio was increased to realize faster combustion and mitigate knocking combustion. In addition, LIVC strategy and EGR was also applied to maximize the fuel consumption enhancement. 48V electric supercharger which enables lower back pressure and less in-cylinder residuals compared to turbocharer systems, was equipped and provided boosting covering whole engine speed range . Electrical energy required for electric superchargers could be sufficiently supplied by 48V mild hybrid system. The combination of these synergistic technologies enabled the realization of the…