Torque characteristics and fuel efficiency of various gasoline engine concepts

1984 ◽  
Author(s):  
D Gruden ◽  
H Richter
Keyword(s):  
Gasoline Engine ◽  
Fuel Efficiency

TWC-SCR Aftertreatment System Evaluation for a Lean Burn Gasoline Engine Operating in HCCI, SACI, and SI Combustion Modes

2016 ◽  
Author(s):  
Jordan Easter ◽  
Stanislav V. Bohac
Keyword(s):  
Conversion Efficiency ◽  
Gasoline Engine ◽  
Fuel Efficiency ◽  
Compression Ignition ◽  
Scr Catalyst ◽  
Advanced Combustion ◽  
Nox Conversion ◽  
Combustion Modes ◽  
Scr System ◽  
Nox Conversion Efficiency

Low temperature and dilute Homogenous Charge Compression Ignition (HCCI) and Spark Assisted Compression Ignition (SACI) can improve fuel economy and reduce engine-out NOx emissions to very low values, often less than 30 ppm. However, these combustion modes are unable to achieve stringent future regulations such as SULEV 30 without the use of lean aftertreatment. Though active selective catalytic reduction (SCR) with urea injection and lean NOx traps (LNT) have been investigated as options for lean gasoline engines, a passive TWC-SCR system is investigated in this work because it avoids the urea storage and dosing hardware of a urea SCR system, and the high precious metal cost of an LNT. The TWC-SCR concept uses periodic rich operation to produce NH3 over a TWC to be stored on an SCR catalyst for subsequent NOx conversion during lean operation. In this work a laboratory study was performed with a modified 2.0 L gasoline engine that was cycled between lean HCCI and rich SACI operation, or between lean and rich SI (spark ignited) combustion, to evaluate NOx conversion and reduced fuel consumption. Different lambda values during rich operation and different times held in rich operation were investigated. Results are compared to a baseline case in which the engine is always operated at stoichiometric conditions. SCR system simulations are also presented that compare system performance for different levels of stored NH3. With the configuration used in this study, lean/rich HCCI/SACI operation showed a maximum NOx conversion efficiency of 10%, while lean/rich SI operation showed a maximum NOx conversion efficiency of 60%. However, if the low conversion efficiency of lean/rich HCCI/SACI operation could be improved through higher brick temperatures or additional SCR bricks, simulation results indicate TWC-SCR aftertreatment has the potential to provide near-zero SCR-out NOx concentration and increased system fuel efficiency. In these simulations, fuel efficiency improvement relative to stoichiometric SI were 7 to15% for lean/rich HCCI/SACI with zero tailpipe NOx and −1 to 5% for lean/rich SI with zero tailpipe NOx emissions. Although previous work indicated increased time for NH3 to start forming over the TWC during rich operation, less NH3 production over the TWC per fuel amount, and increased NH3 slip over the SCR catalyst for advanced combustion systems, if NOx conversion efficiency could be enhanced, improvements in fuel economy and low engine-out NOx from advanced combustion modes would more than make up for these disadvantages.

Minimum Backpressure Wastegate Control for a Boosted Gasoline Engine With Low Pressure External EGR

2016 ◽  
Author(s):  
Shima Nazari ◽  
Anna Stefanopoulou ◽  
Jason Martz
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Fuel Efficiency ◽  
Engine Performance ◽  
Low Pressure ◽  
Gasoline Direct Injection ◽  
Efficiency Gain ◽  
Engine Simulation ◽  
Trade Offs ◽  
Torque Response

Turbocharging and downsizing (TRBDS) a gasoline direct injection (GDI) engine can reduce fuel consumption but with increased drivability challenges compared to larger displacement engines. This tradeoff between efficiency and drivability is influenced by the throttle-wastegate control strategy. A more severe tradeoff between efficiency and drivability is shown with the introduction of Low-Pressure Exhaust Gas Recirculation (LP-EGR). This paper investigates and quantifies these trade-offs by designing and implementing in a one-dimensional (1D) engine simulation two prototypical throttle-wastegate strategies that bound the achievable engine performance with respect to efficiency and torque response. Specifically, a closed-wastegate (WGC) strategy for the fastest achievable response and a throttle-wastegate strategy that minimizes engine backp-pressure (MBWG) for the best fuel efficiency, are evaluated and compared based on closed loop response. The simulation of an aggressive tip-in (the driver’s request for torque increase) shows that the wastegate strategy can negotiate a 0.8% efficiency gain at the expense of 160 ms slower torque response both with and without LP-EGR. The LP-EGR strategy, however offers a substantial 5% efficiency improvement followed by an undesirable 1 second increase in torque time response, clarifying the opportunities and challenges associated with LP-EGR.

Preliminary Investigation of Dilution Strategies to Control Engine Torque During Transient Events

2001 ◽  
Author(s):  
R. D. Maugham ◽  
N. D. Vaughan ◽  
C. J. Brace ◽  
S. W. Murray
Keyword(s):  
Gasoline Engine ◽  
Fuel Efficiency ◽  
Preliminary Investigation ◽  
Torque Control ◽  
Test Program ◽  
Lean Burn ◽  
Engine Torque ◽  
Variable Transmission ◽  
Transient Events ◽  
Initial Results

Abstract A continuously variable transmission (CVT) allows a powertrain controller the freedom to develop a required output power at a range of engine torque and speed conditions. This flexibility can be used to maximise fuel efficiency. Due to low frictional and pumping losses a gasoline engine’s fuel efficiency is maximised at low speed, high torque conditions. However due to the reduced torque margin available, controlling a gasoline engine in this region compromises transient vehicle response. Dilution torque control, using EGR or lean burn, has the potential to maintain the economy gains available using a CVT powertrain whilst improving a vehicle’s driveability. This paper introduces preliminary work that has been undertaken to investigate the potential of charge dilution to control steady state engine torque. A test rig has been developed based around an engine fitted with variable cam phasing and an external EGR system. The paper contains a discussion of initial results of a lean dilution test program used to demonstrate the principle.

Model Predictive Air-Fuel Ratio Control for an Integrated Gasoline Engine and Three-Way Catalytic Converter System

2018 ◽  
Author(s):  
Kuo Yang ◽  
Pingen Chen
Keyword(s):  
Gasoline Engine ◽  
Combustion Engine ◽  
Catalytic Converter ◽  
Fuel Efficiency ◽  
Integrated System ◽  
Oxygen Storage ◽  
System Control ◽  
Fuel Ratio ◽  
Conversion Efficiencies ◽  
Control Methodology

With increasingly demanding regulations on engine emission and fuel efficiency, the optimization of the internal combustion engine and the after-treatment integrated system has become a critical research focus. To address such an issue, this paper aims to achieve a better trade-off between the fuel consumption of a spark-ignited (SI) engine and emission conversion efficiencies of a Three-Way Catalytic converter (TWC) system. A Model Predictive Control (MPC)-based integrated engine and TWC control methodology is presented, which is able to optimize Air/Fuel Ratio (AFR) to maintain oxygen storage of TWC at a desired level and thus meet the tailpipe NOx, CO and HC emission requirements. The effectiveness of the presented control methodology is validated in simulation. Compared with the existing dithering-based AFR control, the proposed MPC-based AFR control can improve CO emission conversion efficiencies by 8.42% and 4.85% in simplified US06 and UDDS driving cycles, respectively. At the same time, Nitrogen Oxides (NOx) conversion efficiency maintains above the required limit of 95% and the fuel efficiency remains at the same level as the existing control methodology in production as well. Such an integrated engine-aftertreatment system control can be instrumental in improving engine efficiency and emission reduction performance.

Electric torque assist and supercharging of a downsized gasoline engine in a 48V mild hybrid powertrain

2020 ◽  
pp. 095440702096895
Author(s):  
Feihong Xia ◽  
Philip Griefnow ◽  
Florian Tidau ◽  
Moritz Jakoby ◽  
Serge Klein ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Gasoline Engine ◽  
Fuel Efficiency ◽  
Measurement Data ◽  
Electric Energy ◽  
Operating Conditions ◽  
Hybrid Powertrain ◽  
Efficient Operation ◽  
Electric Energy Consumption ◽  
Mild Hybrid

48V systems enable not only mild hybrid functionalities such as recuperation or torque assist by a belt-driven starter generator (BSG), but also electrification of accessories and the engine boosting system. To maximize the powertrain efficiency, a proper layout of the electrified system and an optimized distribution of the electric power during transient operation is essential. In this study, a vehicle co-simulation of a conventional powertrain with a downsized turbocharged gasoline engine is extended by a 48V system with an electric compressor (eC) and a BSG. The control functions of the eC and BSG are based on a state-of-the-art vehicle application and calibrated for transient operating conditions. The engine model, which is built using a one-dimensional crank angle resolved approach in GT-POWER, has been validated with measurement data and is used to predict the interaction between the eC and the engine air path. The investigations using the simulation platform show that the 48V eC and the BSG can significantly improve the fuel effïciency if the electric energy consumption is initially neglected. However, when considering the electric energy consumption within the vehicle co-simulation, efficient operation is particularly depending on driver torque demand, the battery state-of-charge and charging effïciency. Hence, intelligent operating strategies are necessary to take advantage of the better torque response and improve fuel consumption at the same time.

Layer-by-layer mixing in engines with direct gasoline injection

2020 ◽  
Keyword(s):  
Diesel Engine ◽  
Internal Combustion Engine ◽  
Gasoline Engine ◽  
Combustion Engine ◽  
Direct Injection ◽  
Fuel Efficiency ◽  
Layer By Layer ◽  
Engine Fuel ◽  
Working Process ◽  
Layered Charge

Features of the design and operation of engines with direct injection of gasoline into the cylinders and layer-by-layer mixing are considered. Opportunities of improving the engine fuel efficiency and exhaust gases toxicity characteristics with this organization of the working process are shown. Problems arising when organizing such a working process of a gasoline engine are noted. Keywords internal combustion engine; diesel engine; gasoline engine; direct injection; layer-by-layer mixing; layered charge; lean mixture

Model-Based Predictive Control and Dithering Control for an Integrated Gasoline Engine and Three-Way Catalytic Converter System

2021 ◽  
Author(s):  
Kuo Yang ◽  
Pingen Chen
Keyword(s):  
Predictive Control ◽  
Gasoline Engine ◽  
Catalytic Converter ◽  
Fuel Efficiency ◽  
Operating Conditions ◽  
Oxygen Storage ◽  
Model Based ◽  
Emission Regulation ◽  
Fuel Efficiency Improvement ◽  
Conversion Efficiencies

Abstract Controls of integrated gasoline engine and after-treatment systems are critical for fuel efficiency improvement and emission regulation. This paper aims to develop novel model-based Three-Way Catalytic converter (TWC) controls to reduce the fuel consumption and tailpipe emissions for a gasoline engine. A model-based dither control and a nonlinear model predictive control (MPC)-based control, are presented, respectively. The proposed TWC dither control utilizes a systematically designed dither cycle configuration (including dithering amplitude, offset, and frequency) based on a control-oriented model, with the capability to adapt the dither cycle configuration to various engine operating conditions. The MPC control can optimize engine air-fuel ratio (AFR) to maintain the oxygen storage of TWC at a desired level and thus meet the tailpipe NOx, CO and HC emission requirements. The efficacies of both model-based TWC controls are validated in simulation with MPC control improving CO emission conversion efficiencies by 8.42% and 4.85% in simplified US06 and UDDS driving cycles, when compared to a baseline dithering-based AFR control. Meanwhile, NOx emission conversion efficiency is maintained above the required limit of 95%, while the fuel efficiency remains at the same level as the baseline control methodology.

Diesel Engine: Applications of Aluminum Alloys

2019 ◽  
Author(s):  
Mihriban Pekguleryuz ◽  
Erol Ozbakir ◽  
Amir Rezaei Farkoosh
Keyword(s):  
Diesel Engine ◽  
Aluminum Alloys ◽  
Gasoline Engine ◽  
Volume Fraction ◽  
Tensile Deformation ◽  
Fuel Efficiency ◽  
High Volume ◽  
Environmental Benefits ◽  
Performance Requirements ◽  
New Research

The Diesel engine, introduced by Rudolph Diesel in 1892, achieves a higher combustion ratio and fuel efficiency, has lower CO2 emissions per mile than the gasoline engine and is considered to be one of the most viable environmentally friendly technologies for vehicles. “Clean Diesel” using lower sulfur content fuel has become available since 2006. Currently, the Diesel engine and cylinder head are mostly cast iron to withstand the high compression pressures and temperatures of Diesel operation. Further weight reduction (40%–55%) via aluminum substitution in the Diesel engine would result in substantial fuel economy and increased environmental benefits. Current aluminum alloys cannot meet the requirements of the Diesel engine and a new research topic has emerged in aluminum materials technology to address these requirements. The main issue with aluminum alloys is the low resistance to thermal fatigue that results from the constrained expansion and contraction of the material in the interval regions leading to compressive creep deformation at 300°C during engine heat-up and to tensile deformation around 150°C during engine cooldown. This article discusses the performance requirements and the design principles for aluminum alloys for Diesel engine applications. Efforts on the modification of A356 and A319 alloys via Cu, Mg, Ni, Cr, V, Zr, Ti, and Mn addition are reviewed. Recent studies on Mn/Mo addition are presented and the related principles are introduced in designing high volume fraction, thermally stable, and uniform nanoscale dispersoids using solutes with opposite partitioning coefficients in aluminum.

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