Development of 1.5L Dedicated Hybrid Engine with 42.6% Brake Thermal Efficiency

2021 ◽  
Keyword(s):  
Thermal Efficiency ◽  
Mass Production ◽  
Exhaust Gas ◽  
Miller Cycle ◽  
Brake Thermal Efficiency ◽  
Technology Application ◽  
Atkinson Cycle ◽  
Lower Viscosity ◽  
New Development ◽  
Gas Recirculation

To achieve higher brake thermal efficiency (BTE) and improve vehicle economy, the new development of dedicated hybrid engine (DHE), adopting the Atkinson or Miller cycle, has been becoming the current development trends. A base 1.5L natural aspiration (NA) engine with deep Atkinson cycle has been developed for dedicated hybrid vehicle application, which can achieve the highest BTE of 41.19%. In order to achieve higher BTE, several potential technologies which are easy for mass production application have been studied progressively, such as, higher compression ratio (CR), optimized exhaust gas recirculation (EGR) pick point, lower EGR temperature, higher EGR rate, higher RON number fuels, heat transfer reduction by polishing valve head, light boost, lower viscosity oil. The results show the combined technology application can achieve the highest engine BTE of 42.59%. This paper provides the studied technical routine and the achieved benefits step by step.

The impact of water injection and exhaust gas recirculation on combustion and emissions in a heavy-duty compression ignition engine operated on diesel and gasoline

2019 ◽  
Vol 21 (8) ◽  
pp. 1555-1573 ◽  
Author(s):  
Michael Pamminger ◽  
Buyu Wang ◽  
Carrie M Hall ◽  
Ryan Vojtech ◽  
Thomas Wallner
Keyword(s):  
Thermal Efficiency ◽  
Water Injection ◽  
Combustion Process ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Brake Thermal Efficiency ◽  
Fuel Ratio ◽  
Main Injection ◽  
Gas Recirculation ◽  
Diesel Operation

Steady-state experiments were conducted on a 12.4L, six-cylinder heavy-duty engine to investigate the influence of port-injected water and dilution via exhaust gas recirculation (EGR) on combustion and emissions for diesel and gasoline operation. Adding a diluent to the combustion process reduces peak combustion temperatures and can reduce the reactivity of the charge, thereby increasing the ignition-delay and, allowing for more time to premix air and fuel. Experiments spanned water/fuel mass ratios up to 140mass% and exhaust gas recirculation ratios up to 20vol% for gasoline and diesel operation with different injection strategies. Diluting the combustion process with either water or EGR resulted in a significant reduction in nitrogen oxide emissions along with a reduction in brake thermal efficiency. The sensitivity of brake thermal efficiency to water and EGR varied among the fuels and injection strategies investigated. An efficiency breakdown revealed that water injection considerably reduced the wall heat transfer; however, a substantial increase in exhaust enthalpy offset the reduction in wall heat transfer and led to a reduction in brake thermal efficiency. Regular diesel operation with main and post injection exhibited a brake thermal efficiency of 45.8% and a 0.3% reduction at a water/fuel ratio of 120%. The engine operation with gasoline, early pilot, and main injection strategy showed a brake thermal efficiency of 45.0% at 0% water/fuel ratio, and a 1.2% decrease in brake thermal efficiency for a water/fuel ratio of 140%. Using EGR as a diluent reduced the brake thermal efficiency by 0.3% for diesel operation, comparing ratios of 0% and 20% EGR. However, a higher impact on brake thermal efficiency was seen for gasoline operation with early pilot and main injection strategy, with a reduction of about 0.8% comparing 0% and 20% EGR. Dilution by means of EGR exhibited a reduction in nitrogen oxide emissions up to 15 g/kWh; water injection showed only up to 10 g/kWh reduction for the EGR rates and water/fuel ratio investigated.

Development of an exhaust gas recirculation strategy for an acetylene-fuelled homogeneous charge compression ignition engine

2010 ◽  
Vol 224 (7) ◽  
pp. 941-952 ◽  
Author(s):  
K Sudheesh ◽  
J M Mallikarjuna
Keyword(s):  
Thermal Efficiency ◽  
Homogeneous Charge Compression Ignition ◽  
Exhaust Gas Recirculation ◽  
Electrical Heating ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Brake Thermal Efficiency ◽  
Load Limit ◽  
Gas Recirculation ◽  
Load Conditions

This paper deals with experimental investigations carried out to develop an exhaust gas recirculation (EGR) strategy for an acetylene-fuelled homogeneous charge compression ignition (HCCI) engine. This study involves an analysis of the external inlet charge heating, the use of a mix of hot EGR and cool EGR to extend the load range, and the performance of the engine in the acetylene HCCI mode. First, experiments are conducted on a single-cylinder engine in the acetylene HCCI mode with external electrical heating at different load conditions, and the best inlet charge temperatures at each load condition are obtained. Second, hot EGR or a mix of hot EGR and cool EGR (i.e. the EGR strategy) is used to reduce or eliminate external charge heating and to extend the upper load limit, or to improve the brake thermal efficiency. In both cases, the engine performance is compared with that of the conventional diesel compression ignition (CI) mode. It is found that with EGR, above 25 per cent of load, the upper load limit at different inlet charge temperatures increases by about 16 28 per cent without any external charge heating. Below 25 per cent of load, the electrical heating at different inlet charge conditions is reduced by about 67–87 per cent. The brake thermal efficiency increases by 5–24 per cent under all the load conditions and it is comparable with that in the conventional CI mode. In the HCCI mode, nitrogen oxide levels are less than 20ppm. Smoke levels are always lower than 0.1 Bosch smoke unit. Hydrocarbon and carbon monoxide emissions are relatively higher than for the conventional CI mode.

scholarly journals A Theoretical Study on the Thermodynamic Cycle of Concept Engine with Miller Cycle

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1051
Author(s):  
Jungmo Oh ◽  
Kichol Noh ◽  
Changhee Lee
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Engine Performance ◽  
Thermodynamic Cycle ◽  
Expansion Ratio ◽  
Boost Pressure ◽  
Miller Cycle ◽  
Compression Pressure ◽  
Air Mass ◽  
Atkinson Cycle

The Atkinson cycle, where expansion ratio is higher than the compression ratio, is one of the methods used to improve thermal efficiency of engines. Miller improved the Atkinson cycle by controlling the intake- or exhaust-valve closing timing, a technique which is called the Miller cycle. The Otto–Miller cycle can improve thermal efficiency and reduce NOx emission by reducing compression work; however, it must compensate for the compression pressure and maintain the intake air mass through an effective compression ratio or turbocharge. Hence, we performed thermodynamic cycle analysis with changes in the intake-valve closing timing for the Otto–Miller cycle and evaluated the engine performance and Miller timing through the resulting problems and solutions. When only the compression ratio was compensated, the theoretical thermal efficiency of the Otto–Miller cycle improved by approximately 18.8% compared to that of the Otto cycle. In terms of thermal efficiency, it is more advantageous to compensate only the compression ratio; however, when considering the output of the engine, it is advantageous to also compensate the boost pressure to maintain the intake air mass flow rate.

Development of Gasoline Direct Injection Engine for Improving Brake Thermal Efficiency Over 44%

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Dongwon Jung ◽  
Byeongseok Lee ◽  
Jinwook Son ◽  
Soohyung Woo ◽  
Youngnam Kim
Keyword(s):  
Thermal Efficiency ◽  
Direct Injection ◽  
Stability Limit ◽  
Spark Ignition ◽  
Gasoline Direct Injection ◽  
Brake Thermal Efficiency ◽  
Gasoline Direct Injection Engine ◽  
Combustion Duration ◽  
Test Engine ◽  
Gas Recirculation

Abstract This study demonstrates the effects of technologies applied for the development of gasoline direct injection (GDI) engine for improving the brake thermal efficiency (BTE). The test engine has a relatively high stroke to bore ratio of 1.4 with a displacement of 2156 cm3. All experiments have been conducted for stoichiometric operation at 2000 RPM. First, since compression ratio (CR) is directly related to the thermal efficiency, four CR were explored for operation without exhaust gas recirculation (EGR). Then, for the same four CR, EGR was used to suppress the knock occurrence at high loads, and its effect on initial and main combustion duration was compared. Second, the shape of intake port was revised to increase tumble flow for reducing combustion duration, and extending EGR-stability limit further. Then, as an effective method to ensure stable combustion for EGR-diluted stoichiometric operation, the use of twin spark ignition (SI) system is examined by modifying both valve diameters of intake and exhaust, and its effect is compared against that of single spark ignition. In addition, the layout of twin spark ignition was also examined for the location of front-rear and intake-exhaust. To get the maximum BTE at high load, 12 V electronic super charger (eSC) was applied. Under the condition of using 12 V eSC, the effect of intake cam duration was identified by increasing from 260 deg to 280 deg. Finally, 48 V eSC was applied with the longer intake camshaft duration of 280 deg. As a result, the maximum BTE of 44% can be achieved for stoichiometric operation with EGR.

Application of the Passive MAHLE Jet Ignition System and Synergies with Miller Cycle and Exhaust Gas Recirculation

2020 ◽  
Author(s):  
Adrian Cooper ◽  
Anthony Harrington ◽  
Michael Bassett ◽  
Simon Reader ◽  
Michael Bunce
Keyword(s):  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Miller Cycle ◽  
Ignition System ◽  
Gas Recirculation

Impact of Oxygenated Additives on Performance Characteristics of Methyl Ester in IC Engine

2016 ◽  
Vol 852 ◽  
pp. 724-728 ◽  
Author(s):  
D. Yuvarajan ◽  
K. Pradeep ◽  
S. Magesh Kumar
Keyword(s):  
Thermal Efficiency ◽  
Butyl Alcohol ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Compression Ignition Engine ◽  
Ic Engine ◽  
Oxygenated Additives ◽  
Lower Viscosity ◽  
Exhaust Gas Temperature ◽  
The Impact

In this present work, the impact of blending n-butyl alcohol, a next generation biofuel with jatropha biodiesel on the performance of a diesel engine are examined. Tests were performed on a constant speed compression ignition engine using n-butyl alcohol / jatropha biodiesel blends. N-butyl alcohol was added to jatropha biodiesel by 10, 20 and 30% by volume. Performance parameters namely break thermal efficiency (BTE), Brake specific fuel consumption (BSFC) and Exhaust gas temperature (EGT) were analyzed in this work. It was experimentally found that by adding n-butyl alcohol to neat jatropha biodiesel, significant reduction in viscosity was observed. In addition, break thermal efficiency was increased by 0.8 % due to improved atomization of the blends. Further, brake specific fuel and exhaust gas temperature was further reduced due to lower viscosity and improved combustion rate with addition of n-butyl alcohol to jatropha biodiesel.

Thermodynamic Considerations Regarding the Use of Exhaust Gas Recirculation for Conventional and High Efficiency Engines

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Jerald A. Caton
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Thermal Efficiency ◽  
High Efficiency ◽  
Convective Heat Transfer Coefficient ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Gas Recirculation

During the last several decades, investigations of the operation of internal combustion engines utilizing exhaust gas recirculation (EGR) have increased. This increased interest has been driven by the advantages of the use of EGR with respect to emissions and, in some cases, thermal efficiency. The current study uses a thermodynamic engine cycle simulation to explore the fundamental reasons for the changes of thermal efficiency as functions of EGR. EGR with various levels of cooling is studied. Both a conventional (throttled) operating condition and a high efficiency (HE) operating condition are examined. With no EGR, the net indicated thermal efficiencies were 32.1% and 44.6% for the conventional and high efficiency engines, respectively. For the conditions examined, the cylinder heat transfer is a function of the gas temperatures and convective heat transfer coefficient. For increasing EGR, the gas temperatures generally decrease due to the lower combustion temperatures. For increasing EGR, however, the convective heat transfer coefficient generally increases due to increasing cylinder pressures and decreasing gas temperatures. Whether the cylinder heat transfer increases or decreases with increasing EGR is the net result of the gas temperature decreases and the heat transfer coefficient increases. For significantly cooled EGR, the efficiency increases partly due to decreases of the heat transfer. On the other hand, for less cooled EGR, the efficiency decreases due at least partly to the increasing heat transfer. Two other considerations to explain the efficiency changes include the changes of the pumping work and the specific heats during combustion.

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