Experimental study on the effects of injection parameters and exhaust gas recirculation on combustion, emission and performance of Atkinson cycle gasoline direct-injection engine

The efficiency improvement and emissions reduction potential of lean and exhaust gas recirculation (EGR)-dilute operation of spark-ignition gasoline engines is well understood and documented. However, dilute operation is generally limited by deteriorating combustion stability with increasing inert gas levels. The combustion stability decreases due to reduced mixture flame speeds resulting in significantly increased combustion initiation periods and burn durations. A study was designed and executed to evaluate the potential to extend lean and EGR-dilute limits using a low-energy transient plasma ignition system. The low-energy transient plasma was generated by nanosecond pulses and its performance compared to a conventional transistorized coil ignition (TCI) system operated on an automotive, gasoline direct-injection (GDI) single-cylinder research engine. The experimental assessment was focused on steady-state experiments at the part load condition of 1500 rpm 5.6 bar indicated mean effective pressure (IMEP), where dilution tolerance is particularly critical to improving efficiency and emission performance. Experimental results suggest that the energy delivery process of the low-energy transient plasma ignition system significantly improves part load dilution tolerance by reducing the early flame development period. Statistical analysis of relevant combustion metrics was performed in order to further investigate the effects of the advanced ignition system on combustion stability. Results confirm that at select operating conditions EGR tolerance and lean limit could be improved by as much as 20% (from 22.7 to 27.1% EGR) and nearly 10% (from λ = 1.55 to 1.7) with the low-energy transient plasma ignition system.

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Particulate emissions from a highly boosted gasoline direct injection engine

International Journal of Engine Research ◽

10.1177/1468087417710583 ◽

2017 ◽

Vol 19 (3) ◽

pp. 347-359 ◽

Cited By ~ 21

Author(s):

Felix Leach ◽

Richard Stone ◽

Dave Richardson ◽

Andrew Lewis ◽

Sam Akehurst ◽

...

Keyword(s):

Particle Number ◽

Fuel Injection ◽

Direct Injection ◽

Injection Pressure ◽

Back Pressure ◽

Gasoline Direct Injection ◽

Exhaust Gas ◽

Fuel Injection Pressure ◽

Gas Recirculation ◽

Operating Points

Downsized, highly boosted, gasoline direct injection engines are becoming the preferred gasoline engine technology to ensure that increasingly stringent fuel economy and emissions legislation are met. The Ultraboost project engine is a 2.0-L in-line four-cylinder prototype engine, designed to have the same performance as a 5.0-L V8 naturally aspirated engine but with reduced fuel consumption. It is important to examine particle number emissions from such extremely highly boosted engines to ensure that they are capable of meeting current and future emissions legislation. The effect of such high boosting on particle number emissions is reported in this article for a variety of operating points and engine operating parameters. The effect of engine load, air–fuel ratio, fuel injection pressure, fuel injection timing, ignition timing, inlet air temperature, exhaust gas recirculation level, and exhaust back pressure has been investigated. It is shown that particle number emissions increase with increase in cooled, external exhaust gas recirculation and engine load, and decrease with increase in fuel injection pressure and inlet air temperature. Particle number emissions are shown to fall with increased exhaust back pressure, a key parameter for highly boosted engines. The effects of these parameters on the particle size distributions from the engine have also been evaluated. Significant changes to the particle size spectrum emitted from the engine are seen depending on the engine operating point. Operating points with a bias towards very small particle sizes were noted.

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Study of particulate matter and gaseous emissions in gasoline direct injection engine using on-board exhaust gas fuel reforming

Applied Energy ◽

10.1016/j.apenergy.2016.07.100 ◽

2016 ◽

Vol 180 ◽

pp. 245-255 ◽

Cited By ~ 36

Author(s):

M. Bogarra ◽

J.M. Herreros ◽

A. Tsolakis ◽

A.P.E. York ◽

P.J. Millington

Keyword(s):

Particulate Matter ◽

Direct Injection ◽

Gasoline Direct Injection ◽

Exhaust Gas ◽

Gaseous Emissions ◽

Fuel Reforming ◽

Direct Injection Engine ◽

Gasoline Direct Injection Engine ◽

Gas Fuel

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

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4048152 ◽

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.

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