Study of water direct injection on knock control and combustion process of a high compression ratio GDI engine

Fuel ◽  
2021 ◽  
Vol 306 ◽  
pp. 121631
Author(s):  
Qirui Zhang ◽  
Yiqiang Pei ◽  
Yanzhao An ◽  
Zhong Peng ◽  
Jing Qin ◽  
...  
Keyword(s):  
Compression Ratio ◽  
Direct Injection ◽  
Combustion Process ◽  
High Compression Ratio ◽  
High Compression ◽  
Gdi Engine ◽  
Knock Control

Experimental study of knock combustion and direct injection on knock suppression in a high compression ratio methanol engine

Fuel ◽  
2021 ◽  
pp. 122505
Author(s):  
Qimeng Duan ◽  
Xiaojun Yin ◽  
Xiaochen Wang ◽  
Hailiang Kou ◽  
Ke Zeng
Keyword(s):  
Experimental Study ◽  
Compression Ratio ◽  
Direct Injection ◽  
High Compression Ratio ◽  
High Compression

Controlled ASSCI With Moderate Auto-Ignition for Engine Knock Suppression in a GDI Engine With High Compression Ratio

2014 ◽  
Author(s):  
Hui Liu ◽  
Zhi Wang ◽  
Jianxin Wang ◽  
Mengke Wang ◽  
Wanli Yang
Keyword(s):  
Heat Release ◽  
Compression Ratio ◽  
High Compression Ratio ◽  
Two Stage ◽  
Second Stage ◽  
High Compression ◽  
Auto Ignition ◽  
Crank Angle ◽  
Engine Knock ◽  
Gdi Engine

This paper presents an experimental study on controlled ASSCI (Assisted Spark Stratified Compression Ignition) for engine knock suppression in a GDI engine with high compression ratio. The direct injection is used for forming desired stoichiometric stratified mixture at WOT condition without turbo-charging. The engine is filled with 20% cooled external EGR and the ignition timing is maintained at MBT point. The combustion characteristics of the desired stoichiometric stratified mixture show two-stage heat release, where the first stage is caused by spark ignition and the second stage is due to moderate auto-ignition. Compared with engine knock, the second stage heat release of controlled ASSCI shows smooth pressure curve without pressure oscillation. This is due to the low energy density mixture around the cylinder wall caused by cooled external EGR. The stratified mixture could suppress knock. Fuel economy and combustion characteristics of the baseline and the controlled ASSCI combustion were compared. The baseline GDI engine reaches a maximum of 8.9 bar BMEP with BSFC of 291 g/(kWh), the controlled ASSCI combustion achieves a maximum of 8.3 bar BMEP with BSFC of 256 g/(kWh), improving the fuel economy over 12% while maintaining approximately the same power. CA50 (the crank angle of 50% heat release) of the controlled ASSCI is detected at 8.4° CA ATDC, which is 17.4° CA advanced than that of the baseline while the combustion duration of the controlled ASSCI is 52.84dG CA, 16.6° CA longer than that of the baseline caused by diluted mixture and two-stage heat release. The COV of the controlled ASSCI is 1.4%, 2.1% lower than that of the baseline. The peak pressure (Pmax) and the maximum pressure rise rate (PRRmax) of the controlled ASSCI are 59.7 bar and 2.2 bar/° CA, 22.9 bar and 1.5 bar/° CA higher than that of the baseline respectively. The crank angle of Pmax and PRRmax of the controlled ASSCI are 11° CA ATDC and −1° CA ATDC, 15.4° CA and 17.2° CA earlier than that of the baseline. The results show that controlled ASSCI with two-stage heat releases is a potential combustion strategy to suppress engine knock while achieving high efficiency of the high compression ratio gasoline engine.

Limits of compression ratio in spark-ignition combustion with methanol

2021 ◽  
pp. 146808742110433
Author(s):  
Christian Wouters ◽  
Patrick Burkardt ◽  
Stefan Pischinger
Keyword(s):  
Compression Ratio ◽  
Direct Injection ◽  
Spark Ignition ◽  
Combustion Stability ◽  
High Compression Ratio ◽  
Lean Burn ◽  
Promising Alternative ◽  
Excess Air ◽  
High Compression ◽  
Lean Limit

A shift toward a circular and [Formula: see text]-neutral world is required, in which rapid defossilization and lower emissions are realized. A promising alternative fuel that has gained traction is methanol, thanks to its favorable and clean-burning fuel properties as well as its ability to be produced in a carbon-neutral process. Especially methanol’s high knock resistance and its combustion stability offer the opportunity to operate an engine at both a high compression ratio and a high excess air dilution. Although methanol has been investigated in series-production engines for passenger car applications, there is a lack of investigations on a dedicated engine that can operate at methanol’s knock limit. In this paper, methanol’s knock limitation is experimentally assessed by applying high compression ratios to a direct injection spark-ignition single-cylinder research engine. To that end, four compression ratios were investigated: 10.8, 15.0, 17.7, and 20.6. With compression ratios of 15.0 and 17.7, the lean-limit was increased to excess air ratios of 2.0 and 2.1, respectively, compared to 1.7 at a compression ratio of 10.8. For the highest compression ratio of 20.6, the maximum lean burn limit was increased to an excess air ratio of 1.9 due to achieving the maximum cylinder pressure limit. Despite the minor increase in lean-limit, a maximum indicated efficiency of 48.7% was achieved with the highest compression ratio of 20.6. However, even at this high compression ratio, methanol did not show a knock limitation. The investigations in this work provide profound knowledge for future engine investigations with methanol.

Direct Injection of CNG on High Compression Ratio Spark Ignition Engine: Numerical and Experimental Investigation

2011 ◽  
Author(s):  
Benoit Douailler ◽  
Frederic Ravet ◽  
Vivien Delpech ◽  
Dominique Soleri ◽  
Benjamin Reveille ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Compression Ratio ◽  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
High Compression Ratio ◽  
High Compression

scholarly journals Experimental Investigation of Diluents Components on Performance and Emissions of a High Compression Ratio Methanol SI Engine

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3366
Author(s):  
You Zhou ◽  
Wei Hong ◽  
Ye Yang ◽  
Xiaoping Li ◽  
Fangxi Xie ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Compression Ratio ◽  
Combustion Process ◽  
Spark Ignition ◽  
Chemical Effect ◽  
High Compression Ratio ◽  
Lean Burn ◽  
High Compression ◽  
Wide Range

Increasing compression ratio and using lean burn are two effective techniques for improving engine performance. Methanol has a wide range of sources and is a kind of suitable fuel for a high-compression ratio spark-ignition lean burn engine. Lean burn mainly has a dilution effect, thermal effect and chemical effect. To clarify the influences of different effects and provide guidance for improving composition of dilution gases and applications of this technology, this paper chose Ar, N2 and CO2 as diluents. A spark-ignition methanol engine modified from a diesel engine with a compression ratio of 17.5 was used for the experiments. The results obtained by using methanol spark ignition combustion indicated that at engine speed of 1400 rpm and 25% load, NOx dropped by up to 77.5%, 100% and 100% by Ar, CO2 and N2. Gases with higher specific heat ratio and lower heat capacity represented by Ar exhibited the least adverse effect on combustion and showed a downward break-specific fuel consumption (BSFC) trend. Gas with high specific heat capacity represented by CO2 can decrease NOx and total hydro carbons (THC) emissions at the same time, but the BSFC of CO2 showed the worst trend, followed by N2. Gas affecting the combustion process like CO2 had chemical effect.

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