Modified Compression Ratio Effect on Brake Power of Single Piston Gasoline Engine Utilizing Producer Gas

The approach of this research is to enlarge the knowledge about the methodologies to increase the maximum achievable load degree in the context of gasoline CAI engines. This work is the continuation of a previous work related to the study of the water injection effect on combustion, where this strategy was approached. The operating strategies to introduce the water and the interconnected settings were deeply analyzed in order to optimize combustion and to evaluate its potential to increase the maximum load degree when operating in CAI. During these initial tests, the engine was configured to enhance the mixture autoignition. The compression ratio was high compared to a standard gasoline engine, and suitable fuel injection strategies were selected based on previous studies from the authors to maximize the reactivity of the mixture, and get a stable CAI operation. Once water injection proved to provide encouraging results, the next step dealt in this work, was to go deeper and explore its effects when the engine configuration is more similar to a conventional gasoline engine, trying to get CAI combustion closer to production engines. This means, mainly, lower compression ratios and different fuel injection strategies, which hinders CAI operation. Finally, since all the previous works were performed at constant engine speed, the engine speed was also modified in order to see the applicability of the defined strategies to operate under CAI conditions at other operating conditions. The results obtained show that all these modifications are compatible with CAI operation: the required compression ratio can be reduced, in some cases the injection strategies can be simplified, and the increase of the engine speed leads to better conditions for CAI combustion. Thanks to the analysis of all this data, the different key parameters to manage this combustion mode are identified and shown in the paper.

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Research of NOx Emissions Characteristic of Engine Fuelled with M40

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.382.22 ◽

2011 ◽

Vol 382 ◽

pp. 22-25

Author(s):

Xin Guang Li ◽

Bing Yuan Han ◽

Rong Hai Yang

Keyword(s):

Experimental Data ◽

Numerical Simulation ◽

Simulation Model ◽

Compression Ratio ◽

Gasoline Engine ◽

Volume Ratio ◽

Nox Emissions ◽

Cylinder Pressure ◽

Variable Parameters ◽

Vehicle Engine

A numerical simulation model for gasoline engine was established by GT-POWER in order to study the NOx emissions characteristic of vehicle engine fuelled with M40 (the methanol and the gasoline in volume ratio 40∶60) and was validated by Experimental data. Based on the model, the variable parameters study including air-fuel radio, compression radio and ignition advance angle were carried out. The model results showed that the compression radio and the air-fuel radio played an important role during the NOx emissions characteristic. There is a significant improvement of the NOx emissions with the compression ratio increases. The cylinder pressure increased with the improvement of the compression ratio brought out the NOx emissions rise. With the improvement of the air-fuel ratio, NOx emissions increased first and then decreased. A larger ignition advance angle can increase the pressure and the temperature of the cylinder.

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A study of combustion improvement of a small gasoline engine by using the high compression ratio

The Proceedings of Yamanashi District Conference ◽

10.1299/jsmeyamanashi.2016.458 ◽

2016 ◽

Vol 2016 (0) ◽

pp. 458

Author(s):

Kensuke KONDO ◽

Tadashige KAWAKAMI

Keyword(s):

Compression Ratio ◽

Gasoline Engine ◽

High Compression Ratio ◽

High Compression

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Some aspects concerning the combination of downsizing with turbocharging, variable compression ratio, and variable intake valve lift

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1243/09544070jauto449 ◽

2007 ◽

Vol 221 (10) ◽

pp. 1287-1294 ◽

Cited By ~ 33

Author(s):

A C Clenci ◽

G Descombes ◽

P Podevin ◽

V Hara

Keyword(s):

Compression Ratio ◽

Gasoline Engine ◽

Control Method ◽

Operation Time ◽

Spark Ignition Engine ◽

Valve Lift ◽

Boost Pressure ◽

Intake Valve ◽

Variable Compression Ratio ◽

Variable Compression

The inefficient running of the spark ignition engine at part loads due to the load control method but, mostly, their major weighting in the vehicle's operation time justifies the interest in the technical solutions, which act in this particular operating range. These drawbacks encountered at low part loads are even more amplified when considering larger engines. For instance, it is well known that, at the same engine load, a larger engine is more throttled than a smaller engine; therefore the concerns are the higher pumping work, the lower real compression ratio, and the overall mechanical efficiency, which is also lower. One solution is a reduction in the displacement without affecting the power output. This is what is now commonly known as the downsizing technique. The combination of downsizing and uploading an engine has been known for a long time. However, the conversion, in an acceptable way, of this potential to actual practice is very challenging. On the one hand, the degree of the downsizing is related to the boost pressure. In order to cope with the knocking phenomenon, the downsized high-pressure turbocharged gasoline engine requires a lower volumetric compression ratio that limits the efficiency on part loads. Therefore, the degree of the downsizing has been limited and, thus, the possible fuel consumption reduction has not yet been fully achieved. On the other hand, other problems are encountered when considering a downsized turbocharged gasoline engine: insufficient low-end torque, poor starting performance, and turbo lag. In order to solve these problems an effective combination of the downsized turbocharged gasoline engine with additional technologies is needed. Thus, the paper will present a so-called adaptive thermal engine, which has at the same time a variable compression ratio and a variable intake valve lift. It will then be demonstrated that it is highly suitable for turbocharging, thus resulting in a high downsizing factor.

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The Miller cycle effects on improvement of fuel economy in a highly boosted, high compression ratio, direct-injection gasoline engine: EIVC vs. LIVC

Energy Conversion and Management ◽

10.1016/j.enconman.2013.12.022 ◽

2014 ◽

Vol 79 ◽

pp. 59-65 ◽

Cited By ~ 77

Author(s):

Tie Li ◽

Yi Gao ◽

Jiasheng Wang ◽

Ziqian Chen

Keyword(s):

Compression Ratio ◽

Fuel Economy ◽

Gasoline Engine ◽

Direct Injection ◽

Miller Cycle ◽

High Compression Ratio ◽

High Compression ◽

Direct Injection Gasoline Engine

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Application of Over-Expansion Cycle to a Larger Gasoline Engine With Late-Closing of Intake Valves

Design, Application, Performance and Emissions of Modern Internal Combustion Engine Systems and Components ◽

10.1115/icef2002-484 ◽

2002 ◽

Author(s):

Seiichi Shiga ◽

Kenji Nishida ◽

Shizuo Yagi ◽

Youichi Miyashita ◽

Yoshiharu Yuzawa ◽

...

Keyword(s):

Compression Ratio ◽

Thermal Efficiency ◽

Gasoline Engine ◽

Engine Performance ◽

Mechanical Efficiency ◽

Expansion Ratio ◽

Brake Thermal Efficiency ◽

Gasoline Engines ◽

Cylinder Test ◽

Test Engine

This paper presents further investigation into the effect of over-expansion cycle with late-closing of intake valves on the engine performance in gasoline engines. A larger single-cylinder test engine with the stroke volume of 650 cc was used with four kinds of expansion ratio (geometrical compression ratio) from 10 to 25 and four sets of intake valve closure (I.V.C.) timings from 0 to 110 deg C.A. ABDC. Late-closing has an effect of decreasing the pumping work due to the reduction of intake vacuum, althogh higher expansion ratio increases the friction work due to the average cylinder pressure level. Combining the higher expansion ratio with the late-closing determines the mechanical efficiency on the basis of these two contrastive effects. The indicated thermal efficiency is mostly determined by the expansion ratio and little affected by the nominal compression ratio. The value of the indicated thermal efficiency reaches to 48% at most which is almost comparable with the value of diesel engines. The improvement of both indicated and brake thermal efficiency reaches to 16% which is much higher than ever reported by the authors. A simple thermodynamic calculation could successfully explain the behavior of the indicated thermal efficiency. The brake thermal efficiency could also be improved due to the increase in both mechanical and indicated efficiencies.

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Effects of Different LPG Fuel Systems on Performances of Variable Compression Ratio Single Cylinder Engine

Design, Application, Performance and Emissions of Modern Internal Combustion Engine Systems and Components ◽

10.1115/icef2002-519 ◽

2002 ◽

Cited By ~ 1

Author(s):

G. H. Choi ◽

J. H. Kim ◽

Christian Homeyer

Keyword(s):

Liquid Phase ◽

Heat Release ◽

Compression Ratio ◽

Power Output ◽

Alternative Fuels ◽

Gasoline Engine ◽

Cylinder Pressure ◽

Maximum Heat ◽

Spark Timing ◽

Test Engine

Since the early 20th century, most ground vehicles are driven with gasoline and diesel. The degradation of the environment affects human on earth unless the quality of the air is improved. One of the alternative fuels, LPG, is potentially capable of lowering vehicular emissions when compared to gasoline or diesel. There is a penalty in power output resulting from the use of LPG because the engine can induce less amount of air with Mixer system comparing with gasoline engine. Currently, the liquid-phase LPG is injected into the intake port of the engine, the fuel vaporizes enroute to the combustion chamber. Therefore, the performance and combustion processes of the tested engine are investigated with different LPG fuel systems. The test engine was developed and named heavy-duty VACRE. The test engine for this work operates 1400rpm with MBT conditions. The major conclusions of the work include; 1) The power output of LPi system with liquid-phase is approximately 17% higher than that of vapor-phase Mixer system due to increases of volumetric efficiency. And the MBT spark timing of LPi system is approximately 25% more advanced than that of Mixer system at λ value 1.0; 2) The LPi system shows both the maximum heat release rate and the cumulative heat release to be approximately 20% higher than the Mixer system; 3) Maximum cylinder pressure decrease with increase of compression ratio and a point of maximum cylinder pressure is delayed with high compression ratio.

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