Thermodynamic Cycles of Internal Combustion Engines for Increased Thermal Efficiency, Constant-Volume Combustion, Variable Compression Ratio, and Cold Start

2007 ◽  
Author(s):  
Yiding Cao
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Cold Start ◽  
Internal Combustion ◽  
Constant Volume ◽  
Combustion Engines ◽  
Variable Compression Ratio ◽  
Thermodynamic Cycles ◽  
Variable Compression

scholarly journals Temperature, Heat Distribution and Performance Analysis in a Variable Compression Ratio Internal Combustion Engine

2020 ◽  
Vol 8 (5) ◽  
pp. 4825-4829
Keyword(s):  
Heat Loss ◽  
Compression Ratio ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Mechanical Energy ◽  
Cooling Water ◽  
Internal Combustion ◽  
Heat Distribution ◽  
Variable Compression Ratio ◽  
Variable Compression

The internal combustion engines are also known as heat engines because of the utilization of heat energy of the fuel to convert it in to mechanical energy of the engine which finally runs the vehicle. Therefore, it is necessary to examine the generation and utilization of heat inside and outside the engine. For the above mentioned purpose, a variable compression ratio engine was used to perform experiment. The heat distribution of the used engine was investigated to recognize the heat loss areas from the engine. The experiments were performed by changing compression ratio from 15 to 21 and an optimum compression ratio was found. The experiments are further extended to find an optimum load value at standard compression ratio of the engine. The analysis was performed by using various factor of heat utilization such as heat supplied by fuel, heat equivalent to brake power, heat loss to exhaust gases, heat loss to engine cooling water and heat unaccounted. The proposed research will be useful to overcome the challenges during selection of compression ratio for design of an engine in industries.

scholarly journals Determination of Combustion Process Model Parameters in Diesel Engine with Variable Compression Ratio

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Saša Milojević ◽  
Radivoje Pešić
Keyword(s):  
Diesel Engine ◽  
Compression Ratio ◽  
Process Model ◽  
Internal Combustion Engines ◽  
Combustion Process ◽  
Exhaust Emission ◽  
Model Parameters ◽  
Connecting Rod ◽  
Variable Compression Ratio ◽  
Variable Compression

Compression ratio has very important influence on fuel economy, emission, and other performances of internal combustion engines. Application of variable compression ratio in diesel engines has a number of benefits, such as limiting maximal in cylinder pressure and extended field of the optimal operating regime to the prime requirements: consumption, power, emission, noise, and multifuel capability. The manuscript presents also the patented mechanism for automatic change engine compression ratio with two-piece connecting rod. Beside experimental research, modeling of combustion process of diesel engine with direct injection has been performed. The basic problem, selection of the parameters in double Vibe function used for modeling the diesel engine combustion process, also performed for different compression ratio values. The optimal compression ratio value was defined regarding minimal fuel consumption and exhaust emission. For this purpose the test bench in the Laboratory for Engines of the Faculty of Engineering, University of Kragujevac, is brought into operation.

Applying Thermodynamics in Search of Superior Engine Efficiency

2005 ◽  
Vol 127 (3) ◽  
pp. 670-675 ◽  
Author(s):  
Charles A. Amann
Keyword(s):  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Heat Engine ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Closed Cycle ◽  
Engine Efficiency ◽  
Operating Cycles ◽  
Thermodynamic Processes

Historically, a succession of thermodynamic processes has been used to idealize the operating cycles of internal combustion engines. In this study, the 256 possible combinations of four reversible processes—isentropic, isothermal, isochoric, and isobaric—are surveyed in search of cycles promising superior thermal efficiency. Regenerative cycles are excluded. The established concept of the air-standard cycle, which mimics the internal combustion engine as a closed-cycle heat engine, is used to narrow the field systematically. The approach relies primarily on graphical interpretation of approximate temperature-entropy diagrams and is qualitative only. In addition to identifying the cycles offering the greatest efficiency potential, the compromise between thermal efficiency and mean effective pressure is addressed.

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