Heat transfer in internal combustion engines

2012 ◽  
pp. 364-384 ◽  
Author(s):  
Richard Stone
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Combustion Engines

Maximum efficiencies for internal combustion engines: Thermodynamic limitations

2017 ◽  
Vol 19 (10) ◽  
pp. 1005-1023 ◽  
Author(s):  
Jerald A Caton
Keyword(s):  
Heat Transfer ◽  
Internal Combustion Engines ◽  
High Efficiency ◽  
Pressure Rise ◽  
Internal Combustion ◽  
Thermodynamic Evaluation ◽  
Combustion Engines ◽  
Automotive Engine ◽  
Specific Heats ◽  
Cycle Simulation

The thermodynamic limitation for the maximum efficiencies of internal combustion engines is an important consideration for the design and development of future engines. Knowing these limits helps direct resources to those areas with the most potential for improvements. Using an engine cycle simulation which includes the first and second laws of thermodynamics, this study has determined the fundamental thermodynamics that are responsible for these limits. This work has considered an automotive engine and has quantified the maximum efficiencies starting with the most ideal conditions. These ideal conditions included no heat losses, no mechanical friction, lean operation, and short burn durations. Then, each of these idealizations is removed in a step-by-step fashion until a configuration that represents current engines is obtained. During this process, a systematic thermodynamic evaluation was completed to determine the fundamental reasons for the limitations of the maximum efficiencies. For the most ideal assumptions, for compression ratios of 20 and 30, the thermal efficiencies were 62.5% and 66.9%, respectively. These limits are largely a result of the combustion irreversibilities. As each of the idealizations is relaxed, the thermal efficiencies continue to decrease. High compression ratios are identified as an important aspect for high-efficiency engines. Cylinder heat transfer was found to be one of the largest impediments to high efficiency. Reducing cylinder heat transfer, however, is difficult and may not result in much direct increases of piston work due to decreases of the ratio of specific heats. Throughout this work, the importance of high values of the ratio of specific heats was identified as important for achieving high thermal efficiencies. Depending on the selection of constraints, different values may be given for the maximum thermal efficiency. These constraints include the allowed values for compression ratio, heat transfer, friction, stoichiometry, cylinder pressure, and pressure rise rate.

Thermophysical Properties of Working Substance and Heat Transfer in a Hydrogen Combustion Engine

2003 ◽  
Author(s):  
T. Shudo ◽  
H. Oka
Keyword(s):  
Heat Transfer ◽  
Combustion Chamber ◽  
Heat Loss ◽  
Thermophysical Properties ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Spark Ignition ◽  
Hydrogen Combustion ◽  
Spark Ignition Engine ◽  
Combustion Engines

Hydrogen is a clean alternative to fossil fuels for internal combustion engines and can be easily used in spark-ignition engines. However, the characteristics of the engines fueled with hydrogen are largely different from those with conventional hydrocarbon fuels. A higher burning velocity and a shorter quenching distance for hydrogen as compared with hydrocarbons bring a higher degree of constant volume and a larger heat transfer from the burning gas to the combustion chamber wall of the engines. Because of the large heat loss, the thermal efficiency of an engine fueled with hydrogen is sometimes lower than that with hydrocarbons. Therefore, the analysis and the reduction of the heat loss are crucial for the efficient utilization of hydrogen in internal combustion engines. The empirical correlations to describe the total heat transferred from the burning gas to the combustion chamber walls are often used to calculate the heat loss in internal combustion engines. However, the previous research by one of the authors has shown that the widely used heat transfer correlations cannot be properly applied to the hydrogen combustion even with adjusting the constants in them. For this background, this research analyzes the relationship between characteristics of thermophysical properties of working substance and heat transfer to the wall in a spark-ignition engine fueled with hydrogen.

Evaluation of Heat Transfer Models With Measurements in a Hydrogen-Fuelled Spark Ignition Engine

2010 ◽  
Author(s):  
Joachim Demuynck ◽  
Sebastian Verhelst ◽  
Michel De Paepe ◽  
Henk Huisseune ◽  
Roger Sierens
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Thermodynamic Model ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Hydrogen Combustion ◽  
Spark Ignition Engine ◽  
Combustion Engines ◽  
Combustion Properties ◽  
Transfer Models

Hydrogen-fuelled internal combustion engines are still investigated as an alternative for current drive trains because they have a high efficiency, near-zero noxious and zero tailpipe greenhouse gas emissions. A thermodynamic model of the engine cycle enables a cheap and fast optimization of engine settings for operation on hydrogen. The accuracy of the heat transfer sub model within the thermodynamic model is important to simulate accurately the emissions of oxides of nitrogen which are influenced by the maximum gas temperature. These emissions can occur in hydrogen internal combustion engines at high loads and they are an important constraint for power and efficiency optimization. The most common models in engine research are those from Annand and Woschni, but they are developed for fossil fuels and the heat transfer of hydrogen differs a lot from the classic fuels. We have measured the heat flux and the wall temperature in an engine that can run on hydrogen and methane and we have investigated the accuracy of simulations of the heat transfer models. This paper describes an evaluation of the models of Annand and Woschni with our heat flux measurements. Both models can be calibrated to account for the influence of the specific engine geometry on the heat transfer. But if they are calibrated for methane, they fail to calculate the heat transfer for hydrogen combustion. This demonstrates the models lack some gas or combustion properties which influence the heat transfer process in the case of hydrogen combustion.

Calculation of Exhaust Gas Heat Produce for Ron 95, Ron97 and Vpower Racing Base Fuels use in Internal Combustion Engines

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
I.B. Lias ◽  
H.B. Sharudin ◽  
M.H.B. Ismail ◽  
A.M.I.B. Mamat
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Exhaust System ◽  
Internal Combustion ◽  
Exhaust Gas ◽  
Combustion Engines ◽  
Exhaust Temperature ◽  
Different Types

The purpose of this study is to identify and analyse the calculation of exhaust gas heat produce (EGHP) in internal combustion engine (ICE) based on three types of fuel used specifically Petrol Ron 95, Petrol Ron 97 and Vpower racing base. The experimental test rig has used 1.6 CamPro Proton engine with 1561cc capacity and dynamometer. The calculation has used the basic formula of heat transfer equation and heat loss through the exhaust that included the mass flow rate of exhaust gas, specific heat of exhaust gas and temperature gradient. The exhaust temperature of ICE is generally in range from 400C to 600C and exhaust gas heat transfer affects the emissions burn-up in the exhaust system. This contributes significantly to the engine requirement. The experimental data was statistically analysed to identify the unknown parameter. High correlation of data variables can be determined based on the heat loss produced or EGHP. This also has significance by using different types of fuel in ICE.

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