Experimental and numerical analysis of engine gas exchange, combustion and heat transfer during warm-up

Boretti, Alberto and Lodi, Faisal and Watson, Harry and Brear, Michael and Dingli, Robert and Jin, Seong-Ho and Voice, Glen and Will, Frank (2008) Experimental and numerical analysis of engine gas exchange, combustion and heat transfer during warm-up. In: 2008 SAE International Powertrains, Fuels and Lubricants Congress, June 23-25, 2008, Shanghai, China.

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Abstract

This paper presents experimental and computational results obtained on an in line, six cylinder, naturally aspirated, gasoline engine. Steady state measurements were first collected for a wide range of cam and spark timings versus throttle position and engine speed at part and full load. Simulations were performed by using an engine thermo-fluid model. The model was validated with measured steady state air and fuel flow rates and indicated and brake mean effective pressures. The model provides satisfactory accuracy and demonstrates the ability of the approach to produce fairly accurate steady state maps of BMEP and BSFC. However, results show that three major areas still need development especially at low loads, namely combustion, heat transfer and friction modeling, impacting respectively on IMEP and FMEP computations. Satisfactory measurement of
small IMEP and derivation of FMEP at low loads is also a
major issue.

Measurements of fuel consumption were then collected during warm up for different configurations of the cooling system, with a standard mechanical water pump (MWP) and an electrical water pump (EWP), at a constant BMEP and engine speed. Simulations were performed by using the previous model to compute IMEP and FMEP. Modeling friction during warm-up, when temperatures of head metal, block metal, coolant and oil are well below hot steady values and decoupled to some extent (split or no flow coolant tests) proves to be challenging. Computational results complement the experimental data, demonstrating the utility of the
integrated approach in improving the design of the cooling system for faster warm-up.

Item Type:Conference or Workshop Item (Presentation)
Additional Information:This paper presents experimental and computational results obtained on an in line, six cylinder, naturally aspirated, gasoline engine. Steady state measurements were first collected for a wide range of cam and spark timings versus throttle position and engine speed at part and full load. Simulations were performed by using an engine thermo-fluid model. The model was validated with measured steady state air and fuel flow rates and indicated and brake mean effective pressures. The model provides satisfactory accuracy and demonstrates the ability of the approach to produce fairly accurate steady state maps of BMEP and BSFC. However, results show that three major areas still need development especially at low loads, namely combustion, heat transfer and friction modeling, impacting respectively on IMEP and FMEP computations. Satisfactory measurement of small IMEP and derivation of FMEP at low loads is also a major issue. Measurements of fuel consumption were then collected during warm up for different configurations of the cooling system, with a standard mechanical water pump (MWP) and an electrical water pump (EWP), at a constant BMEP and engine speed. Simulations were performed by using the previous model to compute IMEP and FMEP. Modeling friction during warm-up, when temperatures of head metal, block metal, coolant and oil are well below hot steady values and decoupled to some extent (split or no flow coolant tests) proves to be challenging. Computational results complement the experimental data, demonstrating the utility of the integrated approach in improving the design of the cooling system for faster warm-up.
Keywords:Gas exchange, combustion, Heat transfer, Warm-up
Subjects:H Engineering > H230 Transport Engineering
H Engineering > H330 Automotive Engineering
H Engineering > H311 Thermodynamics
Divisions:College of Science > School of Engineering
ID Code:4648
Deposited By: Seong-Ho Jin
Deposited On:26 Aug 2011 10:18
Last Modified:26 Aug 2011 10:30

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