The Effect of Intake Temperature in a Turbocharged Multi Cylinder Engine Operating in HCCI Mode

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The Effect of Intake Temperature in a Turbocharged Multi Cylinder Engine Operating in HCCI Mode. / Johansson, Thomas; Tunestål, Per; Johansson, Bengt; Aulin, Hans.

In: SAE International Journal of Engines, Vol. 2, No. 2, 2009-24-0060, 13.09.2009, p. 452-466.

Research output: Contribution to journalArticle

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TY - JOUR

T1 - The Effect of Intake Temperature in a Turbocharged Multi Cylinder Engine Operating in HCCI Mode

AU - Johansson, Thomas

AU - Tunestål, Per

AU - Johansson, Bengt

AU - Aulin, Hans

PY - 2009/9/13

Y1 - 2009/9/13

N2 - The operating range in HCCI mode is limited by the excessive pressure rise rate and therefore high combustion induced noise. The HCCI range can be extended with turbocharging which enables increased dilution of the charge and thus a reduction of combustion noise. When the engine is turbocharged the intake charge will have a high temperature at increased boost pressure and can then be regulated in a cooling circuit. Limitations and benefits are examed at 2250 rpm and 400 kPa indicated mean effective pressure. It is shown that combustion stability, combustion noise and engine efficiency have to be balanced since they have optimums at different intake temperatures and combustion timings. The span for combustion timings with high combustion stability is narrower at some intake temperatures and the usage of external EGR can improve the combustion stability. It is found that the standard deviation of combustion timing is a useful tool for evaluating cycle to cycle variations. One of the benefits with HCCI is the low pumping losses, but when load and boost pressure is increased there is an increase in pumping losses when using negative valve overlap. The pumping losses can then be circumvented to some extent with a low intake temperature or EGR, leading to more beneficial valve timings at high load.

AB - The operating range in HCCI mode is limited by the excessive pressure rise rate and therefore high combustion induced noise. The HCCI range can be extended with turbocharging which enables increased dilution of the charge and thus a reduction of combustion noise. When the engine is turbocharged the intake charge will have a high temperature at increased boost pressure and can then be regulated in a cooling circuit. Limitations and benefits are examed at 2250 rpm and 400 kPa indicated mean effective pressure. It is shown that combustion stability, combustion noise and engine efficiency have to be balanced since they have optimums at different intake temperatures and combustion timings. The span for combustion timings with high combustion stability is narrower at some intake temperatures and the usage of external EGR can improve the combustion stability. It is found that the standard deviation of combustion timing is a useful tool for evaluating cycle to cycle variations. One of the benefits with HCCI is the low pumping losses, but when load and boost pressure is increased there is an increase in pumping losses when using negative valve overlap. The pumping losses can then be circumvented to some extent with a low intake temperature or EGR, leading to more beneficial valve timings at high load.

U2 - 10.4271/2009-24-0060

DO - 10.4271/2009-24-0060

M3 - Article

VL - 2

SP - 452

EP - 466

JO - SAE International Journal of Engines

JF - SAE International Journal of Engines

SN - 1946-3944

IS - 2

M1 - 2009-24-0060

ER -