On HCCI Engine Knock

Andreae, Morgan; Cheng, Wai K.; Kenney, Thomas E.; Yang, Jia

doi:10.4271/2007-01-1858

Cited by 78 publications

(29 citation statements)

References 10 publications

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“…By increasing the air dilution in the cylinder with turbocharging the audible noise is suppressed and therefore the operating range can be extended. The pressure rise rate can be measured in bar/CAD or MPa/ms [19] and is used to impose a operating limit. But neither of these catch the real combustion noise when the engine is supercharged.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Intake Temperature in a Turbocharged Multi Cylinder Engine operating in HCCI mode

Johansson¹,

Johansson²,

Tunestål³

et al. 2009

SAE Int. J. Engines

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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.

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Section: Resultsmentioning

confidence: 99%

The Effect of Intake Temperature in a Turbocharged Multi Cylinder Engine operating in HCCI mode

Johansson¹,

Johansson²,

Tunestål³

et al. 2009

SAE Int. J. Engines

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show abstract

“…The fuel species used in the experiment was iso-octane, and an iso-octane reaction mechanism suggested by [10] was used in the numerical simulation to model chemistry. A 0.5 degree sectored mesh with bowl geometry and crevice volume is prepared and used in the numerical simulation, which is shown in Figure 6.…”

Section: Figure 5 Engine Schematic Diagram Used In Experimentsmentioning

confidence: 99%

“…The MPRR is most widely used because it is simple and easily obtainable from engine data. The criterion for onset of pressure oscillation [8] is deemed not appropriate for HCCI combustion in which pressure oscillations have often been observed without significant audible knock [10]. The ringing index (RI) is based on the acoustic energy flux produced by the oscillating charge pressure [9] 1 , and is increasingly being used in the literature.…”

Section: Nvh Metricmentioning

confidence: 99%

A University Consortium on Low Temperature Combustion for High Efficiency, Ultra-Low Emission Engines

Assanis¹,

Chen²,

Cheng³

et al. 2009

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“…(See definitions/ abbreviations section at the end of the paper for explanation of the symbols.) Thus local pressure will build up if the heat release term is large compare to the volumetric expansion term [14,15]:…”

Section: Modes Of Knock Combustionmentioning

confidence: 99%

The Anatomy of Knock

McKenzie¹,

Cheng²

2016

SAE Technical Paper Series

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The combustion process after auto-ignition is investigated. Depending on the non-uniformity of the end gas, auto-ignition could initiate a flame, produce pressure waves that excite the engine structure (acoustic knock), or result in detonation (normal or developing). For the "acoustic knock" mode, a knock intensity (KI) is defined as the pressure oscillation amplitude. The KI values over different cycles under a fixed operating condition are observed to have a log-normal distribution. When the operating condition is changed (over different values of , EGR, and spark timing), the mean () of log (KI/GIMEP) decreases linearly with the correlationbased ignition delay calculated using the knock-point end gas condition of the mean cycle. The standard deviation  of log(KI/GIMEP) is approximately a constant, at 0.63. The values of  and  thus allow a statistical description of knock from the deterministic calculation of the ignition delay using the mean cycle properties

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On HCCI Engine Knock

Cited by 78 publications

References 10 publications

The Effect of Intake Temperature in a Turbocharged Multi Cylinder Engine operating in HCCI mode

The Effect of Intake Temperature in a Turbocharged Multi Cylinder Engine operating in HCCI mode

A University Consortium on Low Temperature Combustion for High Efficiency, Ultra-Low Emission Engines

The Anatomy of Knock

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