Abstract

A possibility to control the auto-ignition timing and the heat release process was experimentally examined. Through a macroscopic analysis of the controlled auto-ignition (CAI), two physical parameters were introduced to explain the CAI condition. These are TAI, which is the in-cylinder gas temperature at the end of compression stroke, and DT, which indicates the heat capacity of the working gas. The experimental analysis revealed that TAI dominates the onset of auto-ignition and DT dominates its heat rising process. If these parameters were maintained in certain ranges, desirable CAI should be generated. The both parameters are thermo-dynamically calculated with the exhaust gas recirculation (EGR) ratio and the equivalence ratio only.In order to examine the gas exchange state that allows of the above-mentioned condition, a typical gas exchanging chart that represents all the possible gas-exchange states in a naturally aspirated four-stroke engine was introduced. On this map, the CAI area and the surroundings were carefully plotted. As the result, it was revealed that there was the approach to the CAI from the SI combustion with a sequence of low-temperature combustion due to the dilution on the map.The experimental results finally suggest that BSFC and BSNOx of a 1300 cm3 motorcycle could be decreased by 20% and 90% respectively in the LA-4 mode, by utilizing the sequence of the low-temperature combustion including the CAI.

References

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Author (organization or company)

• Hideaki MORIKAWA（Motorcycle R&D Center）

Publication Information

Article of Honda R&D Technical Review Vol.23 No.1 (73 - 79)

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