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Experimental Investigation on the Effect of Equivalent Ratio and Engine Speed on Cyclic Variation of DME HCCI Combustion and Performance Parameters |
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| รหัสดีโอไอ | |
| Title | Experimental Investigation on the Effect of Equivalent Ratio and Engine Speed on Cyclic Variation of DME HCCI Combustion and Performance Parameters |
| Creator | Kanit Wattanavichien |
| Contributor | Teerawut Rakyhao |
| Publisher | Thai Society of Mechanical Engineers |
| Publication Year | 2557 |
| Keyword | HCCI, DME, low temperature reaction, high temperature reaction, cyclic variation. |
| Abstract | Combustion in HCCI engines is a controlled autoignition of pre-mixed fuel, air and residual gas. Since there is no direct control on the start of combustion process, the onset of HCCI combustion depends on the auto ignition of fuel/air mixture. This experimental work is conducted to provide insight into HCCI combustion phasing for DME fuel using statistical techniques. In this study, combustion and performance parameters of HCCI engine fueled with DME were investigated using a modified single cylinder, four-stroke engine. Port fumigation mixer is used for preparing homogeneous charge for HCCI engine. The experiments were conducted with ambient intake air temperature and different airfuel ratios at constant engine speed (1200, 1300 and 1400 rpm). For each test condition, P-? diagram of 120 consecutive combustion cycles at steady state operation were recorded. Consequently, cycle-to-cycle variations of the main combustion parameters and performance parameters were analyzed. To evaluate the cyclic variations of DME HCCI combustion parameters, coefficient of variation (COV) and standard deviation of parameters were calculated for every engine operating condition. The experimental results show that the duration of low temperature reaction plays an important role on HCCI combustion, particularly at higher engine speeds. The low temperature reaction appearance, ?LTR, and high temperature reaction appearance, ?HTR, as function of the equivalence ratio for different engine speeds versus the crank-angle does not show high sensitivity to the equivalence ratio and to the engine speed. The knowledge of the duration of the different phases of combustion, as well as cycle-to-cycle variations phenomena of the main combustion and performance parameters, is useful for the definition of regulation strategies. |
