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Investigation on Emission Characteristics of Direct Injection Spark-Ignition Methanol Engine

Author: CuiFengYun
Tutor: YuXiuMin
School: Jilin University
Course: Power Machinery and Engineering
Keywords: Engine Direct injection Ignition Methanol Emission characteristics
CLC: TK464
Type: Master's thesis
Year: 2011
Downloads: 111
Quote: 0
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Abstract

Methanol (CH ₃ OH) is considered to be one of the most promising alternative fuels for an internal combustion engine, this is mainly because methanol with gasoline, diesel same applicable, easy to store and transport characteristics, and the source very rich, can be extracted from coal, natural gas, as well as a variety of renewable resources. The world's proven reserves, accounting for 15% of China's coal, oil accounted for 2.7%, natural gas accounted for 0.9%. Coal preparation of methanol, and is conducive to the development and use of China's abundant coal resources. Although methanol is a good alternative fuels, but the methanol combustion in addition to a conventional HC, CO, and NOX emissions of formaldehyde and unburned methanol. The emissions of formaldehyde (HCHO) in methanol engine exhaust and unburned methanol (CH ₃ OH) is much higher than the gasoline engine. Formaldehyde can irritate the eye mucous membranes, throat and bronchial, blood poisoning, there is genotoxic and carcinogenic activity, its photochemical effect and the destruction of the ozone layer is also very strong, so the concentration of formaldehyde in the work environment should be less than 0.5ppm. Pure methanol, a direct injection spark ignition engine combustion and ignition advance angle through self-developed engine control system, fuel injection advance angle, the excess air ratio and intake air temperature of the power of the engine as well as conventional emissions impact emissions and unconventional. Meanwhile, unconventional emissions of formaldehyde, and the acquisition method of the unburned methanol and detected using the method of gas chromatography and high performance liquid chromatography combined measurement of formaldehyde in the exhaust gas as well as emissions of unburned methanol. The conclusions are as follows: 1. Ignition advance angle power performance and emission engine torque with the ignition advance angle postpone the first rise in ignition advance angle is BTDC 15 ° CA when the highest value, and then with the ignition advance angle postponement of gradual decline. NOx emissions decreased With delayed ignition advance angle. From the ignition advance angle on the ending point of 25 ° CA before 1500-2400ppm quickly dropped to the ignition advance angle of 5 ° CA BTDC dozens ppm. HC emissions defer declined with the ignition advance angle, but the downward trend is not obvious, and at low speeds and fuel injection advance angle postponed emissions. CO emissions by the ignition advance angle change, high speed and injection advance angle of advance, with the ignition advance angle postponed downward trend in other cases with delayed ignition advance angle CO emissions basic changed. Unburned methanol emissions with the ignition advance angle postpone the downward trend ignition advance angle more postponed downward trend is more obvious, and formaldehyde emissions with the ignition advance angle to postpone the rise. Injection advance angle on the power performance and emission as the injection advance angle postpone engine torque decreases and the torque at low speed is higher. NOx emissions with the delayed injection advance angle downward trend, and the downward trend is more obvious. Overall emissions than 2200/min and 2800/min speed 2500r/min. HC emissions gradually increased with the injection advance angle delayed, in 325 ° CA BTDC, HC emissions highest, followed by decreased with the injection advance angle postponed, but the change is very small. 2200r/min speed under the overall emissions, HC emissions only from the fuel injection advance angle is the only point 354 ° CA before 265ppm, to rise to the top dead point 325 ° CA before 282 ppm. That injection advance angle HC emissions impact is not great. CO emissions with the delayed injection advance angle is gradually increased, but the change is not great. 2800r/min speed under high CO emissions, CO emissions from the fuel injection advance angle is the only point 354 ° CA before rose to 2.50% on the ending point of 310 ° CA 2.86%, increased by only 0.36%. Therefore, that injection advance angle on CO emissions is not great. Emissions of unburned methanol as the injection advance angle postpone the rise, and the upward trend is more obvious, and formaldehyde emissions are slightly higher with the injection advance angle postponed first, then with the injection advance angle postponed sharply decline. Excess air coefficient of dynamic and emissions. With the increase in excess air ratio (the injection pulse width is reduced in the case of throttle opening degree unchanged), the mixture thinning, torque down. With the increase in NOx emissions in excess air coefficient in the range of test conditions significantly decreased, and in a time of low speed high overall emissions. In 2200r/min, NOx emissions decreased from λ = 0.9 hours, more than 2000 ppm, to λ = 1.2 when dozens of ppm. The first reduce HC emissions with increasing excess air ratio, minimum λ = 1.0, and then with increasing excess air ratio increased, but the change is not obvious. CO emissions decreased with increasing excess air ratio is very obvious, rotational speed n = 2200r/min and 2500r/min and 2800r/min CO emissions, respectively, from λ = 0.9 when 1.6%, 2.1% and 2.5%, sharply down to λ = 1.3 to 0.1-0.2%. Unburned methanol emissions increases with increasing excess air coefficient, and the rising trend is more obvious, and formaldehyde emissions decrease with increasing excess air coefficient. Intake air temperature of the power performance and emission intake air temperature less torque, but the influence of conventional emissions. With the intake air temperature rises, NOx, HC and CO emissions have increased significantly. The emissions of unburned methanol is reduced as the intake air temperature rises, while the emissions of formaldehyde increases with the intake air temperature rises.

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CLC: > Industrial Technology > Energy and Power Engineering > Internal combustion engine > Alternative fuel internal combustion engine > Alternative fuel internal combustion engine
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