Research On Performance Optimization Of CNG Motorcycle Engine Based On GT-Power

With the rapid development of world economy, The amount of motor vehicle, increasing year by year, the resulting shortage of global oil resources and worsening environmental pollution, in order to fully implement the energy saving and environmental protection, China has been incorporate motor vehicle energy saving and emission into the basic national policy, and to develop the corresponding long-term planning framework.China is a big country motorcycle production and sales of its holdings increased year by year, by the end of June 2009, the National Motorcycle retain reached 91 226 621 units, accounting for 51.67% of total motor vehicle, motorcycle industry in China started late, technological backwardness, higher energy consumption and emissions, combined with the success of energy saving automotive industry experience, search for alternative fuels is the key to improve motorcycle high energy consumption and high emissions. natural gas, liquefied petroleum gas is the preferred alternative fuel, because of technical maturity, low pollution emissions, cheap, abundant resources and so on, in the automotive industry natural gas has been recognized by the people. Currently, the research on the single fuel LPG and dual fuel motorcycle petrol-compressed natural gas (CNG), gas-LPG motorcycle were more, the single-fuel CNG motorcycle were rare.According to the business of providing motorcycle gasoline engine structural parameters, valve lifting curves, flow coefficient, external characteristic power and torque data, use of the engine performance simulation software GT-Power to establish a more precise petrol engine simulation model; establishment the ethane, butane fuel depot, and to use validated gasoline engine model of natural gas engine performance simulation; aimed at CNG engine dynamic performance deficiencies, This paper analyzes the compression ratio, intake and exhaust systems, valve timing on the engine dynamic performance, and put forward the corresponding improvement program.As the gas composition difference, fuel density, stoichiometric, low calorific value and combustion potential are changed, the results show that the engine cylinder maximum combustion pressure, maximum combustion temperature, volumetric efficiency, power, torque increase with the decrease of methane content in natural gas, ethane, propane, butane content increases, the establishment of fuel depots in this paper's make the computational accuracy is improved. On the engine compression ratio and other parameters of the optimization, So that the dynamic performance of the CNG engine in most of the speed range have been improved in varying degrees, of which the maximum power increased from 6.42 kW to upgrade to 6.64 kW, improved 3.30%, maximum torque from the original 8.87 N?m upgraded to 9.47 N?m, improved 6.85%. Meanwhile, the engine's fuel economy also improved, the biggest drop has reached 3.62%. This study results can be part of the new models of development to provide certain information, has some practical value.