| According to the low inlet pressure, decreased filling coefficient and diesel engine powerof the original rural machinery result from high altitude and thin air in plateau area, and theissue about severe shortage of biogas in winter and rest in summer result from popularize andconstruction of rural small and medium-sized methane project, it developing a compressionignition gas/diesel dual fuel engine on the basis of small ZS1115single cylinder diesel engine,the regional purified biogas and a small amount of diesel base on purification, storage andprocessing of the regional biogas, this paper has carried on the thorough research on severalaspects as follows:（1）It obtained the best compression ratio（18.5:1）of ZS1115single cylinder smalldiesel engine in plateau area through theoretical calculation taking the regional environmentof plateau area as the research object; carried out an power recovery experiment in the regioncompared to the original diesel engine power trend under the standard conditions, and plot therelational graph of compression ratio and power to verify the minimum loss of power whencompression ratio was （19:1）in plateau area versus ZS1115, so it determine the bestcompression ratio （19:1）to maintain the original diesel engine power after test analysis; Byensuring the changeless stress at the end of the compression, the engine combustion chambervolume was to be modified, which made the modified engine fulfill the requirements of theoriginal machine mechanical strength.（2）Based on the new biogas industry in plateau area, it applied the area gas toagricultural machinery, in this paper the biogas was purified through the dust collector, CO2purification, desulfurization tower and drying oven, after getting rid of impurity compositionof biogas, promoting biogas methane content to more than90%, it raising the combustibleingredients, result in high burning calorific value, at the same time, it reduce influence of theother impurities composition on engine performance, moreover, the composition of purifiedbiogas was close to the natural gas, which enlarged the engine fuel using range and themachine market.（3）It had a study on air intake system, fuel supply system and speed control system forgas/diesel dual fuel engine, based on the theoretical analysis of the mixer features, there designed a venturi mixer and got optimization of the structural parameters and2d figure ofmixer with the help of the first generation of prototype test analysis; then designed the theorymodel of oil/gas corrector, fuel quantity control device and a gas throttle linkage device withgovernor system, in the end, it completed the first generation of prototype, with which hascarried on the preliminary test to some critical components, and meet the requirements of thefunction of the dual fuel engine.（4）There had been a comparison test between the original machine and the firstgeneration of prototype on the basis of20%fuel quantity, it analyzed the influence of fueldelivery advance angle and compression ratio on the power performance and fuel economy oftwo types engine and adjusted the parameters, the results showed that not only improved thedual fuel engine fuel economy, but also meet engine performance level for the optimum fuelconsumption in the engine maximum torque speed position after fuel delivery advance angleahead; it verified the best compression ratio of dual fuel engine （19:1） and the best fueldelivery advance angle （24°）.After the test of the first generation prototype, the modified scheme is feasible, it can notreduce the dynamic performance of original diesel engine in plateau region, improve fueleconomy, and reduce emissions of pollutants; not only saved energy, but also improved thebiogas utilization and reduce pollution, in a word, the success of dual fuel engine in plateauarea provided certain guiding and promoting role on research and application in agriculturalpower. |
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