Thermodynamic Study Of A Wobble-plate Diesel Engine With Over-expand Miller Cycle

Power density is a parameter to indicate comprehensive performance of engine. Highpower density is a technical trend for future engine, which means good economy, high poweroutput, small package size and light weight, and it must be easy, safe and reliable forcustomer. Wobble-plate diesel engine is a new type of engine with high power and volumecharacteristics. The engine thermodynamic process analysis directly affect the engineperformance. This paper conducted a comprehensive study for a variety of engine cycle. Canprovide the basis of the thermodynamic theory for development of wobble-plate enginebased on the miller cycle.1）Based on law of thermodynamics, Establish three kinds of ideal cycle enginethermodynamic model, namely equal volumetric heating, Isobaric heating, mixing heatingmodel. Then calculate maximum cycle power and thermal efficiency of the ideal engine cycle.Finally by comparing the three kinds of ideal cycle, get the engine thermal efficiency andpower variation trends with the compression ratio, the maximum temperature, the maximumexplosion pressure. The results indicate that the compression ratio is an important parameterin the thermodynamic cycle.2）By the calculation method of certain program, firstly build a ultra-expansion heatcycle model in accordance with the laws of thermodynamics. Then use MATALABprogramming software to calculate the power and thermal efficiency as the four given options.Finally, draw the conclusions that the miller cycle ultra-expansion has a higher thermalefficiency than the other cycles. It provides a theoretical support for thermodynamic cycle ofthe wobble-plate-type diesel engine.3）By contrasting working principle of wobble plate type diesel engines and dieselengine, draw the similarity conclusion between them. Then apply the miller cycle to thewobble-plate-type diesel engine. Establish thermodynamic model, set the relevant data,change the parameters of compression ratio and maximum burst pressure, using MATALAB programming software compute power and thermal efficiency, make analysis of compressionratio, maximum burst pressure, expansion ratio, the maximum temperature to found powerand of thermal efficiency influence factor to the miller cycle wobble diesel engine. Andcompare them to draw conclusions that the miller cycler thermal efficiency of the dieselengine is2%higher than double combustion cycle diesel, power of miller cycle wobble dieselengine is10%higher than dual combustion cycle diesel engine.This paper verified miller cycle is able to achieve ultra-expansion cycle by contrastingand analyzing the established thermodynamic model. For a wobble plate type diesel engine,one wobble plate performs intake compression, another performs the expansion exhaustfunction. The expansion plate diameter can be designed larger than the compression plane. asresult, achieve a ultra-expansion of the miller cycle. Such a miller cycle high efficiencyachieved in wobble-plane-type diesel engine can prove that the new type of a wobble platetype diesel engine has study value and significance.