The Key Technologies Of The Two-cylinder Diesel Engine In Passenger Cars

The proposal of2-cylinder diesel engine as mini-bus's power was proposed after analyzing the worldwide development tendency of diesel engien for passenger car. Aim at the key technical difficult problem of2-cylinder for passenger car, noise, vibration, dynamic property, economy property and emission of exhaust of2-cylinder diesel engine was investigated:(1) Compared and investigated the balance characteristic and the impact on turbocharger for0—180°and0—360°crankshaft layout of2-cylinder diesel engine,0—360°rankshaft layout was proposed, the single balance shaft system was designed. The impact of the different crankshaft unbalance weight on main bearing load, axis load, the minimum oil film thickness and friction loss was investigated, according to this investigation, the balance system of2-sylinder diesel engine was defined. Analysed the Crankshaft torsional vibration characteristic, the torisional vibration damper was designed. Investiged the speed fluctuantion and torque fluctuantion characteristic of2-cylinder diesel engien, then the flywheel's inertia was defined.(2) The effect on the volumetric efficiency, brake specific fuel consumption, Pumping mean effective pressure and the engine's performance of diferent valve timing was presented by using of DOE and valve timing optimization softerware, considering the performance of diesel engien at low and high speed, the optimal valve timing was defined. Then calculated the dynamics characteristic such as contact stress, Hz-stress between cam and roller of rocker and valve seating velocity.(3) The gas-exchange characteristic and the difficult problem of turbocharger matching of2-cylinder diesel engien was investigated. The waste-gate turbocharger was used, by modified the size of turbo and compressor, and by modified the shap of compressor impeller to increase the turbocharger's efficiency; Investigated the effect on EGR distributing of different EGR pipe structure and different EGR intake pisition, then optimized the EGR pipe structure and EGR intake pisition to improve the of EGR distributing.(4) Investigated on layout, fuel system, cooling system and lubricating system was defined. Carried on the combustion development on the test bench, experimental research on pistion chamber, turbo-charger, nozzle parameter(spray angle,diameter of hole, number of hole, flow), NTP(Nozzle Tip Protrusion), the combustion system was defined, optimized the gear ration of vehicle, improved the vehicle peformance.A common rail,4valves per cylinder, turbocharged,2-cylinder diesel engien was developed, and was appledt to the vehicle, the result of development show:The performance of this2-cylinder diesel engien can meet the requirement of passenger car, and the emission of exhaust can meet the requirement of Euro Ⅳ. Power can reach to43kW per liter, and torque can reach to136N.m per liter.