Research On The Combustion Characteristics Of Q-HCⅡ With Gasoline/Diesel Dual Fuel

To solve the problem of petroleum resource shortage, many countries devote in the research of new engine combustion mode to decrease fuel consumption. Quasi-Homogeneous Charge Induced Ignition(Q-HCⅡ) is one of the advanced combustion mode. It injects gasoline into intake port and is induced by micro diesel in cylinder. Lots of experiments done by scholars home and abroad, prove its feasibility. However, all of the experiments are conducted on the engine only with one cylinder adapted. Also, the coupling relationship between EGR and boosting pressure is neglected at the same time. So, the experimental results are different with real performance of Q-HCII to some extent.In this paper, a simulation using AVL BOOST software is conducted firstly. The main object of it is to research the influence of gasoline/diesel ratio on the combustion characteristics of Q-HCII and provide guidance to the experiments follow-up. Then, build the original engine test bench and carry out the calibration experiment to provide comparison data for dual fuel engine. The calibration experiment mainly includes external characteristic, load characteristic, universal characteristic and ESC tests. Finally, adapt the original engine and test bench to meet the requirement of Q-HCII experiment. All six cylinders of original engine need to be adapted, the intake and exhaust systems don’t change with their original form, gasoline injecting system and open controlling system are added meanwhile. Besides, the intake boosting of adapted engine is provided with VNT turbocharger, not air compressor, this can reflect the effects caused by the coupling relationship between EGR and boosting pressure accurately, so the performance of Q-HCII can be showed sufficiently. In the case of adding DOC after-treatment device only, the ESC tests of adapted engine in Q-HCII mode could meet Euro-V emission standards, with proper gasoline/diesel ratio, optimized injection strategy, intake boosting, EGR inter-cooling, etc. On that basis, the performance and fuel consumption, etc. should be tested to study the combustion characteristics and fuel economy of Q-HCII. At the same time, compare the experimental results with BOOST simulation results and provide reference to the application of Q-HCII.