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The dual-fuel engine represents in principle a simple flexible approach to employing gaseous fuels in conventional diesel engines. Compared to the use of hydrogen in spark ignition engines, there is relatively limited information about its effect when present as a supplementary fuel in suitably modified conventional compression ignition engines. This is especially for engines of the IDI type and when employing only low concentrations of hydrogen in the intake air while retaining the injection of large diesel fuel quantities. In the present contribution, a 3D-CFD model based on KIVA 3, developed with a “reduced” detailed chemical kinetics of 294 elementary reaction steps with 79 chemical species for diesel fuel combustion which includes 20 steps for the oxidation of hydrogen, is outlined.

In order to pursue further improvements to the performance and emissions of small size dual fuel engines with a swirl chamber, a 3KC1 ISUZU engine setup was rebuilt, and a 3D-CFD model based on KIVA was developed. The simulation incorporates a reduced detailed chemical kinetics for the diesel fuel but with detailed chemical kinetics for the gaseous fuel component, mainly methane while considering the turbulence function to simulate the combustion processes and associated performance of a dual fuel engine with a swirl chamber. The effects of changes in the quantities of the liquid fuel pilot and gaseous fuels on the combustion processes, engine performance, cyclic variations, and emissions were investigated both experimentally and numerically.

In this paper, a diesel particulate filter system which uses needle felt as filtering medium to collect diesel particulates has been developed and tested in practical operation of the urban bus. The system includes a bag filter, an exhaust cooler, and a control unit. It was installed under the chassis of a YZL 6730C diesel bus, which operates in a loop route mostly with heavy load. The bus has covered more than 5,000km, during which there was no failure of the filter system to cause bus abnormal operation. It needs to be cleaned for about 50km, and the collected particulate matter has to be discharged for every 1200km. It can operate reliably and easily with very high collection efficiency. The collected particulate matter is analyzed by GC (Gas Chromatography)/MS (Mass Spectrometer), it is found that the collected particulate matter contains many poisonous and carcinogen substances and the filter is also effective to collect some of the SOF.

In this paper, plasma technology is used for diesel particulate treatment for a minibus manufactured by Hyundai Company. A Corona Discharged Particulate Plasma Collector (CDPPC) is developed and tested for removal of the diesel particulates. Firstly, experimental research of two CDPPCs are made on an engine dynamometer test bed. Performances of the CDPPCs are investigated including particulate reduction efficiency, pressure drop, and the influential factors are also checked. The tested engine is a D4BX Diesel engine equipped with the minibus. Secondly, the CDPPCs are tested with the minibus on a chassis dynamometer based on FTP 75 Driving Cycle. The results showed that the CDPPC could reduce the engine exhaust smoke to almost zero at low engine speed and the pressure drop of the CDPPC is comparative to the muffler. The most influential factors are the HVSS (High Voltage Supply System) Voltage and the engine speed.

The velocity and turbulence intensity profiles at exit of intake valve from typical SI engine intake ports (horizontal and sloping directed ports) were measured by hot wire anemometry (HWA) in a steady flow rig. The characteristics of velocity and turbulence intensity distribution under different valve lifts and at distances along valve axis were analysed and compared between above two intake ports. Results showed that velocity and turbulence intensity profiles are strongly dependent on intake port form,valve lift and surrounding geometry,they vary not only around valve head periphery but also along valve axis.

Based on 3- dimensional velocity data at intake valve exit area of typical SI engine intake ports (horizontal and sloping directed ports) measured by hot wire anemometry in a steady flow rig, the magnitudes and compositions of inflow angular momentum flux and swirl ratios at the end of induction process generated by each velocity component were computed at different intake valve lifts and distances along valve axis. A microscopic evaluation method was provided for evaluating intake port characteristics according to intake valve exit flow field.

In order to improve the compactness and simplify the structure of diesel particulate bag filter, a preliminary design and test of an envelope bag filter were carried out, and the results confirmed that it is unpractical to adopt envelope bag in diesel particulate bag filter design. Therefore, another double-layer tube bag filter was developed which has a compact and simple structure. The filter was tested on a 485Q diesel engine dynamometer bench, and the results showed that it worked reliably with particulate collection efficiency more than 90% and its effect on diesel economy no more than 1%.