Search Results

During the development of dual intake port for a lean burn engine, the conventional method of port characterization, using flow coefficients, was found to be inadequate. A suitable strategy was devised which uses the results from steady state flow bench to compute the total flow through the port at an indicative engine speed and for a particular valve lift behavior. A proper basis for comparison of the baseline single intake port with the developed dual intake port was thus arrived at.

Engine maps consisting of three-dimensional contour plots of engine performance parameters such as bsfc in the engine speed - bmep plane give a large amount of information in a very concise manner. Such maps can be drawn for many more parameters of interest if a high speed data acquisition system, such as E-DACS (Engine Data Acquisition and Control System) which was developed in-house, is used to obtain the transient data of combustion chamber pressure. New maps of: pmax, (dp/dθ)max, etc. from the pressure-crank angle data; isfc, imep, pumping losses, etc. from the pressure-volume data; ignition delay, burn angle, maximum rate of burning, maximum burnt gas temperature, etc. after conducting heat release analysis using the pressure-crank angle data, can be generated. Such an enlarged view offered by these new sets of engine maps will definitely prove useful to engineers, giving them newer insights.

Heat release analysis brings out the various phenomena that cause the development of the combustion chamber pressure. A three-zone heat release model computes the rate of heat release and other properties of all the three zones (representing vaporized fuel, unburnt and burnt gas zones) from measured pressure-crank angle data obtained from an instrumented engine. It is a useful diagnostic tool giving a great deal of information about an existing engine. Heat release analyses for five different operating conditions have been conducted for a DI diesel engine. Also, ignition delay, wall heat losses and mass, volume and temperature in each of the three zones have been computed. It is found that the overall quality of the computed heat release rates are strongly dependent on the accuracy of the measured pressure data. The model can be integrated to a high speed data acquisition system for concurrent analysis of the heat release patterns.