Abstract
A high speed data acquisition system for multi-cylinder spark ignition engine was developed in order to measure the indicator diagrams of each cylinder simultaneously. The measurement system consist of computer,16-channel high speed data acquisition board, Kistler spark plug pressure sensor, crank angle signal generator, charge amplifier and oscillograph. The maximum sampling frequency of this system is 1MHz. The maximum input signals are 16 channels at the same time. The frequency of sampling, the numbers of signal and the sampling data quantity of the system can be controlled by the sampling program.
A carburetor S.I. engine that has been reconstructed into a dual-fuel engine was tested in this research. Firstly, this S.I. engine was motored by a 37KW electric engine and the engines revolution was change by a 4-position transmission. At lease 50 cycles pressure data of each cylinder were measured. The average value and the fluctuant coefficient of maximum pressure weren calculated. The comparison among different cylinders inlet air quantity was made using the maximum pressures average value. Then the combustion pressures of each cylinder were measured continuously and simultaneously on condition that burning gasoline and compressed natural gas (CNG). The comparisons of combustion and variation among each cylinder were made using the averaged value and the variation coefficient of the maximum combustion pressure.