Kazuo Iinuma

Thermodynamic and experimental determinations of knock intensity by using a spark-ignited rapid compression machine

Abstract By use of thermodynamic theory, the intensity of engine knock was calculated in tems of the energy of gas vibration which occurs when the end gas ignites spontaneously. In the theory, it is assumed that the gas vibration energy originates from the difference between displacement works of two types of burned gases which are produced by the flame propagation and the spontaneous ignition processes. Results of the theory were successfully verified by the experiment by using a spark-ignited rapid compression machine. In the experiment, the energy of gas vibration accompanied by knock was determined by application of the FFT method to the pressure record. The agreement between theoretical and experimental results suggests that in order to give a general validity to the knock intensity, it is reasonable to use the vibration energy as a quantitative measure.

The effect of dc to 10 MHz electric field on flame luminosity and carbon formation

The effect of electric fields, dc and ac at frequencies up to 10 MHz and the maximum strength of about 3 kV/cm, on the luminosity and soot emission of flames was investigated by using a counter-flow diffusion burner and a nozzle burner. The luminosity, with both diffusion and premixed flames of acetylene and air, was found to be a complicated function of the frequency, electric field strength and gas flow rate. Under certain conditions, the luminosity could be either increased or decreased by up to a factor of about two. There was no effect on the soot emission from the counter-flow diffusion flame at frequencies above 500 kHz. The observations can be successfully explained by adopting a simple model for the growth of carbon particles.

Spark Discharge Characteristics and Igniting Ability of Capacitor Discharge Ignition Systems

Abstract The spark discharge characteristics and the minimum ignition energy of capacitor discharge ignition (CDI) systems, were investigated using several types of ignition coils and primary capacitors. The mechanism of energy transfer from the primary capacitor to the spark is explained by a simple theory taking into account the spark voltage-current characteristics. The minimum ignition energy for propane-air mixtures is lowest for sparks of about 100 kHz frequency and 20-50 μsec duration. In order to evaluate the igniting ability of a total system, the minimum stored energy needed for ignition is employed. The lowest values of these two minimum energies can be obtained by ignition coils whose specifications are considerably different from those of currently used coils.

Power and energy measurements of transient electric discharge

A simple and inexpensive calculating device for electrical power and energy of transient electric discharges is described. The calculation is made by multiplication of the voltage and current of the discharge by use of wideband integrated circuits.