Abstract
The authors' group has been developed an LDA flow rate meter based on laser-Doppler anemometer (LDA) for an instantaneous fuel injection rate measurement. This flow rate meter that does not affect the downstream spray can realize the simultaneous measurements of the dynamic fuel injection rate and of the spray characteristics. The transient flow rate can be useful to understand the spray characteristics. The LDA flow rate meter only measures one point time-series velocity on the center of circular pipe. It provides instantaneous time-series flow rate and integral mass of the fuel flow. In this paper, the LDA flow rate meter measured the high pressure injection system for the direct-injection engine. The pipe diameter of the measuring section of the LDA flow meter is tested for improving the measurement accuracy of the high pressure fuel injection rate. In the measurement, the fuel pressure is changed from 5MPa to 20MPa and injection time is changed from 0.5ms to 5ms. The integral masses by the LDA flow meter are compared with the results by a mass balance.
