Yuzo Kadomukai

Abnormal combustion detection and vibration reduction system

An apparatus and a method for detecting abnormal combustion in an internal combustion engine and an apparatus and a method for controlling vibration caused by abnormal combustion. The apparatus for detecting abnormal combustion includes a unit for detecting the rotation of an internal combustion engine, a unit for calculating rotation angular acceleration on the basis of the detected rotation, a unit for comparing the rotation angular acceleration at the position of a predetermined crank angle in one cycle of the operation of the internal combustion engine with a predetermined reference value, and a unit for judging from the comparison result whether abnormal combustion occurs in the internal combustion engine. The apparatus for reducing vibration caused by abnormal combustion offsets vibration caused by abnormal combustion and vibration of an electric generator to each other by passing a pulse-like field current in the electric generator in response to detection of abnormal combustion to generate vibration torque in the electric generator.

Fuel Spray Pattern Control Using L-Step Nozzle for Swirl-Type Injector

We propose a spray pattern control method for swirl-type injectors in direct injection (Dl) gasoline engines. An L-cut orifice nozzle (L-Step nozzle) that produces a horseshoe spray pattern is used to create a rich and lean concentration region. To further control the distribution of fuel, the relationship between the nozzle geometry and the spray pattern is investigated. The mechanism for a horseshoe spray formation is hypothesized and verified through experiment. The spray shape and fuel distribution is found to be controllable by configuring the L-cut step-walls. Furthermore, it is discovered that independent control of rich and lean region distribution is possible by arranging the step-wall position and height.

Experimental Characterization of Flat-Spray Injector in Gasoline Direct Injection Engines

A flat spray pattern was proposed in order to improve conventional stratified-charge combustion systems in a direct-injection (DI) gasoline engine. Swirl injectors with a V-groove nozzle and a rectangular-groove nozzle were newly designed. The characteristics of newly designed injector nozzles were examined experimentally under various ambient pressure and fuel pressure conditions. The fuel spray characteristics were tested in a pressure chamber. The injected fuel-spray was illuminated by a YAG-laser sheet and their images were captured by CCD cameras. The atomization of fuel spray in the V-groove and U-groove nozzle was also investigated experimentally. It was shown that the V-groove and the U-groove nozzles generate a well-atomized flat fuel-spray pattern that can be controlled by adjusting the groove-depth. It was also shown that the flat fuel-spray pattern was not susceptible to ambient pressure variations.