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A high-performance road profile measuring system has developed. The measuring system consists of four laser displacement sensors and an optical speed sensor. It has the advantage of making high-accuracy measurements during a regular run, on a public road, and without any traffic restriction. The measurement is hardly affected by bouncing and pitching motions of the vehicle. The four displacement sensors are arranged at unequal intervals in the direction of vehicle. A road profile is calculated from sensor outputs. This paper describes not only the development of this unique measuring system but also its application to a vehicle behavior. Significant measurements of typical and peculiar public roads in Japan and Northern Europe by the measuring vehicle have been performed for the last few years. The features of these roads are described by the power spectrum densities and the profiles.

We propose a flat spray pattern to improve conventional stratified-charge combustion systems in a direct-injection (DI) gasoline engine. Swirl-type DI fuel injectors with a V-groove cut orifice nozzle (V-groove nozzle) and a rectangular-groove cut orifice nozzle (U-groove nozzle) are newly designed. We examine experimentally the characteristics of newly designed injector nozzles under various ambient pressure and fuel pressure conditions. The fuel spray characteristics were tested inside an experimental pressure chamber. The resulting spray patterns were illuminated by YAG-laser sheet and recorded by CCD cameras. The atomization of fuel-spray in the V-groove and U-groove nozzle was also investigated. These experiments showed that the V-groove and the U-groove nozzles generate a well-atomized flat fuel-spray pattern that can be controlled by the orifice-depth and it is robust under ambient pressure variations.