Search Results

The Variable Orifice Nozzle (VON), has been developed to improve diesel combustion by changing the cross-sectional area of the injection hole. The area of the nozzle orifice is continuously controlled by the rotary valve, one component of the VON. The discharge coefficient of the VON was increased by simulating an internal flow in the nozzle tip. The VON performances were evaluated by its rate of injection, injection pressure, spray droplet diameter and instantaneous photographs taken by a high speed camera. These results show that, injection characteristics and spray patterns respond to the nozzle orifice area which is changed by the rotary valve from larger to smaller. The orifice area controlled nozzle provides higher maximum pressure and a longer injection duration than the conventional hole nozzle without full-load point of the injection pump. A smaller nozzle orifice has a wider spray angle compared with larger nozzle orifice.

One of countermeasures for exhaust emissions from a diesel engine, especially, DI diesel engine, is the use of a super high pressure injection system with a small hole diameter. However, the system needs greater driving force than that with normal injection pressure, and its demerit is increase in NOx, although soot is decreasing. Then, authors propose the new concept on the simultaneous reduction of NOx and soot. The concept is that the utilization of flash boiling phenomenon in a diesel engine. The phenomenon can be realized by use of the injection of fuel oil with CO2 gas dissolved. Flash boiling facilitates the distinguished atomization of fuel oil and CO2 gas contributes to realizes the internal EGR during combustion. Fundamental information on the characteristics of a flash boiling spray of n-tridecane with CO2 gas dissolved is described in this paper, as a first step.

This paper describes the characteristics and mechanism of crankshaft impact noise that radiates from the cylinder body at full load medium engine speeds, based on the mechanism for axial vibration of crankshaft coupled with torsional vibration of crankshaft.