A Study on a mechanical continuously variable injection timing system for improvement of agricultural small diesel DI engine

Abstract

This paper presents the development of a MCVIT (mechanical continuous variable injection timing) system for evaluating effects of injection timing – one of the efficiently experimental methods for improving diesel engine performance and emission characteristics to match modern emission regulations and bio-fuels. A MCVIT system has been designed and built with the ability to adjust freely and directly the injection timing for a wide range from 0 to 40°CA BTDC (before top dead center) while keeping the same injection pressure rate. Some experiments have been done to verify its significant specifications such as friction torque – speed curve, accuracy and stability. The results show that the maximum friction torque of this system is around 2.6N.m over range of engine speed and its maximum deviation is ±1.0°CA over a large range of testing injection timing. Preliminary study on VIKYNO RV215-2 agricultural small diesel DI engine has also proved that the engine performance and emission characteristics are directly influenced by injection timing. Thus the developed MCVIT system is an efficient and low cost tool for R&D activities in small diesel engines.