Experimental Consideration on Speed Control of Main Diesel Engine by DDC System

Abstract

This paper has two objects, one is to present a new computer control system for a digital control system (DDC) instead of a conventional governor for the main diesel engine and another is to discuss a control law based on the discrete type of the PID controller.
In general, in the case of operating the diesel engine, the governor is indespensable because of its unstable control characteristics, and has played very important roll so far. But, with year there have been a lot of requests to the engine governor, for example, how to overcome the propeller racing, how to decrease fuel oil consumption and so on. In particular, the propeller racing in the rough sea has been a very serious problem in the ocean going ship, because this phenomenon breaks down the propulsion system and then decrease its reliability. Consequently, for studying on such serious and difficult problems, we constructed a new DDC system for the marine systems at the same time when the training ship“SHIOJIMARU”was built up in 1988.
Next, we investigate the characteristics of on the discrete type of the PID theory from the viewpoint of practical techniques. More, we propose our new control method for the speed control of the diesel engine and then on the basis of our new method, we provide the outline of software used in our sea test.
Finally, the DDC based on the computer system is proved to be very useful system by illustrating our experimental results.