Fig. 1 Engine total electronic control system
In particular, the fuel injection timing is controlled to the optimum based on the performance estimation calculation or the performance confirmation test done in advance. So, fine adjustment can be added at each running point.
Fig. 3 shows the comparison of the in-cylinder cycle to be realized between by the total electronic control system and by the conventional cam-type system. In the electronically controlled fuel injection system, the combustion duration can be shortened by shortening the injection duration. So, at the rated condition (a), the fuel injection timing can be set to be later than that of the conventional cam-type system, aiming at the low-NOx cycle without making the fuel consumption worse. On the other hand in a case of the lower load (b), the real compression ratio can be increased by advancing the exhaust valve closing timing (EVC), which leads to the better combustion and the lower fuel consumption.
Based on the above-described results of examination, the total electronic control system is constructed, in which each control system is efficiently and surely operated. The control processes include the two categories, one with the short time constant for such as the fuel injection system, the exhaust valve system, the starting system and the governor, and another with the long time constant for such as the VG turbocharger, the scavenging air swirl control, the cylinder lubrication system and the cooling system.
The controller reads and judges the command from the bridge as indicated in Table 2, and determines the opening/closing timing of the fuel injection, the exhaust valve, the nozzle angle of the VG turbocharger, the scavenging air swirl guide blade angle, the feed rate of lubrication oil and the quantity of cooling water.
