Design of LPG Injection Mechanism with PID Control for 1 kVA Generator Set

Abstract

Injection of LPG fuel in generator set engine using carburetor technology have not been controlled yet so that LPG fuel consumption become inefficient at dynamic condition such as variation of fuel quality and different load on the generator. The inefficient fuel combustion will produce the bad emissions of combustion waste. Thus, it needs to be controlled in order to reduce the emission on fuel control mechanisms. This research proposes a microcontroller based fuel control system using openloop and closed-loop control in the 1 kVA generator set. The open-loop control test is performed to obtain the characteristic of throttle angle and injection duration. After that, the result of open-loop control test is used as inputs for closed-loop control that use PI and PID control at different load scenarios. The system is tested in two scenarios, scenario 1 is the generator driving 335 Watt load and scenario 2 the generator is driving 555 Watt load. On the PI Control test with Kp at 4.14 and Ki at 1.67, the generator time response is 3.1 seconds at scenario 1 and 3.6 seconds at scenario 2. Then on the PID control test with Kp at 5.52, Ki at 1 and Kd at 0.25, time response at the generator is 2.6 seconds at scenario 1 and 2.7 seconds at scenario 2. The fuel pressure can be reduced to 2.45 psi at loading scenario 1 and reduced to 2.82 psi at loading scenario 2 compared when using a carburetor. That closed-loop control is applied to increase the efficiency of fuel consumption that is directly influenced the reducing of emission from combustion.