This study investigates experimentally Air-fuel ratio feedback control with a fuel valve in a LPG engine. The fueling valve is controlled by electronic control unit which is made with micro computer. Various control logics are employed and then PID control is adopter as a proper logic for own system and Air-fuel ratio feedback control by PID control was experimentally of various operation area with the stable control algorithm of PID control that was earned from the former experiment. On the process the experiment, determination experiment of each control part coefficient was the biggest variable among the whole result of experiment. We could know as a result of experiment that the lange of overshoot is bigger as the proportional control part os bigger integral control part is related with the delay time and coefficient of differential control part is related with the decrease of overshoot range from the experiment of various operation area we could also analyse consequently that direct fuel control in the fuel value makes more stable control status in rare operation and low load area.

Abstract
 1. 서론
 2. 배기가스 저감 장치
  2.1 삼원촉매변환기 정화효율
  2.2 LPG 엔진 공연비
  2.3 LPG엔진 공연비 제어
 3. 실험장치 및 방법
  3.1 실험장치
  3.2 실험방법
 4. 실험결과 및 고찰
  4-1. PID 제어 계수결정
  4-2. 제어기법 비교 실험 결과
  4-3. 여러 운전영역에서의 PID제어 결과
 5. 결론
 참고문헌

• 박성천(서울산업대학교 자동차공학과) | S. C. PARK