A Study on the Response Performances under Transient Operating Conditions in a Turlblocharged Diesel Engine

터보과급 디젤기관의 과도운전시 응답성능에 관한 연구

This study describes the response performances of actual engine speed, turbocharger speed, air mass flow rate through engine, boost pressure ratio, exhaust temperature and combustion efficiency for a six-cylinder four-stroke turbocharged diesel engine during the change in operating conditions by using the computer simulation with test bed. In order to obtain the transient conditions, a suddenly large load was applied to the simulation engine with the several kinds of inertia moment in turbocharger and engine, and engine set speed. From the results of this study, the following conclusions were summarized The inferior response performances was mainly caused by turbocharger lag, and air mass flow rate and boost pressure ratio were closely related to the turbocharger speed. A reduced moment of turbocharger inertia resulted in less transient speed drop and much faster recovery to the steady state of the engine. The increase of moment of engine inertia reduced cyclic variation of engine speed. When a large load was applied to the engine at high speed, the engine could be fastly recovered. However, when the same load was applied to the engine at low speed, the engine was stalled.

본 연구에서는 정상운전 중인 4사이클 6실린더 터보과급 디젤기관에 갑자기 큰 부하가 작용하였을 경우, 기관 및 과급기 관성 모멘트의 변화가 기관과 과급기의 실제 회전속도, 압축기 압력비, 실린더내 공기유량, 연소효율, 배기온도 등의 과도 응 답성능에 미치는 영향을 시뮬레이션해석과 실험을 통하여 규명하였다.