S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Mechanical Aerospace Engineering (기계항공공학부) Theses (Master's Degree_기계항공공학부)
A Study on the Transient Performance of a Diesel Engine Using a High-Frequency Engine Model and a Thermal Management Model
- 공과대학 기계항공공학부
- Issue Date
- 서울대학교 대학원
- High Frequency Engine Model ; Thermal Management Model ; Semi-iterative Simulation ; Cold-start Condition ; Thermal mass model ; Friction model ; Heat Transfer model ; Coolant model ; Lubricant model
- 학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2013. 8. 민경덕.
- According the continuously tightening restrictions on emissions of internal combustion engines and fuel economy, numerous researches on combustion, driving strategies and the improvement of thermal efficiency have proceeded worldwide. The engine thermal management system (ETM), recognized as a measure for the enlargement of the engine efficiency, is the field which concerns the investigation of the heat transfers between engine and powertrain parts, and the improvement of fuel economy by controlling and reuse of the thermal energy. Recent researches, as parts of the Smart Cooling field, concern the technologies which improve the thermal efficiency of internal combustion engines by controlling the coolant and lubricant flows at transient operating conditions, and development of a new cooling model.
The transient conditions stand for the change between engine operating conditions and the period in which engine is adequately warmed up. Particularly at the cold atmospheric condition, the engine thermal efficiency is seriously decreased due to the excessive heat losses since the coolant and lubricant are not sufficiently warmed.
Even though there are numerous researches on the cold-start and transient operating conditions, there also needs a precise simulation model to describe above transient conditions.
In this study, a simulation model was developed to observe the total heat losses and the temperature changes at the transient operating conditions by considering both the 1-d engine model and the engine thermal management model. The model considers the combustion heat loss, the friction heat loss and the exhaust heat loss altogether. The combustion heat loss is calculated at the 1-D engine model at each time step. The performance of the target diesel engine at the transient operating condition was measured based on the simulation model.