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Optimization of a Spark Ignition Engine Knock and Performance Using the Epsilon-Constrained Differential Evolution
Yalin Kou1,2, Ying Gao1,2, Yuelin You1,2
1State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130025, China.
ACS Omega
|September 19, 2022
Summary
Optimizing spark ignition engine parameters like exhaust gas recirculation and valve timing significantly reduces engine knock. This research enhances thermal efficiency and power output while minimizing fuel consumption under heavy load conditions.
Area of Science:
- Combustion Engine Optimization
- Internal Combustion Engines
- Thermodynamics and Efficiency
Background:
- Engine knock limits thermal efficiency in spark ignition engines, especially under heavy loads.
- Knock occurrence is influenced by multiple simultaneous operating parameters.
- Optimizing engine parameters is crucial for improving economic and power performance under knock conditions.
Purpose of the Study:
- To investigate the effects of multiple variables on engine performance under knock limits.
- To optimize engine operating parameters for maximum volumetric efficiency, brake mean effective pressure, and minimum brake specific fuel consumption.
- To minimize knock index and engine performance damage caused by knock suppression.
Main Methods:
- A one-dimensional simulation engine model was established and verified using bench test data (2800 rpm, 11.42 bar).
- Four engine operating parameters (exhaust gas recirculation rate, exhaust valve timing, spark timing, intake valve timing) were optimized.
- Epsilon-constrained differential evolution and multi-objective differential evolution algorithms were employed for optimization.
Main Results:
- The epsilon-constrained differential evolution algorithm reduced the knock index by 73.3%, with a 10.2% decrease in brake mean effective pressure and a 0.07% increase in brake specific fuel consumption.
- The multi-objective differential evolution algorithm yielded a Pareto optimal solution set, achieving a 64.4% knock index decrease, 5.78% brake mean effective pressure decrease, and 1.45% brake specific fuel consumption decrease.
Conclusions:
- Both optimization algorithms successfully adjusted engine operating parameters to mitigate knock.
- The epsilon-constrained method prioritized knock reduction, while the multi-objective approach offered a balance between knock reduction and performance metrics.
- Optimized parameters can significantly improve engine efficiency and power output while managing knock in spark ignition engines.
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