Engine Simulations

The LIM Engine

LIM Technology, LLC currently has three running engine prototypes with LIM camless valves installed. The supercharged LIM 353 (i.e. – 3 cylinder, 53cuin/cyl) engine with mechanical fuel injection and 4-valve/cylinder sprung induction system was selected as the baseline prototype for the current investigation. The piston topology in this engine is mimicked after a Duramax combustion system. The engine was retrofitted using a Bosch 23kpsi injection system with magneto-strictive injectors.

A TECAT Engineering fuel controller managed multi-pulse fuel delivery during all dynomometer test sessions which were conducted at McLaren Performance Engines in Livonia, Michigan. The LIM valves were instrumented with high speed sensors to better understand valve behavior during engine operation. In-cylinder high speed pressure measurements were obtained to observe combustion characteristics as well. Low speed data were recorded to evaluate system performance and fuel economy.

After testing was complete, a first principles numerical model was developed to simulate the LIM engine cycle and valve behavior. The model provides for changes to key valve dimensions, valve mass, spring tension and pre-load, and can be modified to simulate active valve control as well. Using this simulation, an extensive analysis and optimization of the existing LIM353 system was conducted to assess potential performance of this system in contrast to what was observed during actual baseline engine testing. Simulated changes in valve/spring design, manifold design, porting, and supercharger design were evaluated in an attempt to improve overall system performance and fuel economy.

LIMSIM