Adaptive control approach for cylinder balancing in a hydraulic linear engine

This paper considers cylinder balancing of a novel hydraulic linear engine developed by the United States Environmental Protection Agency as an evolution of previous free-piston engine concepts. We employ an adaption algorithm that adjusts individual fuel injector commands to ensure the estimated kinetic energy of the crank tracks a set point. A control-oriented model and a high-fidelity model demonstrate the adaptive controller performance. The algorithm successfully reduces perturbations by 99% at a target speed of 1000 RPM. Additionally, the algorithm enables the engine to operate with different loads and conditions in each cylinder.