Design, Modeling, and Control of a HCCI Free Piston Engine


Design, Modeling, and Control of a HCCI Free Piston Engine

A Free Piston Engine (FPE) is a device where the linear motion of the piston is not constrained by a crankshaft. The advantage of this setup is the ability to run with varying compression ratios, thus enabling multi-fuel capability and Homogeneous Charge Compression Ignition (HCCI). The nature of this device requires precise control over the fuel, air, and piston motion. To enable this, a deep understanding of the constituent processes and hardware subsystems is necessary. One of these processes is the in-cylinder mixing between fresh air/fuel mixtures and hot, residual exhaust gas. CFD analysis using FLUENT is used to characterize the behavior of in-cylinder fluid motion. CHEMKIN is used to simulate the chemical reaction inside the combustion chamber. The power generated by FPE can be captured and transformed to fluid power or electrical power using a linear pump or alternator. For the linear alternator, to find the induced voltages and currents and also the opposing forces, it is necessary to model its magnetic circuit. To do this Maxwell-2D was employed and 2D axisymmetric analysis of the linear alternator was performed. Based on the coil flux linkages data obtained from this analysis, a Simulink model was developed using MATLAB which makes it easier to integrate the linear alternator model into FPE model and perform a thorough analysis of the device.

A bibliography of this group’s publications is attached.

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