Fabrication of Rapid Compression Machine with Variable Compression Ratio - A Review

The Rapid compression machine (RCM) is an excellent tool to direct measure ignition delay (ID) of combustible mixtures at a high pressure. This paper, highlight the method to assemble a RCM with adjustable stroke length and compression ratio. The assembled RCM consist of mainly three parts; driver cylinder assembly, piston assembly and receiver cylinder assembly. Driver cylinder assembly consists of piston cylinder with combustion chamber, multi-hole nozzle to inject the fuel, piezoelectric sensor, pressure gauge to measuring the in-cylinder air pressure, electric heater to heat the compressed air, heated plate to ignite the fuel. Piston assembly is the middle portion of RCM acts as a connector of the driver assembly and receiver assembly. Receiver cylinder assembly also contain the piston cylinder and this piston is connected to another piston through the piston rod, which is fitted inside the driver cylinder and mainly consists of fuel injector, pressure gauge for measuring in-pressure cylinder and temperature sensor to measure heated air temperature, air heating coil Receiver cylinder contains movable plates which is used to varying the movement of length along the axial direction to varying the clearance volume. The present RCM is based on the concept of combustion of charge (fuel and air) in both cylinders placed in opposite ends which is different from the concept used in the earlier RCMs. In the earlier RCMs the energy is created inside the driver cylinder by increasing the temperature and pressure with the help of the compressor and heater rather than by using the combustion process.