Thermodynamic Simulation of Turbocharged Intercooled Stoichiometric Gas Engine

To uprate from 90 kW to 135 kW in power and upgrade the emission from Euro-II to Euro-V a base 6-cylinder naturally aspirated engine was turbocharged and after-cooled, and the fuelling method was changed from Carburetion to Multi-Point Fuel Injection (MPFI). EGR is allowed to flow from the exhaust manifold to the inlet of the compressor. The EGR flow controlled by fixed orifice was used to limit thermal loading of turbocharger. The thermodynamic model was used to optimize the ignition timing and predict the engine performance over the operating range of speed and load while allowing stoichiometric combustion. Optimum turbocharger, diameter of the EGR-pipe and the throttle body size were selected based on thermodynamic simulation. The 3-way catalytic converter and the silencer at the turbine outlet were also simulated.

The real engine was developed based on the simulation and the engine performance. Power output and Specific Fuel Consumption, NO_x and heat release rate from the model were found to be agreeing well with the experiments on the real engine. Considerable time was saved at the engine test bed because the thermodynamics and gas exchange could be simulated accurately.