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Vehicle start-stop systems are becoming increasingly prevalent on internal combustion engine (ICE) because of the capability to reduce emissions and fuel consumption in a cost effective manner. Thus, the ICE undergoes far more starting events, therefore, the behaviour of ICE during start-up becomes critical. In order to simulate and optimise the engine start, Model in the Loop (MiL) simulation approach was selected. A proceduralised cranking test has been carried out on a 2.0-liter turbocharged, gasoline direct injection (GDI) engine to collect data. The engine behaviour in the first 15 seconds was split into eight different phases and studied. The engine controller and the combustion system were highly transient and interactive. Thus, a controller model that can set accurate boundary conditions is needed. The relevant control functions of throttle opening and spark timing have been implemented in Matlab/Simulink to simulate the behaviours of the controller.

Stringent regulations on fuel economy have driven major innovative changes in the internal combustion engine design. (E.g. CAFE fuel economy standards of 54.5 mpg by 2025 in the U.S) Vehicle manufacturers have implemented engine infrastructure changes such as downsizing, direct injection, higher compression ratios and turbo-charging/super-charging to achieve higher engine efficiencies. Fuel properties therefore, have to align with these engine changes in order to fully exploit the possible benefits. Fuel octane number is a key metric that enables high fuel efficiency in an engine. Greater resistance to auto-ignition (knock) of the fuel/air mixture allows engines to be operated at a higher compression ratio for a given quantity of intake charge without severely retarding the spark timing resulting in a greater torque per mass of fuel burnt. This attribute makes a high octane fuel a favorable hydrocarbon choice for modern high efficiency engines that aim for higher fuel economy.