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A unique, temperature controlled, single-cylinder engine test facility was designed and constructed to simulate cold starting of a car engine. The temperature of the coolant, oil, fuel and air used by the engine can be individually controlled to -29°C. Moreover, the engine is enclosed in a temperature controlled insulated chamber. With this facility the conditions that occur in a car engine as it cranks and starts, can be quickly duplicated and maintained for detailed study. The supply equivalence ratio values for starting the engine were determined using either gasoline with port fuel injection or propane as a premixed charge. For gaseous propane, the supply equivalence ratio for starting was nearly constant at all temperatures studied. However, for gasoline the supply equivalence ratio for starting increased as the temperature was lowered. The significance of these findings is discussed.

A quick and repeatable test procedure has been developed to investigate cold-start spark plug fouling using a single-cylinder test facility which is capable of quickly cooling the engine back to the test temperature. With a constant engine speed of 140 rpm, the fuel flow is controlled for a 5 minute start/idle period, followed by a 5 minute cool-down period with the fuel off. This facility dramatically reduces the cold-soak period of a cold start which would otherwise require hours. Under conditions where carbon fouling occurs, the effects of fuel calibration, fuel properties (aromaticity, vapor pressure, and surfactant additives), and spark properties (energy and gap size) on the number of cold starts, the spark waveforms, and the electrical-shorting mode were investigated. Fuel calibration had the strongest influence. The relative roles of soot and water and of different soot formation mechanisms are discussed.