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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.

Statistically designed experiments with a port fuel injected, single-cylinder engine were run to determine the effects of injector-, engine-, and fuel-related variables on exhaust smoke and hydrocarbon (HC) emissions. Among injector-related variables, targeting the fuel spray at the inlet valve centerline toward the valve head resulted in low smoke and HC emissions. These factors apparently help break up the fuel spray and they help subsequent vaporization of the fuel droplets. Among engine-related variables, high coolant temperatures and lean mixtures resulted in less smoke and HC emissions, probably because of better fuel vaporization. Gasolines with aromaticity and 90% point close to the maximum of the ranges of commercial gasolines significantly increased HC and smoke emissions compared with gasolines representing the average or minimum values, of these ranges.