Engine temperature control system

An engine temperature control system for maintaining the temperature of coolant, in the engine jacket of an internal combustion engine, within desired narrow limits despite wide variations of external conditions and load on the engine, where a flow control valve controls the coolant flow from the engine jacket to a radiator having controllable shutters for varying the amount of ram air striking the radiator, and where a variable speed fan drive controls the amount of air blown through the radiator, said engine temperature control system comprising:

• a temperature sensor for sensing the temperature of the coolant in the engine jacket;
• means responsive to said temperature sensor for producing a controlled fluid pressure which is a function of and represents the sensed temperature;
• and means, responsive to the fluid pressure, for sequentially operating the flow control valve, radiator shutters and variable speed fan drive as the sensed coolant temperature rises through predetermined low, medium and high temperature ranges,
• the flow control valve increasing the amount of coolant circulating through the radiator as the sensed temperature increases in the low temperature range, the radiator shutters increasing the amount of ram air impinging on the radiator as the sensed temperature increases in the medium temperature range, and the fan drive increasing the amount of air pulled through the radiator as the temperature increases in the high temperature range.

An engine temperature control system for controlling the temperature of coolant in the engine jacket of an internal combustion engine, where the coolant may be circulated, via a flow control valve, around the engine jacket and through a radiator having controllable shutters for varying the amount of ram air that may impinge on the radiator, a variable speed fan drive being provided to control the amount of air blown through the radiator, said engine temperature control system comprising:

• a temperature sensor for sensing the temperature of the coolant in the engine jacket;
• means responsive to said temperature sensor for producing a pulse width modulated signal having a duty cycle which is proportional to the sensed temperature;
• a source of pressurized fluid;
• means, coupled to said source of pressurized fluid and responsive to said pulse width modulated signal, for producing a controlled fluid pressure which is proportional to the sensed temperature;
• means for utilizing said controlled fluid pressure, when the sensed coolant temperature is in a relatively low temperature range, for controlling the position of the coolant flow control valve to vary the amount of coolant diverted to and flowing through the radiator, the flow control valve being fully open to circulate all of the coolant through the radiator when the sensed coolant temperature is at the high end of the low temperature range;
• means for utilizing said controlled fluid pressure, when the sensed coolant temperature is in a medium temperature range above the low temperature range, for adjusting the position of the radiator shutters to vary the amount of ram air striking the radiator, the shutters being fully open to maximize the amount of ram air when the sensed coolant temperature is at the high end of the medium temperature range;
• and means for utilizing said controlled fluid pressure, when the sensed coolant temperature is in a relatively high temperature range above the medium temperature range, for varying the speed of the fan drive to control the amount of air pulled through the radiator, thereby to maintain the coolant temperature within desired narrow temperature limits regardless of external conditions and load on the engine.