Controlling engine coolant flow and valve assembly therefor

A system for controlling flow of coolant in a circuit comprising an internal combustion engine and a heat engine coolant to passenger compartment air in a vehicle, said system comprising:

• (a) heat exchanger means having an inlet and an outlet which is connected to the engine for coolant flow therethrough;
• (b) transducer means operative to sense temperature in the vehicle passenger compartment, said transducer means operative in response to said sensed temperature to provide an electrical temperature feedback signal;
• (c) electrically actuatable valve means with the inlet thereof receiving heated coolant from the engine with the outlet of said valve means, said valve means having a housing means formed of plastic material and defining integrally therewith a flow passage, a motor cavity and a gear box with a stepper motor disposed in said cavity and speed reducer means having an output disposed in said gear box and driven by said stepper motor, said valve means including a rigid pivoted member movable by said speed reducer output between a closed position preventing flow thereover and an open position permitting coolant flow to said heat exchanger, said pivoted member having an elastomeric seating surface for preventing coolant leakage in the closed position;
• (d) logic and power circuit means operable in response to said temperature feedback signal and a comparison thereof with a reference temperature to provide a valve actuation signal for actuating said stepper motor to position said valve member in a preselected position in response to said comparison and thereby control coolant flow for modulating said passenger compartment temperature at said reference temperature.

A system for controlling flow of coolant in a circuit comprising an internal combustion engine and a heat exchanger for transferring heat from the engine coolant to ambient air said system comprising:

• (a) heat exchanger means having an inlet and an outlet which is connected to the engine for coolant flow therethrough;
• (b) transducer means operative to sense engine coolant jacket temperature, said transducer means operative in response to said sensed temperature to provide an electrical temperature feedback signal;
• (c) electrically actuatable valve means with the inlet thereof receiving heated coolant from the engine with the outlet of said valve means discharging to the inlet of said heat exchanger means, said valve means having a housing means formed of plastic material and defining integrally therewith a flow passage, a motor cavity and a gear box with a stepper motor disposed in said cavity and speed reducer means having an output disposed in said gear box and driven by said stepper motor, said valve means including a rigid pivoted member movable by said speed reducer output between a closed position preventing flow thereover and an open position permitting coolant flow to said heat exchanger, said pivoted member having an elastomeric seating surface for preventing coolant leakage in the closed position;
• (d) logic and power circuit means operable in response to said temperature feedback signal and a comparison thereof with a reference temperature to provide a valve actuation signal for actuating said stepper motor to position said valve member in a preselected position in response to said comparison and thereby control coolant flow for modulating said engine temperature at said reference temperature.

A system for controlling flow of coolant in a circuit comprising an internal combustion engine and a heat exchanger for transferring heat from the engine coolant to passenger compartment air in a vehicle, said system comprising:

• (a) heat exchanger means having an inlet and an outlet which is connected to the engine for coolant flow therethrough;
• (b) means for flowing air over said heat exchanger means and discharging same into the passenger compartment;
• (c) transducer means operative to sense temperature of said discharging air closely adjacent said heat exchanger means, said transducer means operative in response to said sensed temperature to provide an electrical temperature feedback signal;
• electrically actuatable valve means with the inlet thereof receiving heated coolant from the engine with the outlet of said valve means discharging to the inlet of said heat exchanger means, said valve means having a housing means formed of plastic material and defining integrally therewith a flow passage, a motor cavity and a gear box with a stepper motor disposed in said cavity and speed reducer means having an output disposed in said gear box and driven by said stepper motor, said valve means including a rigid pivoted member movable by said speed reducer output between a closed position preventing flow thereover and an open position permitting coolant flow to said heat exchanger, said pivoted member having an elastomeric seating surface for preventing coolant leakage in the closed position;
• logic and power circuit means operable in response to said temperature feedback signal and a comparison thereof with a referenced temperature to provide a valve actuation signal for actuating said stepper motor to position said valve member in a preselected position in response to said comparison and thereby control coolant flow for modulating said discharging air at said reference temperature.

A method of controlling coolant flow between an internal combustion engine and an air heat exchanger comprising the steps of:

• (a) providing an electrically operated valve in fluid series flow arrangement in the circuit of coolant flow between said engine and said heat exchanger;
• (b) sensing the temperature of the coolant in said engine and providing an electrical signal representative of said sensed temperature;
• and,
• (c) comparing said sensed temperature signal with a reference temperature signal and generating a valve control signal and controlling the position of said valve to alter coolant flow for modulating engine temperature about said reference temperature;
• and,
• (d) opening said valve sufficiently to effect full flow for a small fraction of the cold engine warm-up interval and flushing said valve of foreign material.

An electrically actuated valve assembly for controlling flow of engine coolant, said valve assembly comprising:

• (a) housing means formed of plastic material and integrally defining a coolant flow passage having an inlet and outlet, a motor casing and a gear box;
• (b) a butterfly valving member disposed in said passage between said inlet and outlet, said valving member pivoted about an axis transverse to the direction of flow and operable for pivoted movement between a closed position of open positions permitting partial or full flow therethrough;
• (c) a shaft extending through the wall of said housing into said passage and journalled therein for rotation with respect thereto, said shaft having the end portion thereof external to said passage including indicator means extending in a direction generally parallel to said butterfly member, said shaft having said valving member attached thereto for providing said pivoted movement upon rotation of said shaft;
• (d) stepper motor means including speed reducer means received in said casing, said speed reducer means received in said gear box having power output shaft means with torque coupling means provided thereon, said torque coupling means engaging said external end portion of said shaft for effecting rotation thereof upon said stepper motor being energized by an electrical control signal.