초록

A microprocessor controlled vehicle relay for high capacity HVAC systems in large high occupancy vehicles is provided that can be configured in different ways to provide a number of operational functions for improved safety as well as greater motor and/or compressor longevity.

대표청구항 ▼

1. A vehicle relay for reducing an initial start-up current to a fan motor upon activation of a vehicle climate control system comprising: a power source;at least one input terminal connectable to said power source;an output terminal connected to the fan motor;a microprocessor electrically connected

1. A vehicle relay for reducing an initial start-up current to a fan motor upon activation of a vehicle climate control system comprising: a power source;at least one input terminal connectable to said power source;an output terminal connected to the fan motor;a microprocessor electrically connected to the input terminal, said microprocessor programmed with a predetermined time delay upon receipt of current;a plurality of transistors electrically connected to an output of the microprocessor;a bypass circuit electrically connected to an output of the relay, the bypass circuit including a relay coil and a switch movable from an open position to a closed position in response to activation of the transistors, said output terminal also being connected to an output of said bypass circuit;a negative temperature coefficient (NTC) resistor electrically connected between the input terminal and the output terminal;said switch of said bypass circuit being open when power is initially applied to said input terminal so that current flows through the NTC resistor to the output terminal and to the motor, said NTC resistor reducing an initial start-up current that is input to the motor upon activation of the climate control system;said microprocessor delaying activation of said transistors for said predetermined time delay after which said microprocessor activates the transistors which activates the bypass relay to close the switch;upon closure of said switch, said NTC resistor being bypassed to allow maximum operating voltage from said power source to be applied to the motor through said bypass relay. 2. The vehicle relay as set forth in claim 1, further comprising a voltage regulator to provide a constant voltage level to the microprocessor. 3. The vehicle relay as set forth in claim 1, further comprising a first diode between the input terminal and the microprocessor and a second diode between the output terminal and said microprocessor, said diodes enabling said terminals to be interchangeable as to which one is connected to the power source and which one outputs current to the fan motor. 4. The vehicle relay as set forth in claim 3, further comprising a third diode between the transistors and the bypass relay, said third diode clamping inductive energy from said bypass relay when said bypass relay is de-energized. 5. The vehicle relay as set forth in claim 1 as installed within a large high occupancy vehicle. 6. A vehicle relay for protecting a compressor in a vehicle climate control system from an engine RPM in excess of the compressor's rating, said relay comprising: a power source;at least a first terminal connectable to said power source;at least a second terminal connected to a clutch of the compressor in the climate control system;a microprocessor electrically connected to the input terminal;a plurality of transistors electrically connected to an output of the microprocessor;a bypass circuit electrically connected to an output of the transistors, the bypass circuit including an inductor and a switch movable from an open position to a closed position in response to activation of the transistors, said output terminal also being connected to an output of said bypass circuit;a third terminal electrically connected to the microprocessor and providing an engine RPM signal to said microprocessor;said microprocessor configured to activate the transistors and the bypass relay to close the switch when power is applied to the first terminal, said clutch for said compressor being engaged in response to a clutch signal received from the relay when said bypass circuit is energized and said bypass circuit switch is closed;said microprocessor configured to monitor the engine RPM signal received from the third terminal and, in response to said RPM signal indicating engine RPM to be in excess of the rating of the compressor, said microprocessor de-energizing said transistors and said bypass circuit to open the switch and disconnect the clutch signal to disengage the clutch and prevent overspeeding of the compressor. 7. The vehicle relay as set forth in claim 6, wherein after disengaging said clutch, said microprocessor continues to monitor the engine RPM signal received from the third terminal and, in response to said RPM signal indicating engine RPM to be below the rating of the compressor, said microprocessor re-energizing said transistors and said bypass circuit to close the switch and reconnect the clutch signal to re-engage the clutch and activate the compressor. 8. The vehicle relay as set forth in claim 6, further comprising a voltage regulator to provide a constant voltage level to the microprocessor. 9. The vehicle relay as set forth in claim 6, further comprising a first diode between the input terminal and the microprocessor and a second diode between the output terminal and said microprocessor, said diodes enabling said terminals to be interchangeable as to which one is connected to the power source and which one outputs current to the fan motor. 10. The vehicle relay as set forth in claim 9, further comprising a third diode between the transistors and the bypass relay, said third diode clamping inductive energy from said bypass relay when said bypass relay is de-energized. 11. The vehicle relay as set forth in claim 7 as installed within a large high occupancy vehicle. 12. A vehicle relay for protecting a compressor clutch from undervoltage in a vehicle climate control system, said relay comprising: a power source;at least a first terminal connectable to said power source;at least a second terminal connected to a compressor clutch in the vehicle climate control system;a microprocessor electrically connected to the input terminal;a plurality of transistors electrically connected to an output of the microprocessor;a bypass circuit electrically connected to an output of the transistors, the bypass circuit including a relay coil and a switch movable from an open position to a closed position in response to activation of the transistors, said output terminal also being connected to an output of said bypass circuit;said microprocessor configured to activate the transistors and the bypass relay to close the switch when power is applied to the first terminal, said clutch for said compressor being engaged in response to a clutch signal received from the relay when said bypass circuit is energized and said bypass circuit switch is closed;an electrical connection between input voltage from the first terminal when connected to the power source and said microprocessor, said microprocessor configured to monitor the input voltage received over the electrical connection and, in response to said input voltage being less than sufficient to fully engage the clutch, said microprocessor de-energizing said transistors and said bypass circuit to open the switch and disconnect the clutch signal to disengage the clutch. 13. The vehicle relay as set forth in claim 12, wherein after disengaging said clutch, said microprocessor continues to monitor the input voltage and, in response to said input voltage being sufficient to fully engage the clutch, said microprocessor re-energizing said transistors and said bypass circuit to close the switch and reconnect the clutch signal to re-engage the clutch. 14. The vehicle relay as set forth in claim 12, further comprising a voltage regulator to provide a constant voltage level to the microprocessor. 15. The vehicle relay as set forth in claim 12, further comprising a first diode between the input terminal and the microprocessor and a second diode between the output terminal and said microprocessor, said diodes enabling said terminals to be interchangeable as to which one is connected to the power source and which one outputs current to the clutch. 16. The vehicle relay as set forth in claim 15, further comprising a third diode between the transistors and the bypass relay, said third diode clamping inductive energy from said bypass relay when said bypass relay is de-energized. 17. The vehicle relay as set forth in claim 13 as installed within a large high occupancy vehicle. 18. A vehicle relay for preventing over-cycling of a condenser in a vehicle climate control system comprising: a power source;at least one input terminal connectable to said power source;an output terminal connected to a clutch of the compressor;a microprocessor electrically connected to the input terminal, said microprocessor programmed with a predetermined time delay upon receipt of current;a plurality of transistors electrically connected to an output of the microprocessor;bypass circuit electrically connected to an output of the transistors, the bypass circuit including a relay coil and a switch movable from an open position to a closed position in response to activation of the transistors, said output terminal also being connected to an output of said bypass circuit;said microprocessor configured to activate the transistors and the bypass relay to close the switch when power is applied to the first terminal, said clutch for said compressor being engaged in response to a clutch signal received from the relay when said bypass circuit is energized and said bypass circuit switch is closed;said microprocessor, upon receipt of current, delaying activation of said transistors for said predetermined time delay after which said microprocessor activates the transistors and the bypass relay to close the switch and generate the clutch signal; andsaid clutch for said compressor being engaged in response to said clutch signal to activate the compressor. 19. The vehicle relay as set forth in claim 18, wherein the predetermined time delay is about 20-30 seconds and said vehicle climate control system is installed in a large high occupancy vehicle. 20. A method for reducing an initial start-up current to a fan motor upon activation of a vehicle climate control system using a vehicle relay that includes at least one input terminal connectable to a power source, an output terminal connected to the fan motor, a microprocessor electrically connected to the input terminal and programmed with a predetermined time delay upon receipt of current, a plurality of transistors electrically connected to an output of the microprocessor, a bypass circuit with a switch electrically connected to an output of the transistors, the output terminal also being connected to an output of the bypass circuit, and a negative temperature coefficient (NTC) resistor electrically connected between the input terminal and the output terminal, the switch of the bypass circuit being open when power is initially applied to the input terminal, the method comprising: applying power to the input terminal with said switch in said bypass circuit being open so that current flows through the NTC resistor to the output terminal and to the motor, said NTC resistor reducing an initial start-up current that is input to the motor upon activation of the climate control system;delaying, by said microprocessor, activation of said transistors for said predetermined time delay;after the predetermined time delay, said microprocessor activating the transistors which activates the bypass relay to close the switch;upon closure of said switch, bypassing said NTC resistor to allow maximum operating voltage from said power source to be applied to the motor through said bypass relay.