# US 4,398,081 A · Stand-by heating/power supply system for a motor vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,398,081 A - Document ID: US4398081A - Status: Granted - Kind: A - Application number: 06/199,974 - Filed: 1980-10-23 - Granted: 1983-08-09 - Earliest claimed: 1980-10-23 - Assignees: Mark H. Moad - Inventors: Mark H. Moad - Web page: https://patentgrep.com/patent/US4398081A ## CPC - B60H 1/034: {from the cooling liquid of the propulsion plant and from an electric heating device} - B60H: ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES ## Abstract A stand-by heating/power supply system for an emergency vehicle, such as an ambulance, has an auxiliary electric heater and pump connected in the conventional heater coolant line adjacent the upstream side of the rear heat exchanger normally employed in such a vehicle. A control unit is connected to supply operating power to this heater and pump and also to operate the heater fan independently of the standard fan control provided in the vehicle. The control unit, in turn, is supplied with operating power upon connection with a conventional residential alternating current power source and includes timer circuits and electronic switches to delay the turning on of the heater pump unit and the fan and other auxiliary electrical power supplies for a predetermined time period after the connection with the alternating power source is made. The time delays for turning on different ones of the utilization devices within the vehicle also is varied, so that no sudden power surge takes place. ## Claims ### Claim 1 In a fluid-cooled motor vehicle having a heating system comprised of a heat exchanger for heating the vehicle interior and a recirculating fluid line interconnecting the heat exchanger and the engine coolant supply and having an electric heater fan controlled by a standard vehicle heater fan control for moving air across the heat exchanger, the improvement comprising a stand-by heating/power supply system including in combination: an auxiliary electric heater and pump connected in series in the recirculation coolant line adjacent the heat exchanger in the vehicle interior, said pump operating to circulate coolant from said auxiliary electric heater first into the heat exchanger in said coolant line and from the heat exchanger to recirculate coolant throughout the entire motor vehicle cooling system so long as said pump is operating; an auxiliary fan control connected to said heater fan for operating said heater fan independently of the standard vehicle fan control; electrically operated auxiliary accessories in the motor vehicle interior; and a control unit mounted in the vehicle and adapted for connection with an electrical power source external to the motor vehicle and having a plurality of outputs respectively connected with said electrically operated accessories, said auxiliary electric heater and pump, and with said auxiliary fan control to maintain said auxiliary accessories in a stand-by operating condition and for operating said auxiliary electric heater, pump and auxiliary fan control when said motor vehicle is inoperative and said control unit is connected with the external power source. ### Claim 2 (depends on 1) The combination according to claim 1 wherein said control unit includes a delay timer switch connected between the external power source and each of the outputs coupled with said auxiliary accessories, said auxiliary fan control and said auxiliary electric heater and pump so that electric power is obtained from the outputs of said control unit at different predetermined time periods after interconnection of said control unit with the external power source. ### Claim 3 (depends on 2) The combination according to claim 2 wherein each of said delay timer switches includes timer means and separate switching means connected in circuit between each of said auxiliary electrically operated accessories, said auxiliary electric heater and pump, and said auxiliary fan control, and said respective outputs therefor; and said timer means are initiated into operation upon connection of said control unit with said external power source and are coupled to said switching means for closing said switching means at different predetermined time intervals. ### Claim 4 (depends on 3) The combination according to claim 3 wherein said switching means comprise solid state switches and said timer means comprise electronic time circuits. ### Claim 5 (depends on 4) The combination according to claim 4 further including means for selectively disabling different ones of said timer means from operation irrespective of the connection of said control unit with the external power source. ### Claim 6 (depends on 1) The combination according to claim 1 wherein the motor vehicle is an emergency vehicle having a rear heating system connected in parallel with a conventional front heating system of the vehicle and wherein the heat exchanger comprises the rear heat exchanger of such emergency vehicle; said auxiliary electric heater and pump is located in the coolant line adjacent said rear heat exchanger immediately on the upstream side thereof to deliver heated coolant first to the heat exchanger, said coolant being circulating throughout the vehicle heating and cooling system to thereby provide heated coolant to the engine of the vehicle as well as to the heat exchanger of the vehicle rear heater. ### Claim 7 (depends on 1) The combination according to claim 1 further including means for selectively disabling said auxiliary electric heater and pump and said auxiliary fan control irrespective of the connection of said control unit with the external power source.