Thermal isolation device for heater core to prevent over-heat damage

• US 5,271,559 A
• Filed: 09/03/1992
• Issued: 12/21/1993
• Est. Priority Date: 09/03/1992
• Status: Expired due to Fees

• Current Assignee: Chrysler Corporation (Stellantis NV)
• Original Assignee: Chrysler Corporation (Stellantis NV)
• Inventors: Naujock, Arthur A.
• Primary Examiner(s): Ford, John K.
• Application Number:
  US07/940,154
• Time in Patent Office: 474 Days
• Field of Search: 237/12.3 B, 237/8 R, 236/34.5, 236/36, 236/93 A, 165/35, 165/38, 165/40, 137/625.5
• US Class Current: 237/12.30B
• CPC Class Codes: B60H 1/00485 Valves for air-conditioning devices, e.g. thermostatic valves valves per se F16K; thermostatic valves per se G05D23/02
• CPC Class Codes: B60H 1/00978 Control systems or circuits characterised by failure of detection or safety means; Diagnostic methods
• CPC Class Codes: G05D 23/1333 measuring the temperature of incoming fluid

Abstract

In a vehicle with a liquid cooled engine and a heat exchanger such as an interior heater for the passenger compartment, an isolation device positioned therebetween for normally permitting flow of liquid from the engine cooling system to the heat exchanger and then back to the engine cooling system but for blocking flow to the heat exchanger when the liquid temperature is excessive. The device including a thermally responsive power means responsive to a high liquid temperature to block liquid flow to the heat exchanger and redirect the flow in bypass relation to the heat exchanger.

Claims

1. An improvement for a vehicle having an engine with a liquid cooling system and an associated heat exchanger core to warm the vehicle interior, the improvement comprising:

a thermal isolation device between the engine cooling system and the heat exchanger core to prevent the passage of liquid to the core when the liquid temperature increases above a maximum desired value, the isolation device normally permitting a flow of liquid from the engine cooling system to the heat exchanger core and back to the engine and alternately blocking flow of liquid to the heat exchanger core when the liquid temperature is above the desirable maximum temperature;

the isolation device having two inlets and two outlets, a first inlet for fluid connection with the engine cooling system for receiving liquid therefrom, a first outlet for fluid connection to the heat exchanger core for passing liquid thereto, a second inlet for fluid connection to the heat exchanger core for receiving liquid back to the isolation device, and a second outlet for fluid connection with the engine cooling system to return liquid thereto;

a first valve member positioned between the first inlet and the first outlet, the first valve member being normally open allowing liquid flow from the engine cooling system to the heat exchanger core;

a second valve member positioned between the second inlet and the second outlet, the second valve member being normally open allowing liquid to return from the heat exchanger to the engine cooling system;

a third valve member positioned between the first inlet and the second outlet, the third valve member being normally closed to block liquid flow from the first inlet directly to the second outlet in bypass relationship to the heat exchanger core;

a temperature responsive thermal power means operatively connected to the three valves and positioned to receive liquid flow from the first inlet, the power means moving in response to a temperature increase to close the first and second valves and open the third valve when the liquid temperature reaches a maximum desired high temperature, whereby excessively hot liquid is prevented from entering either the inlet or outlet of the heat exchanger and liquid flow is directed from the first inlet to the second outlet in bypass relationship to the heat exchanger core.

2. The thermal isolation device set forth in claim 1 in which spring means normally biases the first and second valve members toward its opened position and the third valve member toward its closed position whereby movements of the power element in response to increasing temperature moves the valves against the spring bias to effect valve repositioning.