Fluid heater control apparatus and method with overtemperature protection

• US 6,839,509 B2
• Filed: 02/28/2003
• Issued: 01/04/2005
• Est. Priority Date: 02/28/2003
• Status: Expired due to Fees

• Current Assignee: Valeo Electrical Systems Incorporated (Valeo SE)
• Original Assignee: Valeo Electrical Systems Incorporated (Valeo SE)
• Inventors: Harris, Daryl G., Kuebler, Karl-Heinz
• Primary Examiner(s): CAMPBELL, THOR S
• Application Number:
  US10/377,345
• Publication Number:
  US 20040170414A1
• Time in Patent Office: 676 Days
• Field of Search: 392465-484
• US Class Current: 392/484
• CPC Class Codes: B60S 1/488 electrically
• CPC Class Codes: F24H 9/1818 Arrangement or mounting of electric heating means
• CPC Class Codes: G05D 23/19 characterised by the use of electric means G05D23/1393 takes precedence
• CPC Class Codes: Y10T 137/6416 With heating or cooling of the system

Abstract

A fluid heater apparatus has fluid discharge temperature control to prevent temperature overshoot. A plurality of heater elements are employed and at least certain of the heater elements are independently controllable. At least one of the heater elements is employed as a “finishing” heater element, with the other heating elements deactivated to enable the “finishing” heater element to more slowly elevate the temperature of the fluid in the body from a first temperature reached by activation all or most of the heater elements to the predetermined discharge temperature. One of more of the heater elements may have a different power output than the other heater elements.

Claims

1. A method of heating fluid in a vehicle surface wash fluid discharge apparatus comprising the steps of:

providing fluid in an enclosure;

providing a plurality of heating elements for imparting thermal energy to the fluid;

controlling at least two of the heating elements independent of each other;

activating certain ones of the heating elements for a first time period to impart thermal energy to the fluid to rapidly increase the fluid temperature;

monitoring the temperature of the fluid; and

at a first temperature less than a preset maximum discharge fluid temperature, activating certain ones of the heating elements to more slowly elevate the temperature of the fluid to the preset maximum discharge temperature to minimize overshoot of the fluid temperature above the maximum discharge temperature.

2. The method of claim 1 wherein the step of activating certain heating elements comprise the steps of:

activating all of the heater elements to bring the temperature of the fluid up to the first temperature; and

maintaining at least one of the heater elements in an activated state to elevate the temperature of the fluid from the first temperature to the preset discharge temperature.

3. The method of claim 1 further comprising the step of:

providing at least one of the plurality of heater elements with a different power output than the other heater elements.

4. The method of claim 3 wherein the step of providing at least one heater element with a different power output further comprises the step of:

providing the at least one heater element with a lower power output than the other heater elements.

5. The method of claim 1 wherein the steps of activating certain heating elements further comprise the steps of:

activating certain ones of the heater elements to elevate the temperature of the fluid up to the first temperature;

deactivating the certain ones of the heater elements and activating another heating element to elevate the temperature of the fluid from the first temperature to the preset discharge temperature.

6. An apparatus for heating fluid in a vehicle surface wash fluid discharge system comprising:

means for providing fluid in an enclosure;

a plurality of heating elements for imparting thermal energy to the fluid;

means for controlling at least two of the heating elements independent of each other;

means for activating certain heating elements for a first time period to impart thermal energy to the fluid to rapidly increase the fluid temperature;

means for monitoring the temperature of the fluid; and

means, responsive to the temperature monitoring means at a first temperature less than a preset maximum discharge fluid temperature, for activating another one other of the heating elements to more slowly elevate the temperature of the fluid to the preset maximum discharge temperature more slowly to minimize overshoot of the fluid temperature above the maximum discharge temperature.

7. The apparatus of claim 6 further comprising:

at least one of the heating elements having a different power output than the other heating elements.

8. An apparatus for heating fluid in a vehicle surface wash fluid discharge system comprising:

an enclosure having a fluid flow path therethrough for receiving fluid;

a plurality of heater elements thermally coupled to the enclosure for imparting thermal energy to the enclosure and the fluid in the enclosure; and

control means for controlling the plurality of heater elements, with at least two of the heater elements being controlled independent of each other; and

wherein

the control means includes means for activating at least certain of the heating elements for a first time period to impart thermal energy to the fluid to rapidly increase the temperature of the fluid in the body to a first temperature less than a preset maximum discharge fluid temperature and activating certain heating elements to more slowly elevate the temperature of the fluid in the body from the first temperature to the preset maximum discharge temperature to minimize overshoot of the fluid temperature above the maximum discharge temperature.

9. The apparatus of claim 8 wherein the control means further comprises:

means for deactivating all of the heating elements activated to elevate the temperature of the fluid to the first temperature; and

means for activating at least another one heating element to elevate the temperature of the fluid from the first temperature to the first preset maximum discharge temperature.

10. The apparatus of claim 8 wherein:

at least one of the heater elements has a different power output than the other heating elements.