Compensating for water pump speed variations in a tempered air system for vehicle passenger compartments

• US 4,974,664 A
• Filed: 02/14/1990
• Issued: 12/04/1990
• Est. Priority Date: 02/14/1990
• Status: Expired due to Term

• Current Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Glennon, Thomas F., DeVera, Dennis
• Primary Examiner(s): Ford, John
• Application Number:
  US07/497,873
• Time in Patent Office: 293 Days
• Field of Search: 237/2 A, 237/12.3 A, 237/12.3 B, 165/39, 165/40, 165/42, 165/43, 165/2, 417/293, 417/294
• US Class Current: 165/271
• CPC Class Codes: B60H 1/00885 Controlling the flow of heating or cooling liquid, e.g. valves or pumps B60H1/00899 takes precedence; constructions of valves B60H1/00485
• CPC Class Codes: G05D 23/1919 characterised by the type of controller
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

An automatic control system for regulating the temperature of blower air discharged over a heater core to a vehicle passenger compartment. A thermistor is disposed to sense discharge air adjacent the heater core and provide a temperature signal. An electrical indication is provided of the condition of a servomotor driven valve controlling water flow to the heater core. An electrical reference signal is provided indicative of a user selected relative change of flow discharge air temperature. A signal is provided indicating the speed of the water pump circulating liquid to the heater core. The signals are summed and the valve sums driven until the sum is zero and the valve modulated to maintain the sum at zero for regulating blower air discharge temperature constant.

Claims

1. A system for controlling blower air discharge temperature for heating and cooling a passenger compartment of a motorized vehicle comprising;

(a) a source of heated fluid circulated by pump means driven from the vehicle motor;

(b) blower means, including duct means, operative upon energization to direct a flow of air to the vehicle compartment;

(c) exothermic heat exchanger means disposed in said duct means and connected for circulation of said heated fluid therethrough and operative to heat said flow of air thereupon;

(d) electrically operated valve means disposed in said conduit means and operative to control flow of said fluid through said heat exchanger means;

(e) temperature sensing means disposed proximate said heat exchanger means and operative to sense the temperature of said air flow directed to said passenger compartment, said sensor means operative to provide an electrical temperature signal indicative of changes in said sensed directed air temperature;

(f) speed sensing means disposed to sense the speed of said pump means and operative to provide an electrical flow rate signal indicative of the discharge rate of said pump means;

(g) level control means operative upon user input to provide an electrical relative temperature desired signal;

(h) circuit means including microcomputer means receiving said flow rate signal, said directed air temperature signal and said relative temperature desired signal at the inputs thereof;

for said valve means in accordance with a predetermined algorithm such that said valve varies flow of said heated fluid to regulate changes in temperature of said directed air about a reference level irrespective of changes in the speed of said pump means.

2. The system defined in claim 1, wherein said microcomputer means is operable in response to a user input from said level control means to change said directed air temperature.

3. A method of regulating the temperature of blower discharge air in a vehicle passenger compartment heating system;

(a) providing an exothermic heat exchanger and flowing heated liquid therethrough from an engine driven pump;

(b) forcing a flow of air over the heat exchanger and directing the flow into the vehicle passenger compartment;

(c) providing a motor driven valve for controlling liquid flow to the heat exchanger and providing an electrical indication of the condition of said valve;

(d) sensing the temperature of the air flow over said heat exchanger and providing an electrical temperature signal;

(e) sensing the speed of the pump and generating an electrical pump speed signal;

(f) generating an electrical reference signal indicative of a user selected relative temperature signal;

(g) summing said indication of valve condition, said temperature signal, said pump speed signal and said reference signal;

(h) driving said valve motor until said sum is zero and modulating said valve condition for maintaining said sum at zero.

4. The method defined in claim 3 further comprising the

(a) disposing a refrigerant evaporator in said forced air flow upstream of said heat exchanger, and,

(b) flowing refrigerant through said evaporator.