GB2323682A - Climatic control of a vehicle - Google Patents

Abstract

The time at which use of a vehicle is required is programmed in by the user 38 and the temperature internal and external of the vehicle is sensed 42,44 to determine when to activate a heater so that the desired temperature is achieved at that time. The heater may be an electrical heater driven from a mains connection eg in the garage to avoid running the battery down. Alternatively a fuel burning heater 18 in combination with the vehicle cooling system 10 may be used to warm the vehicle interior.

Description

A Climatic Control Svstem for a Vehicle This invention relates to climatic control systems and in particular to a programmable climatic control system for a vehicle.

It is known to provide a climatic control system for a vehicle which raises and lowers the temperature of a passenger compartment of the vehicle. It is a problem with some known prior art climatic control systems that in very cold climates it takes an inordinate length of time to raise the temperature of the passenger compartment to a comfortable level as the engine takes a long time to warm up.

It is an object of this invention to provide an improved climatic control system for a vehicle.

According to the invention there is provided a climatic control system for a vehicle comprising a temperature alteration means and a control means including a timing means and a programming means, the temperature alteration means being arranged to alter the temperature of a passenger compartment of the vehicle under the control of the control means and the control means being arranged to control the temperature alteration means to achieve a pre-set temperature in the passenger compartment by a pre-set time of day, the pre-set time being programmed by the programming means.

The control means may be arranged to control the temperature alteration means to alter the temperature in the passenger compartment at the latest time possible to achieve the pre-set temperature by the pre-set time of day. The pre-set temperature may be programmed by the programming means.

The control means may further comprise a sensor means and the time and the rate at which the temperature alteration means is controlled to alter the temperature of said compartment may be adjustable in response to signals received from the sensor means.

The sensor means may comprise an interior temperature sensor arranged to provide an interior temperature signal indicative of the interior temperature of the passenger compartment, an exterior temperature sensor arranged to provide an exterior temperature signal indicative of the ambient temperature or a solar heat input sensor arranged to provide a signal indicative of the rate of solar heat input to the passenger compartment.

The temperature alteration means may comprise a fuel burning heater system which may be arranged to heat a coolant fluid of an engine cooling system of the vehicle, and the system may further comprise a heater unit arranged to transfer heat to the passenger compartment from the coolant fluid while the fuel burning heater operates.

The climatic control system may further comprise a pump arranged to pump the coolant fluid around the cooling system when the engine is not running and the coolant fluid is being heated by the fuel burning heater system.

The control means may comprise an air conditioning control system arranged to control the output of heat from the heater unit and a burner control unit in communication with the programming means to control the fuel burning heater system.

The temperature alteration means may comprise an electrically powered heater unit and the heater unit may be powered from a power source not forming part of the vehicle.

The temperature alteration means may comprise at least one thermal battery.

The invention also provides a vehicle having a climatic control system according to the invention.

The invention will now be described by way of example with reference to the accompanying drawings, in which; Figure 1 is a schematic diagram of a climatic control system according to the invention.

Referring to Figure 1, a climatic control system of a vehicle (not shown further) has a coolant circuit 10 which comprises an engine 12, an engine cooling radiator 14, an electric pump 16, a fuel burning heater 18 and a passenger compartment heater unit 20.

The cooling circuit 10 is split into a main circuit 22 and a radiator circuit 24. The main circuit 22 passes through the engine 12, the electric pump 16, the fuel burning heater 18, the heater unit 20 and an engine water pump 28. The water pump 28 is arranged to cycle coolant around the main circuit 22 when the engine 12 is running.

The radiator circuit 24 passes through the engine 12 and the radiator 14 and is separate from the main circuit 22 and thermostatically connected to it by an engine thermostat 26.

The engine 12 is controlled by an engine management system (EMS) 30 which has an engine coolant temperature sensor 32 and is connected to a controller area network bus (CAN) 34.

The climatic control system further comprises a fuel burner control unit 36 arranged to control the heat transfer from the fuel burning heater 18 into the coolant and to control the operation of the electric pump 16.

The fuel burner control unit 36 is programmable through a keypad forming part of a programming unit 38 and is connected to the CAN 34.

The programming unit 38 includes a timing means (not shown separately) arranged to permit programming of pre-set temperatures and pre-set times of day.

An air conditioning controller 40 controls a series of flaps and a blower fan (neither shown separately) within the heater unit 20 and controls how much heat is transferred from the heater unit 20 to the passenger compartment. The air conditioning controller 40 receives signals from temperature sensors comprising: an interior temperature sensor 42 indicative of the interior temperature of the passenger compartment; an exterior temperature sensor 44 indicative of the ambient temperature; and a solar heat input sensor 46 indicative of the solar heat input into the passenger compartment. The air conditioning controller 40 is also connected to the CAN 34.

In cold climates, e.g. ambient temperature below Ooc, the vehicle user programmes the fuel burner control unit 36 using the programming unit 38 to enter a pre-set temperature T for the passenger compartment and a time of day at which the passenger compartment must be at the pre-set temperature T.

The fuel burner control unit 36 periodically samples the inputs from the temperature sensors 42, 44, 46 using the CAN 34 and uses an algorithm based on the thermal capacities of the engine 12 and the passenger compartment, the amount of solar heat input and the rate of heat loss to calculate the time it will take to heat the passenger compartment to the preset temperature T and will turn on the fuel burning heater 18 at the latest possible time to achieve the pre-set temperature T at the pre-set time.

The fuel burning heater 18 heats the coolant which is pumped around the cooling circuit 10 by the electric pump 16 also under control of the fuel burner control unit 36.

The coolant passes through the heater unit 20 and the air conditioning controller 40 controls the heater unit 20 to introduce heat into the passenger compartment until the pre-set temperature T has been reached.

Thereafter the air conditioning controller 40 and the fuel burner control unit 36 communicate via the CAN 34 to maintain the pre-set temperature T by controlling the heater unit 20, electric pump 16 and the fuel burning heater 18.

If the engine 10 is started, the EMS 30 instructs the fuel burning control unit 36 to switch off the electric pump 16 and the coolant is cycled around the cooling circuit 10 by the engine water pump 28.

When the coolant approaches a temperature at which the fuel burning heater unit 18 is no longer needed, the fuel burner control unit 36 turns it off and the passenger compartment temperature is maintained by the air conditioning control unit 40 operating in a conventional manner.

By only turning on the fuel burning heater 18 at the latest possible time, fuel is saved. The programmable nature of the present invention means the vehicle user need only set the time at which the vehicle is required and does not need to guess what time the fuel burning heater 18 needs to be turned on. The user can set one time (e.g. 4.30 p.m. every weekday) and need not adjust that time as the weather turns colder or hotter.

This invention has the further advantage of pre-warming the engine, when used as described above using the fuel heater to heat the engine coolant, and would offer easier engine starting when the vehicle is exposed to low ambient temperatures.

It will be appreciated that the fuel burning heater could be replaced by a heater source run from a different power supply, e.g. an electric heater unit. The power supply may be included in the vehicle, such as a vehicle battery, or may be provided by an external supply such as a domestic power supply plugged into the vehicle overnight or when the vehicle is kept in a garage.

The fuel burning heater could also be replaced by at least one thermal battery which is of the type known to provide a substantially consistent heat output for a predetermined length of time. One type of thermal battery stores heat put into it by turning a crystal structure contained in it into a liquid. Once activated, the batteries re-crystallise the liquid and output heat, which is derived from the latent heat of crystallisation, at a substantially constant rate and will continue to output heat until the recrystallisation process is complete. It is particularly important to control the activation time of the battery, as the re-crystallisation process does not stop once started and the battery will supply a constant output of heat for the duration of the re-crystallisation process and then run out. In this case it is particularly important to activate the heat battery at the latest time possible, in order to ensure that the passenger compartment does not cool down when there is no heat source left in reserve after the battery has run out. The battery could be recharged by putting heat back into it from the vehicle heating system when the engine is running.

It would also be possible to use a fuel burning heater, an electric heater or a thermal battery to heat the passenger compartment directly by passing a stream of air over a heated portion of the respective device and into the passenger compartment.

Claims (18)

1. A climatic control system for a vehicle comprising a temperature alteration means and a control means including a timing means and a programming means, the temperature alteration means being arranged to alter the temperature of a passenger compartment of the vehicle under the control of the control means and the control means being arranged to control the temperature alteration means to achieve a pre set temperature in the passenger compartment by a pre-set time of day, the pre-set time being programmed by the programming means.

2. A climatic control system according to Claim 1 wherein the control means is arranged to control the temperature alteration means to alter the temperature in the passenger compartment at the latest time possible to achieve the pre-set temperature by the pre-set time of day.

3. A climatic control system according to Claim 1 or Claim 2 wherein the pre-set temperature is programmed by the programming means.

4. A climatic control system according to any one of Claims 1 to 3 wherein the control means further comprises a sensor means.

5. A climatic control system according to Claim 4 wherein the time at which the temperature alteration means is controlled to alter the temperature of said compartment is adjustable in response to signals received from the sensor means.

6. A climatic control system according to Claim 4 or Claim 5 wherein the rate at which the temperature alteration means is arranged to alter the temperature of said compartment is adjustable in response to signals received from the sensor means.

7. A climatic control system according to any one of Claims 4 to 6 wherein the sensor means comprises an interior temperature sensor arranged to provide an interior temperature signal indicative of the interior temperature of the passenger compartment.

8. A climatic control system according to any one of Claims 4 to 7 wherein the sensor means comprises an exterior temperature sensor arranged to provide an exterior temperature signal indicative of the ambient temperature.

9. A climatic control system according to any one of Claims 4 to 8 wherein the sensor means comprises a solar heat input sensor arranged to provide a signal indicative of the rate of solar heat input to the passenger compartment.

10. A climatic control system according to any preceding Claim wherein the temperature alteration means comprises a fuel burning heater system.

11. A climatic control system according to Claim 10 wherein the fuel burning heater system is arranged to heat a coolant fluid of an engine cooling system of the vehicle, and the system further comprises a heater unit arranged to transfer heat to the passenger compartment from the coolant fluid while the fuel burning heater operates.

12. A climatic control system according to Claim 11 further comprising a pump arranged to pump the coolant fluid around the cooling system when the engine is not running and the coolant fluid is being heated by the fuel burning heater system.

13. A climatic control system according to Claim 11 or Claim 12 wherein the control means comprises an air conditioning control system arranged to control the output of heat from the heater unit and a burner control unit in communication with the programming means to control the fuel burning heater system.

14. A climatic control system according to any one of Claims 1 to 9 wherein the temperature alteration means comprises an electrically powered heater unit.

15. A climatic control system according to Claim 14 wherein the heater unit is powered from a power source not forming part of the vehicle.

16. A climatic control system according to any one of Claims 1 to 9 wherein the temperature alteration means comprises at least one thermal battery.

17. A climatic control system substantially as described herein with reference to the accompanying drawing.

18. A vehicle having a climatic control system according to any preceding Claim.