WO2009112847A1 - Automotive climate control systems - Google Patents

Automotive climate control systems Download PDF

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Publication number
WO2009112847A1
WO2009112847A1 PCT/GB2009/000692 GB2009000692W WO2009112847A1 WO 2009112847 A1 WO2009112847 A1 WO 2009112847A1 GB 2009000692 W GB2009000692 W GB 2009000692W WO 2009112847 A1 WO2009112847 A1 WO 2009112847A1
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WO
WIPO (PCT)
Prior art keywords
vehicle
engine
air
air conditioning
idling
Prior art date
Application number
PCT/GB2009/000692
Other languages
French (fr)
Inventor
Michael John Ormerod
Original Assignee
Ricardo Uk Limited
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Filing date
Publication date
Application filed by Ricardo Uk Limited filed Critical Ricardo Uk Limited
Publication of WO2009112847A1 publication Critical patent/WO2009112847A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
    • B60H1/00—Heating, cooling or ventilating [HVAC] devices
    • B60H1/00642—Control systems or circuits; Control members or indication devices for heating, cooling or ventilating devices
    • B60H1/00735—Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models
    • B60H1/00764—Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models the input being a vehicle driving condition, e.g. speed
    • B60H1/00771—Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models the input being a vehicle driving condition, e.g. speed the input being a vehicle position or surrounding, e.g. GPS-based position or tunnel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
    • B60H1/00—Heating, cooling or ventilating [HVAC] devices
    • B60H1/00642—Control systems or circuits; Control members or indication devices for heating, cooling or ventilating devices
    • B60H1/00735—Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models
    • B60H1/00764—Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models the input being a vehicle driving condition, e.g. speed
    • B60H1/00778—Control systems or circuits characterised by their input, i.e. by the detection, measurement or calculation of particular conditions, e.g. signal treatment, dynamic models the input being a vehicle driving condition, e.g. speed the input being a stationary vehicle position, e.g. parking or stopping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60H—ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
    • B60H1/00—Heating, cooling or ventilating [HVAC] devices
    • B60H1/00642—Control systems or circuits; Control members or indication devices for heating, cooling or ventilating devices
    • B60H1/0073—Control systems or circuits characterised by particular algorithms or computational models, e.g. fuzzy logic or dynamic models
    • B60H2001/00733—Computational models modifying user-set values

Definitions

  • climate control system embraces both air conditioning systems, which cool and ventilate the interior of the vehicle, and heating systems, which heat and ventilate the interior of the vehicle, and also composite systems, which perform both functions.
  • the application is concerned with minimising the fuel consumption of the motor vehicle in which the climate control system is incorporated.
  • Automotive air conditioning systems are powered by the engine of the vehicle to which they are fitted and this is typically done by connecting the refrigerant compressor directly or indirectly to the engine crankshaft, typically by way of one or more pulley belts.
  • the input power to produce a given amount of refrigeration output is of course constant but if this power is taken from the engine when it is idling or operating under low load, the amount of fuel required to produce the necessary input power will be higher than when the engine is running at relatively high load due to the decreased efficiency of operation under low load conditions, as discussed above.
  • a vehicle that travels a predetermined distance with its air conditioning system operating will use more fuel to power the air conditioning system if there is, for instance, heavy traffic necessitating it to repeatedly stop and start, whereby the engine repeatedly enters idling mode, than if the vehicle travels the same distance at a relatively high speed, not only because the air conditioning system will have to operate for a longer period of time but also because the amount of fuel needed per unit time to power the air conditioning system is greater.
  • the fan is typically an electric fan, which is powered by electricity produced by the vehicle alternator. When the alternator is generating electricity, e.g. because the heating fan is operating, this constitutes an increased load on the vehicle engine.
  • the heated body may be heated by the heat produced by the engine but increasingly electrical heating bodies are used which are again powered by the vehicle alternator. If the heating system is operated whilst the engine is idling or in low load operation this will consume more fuel, due to the inefficiency of operation under low loads discussed above, than to produce the same heating effect when the engine is operating under higher load and thus more efficiently.
  • An idle-stop facility will enhance the fuel economy of a hybrid vehicle but if the vehicle is fitted with an air conditioning system, this system will of course stop operating each time the vehicle engine is switched off and this may result in an unacceptable temperature rise within the vehicle.
  • the heating system may be operated when the vehicle engine is not running, the electrical load of the heater fan and of the heating body, if it is of electrical type, will necessarily have to be taken from the vehicle battery and the inefficiency inherently associated with charging and discharging batteries will mean that the fuel required to subsequently recharge the battery is greater than that which would have been required to power the heating system directly from the vehicle alternator.
  • Fig. 1 shows an implementation of a first embodiment of an automotive climate control system
  • Fig. 2 is a flow chart illustrating an embodiment of a method of operating an automotive air conditioning system
  • Fig. 3 is a flow chart illustrating a further embodiment of a method of operating an automotive air conditioning system
  • Fig. 4 is a flow chart illustrating an embodiment of a method of operating an automotive air heating system
  • Fig. 5 is a flow chart illustrating a further embodiment of a method of operating an automotive air heating system
  • Fig. 6 is a flow chart illustrating a further embodiment of a method of operating an automotive climate control system.
  • an apparatus for and a method of operating an automotive climate control system which is installed in a motor vehicle and is powered by the engine of the vehicle, the climate control system including a temperature sensor and a controller programmed to maintain the temperature within the vehicle substantially at a set value, the method including receiving at the controller a signal indicative of a time when the engine is likely to start idling or operating under low load conditions and adjusting the set value so as to increase the climate control effect to the interior of the vehicle and reducing the output of the climate control system when the engine commences idling or low load operation.
  • Fig. 1 shows an automotive climate control system 10 that is installed in a motor vehicle and is powered by the engine of the vehicle.
  • the climate control system 10 includes a temperature sensor 12, a temperature selector 14, a climate control device 16 and a controller 18.
  • the controller 18 is programmed to maintain the temperature within the vehicle substantially at a set value as set by the temperature selector 14.
  • the climate control device 16 may be one or both of an air conditioning system, the climate control effect of which is to maintain a cooled ambient temperature in a vehicle, or a heating system, the climate control effect of which is to maintain a heated ambient temperature in a vehicle.
  • the climate control effect is the reduction in temperature and, for an air heating system, the climate control effect is an increase in temperature.
  • the controller 18 of the automotive climate control system 10 also has an input for receiving a signal (2) indicative of a time when the engine is likely to start idling or operating under low load conditions signal.
  • the signal may be derived from a telematic device, a global positioning system, a map- based navigation system, a traffic information device, radio traffic reports or from roadside information transmitters or from the controller.
  • the signal may be produced when the vehicle restarts after having stopped.
  • the controller 18 is programmed to adjust the set value so as to reduce or increase (as appropriate given the climate control device operating) the temperature of the interior of the vehicle prior to the time when the engine commences idling or low load operation and reduce the output of the climate control system when the engine commences idling or low load operation.
  • the set value is moved downwardly so as to reduce the temperature within the vehicle prior to the time when the engine commences idling or low load operation, and, when the operating climate control device 16 is a heating system, the set value is moved upwardly so as to increase the temperature within the vehicle prior to the time when the engine commences idling or low load operation. In each case, the output of the climate control system is then reduced when the engine commences idling or low load operation.
  • the automotive climate control system and the described method of operating it is intended to reduce the specific fuel consumption of the vehicle whilst nevertheless maintaining the interior of the vehicle at least substantially within or relatively close to the desired temperature range as set on the temperature selector 14.
  • an automotive air conditioning system which is installed in a motor vehicle and is powered by the engine of the vehicle, the air conditioning system including a temperature sensor 12 and a controller 18 programmed to maintain the temperature within the vehicle substantially at a set value.
  • the method includes receiving 202, and inputting into the controller 18, a signal indicative of a time when the engine is likely to start idling or operating under low load conditions and, in response, moving the set value downwardly 204 so as to reduce the temperature within the vehicle and reducing 206 the cooling output of the air conditioning system when the engine commences idling or low load operation.
  • the desired temperature within the vehicle is set by the user on a temperature selector 14 and the control system of the air conditioning system or the air heating system maintains the temperature within the vehicle substantially at that temperature.
  • the controller was traditionally set such that the temperature within the vehicle cycled within a narrow range. Thus the controller would switch on the cooling output of the air conditioning system when the temperature rises to, say, 1°C above the set temperature and then switches it off again when it falls to, say, I 0 C below the set temperature.
  • the air heating system would be switched on when the temperature falls to, say, I 0 C below the set temperature and would be switched off when the temperature rises to, say, 1°C above the said temperature.
  • More modern systems now use a proportional integral controller to reduce any deviation from the set point.
  • the method proposed takes a totally different course.
  • a signal is derived which indicates a time when the vehicle is likely to start idling or operating under low load conditions, e.g.
  • the controller moves the set value of the temperature, e.g. by between I 0 C and 3 0 C downwardly, so as to lower the temperature within the vehicle when an air conditioning system is in operation.
  • the cooling output of the air conditioning system is reduced or terminated and the temperature within the vehicle will then gradually begin to rise.
  • most stoppages of this sort are relatively brief and the temperature within the vehicle will generally not rise significantly above the previous set value before the vehicle starts moving again at an appreciable speed, that is to say before the engine recommences operation under higher load conditions 208. Normal operation of the air conditioning system is then resumed 210.
  • the control system thus cools the interior of the vehicle to a temperature lower than usual before a stoppage occurs, thereby obviating the necessity to operate the air conditioning system when the vehicle is not moving or is moving only very slowly and the engine is therefore operating under a low load, which is typically 5% or less of the nominal rated output of the engine.
  • the air conditioning system may be powered directly by the engine of the vehicle, that is to say by virtue of a mechanical connection between the crankshaft and the refrigerant compressor, or indirectly, that is to say the refrigerant compressor is electrically operated and is powered by the vehicle battery, which is in turn recharged by the vehicle alternator which is mechanically driven by the engine. If the refrigerant compressor forming part of the air conditioning system is connected to be driven mechanically by the engine at a constant speed relationship with the engine, the reduction in the cooling output may constitute reducing the output to zero, that is to say terminating the output of the refrigerant compressor.
  • the compressor is of variable output type, its cooling output may be reduced to a reduced value whilst running at constant speed. If the refrigerant compressor may be driven at a variable speed with respect to the speed of the engine or if it is electrically driven, its cooling output may be terminated or reduced significantly, as desired.
  • the air conditioning system may include a cooling fan and the cooling output of the air conditioning system may be reduced by reducing the speed of the cooling fan.
  • the method may further include increasing the cooling output of the air conditioning system 312 when the temperature within the vehicle rises to a predetermined value above the set value whilst the engine is in idling or low load operation, as illustrated in Fig. 3, where like numerals refer to like operations as previously described with reference to Fig. 2.
  • the air inlet to automotive air conditioning systems may be selectively connectable to the exterior of the vehicle, which means that the system will draw in air at ambient temperature, and to the interior of the vehicle, which will result in the air within the vehicle being recycled.
  • a greater cooling output is of course required if the inlet air to the air conditioning system is relatively warm and the method may further include connecting the air inlet to the interior of the vehicle after moving the set value downwardly and/or after the engine has commenced idling or low load operation. This is also illustrated in Fig. 3, as operation 314. Both operation 312 and 314 may be implemented or one or the other may be implemented.
  • climate control system described is applicable to conventional motor vehicles, it is applicable also to motor vehicles of hybrid type, including those with an idle-stop facility, that is to say those which are arranged to switch off the vehicle engine when in idling mode in order to save fuel and thus increase the overall efficiency of the engine. If the refrigerant compressor is operated electrically, it is of course possible to operate it at a low output level, or indeed a full output level, even when the engine is not running.
  • FIG. 4 shows an embodiment when the air heating system is in operation 401, and the method includes receiving 402, and inputting into the controller, a signal indicative of a time when the engine is likely to start idling or operating under low load conditions and in response moving the set value upwardly 404 so as to increase the temperature within the vehicle and reducing 406 the heating output of the heating system when the engine commences idling or low load operation.
  • a signal indicative of a time when the engine is likely to start idling or operating under low load conditions and in response moving the set value upwardly 404 so as to increase the temperature within the vehicle and reducing 406 the heating output of the heating system when the engine commences idling or low load operation.
  • most stoppages of this sort are relatively brief and the temperature within the vehicle will generally not fall significantly below the previous set value before the vehicle starts moving again at an appreciable speed, that is to say before the engine recommences operation under higher load conditions 408. Normal operation of the air heating system is then resumed 410.
  • This method is precisely analogous to the method referred to above of operating an air conditioning system but in this case the set value of the temperature is moved upwardly once a signal is received indicating that a period of idling or low load operation is likely in the near future and the interior of the vehicle is then heated up to a temperature somewhat above the previously set temperature, e.g. 2°C to 3 0 C above the previously set temperature.
  • the heating system will be powered by the engine in the sense that it will use heat produced by the engine, e.g. by passing air over a heat exchanger, or alternatively it will use an electrical heater which is powered by the vehicle battery, which is recharged by the vehicle alternator, which is J connected to be mechanically driven by the engine.
  • the fan that is commonly associated with the heat exchanger or electrical heater may also be mechanically or electrically driven.
  • the heat output of the air heating system is reduced or terminated 406. If the air heating system includes an electric heating fan, this may be done by reducing the speed of the heating fan or switching it off entirely. If the air heating system includes an electrical heater, the heating output of the heating system may be reduced by reducing the electrical power consumption of the electrical heater, either to a low value or to zero.
  • a further implementation as illustrated in Fig. 5 involves that the air inlet to the air heating system is selectively connectable 514 to the exterior of the vehicle and to the interior of the vehicle, whereby the air within the vehicle is recycled, and the method may include connecting 514 the air inlet to the interior of the vehicle after moving the set value upwardly and/or after the engine has commenced idling or low load operation. Recycling the air within the vehicle after the set value has been moved upwardly will result in the interior of the vehicle heating up to the new set value more rapidly than would otherwise have been the case.
  • the effect of doing this after the engine has commenced idling or low load operation is to reduce the rate at which the interior of the vehicle will cool down towards ambient temperature during a period of idling or low load operation of the engine.
  • the method may include increasing 512 the heating output of the air heating system when the temperature within the vehicle falls to a predetermined value below the set value whilst the engine is in idling or low load operation, as also illustrated in Fig. 5. Whilst providing an acceptable temperature within the motor vehicle is important for the comfort of the passengers, it is also important that the carbon dioxide content of the air within the vehicle does not rise to an unacceptably high level.
  • the method therefore may also include sensing the CO 2 content of the air within the vehicle 616 and changing the air inlet from being connected to the interior of the vehicle to being connected to the exterior of the vehicle when the CO 2 contents exceeds a predetermined level or if it is likely that the CO 2 content will exceed the predetermined level during the next occasion when it is likely that the engine will commence idling or low load operation.
  • a signal is received indicating that a period of idling or low load operation is imminent, it may be desirable to switch the air conditioning system or the air heating system to be connected to the exterior of the vehicle for a period of time so as to reduce the CO 2 content of the air within the vehicle to a low level such that when the period of idling or low load operation commences it will be acceptable for the air conditioning system or the air heating system to be operated in recycling mode because it will then take some time for the CO 2 content within the vehicle to reach an unacceptably high level.
  • the engine of the vehicle will operate within a range of different levels of efficiency depending on the speed of the engine and the load to which it is subjected.
  • the air conditioning system and the air heating system constitute a load on the engine, when they are in operation, and switching the air conditioning system or the air heating system on or off, thereby altering the load to which the engine is subjected can result in not insignificant changes in the operating efficiency of the engine.
  • the method may make use of this fact and the method may include sensing the efficiency with which the engine is operating or one or more parameters indicative of that efficiency and subsequently increasing or decreasing the output of the air conditioning system or the air heating system if doing so would result in the engine operating at a higher efficiency.
  • switching on the air conditioning system or the air heating system may increase the load to a level at which the engine will operate with a higher efficiency and the control system may be programmed to operate the air conditioning system and/or the air heating system intermittently at times which are selected to maximise the overall operating efficiency of the engine.
  • the signal (2) indicating that the vehicle is likely to have to stop or move very slowly in the relatively near future may be derived from one or more of numerous sources. These include a telematic system, a global positioning system, a map-based navigation system, a traffic information device, radio traffic reports or roadside information transmitters. A further potential source for the signal is a satellite navigation system which may be able to see heavy or stationary traffic or the like ahead on the road. A further possible source of the signal is the controller itself. Thus if the vehicle has already stopped two or three times within a relatively short period of time, the likelihood is that the vehicle is moving forward slowly in a traffic jam and thus that it is likely to stop again in the relatively near future.
  • stoppages may be sensed by the controller which then produces a signal indicative of the fact that a further stoppage is likely in the near future.
  • route learning by the controller, which, by the use of neural networks or the like, will match control variables such as throttle position and speed to learned patterns so as to determine if the vehicle is on a known route involving likely stops at various positions. In this event, the signal will again be produced by the controller itself.
  • an automotive climate control system that is to say an automotive air conditioning system or an automotive air heating system, but also an automotive climate control system per se which is installed in a motor vehicle and connected to be powered by the engine of the vehicle, the system including a temperature sensor and a controller programmed to perform the method referred to above.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Air-Conditioning For Vehicles (AREA)

Abstract

There is provided an apparatus for and a method of operating an automotive climate control system which is installed in a motor vehicle and is powered by the engine of the vehicle, the climate control system including a temperature sensor (12) and a controller (18) programmed to maintain the temperature within the vehicle substantially at a set value, the method including inputting into the controller (18) a signal indicative of a time when the engine is likely to start idling or operating under low load conditions and moving the set value so as to maintain or increase the output of a climate control system (16) to the interior of the vehicle and reducing the output of the climate control system (16) when the engine commences idling or low load operation. The climate control device (16) may be one or both of an air conditioning system, intended to maintain a cooled ambient temperature in a vehicle, or a heating system, intended to maintain a heated ambient temperature in a vehicle.

Description

AUTOMOTIVE CLIMATE CONTROL SYSTEMS
The present application relates to automotive climate control systems, that is to say climate control systems installed on a motor vehicle, and to a method of operating such systems. The term "climate control system" embraces both air conditioning systems, which cool and ventilate the interior of the vehicle, and heating systems, which heat and ventilate the interior of the vehicle, and also composite systems, which perform both functions. The application is concerned with minimising the fuel consumption of the motor vehicle in which the climate control system is incorporated.
Internal combustion engines of all types, that is to say of both spark ignition (SI) and compression ignition (CI) types, run less efficiently when idling or in a low load state than when in a higher load state. Thus the specific fuel consumption of an automotive engine, that is to say the mass of fuel consumed per second per unit power output, improves or reduces with increasing load due to lower pumping losses past the throttle in SI engines and better atomisation and mixing of the fuel in CI engines, together with gas dynamic tuning effects and power per unit torque rising with increasing engine speed.
Automotive air conditioning systems are powered by the engine of the vehicle to which they are fitted and this is typically done by connecting the refrigerant compressor directly or indirectly to the engine crankshaft, typically by way of one or more pulley belts. The input power to produce a given amount of refrigeration output is of course constant but if this power is taken from the engine when it is idling or operating under low load, the amount of fuel required to produce the necessary input power will be higher than when the engine is running at relatively high load due to the decreased efficiency of operation under low load conditions, as discussed above. Thus a vehicle that travels a predetermined distance with its air conditioning system operating will use more fuel to power the air conditioning system if there is, for instance, heavy traffic necessitating it to repeatedly stop and start, whereby the engine repeatedly enters idling mode, than if the vehicle travels the same distance at a relatively high speed, not only because the air conditioning system will have to operate for a longer period of time but also because the amount of fuel needed per unit time to power the air conditioning system is greater.
A similar problem arises with automotive heating systems. These typically include an electric fan which passes air over a heated body in order to heat the air and then blows the heated air into the interior of the motor vehicle. Such systems are also powered by the engine of the vehicle. The fan is typically an electric fan, which is powered by electricity produced by the vehicle alternator. When the alternator is generating electricity, e.g. because the heating fan is operating, this constitutes an increased load on the vehicle engine. The heated body may be heated by the heat produced by the engine but increasingly electrical heating bodies are used which are again powered by the vehicle alternator. If the heating system is operated whilst the engine is idling or in low load operation this will consume more fuel, due to the inefficiency of operation under low loads discussed above, than to produce the same heating effect when the engine is operating under higher load and thus more efficiently.
A slightly different problem arises with hybrid vehicles with an "idle-stop" facility, that is to say a sensor which automatically turns the engine off each time the vehicle engine enters idling mode or has been in that mode for a predetermined period of time. An idle-stop facility will enhance the fuel economy of a hybrid vehicle but if the vehicle is fitted with an air conditioning system, this system will of course stop operating each time the vehicle engine is switched off and this may result in an unacceptable temperature rise within the vehicle. This problem could be overcome by overriding the idle-stop facility and ensuring that the vehicle engine remains running even when the vehicle engine is idling but this would negate much of the benefit to be achieved by a hybrid vehicle and would also mean that the air conditioning system would have to be powered by the vehicle engine in idling mode, which, as discussed above, is inefficient. Alternatively, the air conditioning system could be operated electrically by the vehicle battery but the inefficiency inherently associated with charging and discharging a battery means that this possibility will also lead to an overall increase in the specific fuel consumption of the engine. Similarly, although the heating system may be operated when the vehicle engine is not running, the electrical load of the heater fan and of the heating body, if it is of electrical type, will necessarily have to be taken from the vehicle battery and the inefficiency inherently associated with charging and discharging batteries will mean that the fuel required to subsequently recharge the battery is greater than that which would have been required to power the heating system directly from the vehicle alternator.
The system will now be described by way of example only with reference to the accompanying drawings, in which:
Fig. 1 shows an implementation of a first embodiment of an automotive climate control system;
Fig. 2 is a flow chart illustrating an embodiment of a method of operating an automotive air conditioning system; Fig. 3 is a flow chart illustrating a further embodiment of a method of operating an automotive air conditioning system;
Fig. 4 is a flow chart illustrating an embodiment of a method of operating an automotive air heating system; Fig. 5 is a flow chart illustrating a further embodiment of a method of operating an automotive air heating system; and
Fig. 6 is a flow chart illustrating a further embodiment of a method of operating an automotive climate control system.
There is provided an apparatus for and a method of operating an automotive climate control system which is installed in a motor vehicle and is powered by the engine of the vehicle, the climate control system including a temperature sensor and a controller programmed to maintain the temperature within the vehicle substantially at a set value, the method including receiving at the controller a signal indicative of a time when the engine is likely to start idling or operating under low load conditions and adjusting the set value so as to increase the climate control effect to the interior of the vehicle and reducing the output of the climate control system when the engine commences idling or low load operation.
Fig. 1 shows an automotive climate control system 10 that is installed in a motor vehicle and is powered by the engine of the vehicle. The climate control system 10 includes a temperature sensor 12, a temperature selector 14, a climate control device 16 and a controller 18. The controller 18 is programmed to maintain the temperature within the vehicle substantially at a set value as set by the temperature selector 14. The climate control device 16 may be one or both of an air conditioning system, the climate control effect of which is to maintain a cooled ambient temperature in a vehicle, or a heating system, the climate control effect of which is to maintain a heated ambient temperature in a vehicle. Thus, in an air conditioning system, the climate control effect is the reduction in temperature and, for an air heating system, the climate control effect is an increase in temperature. The controller 18 of the automotive climate control system 10 also has an input for receiving a signal (2) indicative of a time when the engine is likely to start idling or operating under low load conditions signal. For instance, the signal may be derived from a telematic device, a global positioning system, a map- based navigation system, a traffic information device, radio traffic reports or from roadside information transmitters or from the controller. Alternatively, the signal may be produced when the vehicle restarts after having stopped.
In response to the signal (2), the controller 18 is programmed to adjust the set value so as to reduce or increase (as appropriate given the climate control device operating) the temperature of the interior of the vehicle prior to the time when the engine commences idling or low load operation and reduce the output of the climate control system when the engine commences idling or low load operation.
Thus, when the operating climate control device 16 is an air conditioning system, the set value is moved downwardly so as to reduce the temperature within the vehicle prior to the time when the engine commences idling or low load operation, and, when the operating climate control device 16 is a heating system, the set value is moved upwardly so as to increase the temperature within the vehicle prior to the time when the engine commences idling or low load operation. In each case, the output of the climate control system is then reduced when the engine commences idling or low load operation.
The automotive climate control system and the described method of operating it is intended to reduce the specific fuel consumption of the vehicle whilst nevertheless maintaining the interior of the vehicle at least substantially within or relatively close to the desired temperature range as set on the temperature selector 14. There is provided a method of operating an automotive air conditioning system which is installed in a motor vehicle and is powered by the engine of the vehicle, the air conditioning system including a temperature sensor 12 and a controller 18 programmed to maintain the temperature within the vehicle substantially at a set value. Fig. 2 shows an embodiment when the air conditioning system is in operation 201, and the method includes receiving 202, and inputting into the controller 18, a signal indicative of a time when the engine is likely to start idling or operating under low load conditions and, in response, moving the set value downwardly 204 so as to reduce the temperature within the vehicle and reducing 206 the cooling output of the air conditioning system when the engine commences idling or low load operation.
In normal operation of an automotive climate control system, the desired temperature within the vehicle is set by the user on a temperature selector 14 and the control system of the air conditioning system or the air heating system maintains the temperature within the vehicle substantially at that temperature. In a conventional system, in which the air cooling or air heating is either on or off, the controller was traditionally set such that the temperature within the vehicle cycled within a narrow range. Thus the controller would switch on the cooling output of the air conditioning system when the temperature rises to, say, 1°C above the set temperature and then switches it off again when it falls to, say, I0C below the set temperature. Similarly, the air heating system would be switched on when the temperature falls to, say, I0C below the set temperature and would be switched off when the temperature rises to, say, 1°C above the said temperature. More modern systems now use a proportional integral controller to reduce any deviation from the set point. In order to avoid either switching off the air conditioning system when the vehicle is idling or operating under low load conditions, e.g. waiting in a queue of traffic, or powering the air conditioning system by the vehicle engine when it is operating very inefficiently, the method proposed takes a totally different course. A signal is derived which indicates a time when the vehicle is likely to start idling or operating under low load conditions, e.g. when a traffic jam or traffic lights are likely to be encountered, and the controller then moves the set value of the temperature, e.g. by between I0C and 30C downwardly, so as to lower the temperature within the vehicle when an air conditioning system is in operation. When the vehicle actually reaches the traffic jam or the like, the cooling output of the air conditioning system is reduced or terminated and the temperature within the vehicle will then gradually begin to rise. However, in practice most stoppages of this sort are relatively brief and the temperature within the vehicle will generally not rise significantly above the previous set value before the vehicle starts moving again at an appreciable speed, that is to say before the engine recommences operation under higher load conditions 208. Normal operation of the air conditioning system is then resumed 210. The control system thus cools the interior of the vehicle to a temperature lower than usual before a stoppage occurs, thereby obviating the necessity to operate the air conditioning system when the vehicle is not moving or is moving only very slowly and the engine is therefore operating under a low load, which is typically 5% or less of the nominal rated output of the engine.
This results not only in a reduction in the specific fuel consumption of the vehicle but also in a reduction in the emission of harmful pollutants. It will be appreciated that the air conditioning system may be powered directly by the engine of the vehicle, that is to say by virtue of a mechanical connection between the crankshaft and the refrigerant compressor, or indirectly, that is to say the refrigerant compressor is electrically operated and is powered by the vehicle battery, which is in turn recharged by the vehicle alternator which is mechanically driven by the engine. If the refrigerant compressor forming part of the air conditioning system is connected to be driven mechanically by the engine at a constant speed relationship with the engine, the reduction in the cooling output may constitute reducing the output to zero, that is to say terminating the output of the refrigerant compressor. However, if the compressor is of variable output type, its cooling output may be reduced to a reduced value whilst running at constant speed. If the refrigerant compressor may be driven at a variable speed with respect to the speed of the engine or if it is electrically driven, its cooling output may be terminated or reduced significantly, as desired. Alternatively, or additionally, the air conditioning system may include a cooling fan and the cooling output of the air conditioning system may be reduced by reducing the speed of the cooling fan.
In practice, most stoppages are relatively brief and if the temperature within the vehicle has been reduced to a temperature a few degrees below the normal temperature prior to the stoppage, it is likely to be possible in most cases for the output of the air conditioning system to be terminated or substantially reduced for the entire duration of the stoppage. If, however, the stoppage is a long one, the temperature within the vehicle will gradually rise towards ambient temperature and, in order to avoid the temperature rising to an uncomfortable level, the method may further include increasing the cooling output of the air conditioning system 312 when the temperature within the vehicle rises to a predetermined value above the set value whilst the engine is in idling or low load operation, as illustrated in Fig. 3, where like numerals refer to like operations as previously described with reference to Fig. 2.
It is very common for the air inlet to automotive air conditioning systems to be selectively connectable to the exterior of the vehicle, which means that the system will draw in air at ambient temperature, and to the interior of the vehicle, which will result in the air within the vehicle being recycled. A greater cooling output is of course required if the inlet air to the air conditioning system is relatively warm and the method may further include connecting the air inlet to the interior of the vehicle after moving the set value downwardly and/or after the engine has commenced idling or low load operation. This is also illustrated in Fig. 3, as operation 314. Both operation 312 and 314 may be implemented or one or the other may be implemented. Connecting the air inlet to the interior of the vehicle immediately after the set value has been moved downwardly will result in the temperature within the vehicle falling more rapidly than would otherwise be the case. The result of this once the vehicle has commenced idling or low load operation is that the interior of the vehicle will warm up towards ambient temperature more slowly than would otherwise have been the case.
Whilst the climate control system described is applicable to conventional motor vehicles, it is applicable also to motor vehicles of hybrid type, including those with an idle-stop facility, that is to say those which are arranged to switch off the vehicle engine when in idling mode in order to save fuel and thus increase the overall efficiency of the engine. If the refrigerant compressor is operated electrically, it is of course possible to operate it at a low output level, or indeed a full output level, even when the engine is not running. This is, however, not possible in that type of air conditioning system in which the refrigerant compressor is mechanically operated by the engine and the method may include restarting the engine when the temperature within the vehicle rises to a predetermined value above the set value so as to prevent the temperature within such a vehicle rising to an unacceptable level in such a vehicle whilst the engine is switched off. Very similar considerations apply to the load applied to the engine of a motor vehicle by the operation of an air heating system and thus according to a further aspect there is provided a method of operating an automotive air heating system which is installed in a motor vehicle and is powered by the engine of the vehicle, the heating system including a temperature sensor and a controller programmed to maintain the temperature within the vehicle substantially at a set value. Fig. 4 shows an embodiment when the air heating system is in operation 401, and the method includes receiving 402, and inputting into the controller, a signal indicative of a time when the engine is likely to start idling or operating under low load conditions and in response moving the set value upwardly 404 so as to increase the temperature within the vehicle and reducing 406 the heating output of the heating system when the engine commences idling or low load operation. In practice most stoppages of this sort are relatively brief and the temperature within the vehicle will generally not fall significantly below the previous set value before the vehicle starts moving again at an appreciable speed, that is to say before the engine recommences operation under higher load conditions 408. Normal operation of the air heating system is then resumed 410.
This method is precisely analogous to the method referred to above of operating an air conditioning system but in this case the set value of the temperature is moved upwardly once a signal is received indicating that a period of idling or low load operation is likely in the near future and the interior of the vehicle is then heated up to a temperature somewhat above the previously set temperature, e.g. 2°C to 30C above the previously set temperature. The heating system will be powered by the engine in the sense that it will use heat produced by the engine, e.g. by passing air over a heat exchanger, or alternatively it will use an electrical heater which is powered by the vehicle battery, which is recharged by the vehicle alternator, which is J connected to be mechanically driven by the engine. The fan that is commonly associated with the heat exchanger or electrical heater may also be mechanically or electrically driven.
When the traffic jam or the like is actually encountered, the heat output of the air heating system is reduced or terminated 406. If the air heating system includes an electric heating fan, this may be done by reducing the speed of the heating fan or switching it off entirely. If the air heating system includes an electrical heater, the heating output of the heating system may be reduced by reducing the electrical power consumption of the electrical heater, either to a low value or to zero.
As with the method of controlling the air conditioning system, a further implementation as illustrated in Fig. 5 involves that the air inlet to the air heating system is selectively connectable 514 to the exterior of the vehicle and to the interior of the vehicle, whereby the air within the vehicle is recycled, and the method may include connecting 514 the air inlet to the interior of the vehicle after moving the set value upwardly and/or after the engine has commenced idling or low load operation. Recycling the air within the vehicle after the set value has been moved upwardly will result in the interior of the vehicle heating up to the new set value more rapidly than would otherwise have been the case. The effect of doing this after the engine has commenced idling or low load operation is to reduce the rate at which the interior of the vehicle will cool down towards ambient temperature during a period of idling or low load operation of the engine. Similarly the method may include increasing 512 the heating output of the air heating system when the temperature within the vehicle falls to a predetermined value below the set value whilst the engine is in idling or low load operation, as also illustrated in Fig. 5. Whilst providing an acceptable temperature within the motor vehicle is important for the comfort of the passengers, it is also important that the carbon dioxide content of the air within the vehicle does not rise to an unacceptably high level. When the inlet to the air conditioning system or the air heating system is connected to the exterior of the vehicle, the air within the vehicle will be constantly changed and the CO2 content of the air will not rise significantly. However, if the air conditioning system or air heating system is operating in recycling mode, the CO2 content of the air will rise progressively. It is of course important that the CO2 content of the air is not permitted to rise to an unacceptable level. As illustrated in Fig. 6, the method therefore may also include sensing the CO2 content of the air within the vehicle 616 and changing the air inlet from being connected to the interior of the vehicle to being connected to the exterior of the vehicle when the CO2 contents exceeds a predetermined level or if it is likely that the CO2 content will exceed the predetermined level during the next occasion when it is likely that the engine will commence idling or low load operation. Thus if a signal is received indicating that a period of idling or low load operation is imminent, it may be desirable to switch the air conditioning system or the air heating system to be connected to the exterior of the vehicle for a period of time so as to reduce the CO2 content of the air within the vehicle to a low level such that when the period of idling or low load operation commences it will be acceptable for the air conditioning system or the air heating system to be operated in recycling mode because it will then take some time for the CO2 content within the vehicle to reach an unacceptably high level.
The engine of the vehicle will operate within a range of different levels of efficiency depending on the speed of the engine and the load to which it is subjected. The air conditioning system and the air heating system constitute a load on the engine, when they are in operation, and switching the air conditioning system or the air heating system on or off, thereby altering the load to which the engine is subjected can result in not insignificant changes in the operating efficiency of the engine. The method may make use of this fact and the method may include sensing the efficiency with which the engine is operating or one or more parameters indicative of that efficiency and subsequently increasing or decreasing the output of the air conditioning system or the air heating system if doing so would result in the engine operating at a higher efficiency. Thus if the engine is operating under relatively low load, switching on the air conditioning system or the air heating system may increase the load to a level at which the engine will operate with a higher efficiency and the control system may be programmed to operate the air conditioning system and/or the air heating system intermittently at times which are selected to maximise the overall operating efficiency of the engine.
The signal (2) indicating that the vehicle is likely to have to stop or move very slowly in the relatively near future may be derived from one or more of numerous sources. These include a telematic system, a global positioning system, a map-based navigation system, a traffic information device, radio traffic reports or roadside information transmitters. A further potential source for the signal is a satellite navigation system which may be able to see heavy or stationary traffic or the like ahead on the road. A further possible source of the signal is the controller itself. Thus if the vehicle has already stopped two or three times within a relatively short period of time, the likelihood is that the vehicle is moving forward slowly in a traffic jam and thus that it is likely to stop again in the relatively near future. Such stoppages may be sensed by the controller which then produces a signal indicative of the fact that a further stoppage is likely in the near future. As still further possibility is route learning by the controller, which, by the use of neural networks or the like, will match control variables such as throttle position and speed to learned patterns so as to determine if the vehicle is on a known route involving likely stops at various positions. In this event, the signal will again be produced by the controller itself.
There is not only provided a method of operating an automotive climate control system, that is to say an automotive air conditioning system or an automotive air heating system, but also an automotive climate control system per se which is installed in a motor vehicle and connected to be powered by the engine of the vehicle, the system including a temperature sensor and a controller programmed to perform the method referred to above.
There is also provided a computer program including code portions executable by a controller to cause the controller to execute a method of the type referred to above.

Claims

1. A method of operating an automotive air conditioning system which is installed in a motor vehicle and is powered by the engine of the vehicle, the air conditioning system including a temperature sensor and a controller programmed to maintain the temperature within the vehicle substantially at a set value, the method including inputting into the controller a signal indicative of a time when the engine is likely to start idling or operating under low load conditions and moving the set value downwardly so as to reduce the temperature within the vehicle and reducing the cooling output of the air conditioning system when the engine commences idling or low load operation.
2. A method as claimed in Claim 1 in which the air conditioning system includes a refrigerant compressor and the cooling output of the air conditioning system is reduced by reducing the output of the refrigerant compressor.
3. A method as claimed in Claim 1 or 2 in which the air conditioning system includes a cooling fan and the cooling output of the air conditioning system is reduced by reducing the speed of the cooling fan.
4. A method as claimed in any one of Claims 1 to 3 which includes increasing the cooling output of the air conditioning system when the temperature within the vehicle rises to a predetermined value above the set value whilst the engine is in idling or low load operation.
5. A method as claimed in any one of the preceding claims in which the air inlet to the air conditioning system is selectively connectable to the exterior of the vehicle and to the interior of the vehicle, whereby the air within the vehicle is recycled, the method including connecting the air inlet to the interior of the vehicle after moving the set value downwardly and/or after the engine has commenced idling or low load operation.
6. A method as claimed in Claim 4 in which the motor vehicle is of hybrid type arranged to switch off the vehicle engine when in idling mode, the method including restarting the engine when the temperature within the vehicle rises to a predetermined value above the set value.
7. A method of operating an automotive air heating system which is installed in a motor vehicle and is powered by the engine of the vehicle, the heating system including a temperature sensor and a controller programmed to maintain the temperature within the vehicle substantially at a set value, the method including inputting into the controller a signal indicative of a time when the engine is likely to start idling or operating under low load conditions and moving the set value upwardly so as to increase the temperature within the vehicle and reducing the heating output of the heating system when the engine commences idling or low load operation.
8. A method as claimed in Claim 17 in which the air heating system includes an electric heating fan and the heating output of the heating system is reduced by reducing the speed of the heating fan.
9. A method as claimed in Claim 7 or Claim 8 in which the air heating system includes an electrical heater and the heating output of the heating system is reduced by reducing the electrical power consumption of the electrical heater.
10. A method as claimed in any one of Claims 8 to 10 in which the air inlet to the air heating system is selectively connectable to the exterior of the vehicle and to the interior of the vehicle, whereby the air within the vehicle is recycled, the method including connecting the air inlet to the interior of the vehicle after moving the set value upwardly and/or after the engine has commenced idling or low load operation.
11. A method as claimed in Claim 5 or 10 which includes sensing the CO2 content of the air within the vehicle and changing the air inlet from being connected to the interior of the vehicle to being connected to the exterior of the vehicle when the CO2 content exceeds a predetermined level or if it is likely that the CO2 content will exceed the predetermined level during the next occasion when it is likely that the engine will commence idling or low load operation.
12. A method as claimed in any one of the preceding claims which includes sensing the efficiency with which the engine is operating and increasing or decreasing the output of the air conditioning system or the air heating system if doing so would result in the engine operating at a higher efficiency.
13. A method as claimed in any one of the preceding claims in which the said signal is derived from a telematic device, a global positioning system, a map-based navigation system, a traffic information device, radio traffic reports or from roadside information transmitters or from the controller.
14. A method as claimed in any one of Claims 1 to 12 in which the said signal is produced when the vehicle restarts after having stopped.
15. An automotive climate control system which is installed in a motor vehicle and connected to be powered by the engine of the vehicle, the system including a temperature sensor and a controller programmed to perform a method as claimed in any one of the preceding claims.
16. A computer program including code portions executable by a controller to cause the controller to execute a method as claimed in any one of Claims 1 to 14.
PCT/GB2009/000692 2008-03-14 2009-03-13 Automotive climate control systems WO2009112847A1 (en)

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CN109398028A (en) * 2018-10-19 2019-03-01 珠海格力电器股份有限公司 Control method for prolonging endurance time of split air conditioner for truck
CN112406458A (en) * 2019-08-21 2021-02-26 美光科技公司 Intelligent climate control in a vehicle
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EP1591282A2 (en) * 2004-04-27 2005-11-02 Behr GmbH & Co. KG Method for the controlling of an airconditioning system and an airconditioning system for a vehicle
US20060259219A1 (en) * 2005-05-16 2006-11-16 Denso Corporation Vehicle climate control apparatus and method
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DE102013003708A1 (en) * 2013-03-04 2014-09-04 GM Global Technology Operations LLC (n. d. Gesetzen des Staates Delaware) Method for operating motor vehicle, involves automatically changing current temperature of air conditioner for portion of passenger compartment, when deceleration of vehicle approached during stop operation is determined
CN109398028A (en) * 2018-10-19 2019-03-01 珠海格力电器股份有限公司 Control method for prolonging endurance time of split air conditioner for truck
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CN112406458A (en) * 2019-08-21 2021-02-26 美光科技公司 Intelligent climate control in a vehicle

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