JP2013524074A - Hybrid compressor for air conditioning circuit - Google Patents

Abstract

The present invention relates to a hybrid compressor (10) for an air conditioning circuit of a motor vehicle having an engine. The hybrid compressor can be driven by the engine and by the electric motor (20) while driving by the engine is interrupted. In the present invention, the hybrid compressor (10) has a variable capacity compression chamber (101), which has a large stroke volume when the compression chamber (101) is driven by an engine, and a compression chamber. It can vary between a small stroke volume when (101) is driven by an electric motor (20). The present invention can be applied to an automobile having an engine and equipped with an automatic stop and restart system.
[Selection] Figure 1

Description

    The present invention relates to a hybrid compressor for an air conditioning circuit of an automobile equipped with an engine.

  The invention applies particularly advantageously to the field of air conditioning in engine-driven vehicles equipped with an automatic stop and restart system, such as in a system capable of performing a function known as “stop and start”. be able to.

  The “stop and start” function means that, under certain conditions, when the vehicle itself stops, the engine is automatically stopped completely, and then, for example, depending on the driver's behavior that is interpreted as a restart request. This is a function that automatically restarts.

  A typical situation for performing the “stop and start” function is when stopping at a red light. When the vehicle stops with a signal, the “stop” mode of the “stop and start” function drives an automatic stop of the engine, after which the vehicle enters the “start” mode. This makes it possible to automatically restart the engine without using means for initial starting of the motor (for example, a contact key). When the signal turns blue, the “start” mode is in the intention of the driver to step on the clutch pedal, the accelerator pedal, or the driver to restart his / her vehicle, depending on the vehicle's starting function. Upon detecting any other behavior that is interpreted as being, it automatically restarts the motor (especially using an alternator starter). The “stop and start” function is advantageous in terms of saving energy and reducing pollution, especially in urban environments.

  Furthermore, it is known that an air conditioning circuit of a vehicle equipped with an engine includes a cooling fluid compressor. The cooling fluid compressor is driven by the shaft of the engine crankshaft using a belt and a pulley mechanically coupled to the compressor's compression rod. That is, the air conditioning circuit of the vehicle can operate only when the engine is operating. Therefore, the air conditioning does not operate during the stop phase of the vehicle in the “stop and start” function. Therefore, there is a possibility that the set temperature inside the vehicle interior cannot be maintained during the stop phase. As a result, the passengers of the vehicle feel uncomfortable.

  To ensure that the temperature in the passenger compartment is maintained during the engine shutdown phase, the normal compressor driven by the vehicle engine is replaced by a hybrid compressor with two separate compression chambers. It has been proposed to do. One of these hybrid compressors is called a mechanical compressor, and the compression rod of the mechanical compressor is driven by the engine in the same manner as a normal compressor. The other is called an electric compressor, and the compression rod of the electric compressor is driven by an auxiliary electric motor. The compression rods in the two compression chambers are independent.

  Outside the stop phase driven by the “stop and start” function, when the engine is running, the cooling fluid passes through the mechanical compressor driven by the shaft of the engine crankshaft and through the air conditioning circuit. Circulate. At this time, the electric compressor is turned off. Conversely, during the stop phase in the “stop and start” function, the cooling fluid is directed towards the electric compressor, which is driven by an electric motor. Therefore, even if the engine is stopped, the electric compressor performs continuous operation of the air conditioning circuit and maintenance of a comfortable temperature in the passenger compartment.

  However, this type of hybrid compressor has the disadvantage of being large in volume and therefore difficult to integrate together. Furthermore, this hybrid compressor requires a complex valve system to manage the flow of cooling fluid between the two compression chambers when switching from one compressor to the other.

  The object of the present invention is to provide a hybrid compressor for an air conditioning circuit of an automobile equipped with an engine. The hybrid compressor can be driven by the engine and by an electric motor during the stage when the drive by the engine is interrupted. This hybrid compressor is very small, easy to integrate, and allows the thermal and electrical drive modes to be switched from one to the other with a simple operation.

  This object is achieved by the present invention. The reason is that the hybrid compressor according to the invention has a compression chamber with a variable capacity, which can be varied between a large stroke volume and a small stroke volume. For large stroke volumes, the compression chamber is driven by the engine, and for small stroke volumes, the compression chamber is driven by an electric motor.

  Thus, unlike the prior art hybrid compressor described above, which requires two compression chambers, the hybrid compressor in the present invention comprises only a single compression chamber. Therefore, the hybrid compressor in the present invention becomes very small and can be easily integrated. In addition, when changing the drive mode, there is no need to provide a complex valve system for the passage of cooling fluid from one compression chamber to the other. This is because, in the present invention, the compression chamber is single and has only one intake opening and one outlet opening for the cooling fluid.

  It is desirable that the large stroke volume and the small stroke volume are clearly different.

  Under normal operating conditions of the air conditioning circuit, the capacity of the compression chamber is selected for a large stroke volume and the compression rod of the compressor is driven by the engine.

  On the other hand, during the engine suspension phase, particularly during the engine shutdown phase, which is imposed by the “stop and start” function, the passenger compartment is generally already conditioned to comfort conditions, and therefore the engine If the stop phase has a limited duration of the order of several tens of seconds, the cooling power to be supplied by the electric motor to maintain this condition will be significantly lower. This is at least about 1/2 to 1/3 compared to the power to be supplied by the engine. In this case, the capacity of the compression chamber can be reduced to a value that is a small stroke volume, and it is sufficient to keep the electric motor on until the engine is restarted by the “stop and start” function. is there.

  In one preferred embodiment, the compression chamber having a variable volume is a compression chamber having a rotational drive. As an example, the compression chamber is a compression chamber comprising a vane having an adjustable intake volume.

  In the compression chamber provided by the present invention, it is advantageous that the drive of the compression chamber by the engine can be disconnected from the engine for the capacity which is the small stroke volume. The electric motor is uncoupled from the engine and can drive the compression rod with low power. The reason is that the compression chamber operates at a low volume.

  As can be seen from the above, the interruption stage of driving by the engine may be an engine stop stage. More particularly, the engine stop phase is a system stop phase in an automatic engine stop and restart system such as a “stop and start” system.

  Furthermore, the electric motor of the hybrid compressor according to the present invention can be used in other environments, particularly when the interruption stage of driving by the engine is a vehicle acceleration stage. In fact, when the vehicle is accelerating, by mechanically disconnecting the compressor from the engine, the air conditioning circuit can be stopped, thereby removing the resistive torque applied to the crankshaft shaft by the compressor. Are known. Even under this condition, the air conditioning can be maintained by setting the electric motor of the hybrid compressor according to the present invention to the operating state.

  The hybrid compressor according to the invention makes it possible to easily turn on the electric motor during the interruption phase of the drive by the engine. The hybrid compressor includes means for setting the electric motor to an operating state before the engine stop phase begins. Thus, the electric motor is set to the expected operating state before the engine actually stops. The electric motor may be of low power and therefore does not need to overcome a wide range of changes in cooling fluid pressure. This change in pressure is generally a phenomenon that appears in the air conditioning circuit after the air conditioning circuit is completely stopped.

  In practice, the means for setting the electric motor to an operating state are means for detecting an automatic engine stop and an engine stop of the restart system. There are numerous variations of these detection means within the “stop and start” function, which usually depend on the strategy the manufacturer generally chooses by the builder. For example, an example in which an action on a brake pedal is detected when the speed of the vehicle becomes lower than a given threshold value can be given.

  Finally, the invention also relates to an assembly of a hybrid compressor according to the invention and an assembly of an electric motor for driving the hybrid compressor. Here, the electric motor is powered by a low voltage direct current. More specifically, the low voltage direct current is supplied by a 12V network of the vehicle. The present invention greatly simplifies the implementation of a hybrid compressor. The reason is that it does not involve a change in the in-vehicle electrical network.

  The invention and its embodiments will become apparent upon reading the following description with reference to the accompanying drawings. This description is for a non-limiting example.

It is a figure which shows an air-conditioning circuit provided with the hybrid compressor by this invention. FIG. 2 shows the operation of the hybrid compressor shown in FIG. 1 for various states of an automobile equipped with a “stop and start” function. It is a figure which shows the control circuit of the electric motor for driving the hybrid compressor shown in FIG.

FIG. 1 shows a typical air conditioning circuit of an automobile equipped with an engine. The air conditioning circuit includes a cooling fluid compressor 10. The cooling fluid may be an organic fluid, an inorganic fluid, or a eutectic fluid. As a non-limiting example, mention may be made of supercritical carbon dioxide CO ₂ or R134A,, known refrigerant as 1234yf or GAR, (Global Alternative Refrigerant). The pressurized cooling fluid passes through the heat exchanger 11 toward the downstream of the compressor 10. The heat exchanger 11 is called a “gas cooler” for carbon dioxide. For R134A, it is called a “condenser”. The reason is that in this case, the refrigerant initially in the gas phase exits the condenser in liquid phase.

  In the example of FIG. 1, the heat exchanger 11 may be a water type heat exchanger or an air type heat exchanger that is cooled directly by external air.

  Thereafter, the cooling fluid is directed toward the pressure reducing valve 12, and the cooling fluid is cooled before entering the evaporator 13. In the evaporator 13, heat exchange is performed between the cooled refrigerant and the air blown toward the passenger compartment of the vehicle.

  The cooling fluid that is reheated and exits the evaporator 13 then returns to the compressor 10 to perform a new thermal cycle.

  As can be seen from FIG. 1, the compressor 10 shown in FIG. 1 is a hybrid compressor, and this hybrid compressor includes a compression chamber 101 having a variable capacity. The compression rod 102 of the compression chamber 101 can be driven by the crankshaft of a vehicle engine (not shown) via an electric motor 20 or a belt and pulley 30. The pulley 30 can be mechanically coupled to the compression rod 102 by a clutch 31.

During normal operation, the compression rod 102 of the compression chamber 101 is driven by the engine and the pulley 30 is coupled to the compression rod 102 by a clutch 31. Therefore, the capacity of the compression chamber is a large stroke volume value (for example, 90 cm ^{3 to} 110 cm ³ ) close to the maximum capacity. Under this condition, the hybrid compressor 10 can maintain an optimum comfort level inside the passenger compartment regardless of the external temperature, sunshine, and relative humidity.

  However, in some circumstances, the air conditioning compressor may not be driven by the vehicle engine, and therefore the air conditioning circuit may cease operation and maintenance of a comfortable temperature inside the passenger compartment may not be guaranteed. This is particularly the case when the engine is automatically stopped and during the engine stop phase imposed by the restart system. This stop is performed by an automatic engine stop and restart system on a vehicle equipped with a “stop and start” function.

  In order to ensure continuous air conditioning, the electric motor 20 is set to an operating state during this stop phase and the circulation of the cooling fluid in the air conditioning circuit is maintained. That is, it can be considered that the electric motor replaces the engine. Needless to say, the engine is preferably disconnected from the compression rod 102.

  The block diagram shown in FIG. 3 shows how the drive of the compressor 10 is actually switched from the engine to the electric motor 20.

When the engine stop queue STOP is received from the automatic stop and restart system, the electronic control unit 50 of the air conditioning circuit transmits a signal for coupling the electric motor 20 to the power module 51. In response to this signal, the module 51 activates the auxiliary electric motor 103. Thus, the capacity of the compression chamber 101, from the value of the interruption previous large stroke volume of the drive by the engine, a small value of stroke volume (e.g., between 20 cm ³ and 40 cm ³⁾ can be varied. Next, after the pulley 30 is disconnected by the clutch 31, the power module 51 operates the compressor 10 at a sufficient level during the engine stop phase as compared with the initial air conditioning state before the engine stop. Necessary electric power is supplied to the electric motor 20.

When the electric motor 20 takes over from the engine when the engine is stopped, the vehicle compartment of the vehicle is in principle already at a comfortable temperature, and therefore the duration of the stop phase is generally several tens of seconds or less. The cooling power to be supplied by the electric motor 20 may be relatively low. For example, in the conventional mode, a vehicle exposed to the outside air with a relative humidity of 50% to 60% at a high temperature of 25 ° C. to 45 ° C. under sunshine of 1000 W · m ² . In order to ensure comfort in the passenger compartment, 6 kW of cooling power is required. However, if the vehicle is already air-conditioned to a comfortable temperature, the cooling power to be supplied may be between 1 kW and 3 kW depending on the location in the vehicle. Therefore, the comfort in the passenger compartment can be sufficiently maintained with the power of about 500 W to 800 W supplied from the power module 51.

Therefore, the capacity of the compression chamber 101 can be reduced to a small stroke volume (for example, 20 cm ^{3 to} 40 cm ³ ), which is a value close to the minimum capacity as compared with the case of the normal operation state. This value is clearly different from the large stroke volume defined above.

  It goes without saying that the large stroke volume and the small stroke volume need only be the maximum volume and the minimum volume. Thus, in compression chamber 101, switching between these two capacities can be done in a binary fashion, depending on whether the drive for the compression rod of the compression chamber is an engine or an electric motor.

  In view of the fact that the electric power required for an electric motor is relatively low, an electric motor (with or without a brush) is powered by a low-voltage direct current, in particular a vehicle 12V network. , Which can be a current source in the form of a battery 40 or an additional unit (which may or may not be equipped with a storage capacitor).

In practice, the compression chamber 101 having a variable volume can be composed of a compression chamber having a rotational drive (in particular, a conventional compression chamber having vanes). Here, the conventional compression chamber having vanes has an intake volume corresponding to the volume, and the intake volume is changed to a minimum value (for example, 20 cm ³⁾ by changing the position of the intake opening in the compression chamber. ) And a maximum value (eg, 110 cm ³ ).

  FIG. 2 shows the operating state of the engine and electric motor 20 for driving the hybrid compressor 10 of an automobile equipped with a “stop and start” function. A value of 0 corresponds to the motor stop state, and a value of 1 corresponds to the motor operating state.

  As can be seen from this figure, when the engine is stopped by the “stop and start” function, the electric motor 20 according to the present invention is set to the operating state and provides comfort in the passenger compartment during the engine stop phase. Guaranteed to maintain. It should also be noted that setting the electric motor 20 to the operating state can be done by anticipation, i.e. before the engine stop phase is started, which is activated by the "stop and start" function. That is.

  The advantage of setting in this way is that the electric motor provides additional torque that is considered necessary to overcome the resistance torque induced when the cooling fluid pressure is readjusted in the air conditioning circuit It is not necessary. This resistance torque can occur when the engine is stopped. Accordingly, the electric power of the electric motor 20 is set to an appropriate value.

  In order to make this prediction of the electric motor, means realized by the “stop and start” function may be used to detect whether the engine stop condition is satisfied and to stop the engine. it can. When the “stop and start” function determines to stop the engine, the electric motor 20 is immediately set to an operating state before the actual engine stop. The conditions for automatic engine shutdown are determined by the strategy adopted by the car manufacturer. In particular, an action on the brake pedal can be given when the vehicle is traveling at a low speed (for example, at a speed lower than 5 km / h).

  FIG. 2 shows another situation in which the electric motor 20 can be set to an operating state in order to ensure a continuous comfortable temperature while the air conditioning circuit is stopped. In this case, the stop of the air conditioning circuit is not due to the stop of the engine, but is due to the drive pulley 30 being disconnected from the compression rod 102 of the compression chamber 101. This situation can occur while accelerating the vehicle in an attempt to obtain the best response to acceleration demand, for example by applying maximum torque to the shaft of the crankshaft.

  In this case, the electric motor 20 is activated immediately after the engine is disconnected from the compression rod 102.

DESCRIPTION OF SYMBOLS 10 Hybrid compressor 11 Heat exchanger 12 Pressure reducing valve 13 Evaporator 20 Electric motor 30 Pulley 31 Clutch 40 Battery 50 Electronic control unit 51 Power module 101 Compression chamber 102 Compression rod 103 Auxiliary electric motor

Claims (12)

A hybrid compressor (10) for an air conditioning circuit of an automobile equipped with an engine,
The hybrid compressor (10) can be driven by the engine and by an electric motor (20) during the interruption of the drive by the engine, and has a variable capacity compression chamber (101). And
The capacity is in a range between a large stroke volume in which the compression chamber (101) is driven by the engine and a small stroke volume in which the compression chamber (101) is driven by the electric motor (20). A hybrid compressor characterized by being variable.   The hybrid compressor according to claim 1, wherein the large stroke volume and the small stroke volume are different.   3. Hybrid compression according to claim 1 or 2, characterized in that the drive of the compression chamber (101) by the engine can be separated from the engine for the capacity of the small stroke volume. Machine.   The hybrid compressor according to any one of claims 1 to 3, characterized in that the compression chamber (101) having a variable capacity is a compression chamber having a rotational drive.   The hybrid compressor according to claim 4, characterized in that the compression chamber (101) is a compression chamber having vanes and capable of changing the intake volume.   The hybrid compressor according to claim 1, wherein the interruption stage of driving by the engine is an engine stop stage.   The hybrid compressor according to claim 6, wherein the engine stop phase is an automatic engine stop phase and a restart phase of the restart system (“stop and start”).   The hybrid compressor according to claim 1, wherein the engine suspension stage is a vehicle acceleration stage.   9. Hybrid according to any one of the preceding claims, characterized in that it comprises means for bringing the electric motor (20) into an operating state before starting to interrupt driving by the engine. Compressor.   The means for setting the electric motor (20) to an operating state is means for detecting an automatic stop of the engine and a stop ("stop and start") of the engine of a restart system. The hybrid compressor according to claim 9.   11. An assembly of a hybrid compressor (10) according to any one of claims 1 to 10, and an assembly of an electric motor for driving the hybrid compressor, the electric motor (20) having a low voltage An assembly that is powered by direct current.   The assembly according to claim 11, wherein the low-voltage direct current is supplied by a 12V network of the vehicle.

Images