JP2003002043A - Air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner capable of largely reducing an occupied space of an air conditioner unit compared with a conventional sub-engine type air conditioner, increasing a trunk space especially necessary for a sightseeing bus, and maintaining good cooling effects even in a low engine speed range of a traction engine. SOLUTION: A swash plate type hydraulic pump is driven by the traction engine, discharge pressure oil of the hydraulic pump is fed to a hydraulic motor via a flow control valve, and a refrigerant compressor is driven by the hydraulic pump. Even when the traction engine is operated at a low engine speed, an inclination of a swash plate of the hydraulic pump is increased at the low engine speed range, and decrease at a high engine speed range so as to ensure a sufficient oil amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner suitable for use in vehicles, especially tourist buses.

[0002]

2. Description of the Related Art Conventional air conditioners for buses include
A direct-coupled air conditioner in which a refrigerant compressor of a refrigeration cycle is driven by a vehicle running engine, and a so-called sub-engine type air conditioner in which the refrigerant compressor is driven by a dedicated engine separate from the running engine. There is a device.

Since the above-mentioned direct-coupling type air conditioner drives the refrigerant compressor by the traveling engine, there is a problem that the refrigerant flow rate becomes insufficient in the operating region where the engine speed is low and the cooling capacity is lowered. On the other hand, a sub-engine type air conditioner equipped with an engine dedicated to cooling has the advantage that sufficient cooling capacity can be secured by operating the dedicated engine regardless of the operating state of the running engine. It is widely used for tourist buses that require cooling even during long hours of parking.

A conceptual structure of the lower side of the passenger compartment floor of the sightseeing bus equipped with the sub-engine type air conditioner will be described with reference to FIG. 8. Reference numeral 100 generally indicates the body of the sightseeing bus, and 102 represents the passenger compartment floor. , 104 are front wheels, and 106 are rear wheels. Reference numeral 108 denotes an air conditioner unit (hereinafter referred to as an air conditioner unit) disposed under the floor between the front wheels 104 and the rear wheels 106, and 110 denotes a trunk space provided behind the air conditioner unit 108.
112 is the air conditioning unit 108 and the trunk space 1
10 is a tank space in which a combustion tank for a cooling-only engine provided between the tank space 10 and the space 10 is installed.

As shown in the schematic front view of FIG. 9 and the schematic plan view of FIG. 10, the air conditioner unit 108 has a pair of front and rear cross members 114 extending in the vehicle width direction.
Is provided with a frame 116 having a substantially frame shape in a plan view. The frame 116 includes a dedicated engine 118, a refrigerant compressor 122 connected to one end of a crankshaft 120 of the dedicated engine 118, the crankshaft 120, and the like. A radiator 126 which is arranged at an end portion and which is arranged adjacent to a refrigerant fan 124 which is rotated in conjunction with the crankshaft and which cools the cooling water of the special engine 118, and a radiator 126 which is arranged adjacent to the radiator 126. A refrigerant condenser 128 is mounted.

Further, the dedicated engine 1 of the frame 116
An evaporator box 1 having a suction port 130 communicating with the interior of the bus body 100 at the end opposite to 18
32 is mounted, and inside the evaporator box 132, an evaporator 134 and a heater 136 for evaporating the liquefied refrigerant are stored. A fan casing 138 accommodating an evaporator fan is provided at the end of the evaporator box 132 on the side of the dedicated engine 118,
The fan casing 138 is provided with a delivery port 140 that communicates with a duct provided in the passenger compartment of the bus body 100.

The refrigerant compressor 12 is driven by a dedicated engine 118.
2 is driven and cooling is performed, the fan drive shaft 146 is driven by the crankshaft 120 of the dedicated engine 118 via the pulley transmission 142 and the electromagnetic clutch 144, and the evaporator fan is rotated to rotate the air in the vehicle interior. Flows into the evaporator box 132 from the suction port 130, is cooled by passing through the evaporator 134 and becomes cool air, is supplied from the outlet port 140 to the duct in the vehicle interior, and is blown out from the numerous outlet ports provided in the duct. To be done. At this time, the heater 136 is of course inactive. When performing heating, hot water is supplied to the heater 136, the electromagnetic clutch 144 is disengaged, and the fan drive shaft 146 is driven by the electric motor 148. 9 and 10
In, 150 is a preheater for heating.

In the above sub-engine type air conditioner, the refrigerant compressor 122 of the refrigeration cycle is driven by the dedicated engine 118 during the cooling operation, so that sufficient cooling capacity can be produced even when the running engine is stopped or at low speed rotation. However, since the dedicated engine 118 is mounted, the space occupied by the air conditioner unit 108 becomes large, and the trunk space 110 for accommodating luggage such as passengers and passengers necessary for the sightseeing bus becomes small.

[0009]

SUMMARY OF THE INVENTION The present invention was devised to solve the problems of the conventional direct-coupled air conditioner and sub-engine type air conditioner, and has a low engine speed operating range for a running engine. However, it is suitable for vehicles, especially tourist buses, which can secure sufficient cooling capacity and can significantly reduce the space occupied by the air conditioner unit compared with the conventional sub-engine type air conditioner to increase the trunk space. The main purpose is to provide an air conditioner.

[0010]

In order to achieve the above object, the present invention provides a swash plate type hydraulic pump driven by a running engine of a vehicle and a swash plate for controlling the discharge oil amount of the swash plate type hydraulic pump. A control cylinder for setting an inclination angle, and a hydraulic motor that is operated by being supplied with the discharge pressure oil of the swash plate hydraulic pump to drive a refrigerant compressor of a refrigeration cycle,
The control cylinder operates so as to increase the inclination angle of the swash plate when the rotational speed of the traveling engine is low, and decrease the inclination angle of the swash plate when the rotational speed of the engine is high. A vehicle air conditioner is proposed.

In the present invention, the operation mode of the refrigeration cycle is set by the flow control valve having the electromagnetically-operated variable throttle interposed in the pressure oil passage for supplying the discharge pressure oil of the swash plate type hydraulic pump to the hydraulic motor. A hydraulic oil of a corresponding flow rate is supplied to the hydraulic motor, and is set according to the actual rotational speed of the hydraulic motor detected by the rotational speed detecting means for detecting the rotational speed of the hydraulic motor and the operation mode of the refrigeration cycle. The opening of the variable throttle is controlled so as to eliminate the deviation from the target rotational speed of the hydraulic motor, and further, the inclination of the variable throttle is controlled via the control cylinder so that the compression drop amount in the variable throttle becomes substantially constant. It is preferable that the tilt angle of the plate be controlled.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a conceptual layout diagram of an air conditioner arranged below a floor 12 of a vehicle body 10 in a sightseeing bus, in which 14 is a front wheel, 16 is a rear wheel, and 18 is a rear portion of the vehicle body 10. Engine, 20 is a variable displacement swash plate type hydraulic pump driven by the traveling engine 18 via an appropriate transmission device 22 such as a belt transmission device, and 24 is oil for storing hydraulic oil supplied to the hydraulic pump 20. It is a tank.

Reference numeral 26 generally indicates an air conditioner unit disposed below the floor 12 between the front wheels 14 and the rear wheels 16, and the air conditioner unit 26 includes the hydraulic pump 20.
Of any structure, preferably a swash plate type hydraulic motor 28 driven by the discharge pressure oil, a refrigerant compressor 30 driven by the hydraulic motor 28, and a condenser 32 for cooling and liquefying the refrigerant compressed by the refrigerant compressor 30. , An oil cooler 34 for cooling the oil operated by the hydraulic pump 20 and the hydraulic motor 28, an appropriate transmission means 36 such as a belt transmission device
A condenser fan 40 driven by the hydraulic motor 28 via an evaporator, an evaporator 42 that generates cold air by evaporating the liquefied refrigerant that is cooled by the condenser 32, and the evaporator 42 cools the inside air or the outside air such as the outside air. Various members that constitute the refrigeration cycle are provided, such as an evaporator fan 44 that guides the air to be discharged.

As will be described in detail later, the hydraulic motor 28 has a pressure oil metered by a flow rate control valve 48 provided in a pressure oil passage 46 connecting the hydraulic pump 20 and the hydraulic motor 28. And the evaporator fan 44 is driven by the transmission means 36 during cooling, and is disconnected from the transmission means 36 by the electromagnetic clutch 50 when heating is performed during cold weather when the refrigeration cycle does not operate. Driven by 52.

The operation mode of the air conditioner during cooling will be described with reference to the hydraulic circuit and electric circuit diagram of FIG. First, an electromagnetic clutch 54 that transmits power to the power transmission system including the crankshaft of the traveling engine 18, the pump shaft of the hydraulic pump 20, and the transmission means 22 during cooling but interrupts power transmission during non-cooling. A clutch device such as the above is installed, and the variable displacement hydraulic pump 20 is configured such that the control cylinder 56 controls the tilt angle of the swash plate. Further, since the discharge flow rate can be made zero by controlling the inclination angle of the swash plate of the variable displacement hydraulic pump 20, the electromagnetic clutch 54 may not be provided. During the rest of the engine 18 in which hydraulic pressure is not acting on the piston 58 of the control cylinder 56, the swash plate is substantially maximized by the return spring 60 in the control cylinder 56 or an external spring connected to the swash plate. Held in. As is well known in the art, the swash plate hydraulic pump 20 discharges pressure oil in an amount substantially proportional to the tilt angle of the swash plate.

FIG. 6 shows the principle structure of the flow control valve 48 provided in the pressure oil passage 46 for supplying the pressure oil discharged from the hydraulic pump 20 to the hydraulic motor 28. The flow control valve 48 has an orifice member 64 that constitutes a variable throttle whose throttle passage area changes according to the current value of the solenoid 62.
And a pressure difference detecting means 66 for detecting a pressure difference or a pressure drop amount ΔP on the upstream and downstream sides of the orifice member 64. In the case shown, as an example, the orifice member 64
There is shown a differential pressure detecting means 66 including a diaphragm 68 which responds to the differential pressure generated on the upstream and downstream sides and a rod 70 which detects a displacement amount of the diaphragm 68.

The differential pressure ΔP detected as the displacement amount of the rod 70 is supplied to the control unit 72 as an electrically variable amount signal by a potentiometer or the like connected to the rod 70. Above differential pressure or pressure drop ΔP
Is U, the pressure loss coefficient of the throttle portion is ζ, and the density of the pressure oil is ρ, ΔP = 1/2
-Represented by ρ · U ² · ζ. Further, the sectional area of the pressure oil passage 46 is represented by S, the pressure oil discharge amount of the hydraulic pump 20 is represented by Q,
When the cross-sectional area of the pump piston driven by the swash plate of the hydraulic pump is a, the number of pump pistons is b, and the stroke of the pump piston proportional to the tilt angle of the swash plate is L,
Q = U · S = a · b · L · N. The hydraulic pressure adjusting means 80 may have a hydraulically driven throttle valve structure in which the opening is adjusted by responding to the differential pressure of the hydraulic pressure generated on the upstream and downstream sides of the orifice member 64. In this case, The differential pressure detection means 66 can be omitted.

On the other hand, the current value of the solenoid 62 is determined by detecting the actual rotation speed of the hydraulic motor 28 which drives the refrigerant compressor 30 by the rotation speed sensor 74. The target rotation speed of the hydraulic motor 28 is stored in advance in the control unit 72 for each operation mode of the refrigeration cycle generally indicated by reference numeral 76 in FIG. 5, and is input as a signal of the target rotation speed and the rotation speed sensor 74. The actual rotation speed is compared, and a current that increases or decreases according to the deviation between the two is supplied from the drive unit 78 of the control unit 72 to the solenoid 62.

When the current value of the solenoid 62 changes and the orifice member 64 is displaced, the pressure loss coefficient ζ changes and the differential pressure ΔP tends to change, and the signal is supplied to the control unit 72. Control unit 7
Reference numeral 2 compares the target differential pressure set in advance with the actual differential pressure ΔP and sends a drive signal to the drive unit 78 so that they match, that is, the actual differential pressure ΔP is always constant. A drive output is supplied from the drive unit 78 to the hydraulic pressure adjusting unit 80. As a result, the required control oil pressure is sent from the oil pressure adjusting means 80 to the control cylinder 56, the tilt angle of the swash plate of the hydraulic pump 20 is changed, the discharge amount is adjusted, and the pressure drop in the variable throttle portion of the flow control valve 48 is performed. The amount ΔP is controlled so that it is always constant.

The control unit 72 is connected with a cooling selection switch 82 which is manually operated by an occupant of the vehicle to select whether to operate or stop the refrigeration cycle 76, and the switch 82 is closed. As a result, a drive output for connecting the electromagnetic clutch 54 is sent from the drive unit 78, the hydraulic pump 20 is driven by the traveling engine 18, and the refrigeration cycle 76 operates. Further, the control unit is provided with a selection switch 84 for selecting the operation mode of the refrigeration cycle 76 (for example, selection of the strong mode, the normal mode, or the weak mode), and the occupant of the vehicle operates the selection switch 84. The operation mode is selected by manual operation, and the set value ΔP of the pressure drop and the target rotation speed of the hydraulic motor 28 which are different for each mode in the flow control valve 48 are set. In the case of a vehicle equipped with an auto air conditioner,
Assuming that the passenger compartment of the vehicle is operated to switch the temperature of the passenger compartment to, for example, 25 ° C., if the passenger compartment temperature is higher than 25 ° C. (or 25 ° C. ± α) at this time, the driving unit 78 The drive output for connecting the electromagnetic clutch 54 is sent to the hydraulic pump 20 by the traveling engine 18.
Is driven to operate the refrigeration cycle 76. Further, the control unit selects the operation mode of the refrigeration cycle 76 based on the deviation between the temperature inside the vehicle compartment and the set temperature.

The operation mode of the refrigeration cycle 76 will be briefly described. First, as described above, the variable displacement swash plate type hydraulic pump 20 is rotated by the traveling engine 18 to discharge the pressure oil. First, the swash plate of the hydraulic pump 20 is the control cylinder 5
Since the maximum inclination angle is set substantially by the spring 60 of FIG. 6 or an external spring having the same effect, it is shown in FIG. 7 in which the horizontal axis represents the engine speed and the vertical axis represents the pump discharge amount. As described above, at the idle speed Ni of the running engine, a sufficient amount of pressure oil discharge required for the normal mode and the weak mode operation of the refrigeration cycle 76 is secured, and in the strong mode, the idle up speed slightly higher than the idle speed. A hydraulic pump 20 having a capacity such that a sufficient amount of pressure oil discharge is secured in several Niu is used.

The pressure oil discharged from the hydraulic pump 20 is supplied to the pressure oil passage 4
A flow rate control valve 48 installed in the hydraulic pressure control valve 6 supplies the hydraulic motor 28 with a hydraulic oil having an oil amount corresponding to the set operation mode. The hydraulic compressor 28 drives the refrigerant compressor 30 and the condenser fan 40, and also drives the evaporator fan 44. At this time, the electromagnetic clutch 50 connects the hydraulic motor 28 and the shaft of the evaporator fan 44.

The refrigerant compressed by the refrigerant compressor 30 is liquefied by being cooled by the condenser 32, and the liquefied refrigerant is stored in the receiver 86. From the receiver 86, the evaporator 4 is liquefied.
2 and the heat is exchanged with the vehicle interior air or the exterior air or the mixed air of both air that has been gouted by the evaporator fan 44 to generate cold air, and the cold air is blown out into the vehicle interior from the duct. On the other hand, the refrigerant vaporized by the evaporator 42 is returned to the refrigerant compressor 30 again, and the same cycle is repeated thereafter. In FIG. 5, reference numeral 88 is an oil filter.

The above-mentioned components in the refrigeration cycle 76 are arranged below the floor 12 of the vehicle body 10 as the air conditioner unit 26 as already described with reference to FIG.
As shown in FIGS. 2 and 3, the air conditioner unit 26 includes a pair of cross members 90 that extend in the vehicle width direction and are arranged in parallel. A frame-shaped frame is formed by a suitable number of vertical frame members (not shown) in the vehicle front-rear direction, and the hydraulic motor 28, the cooling compressor 36, the condenser 32, the oil cooler 34, and the condenser are formed on the frame. An evaporator box 94 that houses the fan 40, the evaporator 42, and the heater 92 described above is mounted. The evaporator box 94 is provided with a suction port 96 for taking in the inside air of the vehicle interior 10 and the like, and an outlet 98 for supplying cooled cold air (warm air during heating) to a duct in the vehicle interior 10.

Since the hydraulic motor 28 is much smaller than the dedicated engine 118 in the conventional sub-engine type air conditioner and does not require the fuel tank 112 for the dedicated engine 118, the space occupied by the air conditioner unit 26 is reduced. It is possible to greatly reduce the number, and it is possible to effectively expand the trunk space indicated by a white portion by adding a symbol A to the conceptual plan view of FIG. In FIG. 4, the space on the left side of the dotted line is the space for the conventional air conditioner unit 108 and the fuel tank 112. Also,
2 and 3, the portion on the left side of the alternate long and short dash line is an extra space occupied by the conventional air conditioner unit 108.
Furthermore, in FIG. 2 and FIG.
a is a preheater.

Further, a variable capacity swash plate type hydraulic pump 20 is provided.
The amount of pressure oil discharged per revolution is controlled to be large when the rotational speed of the running engine 18 is low and small when the rotational speed of the engine 18 is high, and inevitably and frequently during running. Even when the rotational speed of the running engine 18 changes, the rotational speed of the hydraulic motor 28 is controlled by controlling the variable throttle and the swash plate tilt angle so as to keep the pressure drop ΔP in the flow control valve 48 constant. Since it is possible to maintain a constant number of revolutions depending on the mode, it is possible to perform effective cooling not only while the vehicle is traveling, but also when parking or stopping for a relatively long time, so that a good passenger compartment There is an advantage that can secure the property.

The present invention is not limited to the above embodiment, and can be implemented with appropriate changes and modifications within the scope of the claims. For example, in the above-described embodiment, the evaporator fan 44 is configured to be driven by the hydraulic motor 28 via the transmission means 36 during cooling, but the evaporator fan 44 is provided by providing a hydraulic motor separate from the hydraulic motor 28. Can be modified to drive.

[0028]

As described above, the vehicle air conditioner according to the present invention includes a swash plate hydraulic pump driven by a vehicle running engine, and a swash plate hydraulic pump for controlling the amount of oil discharged from the swash plate hydraulic pump. A control cylinder for setting the inclination angle of the plate, and a hydraulic motor that is operated by being supplied with the discharge pressure oil of the swash plate hydraulic pump to drive the refrigerant compressor of the refrigeration cycle, the control cylinder is the traveling engine. When the engine speed is low, the tilt angle of the swash plate is increased, and when the engine speed is high, the tilt angle of the swash plate is decreased. Compared with this, it is possible to reduce the space occupied by the air conditioner unit and create an effective space that can be used as a trunk space, etc. There is an advantage capable of securing an air conditioner substantially equal cooling effect.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram showing a preferred embodiment of the present invention.

FIG. 2 is a front view of an air conditioner unit 26 shown in FIG.

FIG. 3 is a plan view of the air conditioner unit 26 shown in FIG.

FIG. 4 is a conceptual configuration diagram showing a relationship between an air conditioner unit 26 and a trunk space A in a vehicle body plan view.

5 is a configuration diagram showing a hydraulic pressure, an electric circuit, and a refrigeration cycle of the entire air-conditioning apparatus shown in FIG.

6 is a principle configuration diagram of a flow rate control valve 48 in FIG.

7 is a diagram showing the relationship between the rotational speed of the traveling engine 18 and the discharge flow rate of the hydraulic pump 20 in FIG.

FIG. 8: Air conditioner unit 108 and trunk space 1 of a vehicle equipped with a conventional sub-engine type air conditioner
It is a schematic block diagram which showed the arrangement space of 10.

9 is a front view of the air conditioner unit 108 in FIG.

10 is a plan view of the air conditioner unit 108 shown in FIG.

[Explanation of symbols]

10 ... vehicle body, 12 ... floor, 14 ... front wheel, 16 ... rear wheel,
18 ... Running engine, 20 ... Swash plate hydraulic pump, 26
... Air conditioner unit, 28 ... Hydraulic motor, 30 ... Refrigerant compressor, 30 ... Condenser, 42 ... Evaporator, 46 ...
Pressure oil passage, 48 ... Flow control valve, 56 ... Control cylinder, 6
2 ... Solenoid, 64 ... Orifice member (variable throttle),
66 ... Differential pressure detecting means, 72 ... Control unit, 7
4 ... Revolution sensor, 76 ... Refrigeration cycle.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) F04B 49/06 341 F04B 49/06 341H F term (reference) 3G093 AA12 CA04 CA10 CA11 DA01 DB09 EB06 FA11 FB01 FB02 3H045 AA04 AA12 AA27 AA32 BA02 BA14 BA19 BA20 BA31 CA01 CA06 CA21 CA29 DA09 DA10 DA43 DA47 EA04 EA13 EA14 EA17 EA20 EA33 EA34 EA42 3H070 AA01 BB04 CC11 CC14 DD44 DD55 DD56

Claims (2)

[Claims] 1. A swash plate hydraulic pump driven by a vehicle running engine, a control cylinder for setting an inclination angle of a swash plate for controlling the amount of oil discharged from the swash plate hydraulic pump, and a discharge of the swash plate hydraulic pump. A hydraulic motor that is supplied with pressure oil to operate and drives a refrigerant compressor of a refrigeration cycle,
The control cylinder operates so as to increase the inclination angle of the swash plate when the rotational speed of the traveling engine is low, and decrease the inclination angle of the swash plate when the rotational speed of the engine is high. Vehicle air conditioner. 2. A flow rate according to the operation mode of the refrigeration cycle by a flow rate control valve having an electromagnetically-operated variable throttle interposed in a pressure oil passage for supplying the discharge pressure oil of the swash plate type hydraulic pump to the hydraulic motor. Pressure oil is supplied to the hydraulic motor, and the hydraulic pressure set according to the actual rotational speed of the hydraulic motor detected by the rotational speed detection means for detecting the rotational speed of the hydraulic motor and the operation mode of the refrigeration cycle. The opening of the variable throttle is controlled so as to eliminate the deviation from the target rotation speed of the motor, and further, the swash plate of the swash plate is controlled through the control cylinder so that the pressure drop amount in the variable throttle becomes substantially constant. The vehicle air conditioner according to claim 1, wherein the inclination angle is controlled.