Work vehicle

Abstract

To provide a work vehicle whose air conditioner can be driven by power from a gasoline engine, which is configured to suppress an engine stall even under a situation where loads on the engine increase.SOLUTION: A work vehicle is equipped with: a gasoline engine E; an operation cabin covering a boarding space; an air conditioner which has a compressor 63 that is driven by the gasoline engine E and an air-conditioning unit that generates air flow for air-conditioning that is supplied to the loading space; and an air-conditioner control unit 51 that controls the air conditioner. A compressor driving command for driving the compressor 63 at the time of starting the air conditioner is issued in accordance with engine state information showing a state of the gasoline engine E.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a work vehicle equipped with a gasoline engine and an air conditioning device, the air conditioning device having an air conditioning unit that supplies conditioned air to a passenger space covered by a driver's cabin, and a compressor driven by the gasoline engine. [Background technology]

[0002] Patent Document 1 discloses a gasoline-powered utility vehicle equipped with a driver's cabin that covers a passenger compartment and an air conditioning system that conditions the passenger compartment. The air conditioning system is composed of an air conditioning unit, a condenser, a compressor, a first refrigerant pipe, a second refrigerant pipe, a third refrigerant pipe, and an engine. The air conditioning unit generates an air flow that is supplied to the passenger compartment. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-109645 Summary of the Invention [Problem to be solved by the invention]

[0004] Gasoline engines are less robust in responding to sudden loads than diesel engines, etc. For this reason, in a work vehicle such as that disclosed in Patent Document 1, there is a problem that the engine stalls when the air conditioning unit is turned on and the compressor driven by the engine is operated during a cold start when the engine startup load is high or when an external powered device (PTO device) is in use.

[0005] For this reason, in work vehicles that use power from a gasoline engine to drive an air conditioning device, there is a demand for engine stall prevention even under conditions where the engine is under heavy load. [Means for solving the problem]

[0006] The work vehicle according to the present invention comprises a gasoline engine, a driver's cabin covering a passenger space, an air conditioning device having a compressor driven by the gasoline engine and an air conditioning unit that generates a conditioned air flow to be supplied to the passenger space, and an air conditioning control unit that controls the air conditioning device, wherein a compressor drive command that drives the compressor when the air conditioning device starts is issued according to engine status information that indicates the status of the gasoline engine.

[0007] With this configuration, when the air conditioning system starts, a compressor drive command is issued to drive the compressor in accordance with engine status information indicating the state of the gasoline engine. That is, if the engine status information indicates a low possibility of engine stall due to compressor drive, the compressor is driven, and if the engine status information indicates a high possibility of engine stall due to compressor drive, the compressor drive is refrained from being driven. This prevents engine stalls in this work vehicle even under conditions where the engine load is high.

[0008] A work vehicle is equipped with multiple control units called ECUs. The control units are connected via an on-board LAN or the like, and each performs a function required to operate the vehicle. If one of these control units is an engine control unit that controls the engine based on engine status information such as detected engine speed and engine load, the other control units can acquire engine status information from the engine control unit. The present invention also proposes that the engine status information be generated by the engine control unit that controls the gasoline engine, and that the other control units can acquire the engine status information.

[0009] To avoid engine stall due to compressor operation, an engine output (torque) sufficient to withstand compressor operation is required. An engine has low engine output (torque) at idling speed (starting speed), but as the engine speed increases from the starting speed, the engine output (torque) increases. Therefore, to avoid engine stall due to compressor operation, it is preferable to operate the compressor only when the engine speed rises from near idling speed to a predetermined speed or higher. Therefore, in this invention, the engine status information is engine speed, and a determination condition is set to whether the engine speed has reached the predetermined speed. If the determination condition is not met, the gasoline engine is controlled to satisfy the determination condition, and if the determination condition is met, the compressor operation command is issued. The predetermined speed for the determination condition is determined based on the type of engine, etc.

[0010] The air conditioning unit is turned on and off using controls such as switches and buttons, and an air conditioning start operation signal generated through the operation of such controls is processed by an air conditioning control unit that controls the air conditioning unit. If the air conditioning control unit is implemented as a control unit such as an ECU and is capable of exchanging data with other ECU control units via an in-vehicle LAN or the like, the air conditioning unit start management can be shared with the other control units. Therefore, in one embodiment of the present invention, an air conditioning start operation signal for starting the air conditioning unit is input to the engine control unit via the air conditioning control unit, and the engine control unit issues the compressor drive command. This drives the compressor when the engine is in a state suitable for driving the compressor (a state in which engine stall does not occur).

[0011] In another embodiment of the present invention, a meter control unit is provided that manages meter devices that display the current state of the vehicle and receives the engine speed as an input, and an air conditioner start operation signal for starting the air conditioner is input from the air conditioner control unit to the meter control unit, and the meter control unit issues the compressor drive command based on the engine speed. This also drives the compressor when the engine is in a state suitable for driving the compressor (a state in which engine stall does not occur).

[0012] In another embodiment of the present invention, a meter control unit that manages meter devices that display the current status of the vehicle is provided, and an air conditioner start operation signal for starting the air conditioner device is input from the air conditioner control unit to the engine control unit via the meter control unit, and the engine control unit issues the compressor drive command. This also drives the compressor on the condition that the engine is in a state suitable for driving the compressor (a state in which engine stall does not occur). [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a side view of a utility vehicle. [Figure 2] FIG. 1 is a plan view of a utility vehicle with the cabin removed. [Figure 3] FIG. 1 is a schematic diagram illustrating the configuration of an air conditioner. [Figure 4] FIG. 3 is a block diagram showing the flow of data between control units when the air conditioning device is started. [Figure 5] FIG. 10 is a block diagram showing the flow of data between control units when an air conditioning device is started in another embodiment. [Figure 6] FIG. 10 is a block diagram showing the flow of data between control units when an air conditioning device is started in yet another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] A multipurpose vehicle, which is an example of a work vehicle according to the present invention, will be described below. In the following description, with respect to the multipurpose vehicle, the direction of arrow F shown in the drawings will be referred to as the "front of the vehicle body," the direction of arrow B as the "rear of the vehicle body," the direction of arrow U as the "upper of the vehicle body," the direction of arrow D as the "lower of the vehicle body," the direction of arrow L as the "left of the vehicle body," and the direction of arrow R as the "right of the vehicle body."

[0015] As shown in FIG. 1, the multipurpose vehicle has a body frame 3 that is supported on the ground by a pair of left and right front wheels 1 and a pair of left and right rear wheels 2. The front wheels 1 are drivable and steerable, and the rear wheels 2 are drivable. A driver's section 9, which is a passenger space, is formed at the front of the body frame 3. A luggage rack 4 is provided at the rear of the body frame 3. A gasoline engine E and a transmission T are mounted below the luggage rack 4. The gasoline engine E will hereinafter be referred to simply as engine E.

[0016] This multipurpose vehicle is equipped with a driver's cabin 8 that covers a driver's section 9, and an air conditioning unit 6 that conditions the air inside the driver's cabin 8. The driver's cabin 8 is equipped with a cabin frame 81, a roof 82, a windshield 83, a rear window 84, and a pair of left and right side doors 85 that can be opened and closed. Each of the left and right side doors 85 is fitted with a translucent side glass 85a. The left and right side doors 85 swing open and closed around an opening and closing axis that runs vertically, and have the openable side glass 85a. The roof 82 covers the entire area above the driver's section 9.

[0017] As shown in FIG. 2, the driver's section 9 is provided with a driver's seat 9A and a passenger seat 9B. A steering wheel 90 is disposed in front of the driver's seat 9A, and a dashboard including an instrument panel 92 is disposed in front of the steering wheel 90. A display 94 as a display device and various operation buttons are disposed on the instrument panel 92. The various operation buttons include an air conditioner switch 93 as an operation tool for driving (ON / OFF) the air conditioner device 6. When the air conditioner switch 93 is turned ON, an air conditioner start operation signal (ON operation signal) is output. When the air conditioner switch 93 is turned OFF, an air conditioner stop operation signal (OFF operation signal) is output.

[0018] 3, the air conditioning device 6 includes an air conditioning unit 61, a condenser 62, a compressor 63, a first refrigerant pipe 64, a second refrigerant pipe 65, and a third refrigerant pipe 66. The air conditioning device 6 further includes an air conditioning control unit 51 (see FIG. 4).

[0019] The air conditioning control unit 51 constitutes the control system of the air conditioning device 6, and adjusts the temperature, flow rate, etc. of the conditioned air flow.

[0020] The air conditioning unit 61 is disposed above the driver's cabin 8 (see FIG. 1) and is configured to generate an air flow that is supplied into the driver's cabin 8. The condenser 62 is a condenser for cooling the refrigerant. The condenser 62 is disposed near a radiator (not shown), which is an engine component, and the condenser 62 is cooled together with the radiator by a cooling fan (not shown) of the radiator. The compressor 63 is a compressor for compressing the refrigerant and is disposed near the engine E because it is driven by power from the engine E. An electromagnetic clutch 63a is disposed on a transmission shaft that transmits engine power to the compressor 63. When the engine E is running, when the electromagnetic clutch 63a is engaged, the compressor 63 operates, and when the electromagnetic clutch 63a is disengaged, the compressor 63 stops.

[0021] The first refrigerant piping 64 sends refrigerant from the condenser 62 toward the air conditioning unit 61. The first refrigerant piping 64 is arranged along the vertical frame that constitutes the driver's cabin 8. The second refrigerant piping 65 sends refrigerant from the air conditioning unit 61 toward the compressor 63. The second refrigerant piping 65 is also arranged along the vertical frame that constitutes the driver's cabin 8. The third refrigerant piping 66 sends refrigerant from the compressor 63 toward the condenser 62.

[0022] 4 shows a control unit (ECU) for controlling the air conditioning device 6 in the control system of this multipurpose vehicle. Illustrated here are an air conditioning control unit 51, an engine control unit 52, and a meter control unit 53, all of which are connected to one another via an in-vehicle LAN. The engine control unit 52 provides engine control signals for controlling the engine E to the control devices of the engine E, and receives engine information (based on detection signals from sensors provided in the engine E) such as the engine speed and engine load of the engine E. The meter control unit 53 has a meter device management function that collects data from each control unit and displays the vehicle status (total distance, vehicle speed, remaining fuel, water temperature, gear position, etc.) in real time. It also has a function for controlling the illumination of warning lights that warn of vehicle abnormalities.

[0023] FIG. 4 shows a first example of the data flow from when the air conditioner switch 93 is turned ON until the air conditioner device 6 starts operating. In this first example, when the air conditioner switch 93 is turned ON, an air conditioner start operation signal sent to the air conditioner control unit 51 is transferred to the meter control unit 53. Upon receiving the air conditioner start operation signal, the meter control unit 53 requests the engine speed from the engine control unit 52 and compares the received engine speed with a preset air conditioner operation permission engine speed (predetermined speed). The condition for determining whether the air conditioner is allowed to operate is that the current engine speed has reached the air conditioner operation permission engine speed. If this condition is not met, the meter control unit 53 either requests the engine control unit 52 to increase the engine speed, or waits, assuming that the engine speed is increasing. In either case, if the engine speed increases and the condition is met, the meter control unit 53 issues a compressor drive command (on command) to the compressor 63, more specifically, to the electromagnetic clutch 63a of the compressor 63. As a result, the compressor 63 is driven by engine power, and the air conditioning device 6 starts operating.

[0024] FIG. 5 shows a second form of data flow from when the air conditioner switch 93 is turned ON until the air conditioner device 6 starts operating. In this second form, when the air conditioner switch 93 is turned ON, the air conditioner start operation signal sent to the air conditioner control unit 51 is sent directly to the engine control unit 52. The engine control unit 52 checks whether the current engine speed satisfies the determination condition for allowing the air conditioner to be operated. If the determination condition is not met, the engine control unit 52 either controls the engine speed to increase, or assumes that the engine speed is increasing and waits. In either case, if the engine speed increases and the determination condition is met, the engine control unit 52 issues a compressor drive command (on command) to the compressor 63. This causes the compressor 63 to be driven by engine power, and the air conditioner device 6 starts operating.

[0025] 6 shows a third mode of data flow from when the air conditioner switch 93 is turned ON until the air conditioner device 6 starts operating. In this third mode, when the air conditioner switch 93 is turned ON, an air conditioner start operation signal sent to the air conditioner control unit 51 is transferred to the meter control unit 53. The meter control unit 53, having received the air conditioner start operation signal, further transfers the air conditioner start operation signal to the engine control unit 52. The engine control unit 52, having received the air conditioner start operation signal, determines whether to permit air conditioner operation in the manner described in the second mode above, and finally issues a compressor drive command (ON command) to the compressor 63. As a result, the compressor 63 is driven by engine power, and operation of the air conditioner device 6 starts.

[0026] Although not shown, an air conditioner start operation signal generated when the air conditioner switch 93 is turned on may first be sent to the meter control unit 53, and from there the air conditioner start operation signal may be sent to the air conditioner control unit 51. The subsequent data flow is similar to that described above.

[0027] [Another embodiment] (1) In the above-described embodiment, the air conditioner 6 was described with the cooling function in mind, but the heating function can be obtained by reversing the flow direction of the medium to the compressor 63. Therefore, the present invention is effective for both cooling and heating.

[0028] (2) In the above-described embodiment, the engine status information used to determine whether or not to allow the air conditioner to be driven was the engine speed. However, other engine status information, such as the engine load, the engine speed increase acceleration, or the engine output, may also be used.

[0029] (3) Instead of the electromagnetic clutch 63a, other devices for connecting / disconnecting engine power may be used.

[0030] (4) In the above-described embodiment, when the conditions for determining whether or not the air conditioner is to be operated are not satisfied, a command to increase the rotation speed of the engine E is issued. However, instead of or in addition to this, the use of other devices that consume engine power may be restricted.

[0031] (5) In the above-described embodiment, the present invention is applied to a multipurpose vehicle. However, the present invention can also be applied to all other work vehicles, such as brush cutters, snow plows, tractors, and harvesters.

[0032] The configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradiction arises. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0033] The present invention is applicable to a work vehicle equipped with a gasoline engine and an air conditioning device that utilizes engine power. [Explanation of symbols]

[0034] 1: Front wheel 2: Rear wheel 3: Body frame 4: Cargo bed 6: Air conditioning unit 8: Driver's cabin 9: Driving section 9A: Driver's seat 9B: Passenger seat 51: Air conditioning control unit 52: Engine control unit 53: Meter control unit 61: Air conditioning unit 62: Capacitor 63: Compressor 63a: Electromagnetic clutch 64:First refrigerant pipe 65:Second refrigerant pipe 66:Third refrigerant piping 81: Cabin frame 82: Roof 83: Windshield 84: Rear window 85: Side door 85a: Side glass 90: Steering wheel 92: Instrument panel 93: Air conditioner switch 94: Display E: Engine (gasoline engine) T: Transmission

Claims

1. A gasoline engine and A driver's cabin covering the boarding space, an air conditioning device having a compressor driven by the gasoline engine and an air conditioning unit that generates a conditioned air flow to be supplied to the passenger space; an air conditioner control unit that controls the air conditioner device, In a work vehicle, a compressor drive command for driving the compressor when the air conditioning device is started is issued in accordance with engine status information indicating the status of the gasoline engine.

2. The work vehicle according to claim 1 , wherein the engine status information is generated by an engine control unit that controls the gasoline engine.

3. 3. The work vehicle according to claim 2, wherein the engine status information is engine speed, a determination condition is that the engine speed has reached a predetermined speed, and if the determination condition is not satisfied, the gasoline engine is controlled to satisfy the determination condition, and if the determination condition is satisfied, the compressor drive command is issued.

4. 4. The work vehicle according to claim 3, wherein an air conditioner start operation signal for starting operation of the air conditioner device is input to the engine control unit via the air conditioner control unit, and the engine control unit issues the compressor drive command.

5. a meter control unit that manages meter devices that display the current state of the vehicle and into which the engine rotation speed is input; an air conditioner start operation signal for starting the operation of the air conditioner device is input from the air conditioner control unit to the meter control unit; 4. The work vehicle according to claim 3, wherein the meter control unit issues the compressor drive command based on the engine speed.

6. A meter control unit is provided to manage meter devices that display the current status of the vehicle; 4. The work vehicle according to claim 3, wherein an air conditioner start operation signal for starting operation of the air conditioner device is input from the air conditioner control unit to the engine control unit via the meter control unit, and the engine control unit issues the compressor drive command.

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