Power take-off control system and vehicle

Abstract

This disclosure relates to a power take-off (PTO) control system and a vehicle. The system includes: a pressure device, a valve, a PTO actuator, and a PTO control circuit. The pressure device is connected to the PTO actuator via the valve, and the pressure device provides a compression medium to the PTO actuator through the valve. The PTO actuator includes a PTO engagement switch, and the PTO actuator controls the on / off state of the PTO engagement switch under the action of the compression medium. The PTO control circuit is connected to the valve and the PTO engagement switch, and controls the on / off state of the valve according to a PTO trigger command, and controls the vehicle to enter or exit the PTO state according to the on / off state of the PTO engagement switch. Embodiments of this disclosure can complete the control function of the PTO in an electromechanical automatic transmission vehicle system to achieve idle PTO or driving PTO.

Description

Technical Field

[0001] This disclosure relates to the field of vehicle technology, and more specifically, to a power take-off control system and a vehicle. Background Technology

[0002] The existing power take-off (PTO) control scheme for vehicles with mechanical manual transmissions involves the driver controlling the PTO solenoid valve via a PTO button, thus engaging the gears. This is simple to operate, but requires the driver to determine whether the PTO is engaged and functioning correctly. However, for electromechanical automatic transmissions, which eliminate the clutch pedal, the traditional PTO control method is not feasible. Therefore, the PTO control system needs optimization and improvement to achieve the desired PTO control functionality in electromechanical automatic transmission systems. Summary of the Invention

[0003] To address the aforementioned problems, this disclosure provides a power take-off control system and a vehicle.

[0004] According to a first aspect of the present disclosure, a power take-off (PTO) control system is provided, the system comprising: a pressure device, a valve, a PTO actuator, and a PTO control circuit;

[0005] The pressure device is connected to the power take-off actuator through the valve, and the pressure device is used to provide a compression medium to the power take-off actuator through the valve;

[0006] The power take-off actuator includes a power take-off engagement switch, which is used to control the on / off state of the power take-off engagement switch under the action of the compression medium.

[0007] The power take-off control circuit connects the valve and the power take-off connection switch, and is used to control the on / off state of the valve according to the power take-off trigger command, and to control the vehicle to enter or exit the power take-off state according to the on / off state of the power take-off connection switch.

[0008] Optionally, the valve includes a solenoid valve, and the power take-off control circuit includes: a power take-off trigger switch, a first relay, a second relay, and a gearbox controller;

[0009] The power take-off trigger switch is connected to the positive terminal of the power supply, the first relay and the gearbox controller, and is used to provide the power take-off trigger command when closed, and to supply power to the coil of the first relay;

[0010] The switch of the first relay is located between the positive terminal of the power supply and the positive terminal of the coil of the solenoid valve, and is used to control the power supply to the positive terminal of the coil of the solenoid valve;

[0011] The second relay is connected to the solenoid valve and the gearbox controller, and is used to control the on / off state of the solenoid valve;

[0012] The transmission controller is grounded through the power take-off (PTO) engagement switch and is used to control the vehicle to enter or exit the PTO state according to the on / off state of the PTO engagement switch.

[0013] Optionally, the first terminal of the power take-off trigger switch is connected to the positive terminal of the power supply, and the second terminal of the power take-off trigger switch is connected to the first port of the transmission controller. The first port is an input port. When the power take-off trigger switch is in the closed state and the level of the first port is high, the power take-off trigger command is triggered.

[0014] Optionally, the second terminal of the power-taking trigger switch is connected to the first terminal of the coil of the first relay, and the second terminal of the coil of the first relay is grounded;

[0015] The first terminal of the first relay switch is connected to the positive terminal of the power supply, and the second terminal of the first relay switch is connected to the positive terminal of the coil of the solenoid valve.

[0016] The first relay is used so that when the power take-off trigger switch is in the closed state, the coil of the first relay is energized, the switch of the first relay is in the closed state, and the positive terminal of the coil of the solenoid valve is connected to the positive terminal of the power supply.

[0017] Optionally, the first end of the coil of the second relay is connected to the positive terminal of the power supply, and the second end of the coil of the second relay is connected to the second port of the transmission controller, the second port being an output port;

[0018] The first terminal of the second relay switch is grounded, and the second terminal of the second relay switch is connected to the negative terminal of the solenoid valve coil.

[0019] The second relay is used so that when the coil of the second relay is energized, the switch of the second relay is closed, and the negative terminal of the coil of the solenoid valve is connected to ground.

[0020] Optionally, the transmission controller is configured such that when the first port of the transmission controller is at a high level, the second port of the transmission controller is at a low level.

[0021] Optionally, the third port of the transmission controller is grounded through the power take-off and connection switch. The third port is an input port and is at a high level by default.

[0022] The transmission controller is used to control the vehicle to enter a power take-off state when the level of the third port of the transmission controller is low.

[0023] When the level of the third port of the transmission controller is high, the vehicle is controlled to exit the power take-off state.

[0024] Optionally, the pressure device includes a gas storage tank containing a compression medium, the compression medium including compressed gas;

[0025] The solenoid valve is used to open when its coil is energized and to close when its coil is de-energized.

[0026] Optionally, the power take-off actuator includes a spring connected to the power take-off engagement switch. The spring is used to contract under the action of the compression medium to drive the power take-off engagement switch to close; and to rebound under the action of the loss of the compression medium to drive the power take-off engagement switch to open.

[0027] According to a second aspect of the present disclosure, a vehicle is provided, the vehicle including any of the systems described in the first aspect.

[0028] In summary, this disclosure provides a power take-off (PTO) control system, comprising: a pressure device, a valve, a PTO actuator, and a PTO control circuit. The pressure device is connected to the PTO actuator via the valve, and is used to provide a compression medium to the PTO actuator through the valve. The PTO actuator includes a PTO engagement switch, and is used to control the on / off state of the PTO engagement switch under the action of the compression medium. The PTO control circuit is connected to the valve and the PTO engagement switch, and is used to control the on / off state of the valve according to a PTO trigger command, and to control the vehicle to enter or exit the PTO state according to the on / off state of the PTO engagement switch. This disclosure enables the control function of the PTO in an electromechanical automatic transmission vehicle system to achieve idle PTO or driving PTO.

[0029] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0030] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0031] Figure 1 This is a schematic diagram illustrating a power take-off control system according to an exemplary embodiment.

[0032] Figure 2This is a schematic diagram illustrating a power take-off control system according to an exemplary embodiment.

[0033] Figure 3 This is a block diagram illustrating an electronic device according to an exemplary embodiment.

[0034] Figure 4 This is a block diagram illustrating a vehicle according to an exemplary embodiment. Detailed Implementation

[0035] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0036] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below.

[0037] It should be noted that the concepts of "first," "second," "third," and "fourth" mentioned in this disclosure are used only to distinguish different devices, modules, or units, and are not used to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0038] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0039] Meanwhile, it is understood that the data involved in this technical solution (including but not limited to the data itself, the acquisition or use of the data) shall comply with the requirements of relevant laws, regulations and related provisions.

[0040] First, the application scenario of this disclosure will be explained. The existing power take-off (PTO) control scheme for vehicles with mechanical manual transmissions involves the driver controlling the PTO solenoid valve directly via a PTO button, thus engaging the gear. This is simple to operate, but requires the driver to determine whether the PTO is engaged and functioning correctly. However, for electronically controlled mechanical automatic transmissions, since the clutch pedal is eliminated, the traditional PTO control method cannot be implemented in such systems. Therefore, the PTO control system needs to be optimized and improved to achieve the PTO control function in electronically controlled mechanical automatic transmission vehicles.

[0041] With the increasing application of electromechanical automatic transmissions in light trucks, a safe and reliable power take-off (PTO) control system is needed to enable PTO at idle or while driving. The following describes this disclosure with reference to specific embodiments.

[0042] Figure 1 This is a schematic diagram illustrating a power take-off (PTO) control system according to an exemplary embodiment. Figure 1 As shown, this disclosure provides a power take-off (PTO) control system, which may include: a pressure device 10, a valve 20, a PTO actuator 30, and a PTO control circuit 40.

[0043] The pressure device 10 is connected to the power take-off actuator 30 via a valve 20. The pressure device 10 is used to provide a compression medium to the power take-off actuator 30 through the valve 20. For example, the compression medium can be compressed gas.

[0044] The power take-off (PTO) actuator 30 includes a PTO engagement switch K1 (not shown in the figure), which controls the on / off state of the PTO engagement switch K1 under the action of a compressed medium. The PTO control circuit 40 connects the valve 20 and the PTO engagement switch K1, and controls the on / off state of the valve 20 according to a PTO trigger command, and controls the vehicle to enter or exit the PTO state according to the on / off state of the PTO engagement switch K1. For example, the transmission controller KZQ can control the vehicle to enter the PTO state when the PTO engagement switch K1 is closed, and control the vehicle to exit the PTO state when the PTO engagement switch K1 is open.

[0045] In summary, this disclosure provides a power take-off (PTO) control system, comprising: a pressure device, a valve, a PTO actuator, and a PTO control circuit. The pressure device is connected to the PTO actuator via the valve, and is used to provide a compression medium to the PTO actuator through the valve. The PTO actuator includes a PTO engagement switch, and is used to control the on / off state of the PTO engagement switch under the action of the compression medium. The PTO control circuit is connected to the valve and the PTO engagement switch, and is used to control the on / off state of the valve according to a PTO trigger command, and to control the vehicle to enter or exit the PTO state according to the on / off state of the PTO engagement switch. This disclosure enables the control function of the PTO in an electromechanical automatic transmission vehicle system to achieve idle PTO or driving PTO.

[0046] Figure 2 This is a schematic diagram illustrating a power take-off (PTO) control system according to an exemplary embodiment. Figure 2As shown, valve 20 includes a solenoid valve, and power take-off control circuit 40 includes: power take-off trigger switch K2, first relay J1, second relay J2 and gearbox controller KZQ.

[0047] The power take-off trigger switch K2 is connected to the positive terminal of the power supply, the first relay J1, and the gearbox controller KZQ. It is used to provide a power take-off trigger command when closed and to supply power to the coil of the first relay J1.

[0048] The first relay J1 is positioned between the positive terminal of the power supply and the positive terminal of the solenoid valve coil, used to control the power supply to the positive terminal of the solenoid valve coil. The second relay J2 connects the solenoid valve and the gearbox controller KZQ, used to control the on / off state of the solenoid valve.

[0049] The transmission controller KZQ is grounded through the power take-off (PTO) engagement switch K1, and is used to control the vehicle to enter or exit the PTO state according to the on / off state of the PTO engagement switch K1.

[0050] For example, the transmission controller KZQ can control the vehicle to enter power take-off mode when the power take-off (PTO) engagement switch K1 is closed. After a first set threshold time (which can be calibrated), the clutch is engaged, and power is transmitted from the engine through the clutch, transmission input shaft, and transmission intermediate shaft to the PTO, at which point the PTO begins operation. During the aforementioned first set threshold time, forward or reverse gear can be engaged to achieve power take-off for driving. After the first set threshold time of entering power take-off mode, the transmission controller KZQ does not perform gear shifting or gear engagement actions.

[0051] In some embodiments, after the vehicle enters power take-off (PTO) mode, the transmission controller KZQ can monitor the engine speed. When the engine speed falls below a first preset speed threshold (which is related to engine characteristics and can be calibrated), the clutch is disengaged, preventing the PTO from operating and thus preventing the engine from stalling. Afterwards, if no other operations affect the PTO's operation, the clutch can be re-engaged after a second preset threshold time (which can be calibrated), allowing the PTO to continue operating. This second preset threshold time can be shorter than the first preset threshold time.

[0052] In some embodiments, the first terminal of the power take-off trigger switch K2 is connected to the positive terminal of the power supply, and the second terminal of the power take-off trigger switch K2 is connected to the first port 1 of the transmission controller KZQ. The first port 1 is an input port. When the power take-off trigger switch K2 is closed and the level of the first port 1 is high, the power take-off trigger command is triggered.

[0053] In some embodiments, the second terminal of the power take-off switch K2 is connected to the first terminal of the coil of the first relay J1, and the second terminal of the coil of the first relay J1 is grounded.

[0054] The first terminal of the switch of the first relay J1 is connected to the positive terminal of the power supply, and the second terminal of the switch of the first relay J1 is connected to the positive terminal of the coil of the solenoid valve. The first relay J1 is used so that when the force-taking trigger switch K2 is in the closed state, the coil of the first relay J1 is energized, the switch of the first relay J1 is in the closed state, and the positive terminal of the coil of the solenoid valve is connected to the positive terminal of the power supply.

[0055] In some embodiments, the first end of the coil of the second relay J2 is connected to the positive terminal of the power supply, and the second end of the coil of the second relay J2 is connected to the second port 2 of the gearbox controller KZQ, which is an output port.

[0056] The first terminal of the second relay J2 switch is grounded, and the second terminal of the second relay J2 switch is connected to the negative terminal of the solenoid valve coil. The second relay J2 is used so that when the coil of the second relay J2 is energized, the switch of the second relay J2 closes, and the negative terminal of the solenoid valve coil is connected to ground.

[0057] In some embodiments, the transmission controller KZQ is configured such that when the first port 1 of the transmission controller KZQ is at a high level, the second port 2 of the transmission controller KZQ is at a low level. At this time, the solenoid valve coil is energized, the solenoid valve opens, and the compressed gas in the air reservoir enters the power take-off actuator 30, pushing the spring to contract and causing the power take-off engagement switch K1 to close.

[0058] In some embodiments, the third port 3 of the transmission controller KZQ is grounded through the power take-off switch K1. The third port 3 is an input port and is high level by default.

[0059] The transmission controller KZQ is used to control the vehicle to enter the power take-off state when the level of the third port 3 of the transmission controller KZQ is low.

[0060] When the level of port 3 of the transmission controller KZQ is high, the vehicle is controlled to exit the power take-off state.

[0061] In some embodiments, the pressure device 10 includes a gas storage tank containing a compression medium, which includes compressed gas.

[0062] A solenoid valve is used to open when its coil is energized and close when its coil is de-energized.

[0063] In some embodiments, the power take-off (PTO) actuator 30 includes a spring connected to the PTO engagement switch K1. Under the action of a compression medium, the spring contracts to close the PTO engagement switch K1. When the compression medium is removed, the spring rebounds to open the PTO engagement switch K1.

[0064] The system works as follows:

[0065] When the button of the power take-off trigger switch K2 is pressed, the power take-off trigger switch K2 closes, the level of the first port 1 of the transmission controller KZQ is high, the coil of the first relay J1 is energized, the switch of the first relay J1 closes, and the positive terminal of the solenoid valve coil is connected to the positive terminal of the power supply. When the first port 1 of the transmission controller KZQ is high, the second port 2 of the transmission controller KZQ is low. At this time, the coil of the second relay J2 is energized, the switch of the second relay J2 closes, and the negative terminal of the solenoid valve coil is connected to ground. At this time, the solenoid valve coil is energized, the solenoid valve valve opens, and the compressed gas in the air tank enters the power take-off actuator 30 through the solenoid valve, causing the spring of the power take-off actuator 30 to compress and displace, driving the power take-off engagement switch K1 to close. At this time, the level of the third port 3 of the transmission controller KZQ is low, and the transmission controller KZQ controls the vehicle to enter the power take-off state.

[0066] After the vehicle enters power take-off (PTO) mode, the transmission controller KZQ monitors the vehicle's status. When any of the following conditions are met: the vehicle is powered off, the PTO trigger switch K2 is deactivated, or the vehicle speed exceeds a first preset speed threshold (calibrable) or the engine speed exceeds a second preset speed threshold (calibrable based on hardware safety), where the second preset speed threshold is greater than the first preset speed threshold, the transmission controller KZQ disengages the clutch, cutting off engine power output. Then, the transmission controller KZQ controls the level of the second port 2 to be high, causing the coil of the second relay J2 to de-energize, the switch of the second relay J2 to open, the negative terminal of the solenoid valve coil to disconnect from ground, the solenoid valve coil to de-energize, and the solenoid valve to close. At this time, the compressed gas in the air reservoir cannot enter the PTO actuator 30, the spring of the PTO actuator 30 rebounds, causing the PTO engagement switch K1 to disconnect. At this time, the level of the third port 3 of the transmission controller KZQ is high, and the transmission controller KZQ controls the vehicle to exit PTO mode. The PTO indicator light on the instrument panel can be turned off via a CAN bus signal.

[0067] In summary, this disclosure provides a power take-off (PTO) control system, comprising: a pressure device, a valve, a PTO actuator, and a PTO control circuit. The pressure device is connected to the PTO actuator via the valve, and is used to provide a compression medium to the PTO actuator through the valve. The PTO actuator includes a PTO engagement switch, and is used to control the on / off state of the PTO engagement switch under the action of the compression medium. The PTO control circuit is connected to the valve and the PTO engagement switch, and is used to control the on / off state of the valve according to a PTO trigger command, and to control the vehicle to enter or exit the PTO state according to the on / off state of the PTO engagement switch. This disclosure enables the control function of the PTO in an electromechanical automatic transmission vehicle system to achieve idle PTO or driving PTO.

[0068] Figure 3 This is a block diagram illustrating an electronic device according to an exemplary embodiment. Figure 3 As shown, the electronic device 300 may be a transmission controller KZQ, and may include a processor 301 and a memory 302. The electronic device 300 may also include one or more of a multimedia component 303, an input / output (I / O) interface 304, and a communication component 305.

[0069] The processor 301 controls the overall operation of the electronic device 300. The memory 302 stores various types of data to support the operation of the electronic device 300. This data may include, for example, instructions for any application or method operating on the electronic device 300, and application-related data such as contact data, sent and received messages, pictures, audio, video, etc. The memory 302 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The multimedia component 303 may include a screen and audio components. The screen may be, for example, a touchscreen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signals may be further stored in memory 302 or transmitted via communication component 305. The audio component also includes at least one speaker for outputting audio signals. I / O interface 304 provides an interface between processor 301 and other interface modules, such as a keyboard, mouse, buttons, etc. These buttons may be virtual or physical buttons. Communication component 305 is used for wired or wireless communication between the electronic device 300 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, NB-IoT, eMTC, or other 5G technologies, or combinations thereof, is not limited here. Therefore, the corresponding communication component 305 may include: the aforementioned communication isolation protection circuit, a Wi-Fi module, a Bluetooth module, an NFC module, etc.

[0070] In an exemplary embodiment, the electronic device 300 may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components.

[0071] Figure 4 This is a block diagram illustrating a vehicle according to an exemplary embodiment. Figure 4 As shown, this disclosure also provides a vehicle 400, which includes the power take-off control system described in the preceding embodiments. This power take-off control system is capable of controlling the power take-off of an electromechanical automatic transmission vehicle system to achieve power take-off at idle or while driving. Therefore, the vehicle 400 employing the power take-off control system of this disclosure also possesses the aforementioned advantages.

[0072] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0073] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction, and this disclosure will not describe the various possible combinations separately.

[0074] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A power take-off (PTO) control system, characterized in that, The system includes: a pressure device, valves, a power take-off actuator, and a power take-off control circuit; The pressure device is connected to the power take-off actuator through the valve, and the pressure device is used to provide a compression medium to the power take-off actuator through the valve; The power take-off actuator includes a power take-off engagement switch, which is used to control the on / off state of the power take-off engagement switch under the action of the compression medium. The power take-off control circuit connects the valve and the power take-off connection switch, and is used to control the on / off state of the valve according to the power take-off trigger command, and to control the vehicle to enter or exit the power take-off state according to the on / off state of the power take-off connection switch.

2. The system according to claim 1, characterized in that, The valve includes a solenoid valve, and the power take-off control circuit includes: a power take-off trigger switch, a first relay, a second relay, and a gearbox controller; The power take-off trigger switch is connected to the positive terminal of the power supply, the first relay and the gearbox controller, and is used to provide the power take-off trigger command when closed, and to supply power to the coil of the first relay; The switch of the first relay is located between the positive terminal of the power supply and the positive terminal of the coil of the solenoid valve, and is used to control the power supply to the positive terminal of the coil of the solenoid valve; The second relay is connected to the solenoid valve and the gearbox controller, and is used to control the on / off state of the solenoid valve; The transmission controller is grounded through the power take-off (PTO) engagement switch and is used to control the vehicle to enter or exit the PTO state according to the on / off state of the PTO engagement switch.

3. The system according to claim 2, characterized in that, The first terminal of the power take-off trigger switch is connected to the positive terminal of the power supply, and the second terminal of the power take-off trigger switch is connected to the first port of the transmission controller. The first port is an input port. When the power take-off trigger switch is in the closed state and the level of the first port is high, the power take-off trigger command is triggered.

4. The system according to claim 2, characterized in that, The second terminal of the power take-off trigger switch is connected to the first terminal of the coil of the first relay, and the second terminal of the coil of the first relay is grounded; The first terminal of the first relay switch is connected to the positive terminal of the power supply, and the second terminal of the first relay switch is connected to the positive terminal of the coil of the solenoid valve. The first relay is used so that when the power take-off trigger switch is in the closed state, the coil of the first relay is energized, the switch of the first relay is in the closed state, and the positive terminal of the coil of the solenoid valve is connected to the positive terminal of the power supply.

5. The system according to claim 2, characterized in that, The first end of the coil of the second relay is connected to the positive terminal of the power supply, and the second end of the coil of the second relay is connected to the second port of the gearbox controller, which is an output port; The first terminal of the second relay switch is grounded, and the second terminal of the second relay switch is connected to the negative terminal of the solenoid valve coil. The second relay is used so that when the coil of the second relay is energized, the switch of the second relay is closed, and the negative terminal of the coil of the solenoid valve is connected to ground.

6. The system according to claim 5, characterized in that, The transmission controller is configured such that when the first port of the transmission controller is at a high level, the second port of the transmission controller is at a low level.

7. The system according to claim 2, characterized in that, The third port of the transmission controller is grounded through the power take-off and the switch. The third port is an input port and is at a high level by default. The transmission controller is used to control the vehicle to enter a power take-off state when the level of the third port of the transmission controller is low. When the level of the third port of the transmission controller is high, the vehicle is controlled to exit the power take-off state.

8. The system according to any one of claims 2-7, characterized in that, The pressure device includes a gas storage tank, which stores a compression medium, including compressed gas. The solenoid valve is used to open when its coil is energized and to close when its coil is de-energized.

9. The system according to any one of claims 1-7, characterized in that, The power take-off (PTO) actuator includes a spring connected to the PTO engagement switch. The spring is used to contract under the action of the compression medium to close the PTO engagement switch; and to rebound under the action of the loss of the compression medium to open the PTO engagement switch.

10. A vehicle, characterized in that, The vehicle includes the system described in any one of claims 1-9.

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