Transfer case gear switching device with gear shifting protection function and switching method

Abstract

The invention relates to a transfer case gear switching device with a gear shifting protection function and a switching method. The problem that transfer case gears are damaged due to the fact that a driver switches the transfer case gears in the driving process is solved. The device comprises a transfer case gear switch, a vehicle control unit, a combination instrument and a transfer case electromagnetic valve. When the vehicle speed is zero, the vehicle control unit respectively controls different gear electromagnetic valves to be powered on according to an input gear switch signal so as to control a transfer case shifting fork to move for gear shifting operation; and when the vehicle speed is not zero, if the vehicle control unit receives an input gear signal change, output change is not carried out, that is, the output state that the vehicle speed is kept to be zero last time is not changed until the vehicle speed is zero again, and the vehicle control unit is synchronously switched to a real-time corresponding state according to switching signal input in the state. The situation that the driving safety is affected by frequent operation of a gear shifting switch in the driving process is avoided.

Description

Technical Field

[0001] The invention belongs to the field of commercial vehicles, and in particular relates to a transfer case gear switching device and a switching method with a gear shift protection function. Background Art

[0002] The transfer case gear shifting device widely used in the market at present directly controls the ventilation or de-airing of the transfer case solenoid valve through the transfer case gear switch, and then controls the engagement and disengagement of the front axle gear through the shift fork. Since the gear transmission of the transfer case four-wheel drive low-speed gear is relatively large, the shifting process of this gear usually requires the driver to operate it when parking to prevent damage to the transfer case gear. This scheme only recognizes the position of the transfer case switch when switching the transfer case gear, and does not judge the driving status. It cannot effectively prevent the driver's misoperation, and there is a risk of damaging the transfer case. Summary of the invention

[0003] The present invention uses a vehicle controller to intervene in the transfer case shift control process, thereby solving the problem of damage to the transfer case gears caused by the driver switching the transfer case gears during driving.

[0004] The present invention is achieved by the following technical solutions:

[0005] A transfer case gear switching device with a gear shift protection function, comprising a transfer case gear switch, a vehicle controller, a combination instrument and a transfer case solenoid valve;

[0006] The 4 points of the transfer case gear switch are connected to the power supply, the 3rd and 8th points of the switch are connected to the switch input point of the vehicle controller, the 7th and 10th points of the switch are grounded, and the first point is connected to the vehicle backlight power supply; the vehicle controller is connected to the instrument cluster through the CAN bus, the transfer case solenoid valve control output point is hard-wired to the power supply of the transfer case switching solenoid valve of the three gears; the instrument cluster is hard-wired to the vehicle speed sensor;

[0007] Different transfer case switch positions correspond to different input signals: low level is the transfer case low-speed four-wheel drive gear, high level is the transfer case high-speed four-wheel drive gear, and the suspended state is the transfer case two-wheel drive gear;

[0008] The instrument cluster collects the pulse signal of the vehicle speed sensor, calculates the real-time vehicle speed based on the vehicle speed ratio, tire radius, and odometer pulse information, and sends the vehicle speed information via the CAN bus in the form of a TCO1 (0x0CFE6CEE) message.

[0009] A transfer case gear position switching device and method with a gear shift protection function. When the vehicle speed is zero, the vehicle controller controls the solenoid valves of different gear positions to be energized according to the input gear position switch signal, so as to control the transfer case shift fork to move and perform a gear shift operation. When the vehicle speed is not zero, if the vehicle controller receives a change in the input gear position signal, the output will not be changed, that is, the output state when the vehicle speed was zero the most recent time is kept unchanged until the vehicle speed is zero again. The vehicle controller synchronously switches to a real-time corresponding state according to the switch signal input in this state.

[0010] To prevent the driver from frequently operating the switch while driving because he or she mistakenly believes that the transfer case has not shifted gears, if the vehicle controller detects a change in the input signal during driving, the BCM_AI2 message (0x18FF6221) will send a valid value. When the instrument cluster receives the valid value signal, a warning will be given on the instrument interface: "Shifting the transfer case gear is prohibited during driving."

[0011] The present invention controls the shifting of the transfer case by adding a vehicle controller, thereby realizing the normal switching function of the transfer case gear under safe conditions, solving the problem of damage to the transfer case gears caused by the driver switching the transfer case gears during driving, and at the same time warning the driver through the combination instrument to avoid frequent operation of the shift switch during driving that affects driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is the control principle diagram of the present invention;

[0013] Figure 2 It is the shift logic flow chart of the present invention. DETAILED DESCRIPTION

[0014] The invention mainly consists of a transfer case gear switch (operating device), a vehicle controller (control device), a combination instrument (display device), and a transfer case solenoid valve (actuating device).

[0015] like Figure 1 As shown: 4 points of the transfer case gear switch are connected to the power supply, 3 points and 8 points of the switch are connected to the switch input points of the vehicle controller, 7 points and 10 points of the switch are grounded, and the first point is connected to the vehicle backlight power supply; the vehicle controller is connected to the instrument cluster through the CAN bus, and the transfer case solenoid valve control output point is hard-wired to the power supply of the transfer case switching solenoid valve of the three gears; the instrument cluster is hard-wired to the vehicle speed sensor.

[0016] During the transfer case gear switching process, the driver first operates the transfer case gear switch to input the gear signal into the vehicle controller. Different transfer case switch gears correspond to different input signals: a low level is the transfer case low-speed four-wheel drive gear, a high level is the transfer case high-speed four-wheel drive gear, and a suspended state is the transfer case two-wheel drive gear.

[0017] Secondly, the instrument collects the pulse signal of the vehicle speed sensor, and calculates the real-time vehicle speed based on the vehicle speed ratio, tire radius, odometer pulse and other information, and sends the vehicle speed information through the CAN bus in the form of TCO1 (0x0CFE6CEE) message.

[0018] like Figure 2 As shown, the vehicle controller reads the vehicle speed information via the CAN bus interface and performs the following logical judgment:

[0019] When the vehicle speed is zero: the vehicle controller controls the solenoid valves of different gears to be energized according to the input gear switch signal to control the transfer case fork to move and shift. When the vehicle speed is not zero, if the vehicle controller receives a change in the input gear signal, it will not change the output, that is, keep the output state of the last zero speed unchanged until the vehicle speed is zero again. The vehicle controller will synchronously switch to the real-time corresponding state according to the switch signal input in this state.

[0020] At the same time, in order to prevent the driver from mistakenly thinking that the transfer case has not shifted gears and frequently operating the switch during driving, if the vehicle controller detects a change in the input signal during driving, the BCM_AI2 message (0x18FF6221) will send a valid value. When the instrument cluster receives the valid value signal, it will warn on the instrument interface that "shifting the transfer case gear is prohibited during driving."

[0021] The present invention controls the transfer case solenoid valve to work through the vehicle controller, and while satisfying the transfer case gear shifting function, adds a vehicle speed judgment condition to achieve the purpose of preventing the transfer case gear from being switched during driving. By inputting the transfer case switch signal into the vehicle controller, the vehicle controller judges the vehicle driving state, controls the transfer case solenoid valve to work, and pushes the shift fork to shift gears through the air circuit. It is applied to heavy-duty vehicles to achieve the transfer case gear shifting function while avoiding damage to the transfer case gears.

Claims

1. A transfer case gear shifting device with a gear shift protection function, characterized in that: It includes a transfer case gear switch, a vehicle controller, a combination instrument and a transfer case solenoid valve; the transfer case gear switch is connected to the power supply at 4 points, the switch is connected to the input point of the vehicle controller switch at points 3 and 8, the switch is grounded at points 7 and 10, and the first point is connected to the vehicle backlight power supply; the vehicle controller is connected to the combination instrument through the CAN bus, the transfer case solenoid valve control output point is hard-wired to the power supply of the transfer case switching solenoid valve of the three gears; the combination instrument is hard-wired to the vehicle speed sensor; different transfer case switch gears correspond to different input signals: low level is the transfer case low-speed four-wheel drive gear, high level is the transfer case high-speed four-wheel drive gear, and the suspended state is the transfer case two-wheel drive gear; the combination instrument collects the pulse signal of the speed sensor, and calculates the real-time vehicle speed according to the vehicle speed ratio, tire radius, and odometer pulse information, and sends the speed information through the CAN bus in the form of a TCO1 (0x0CFE6CEE) message.

2. A transfer case gear position switching device and a switching method with a gear shift protection function, characterized in that: According to the gear switching device of claim 1, when the vehicle speed is zero, the vehicle controller controls the solenoid valves of different gears to be energized according to the input gear switch signal, so as to control the transfer case shift fork to move and perform the gear shift operation; when the vehicle speed is not zero, if the vehicle controller receives a change in the input gear signal, the output will not be changed, that is, the output state when the vehicle speed was zero the most recent time is kept unchanged, until the vehicle speed is zero again, and the vehicle controller synchronously switches to the real-time corresponding state according to the switch signal input in this state; To prevent the driver from frequently operating the switch while driving because he or she mistakenly believes that the transfer case has not shifted gears, if the vehicle controller detects a change in the input signal during driving, the BCM_AI2 message (0x18FF6221) will send a valid value. When the instrument cluster receives the valid value signal, a warning will be given on the instrument interface: "Shifting the transfer case gear is prohibited during driving."

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