Exhaust braking method for off-road vehicles in unmanned driving mode

Abstract

This invention proposes an exhaust braking method for off-road vehicles in autonomous driving mode. The off-road vehicle is equipped with an engine controller, a vehicle controller, and an automatic transmission electronic control unit (ATU). The method includes: the vehicle controller acquiring the current vehicle condition and determining whether the current vehicle condition meets preset conditions for opening the exhaust brake switch; when the current vehicle condition meets the conditions for opening the exhaust brake switch, the engine controller responds to a signal command generated by the vehicle and further determines whether the signal command meets preset downshift conditions; when the signal command meets the downshift conditions, it sends a downshift request signal to the ATU; based on the downshift signal, the ATU applies exhaust braking to the current vehicle. This invention can automatically activate exhaust braking based on driving conditions in autonomous driving mode.

Description

Technical Field

[0001] This invention relates to the field of autonomous driving technology, and in particular to an exhaust braking method for off-road vehicles in unmanned driving mode. Background Technology

[0002] Currently, for manned off-road vehicles, the driver needs to manually close the exhaust brake switch according to road conditions, and the exhaust brake can only start working when other conditions are met (such as the accelerator is not pressed, the clutch is not disengaged, the engine speed is greater than the first set value, etc.).

[0003] Since the exhaust brake switch needs to be manually closed in a manned off-road vehicle, the exhaust brake system cannot be directly transplanted to an unmanned off-road vehicle. Instead, the control system structure and control strategy need to be adjusted so that the controller can make comprehensive judgments on relevant signals and then automatically start or stop the exhaust brake to adapt to the unmanned driving mode. Summary of the Invention

[0004] The technical problem this invention aims to solve is that existing technologies require manual closing of the exhaust brake switch, making the exhaust brake system unsuitable for direct application to autonomous off-road vehicles. Instead, adjustments to the control system structure and strategy are necessary, causing inconvenience. Therefore, this invention provides an exhaust brake method for off-road vehicles in autonomous driving mode.

[0005] The technical solution adopted in this invention is that the off-road vehicle includes an engine controller, a vehicle controller, and an automatic transmission electronic control unit. The exhaust braking method for an off-road vehicle in unmanned driving mode includes:

[0006] The vehicle controller obtains the current vehicle status;

[0007] Determine whether the current vehicle condition meets the preset conditions for opening the exhaust brake switch;

[0008] When the current vehicle condition meets the conditions for activating the exhaust brake switch, the engine controller responds to the signal command generated by the vehicle and further determines whether the signal command meets the preset downshift conditions.

[0009] When the signal command meets the downshift condition, a downshift request signal is sent to the automatic transmission electronic control unit.

[0010] Based on the downshift signal, the automatic transmission electronic control unit applies exhaust braking to the current vehicle.

[0011] In one embodiment, the vehicle controller acquires the current vehicle status by acquiring the current vehicle's slope and speed.

[0012] In one implementation, determining whether the current vehicle condition meets the preset conditions for opening the exhaust brake switch includes:

[0013] When the slope is greater than the preset slope setting value and the vehicle speed is greater than the preset vehicle speed setting value, it is determined that the current vehicle condition meets the preset condition for opening the exhaust brake switch.

[0014] In one implementation, the signal command includes:

[0015] Exhaust brake enable signal, exhaust brake switch signal, fuel supply signal, engine speed signal, anti-lock braking system flag signal, brake caliper pressure signal, and AT controller lockout signal.

[0016] In one implementation, the method includes:

[0017] When the exhaust enable signal appears, the fuel supply signal does not appear, the engine speed represented by the engine signal is greater than the preset engine setting value, the exhaust brake switch signal appears, the anti-lock braking system flag signal appears, the brake pressure pump signal represents a pump pressure greater than the preset first pressure setting value, and the AT controller lock-up signal shows a locked state, the engine controller sends a downshift request signal to the automatic transmission electronic control unit and outputs a high level to the exhaust brake solenoid valve;

[0018] The exhaust brake solenoid valve responds to a high-level output to initiate exhaust braking on the current vehicle.

[0019] In one implementation, the method includes:

[0020] When the exhaust enable signal appears, the fuel supply signal does not appear, the engine speed represented by the engine signal is greater than the preset engine setting value, the exhaust brake switch signal appears, the anti-lock braking system flag signal appears, and the AT controller lock signal shows that it is in a locked state, the engine controller sends a downshift request signal to the automatic transmission electronic control unit and outputs a high level to the exhaust brake solenoid valve.

[0021] The exhaust brake solenoid valve responds to a high-level output to initiate exhaust braking on the current vehicle.

[0022] In one implementation, the method includes:

[0023] When the brake pressure caliper signal indicates a caliper pressure greater than a preset second pressure setting value, and the AT controller lockout signal indicates a locked state, the engine controller sends a downshift request signal to the automatic transmission electronic control unit and outputs a high level to the exhaust brake solenoid valve, wherein the second pressure setting value is greater than the first pressure setting value.

[0024] The exhaust brake solenoid valve responds to a high-level output to initiate exhaust braking on the current vehicle.

[0025] In one implementation, the method includes:

[0026] When the exhaust brake enable signal is not present, the engine controller automatically switches to the exhaust brake control strategy in manned driving mode.

[0027] Another aspect of the present invention provides a vehicle configured to implement the off-road vehicle exhaust braking method for unmanned driving mode as described in any of the preceding claims.

[0028] Another aspect of the present invention provides a computer storage medium storing a computer program that, when executed by a processor, implements the steps of the exhaust braking method for an off-road vehicle in an unmanned driving mode as described in any of the preceding claims.

[0029] By adopting the above technical solution, the present invention has at least the following advantages:

[0030] (1) In the unmanned driving mode, the present invention can automatically start the exhaust brake according to the driving conditions, which can effectively prevent the brake heat fade problem of the vehicle when going down a long slope; at the same time, it can automatically shut off the exhaust brake according to the driving conditions, ensuring the vehicle's speed on flat roads.

[0031] (2) When the brake caliper pressure exceeds the second pressure setting value, the exhaust brake can be automatically superimposed on the service brake system, enhancing the service braking capability. This is especially valuable in some vehicles where space constraints necessitate the use of smaller service brakes.

[0032] (3) When the anti-lock braking system flag appears and the brake caliper pressure is less than or equal to the first pressure setting value, the exhaust brake is turned off to prevent the wheels from locking up under the action of the exhaust brake on slippery surfaces.

[0033] (4) When the driverless enable signal does not appear, the control system can automatically switch back to the original manned driving mode without any other related operations, and has the function of automatically adapting to the driving mode. Attached Figure Description

[0034] Figure 1 This is a flowchart of an exhaust braking method for an off-road vehicle in unmanned driving mode according to an embodiment of the present invention;

[0035] Figure 2 A flowchart illustrating the control method for implementing a vehicle controller strategy according to an application example of the present invention;

[0036] Figure 3 A flowchart illustrating the control method for implementing an engine controller strategy according to an application example of the present invention. Detailed Implementation

[0037] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0038] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed feature, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0039] As used herein, the terms “basically,” “approximately,” and similar terms are used as terms of approximation rather than terms of degree, and are intended to describe inherent biases in measured or calculated values ​​that will be recognized by those skilled in the art.

[0040] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] The steps described in the specification and the flowcharts in the accompanying drawings of this invention are not necessarily to be strictly followed according to the step numbers; the execution order of the steps can be changed. Furthermore, certain steps can be omitted, multiple steps can be combined into one step, and / or one step can be broken down into multiple steps.

[0043] The first embodiment of the present invention provides an exhaust braking method for an off-road vehicle in autonomous driving mode, such as... Figure 1 As shown, the specific steps include the following:

[0044] Step S1: The vehicle controller obtains the current vehicle status;

[0045] Step S2: Determine whether the current vehicle condition meets the preset conditions for opening the exhaust brake switch;

[0046] Step S3: When the current vehicle condition meets the conditions for opening the exhaust brake switch, the engine controller responds to the signal command generated by the vehicle and further determines whether the signal command meets the preset downshift conditions.

[0047] Step S4: When the signal command meets the downshift condition, a downshift request signal is sent to the automatic transmission electronic control unit;

[0048] Step S5: Based on the downshift signal, the automatic transmission electronic control unit applies exhaust braking to the current vehicle.

[0049] The method provided in this embodiment will be described in detail step by step below.

[0050] Step S1: The vehicle controller obtains the current vehicle status.

[0051] In this embodiment, at least a vehicle controller, an automatic transmission electronic control unit, an engine controller, supporting testing equipment, and interconnection devices can be configured in vehicles with corresponding requirements.

[0052] In this embodiment, the vehicle controller can obtain the current vehicle status, specifically the current slope and speed of the vehicle.

[0053] It is understandable that the specific parameter selection may include vehicle driving parameters other than gradient and speed. The specific selection can be reasonably adjusted according to the actual needs, and this article does not limit it.

[0054] Step S2: Determine whether the current vehicle condition meets the preset conditions for opening the exhaust brake switch.

[0055] In this embodiment, the vehicle controller can determine whether the current vehicle condition meets the preset conditions for opening the exhaust brake switch.

[0056] Specifically, when the gradient is greater than the preset gradient setting value and the vehicle speed is greater than the preset vehicle speed setting value, it is determined that the current vehicle condition meets the preset condition for opening the exhaust brake switch.

[0057] Understandably, the gradient setting, vehicle speed setting, and conditions for activating the exhaust brake switch can be adjusted within a reasonable range according to actual needs.

[0058] Step S3: When the current vehicle condition meets the conditions for activating the exhaust brake switch, the engine controller responds to the signal command generated by the vehicle and further determines whether the signal command meets the preset downshift conditions.

[0059] In this embodiment, when the engine controller receives a signal from the vehicle controller indicating whether the current vehicle condition meets the preset condition for opening the exhaust brake switch, it determines whether the preset downshifting condition is met based on the signal instruction.

[0060] Specifically, downshifting conditions may include: exhaust brake enable signal, exhaust brake switch signal, fuel supply signal, engine speed signal, anti-lock braking system flag signal, brake caliper pressure signal, and AT controller lock-up signal.

[0061] Understandably, the type of downshift signal can be adjusted within a reasonable range according to actual needs, and this article does not impose any restrictions on this.

[0062] Step S4: When the signal command meets the downshifting conditions, a downshifting request signal is sent to the automatic transmission electronic control unit.

[0063] In this embodiment, meeting the downshifting condition can include the following situations:

[0064] 1) When the exhaust enable signal appears, the fuel supply signal does not appear, the engine speed indicated by the engine signal is greater than the preset engine setting value, the exhaust brake switch signal is active, the anti-lock braking system (ABS) flag signal is active, the brake pressure caliper signal indicates that the brake caliper pressure is greater than the preset first pressure setting value, and the AT controller lockout signal shows the locked state. (All of the above conditions must be met simultaneously.)

[0065] 2) When the exhaust enable signal appears, the fuel supply signal does not appear, the engine speed indicated by the engine signal is greater than the preset engine setting value, the exhaust brake switch signal is active, the anti-lock braking system flag signal is active, and the AT controller lockout signal shows the locked state. (All of the above conditions must be met simultaneously.)

[0066] 3) When the brake pressure caliper signal indicates a brake caliper pressure greater than a preset second pressure setting value, and simultaneously the AT controller lockout signal displays a locked state. (The second pressure setting value is greater than the first pressure setting value.)

[0067] When any of the above conditions are met, the "downshift condition" is satisfied. Furthermore, the engine controller sends a downshift request signal to the automatic transmission electronic control unit and outputs a high level to the exhaust brake solenoid valve.

[0068] Step S5: Based on the downshift signal, the automatic transmission electronic control unit applies exhaust braking to the current vehicle.

[0069] Based on the above steps, when the automatic transmission control unit receives a downshift signal, the exhaust brake solenoid valve receives a high-level output, meaning that the automatic transmission control unit applies exhaust braking to the current vehicle.

[0070] Furthermore, the exhaust brake indicator light can be simultaneously illuminated by sending a signal to the instrument panel via the vehicle network.

[0071] Optionally, when the exhaust brake enable signal is not present, the engine controller can automatically switch to the exhaust brake control strategy in manned driving mode, meaning that the engine controller can be manually operated.

[0072] Compared with existing technologies, the exhaust braking method for off-road vehicles in autonomous driving mode provided in this embodiment has at least the following advantages:

[0073] (1) In the unmanned driving mode, the present invention can automatically start the exhaust brake according to the driving conditions, which can effectively prevent the brake heat fade problem of the vehicle when going down a long slope; at the same time, it can automatically shut off the exhaust brake according to the driving conditions, ensuring the vehicle's speed on flat roads.

[0074] (2) When the brake caliper pressure exceeds the second pressure setting value, the exhaust brake can be automatically superimposed on the service brake system, enhancing the service braking capability. This is especially valuable in some vehicles where space constraints necessitate the use of smaller service brakes.

[0075] (3) When the anti-lock braking system flag appears and the brake caliper pressure is less than or equal to the first pressure setting value, the exhaust brake is turned off to prevent the wheels from locking up under the action of the exhaust brake on slippery surfaces.

[0076] (4) When the driverless enable signal does not appear, the control system can automatically switch back to the original manned driving mode without any other related operations, and has the function of automatically adapting to the driving mode.

[0077] The second embodiment of the present invention is based on the above embodiments, and in conjunction with the appendix. Figures 1 to 3 Here is an application example of the present invention.

[0078] (1) Implementation of vehicle controller strategy

[0079] The gradient sensor signal and vehicle speed signal are input to the vehicle controller. After comprehensively judging the current vehicle speed and current gradient, the vehicle controller decides whether to issue an exhaust brake switch ON signal. The specific implementation steps are as follows (control strategy block diagram shown). Figure 3 ):

[0080] a) System power-on, program starts

[0081] b) Enter the current road gradient and current vehicle speed

[0082] c) Determine if the current slope is greater than the second set value?

[0083] d) If yes, proceed to the next step; otherwise, return to step b).

[0084] e) Determine if the vehicle speed is greater than the third preset value?

[0085] f) If yes, proceed to the next step; otherwise, return to step b).

[0086] g) Issue an exhaust brake ON signal

[0087] h) Return to step b)

[0088] (2) Implementation of Engine Controller Strategy

[0089] The engine controller receives the autonomous driving enable signal, the exhaust brake switch ON signal, the brake caliper pressure signal, the engine speed signal, the anti-lock braking system flag signal, and the AT (automatic) controller lock-up signal (or the clutch engaged signal from the AMT (automatic manual transmission) controller).

[0090] When the brake caliper pressure is greater than the fifth set value and the AT is locked (or the AMT clutch is engaged), the engine controller supplies power to the exhaust brake solenoid valve and simultaneously sends an exhaust brake indicator light illumination signal to the instrument controller via the network. After the exhaust brake valve is energized, the exhaust brake starts to work.

[0091] If the engine controller does not receive an autonomous driving enable signal, it will perform strategy control in the "manned" driving mode.

[0092] When all six conditions are met—autonomous driving enable signal, exhaust brake switch ON signal, current engine speed greater than the first set value, no fuel supply signal, no anti-lock braking system (ABS) working indicator signal, and AT locked (or AMT clutch engaged)—the engine ECU supplies power to the exhaust brake solenoid valve and simultaneously sends an exhaust brake indicator light illumination signal to the instrument cluster controller via the network. Once the exhaust brake solenoid valve is energized, the exhaust brake system begins to operate. Otherwise, the engine controller cancels power supply to the exhaust brake solenoid valve and stops sending the exhaust brake indicator light illumination signal to the instrument cluster controller.

[0093] When all seven conditions are met—autonomous driving enable signal, exhaust brake switch ON signal, current engine speed greater than the first set value, no fuel supply signal, anti-lock braking system (ABS) working indicator signal, brake pressure greater than the fourth set value, and AT locked (or AMT clutch engaged)—the engine controller supplies power to the exhaust brake solenoid valve and simultaneously sends an exhaust brake indicator light illumination signal to the instrument cluster controller via the network, energizing the exhaust brake solenoid valve to begin operation. Otherwise, the engine controller cancels power supply to the exhaust brake solenoid valve and stops sending the exhaust brake indicator light illumination signal to the instrument cluster controller.

[0094] The specific implementation steps of the engine strategy are as follows (control strategy block diagram as shown). Figure 3 ):

[0095] a) The system powers on and the program begins.

[0096] b) Input exhaust brake enable signal, exhaust brake switch ON signal, fuel supply signal, engine speed signal, anti-lock braking system flag signal, brake caliper pressure signal, AT controller lock-up signal (or clutch engaged signal from AMT controller).

[0097] c) Determine if the brake caliper pressure is greater than the fifth set value.

[0098] d) If yes, proceed to step s); otherwise, proceed to the next step.

[0099] e) Determine if the autonomous driving enable signal has appeared.

[0100] f) If yes, proceed to the next step; otherwise, execute the "manned driving mode" subroutine (after the subroutine completes, return to step b).

[0101] g) Is the exhaust brake switch ON signal present?

[0102] h) If yes, proceed to the next step; otherwise, return to step b).

[0103] i) Determine if the current engine speed is greater than the first set value?

[0104] j) If yes, otherwise return to step b).

[0105] k) Determine if a fuel supply signal has appeared.

[0106] l) If yes, go back to step b); otherwise, proceed to the next step.

[0107] m) Determine if the anti-lock braking system (ABS) working indicator signal has appeared.

[0108] If n), proceed to the next step; otherwise, proceed to step q).

[0109] o) Determine if the brake caliper pressure is greater than the fourth set value.

[0110] p) If yes, proceed to the next step; otherwise, return to step b).

[0111] q) Determine if the AT is locked (or the AMT clutch is engaged?)

[0112] r) If yes, proceed to the next step; otherwise, return to step b).

[0113] s) Request downshift from the AT controller (or AMT controller).

[0114] t) Power is supplied to the exhaust brake solenoid valve.

[0115] u) Sends a signal to the instrument controller to illuminate the exhaust brake indicator light.

[0116] v) Return to step b).

[0117] In the third embodiment of the present invention, the flow of the throttle control method for autonomous driving is the same as that of the first or second embodiments. The difference lies in the engineering implementation: this embodiment can be implemented using software plus necessary general-purpose hardware platforms. While hardware implementation is also possible, the former is often a preferred method. Based on this understanding, the method of the present invention can be embodied in the form of a computer software product stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), including several instructions to cause a device (such as a vehicle) to execute the method described in the embodiments of the present invention.

[0118] In summary, compared with the prior art, the present invention has at least the following advantages:

[0119] (1) In the unmanned driving mode, the present invention can automatically start the exhaust brake according to the driving conditions, which can effectively prevent the brake heat fade problem of the vehicle when going down a long slope; at the same time, it can automatically shut off the exhaust brake according to the driving conditions, ensuring the vehicle's speed on flat roads.

[0120] (2) When the brake caliper pressure exceeds the second pressure setting value, the exhaust brake can be automatically superimposed on the service brake system, enhancing the service braking capability. This is especially valuable in some vehicles where space constraints necessitate the use of smaller service brakes.

[0121] (3) When the anti-lock braking system flag appears and the brake caliper pressure is less than or equal to the first pressure setting value, the exhaust brake is turned off to prevent the wheels from locking up under the action of the exhaust brake on slippery surfaces.

[0122] (4) When the driverless enable signal does not appear, the control system can automatically switch back to the original manned driving mode without any other related operations, and has the function of automatically adapting to the driving mode.

[0123] Through the description of specific embodiments, a more in-depth and specific understanding should be gained of the technical means and effects adopted by the present invention to achieve the intended purpose. However, the accompanying drawings are only provided for reference and illustration and are not intended to limit the present invention.

Claims

1. A method for exhaust braking of an off-road vehicle in unmanned driving mode, characterized in that, The off-road vehicle includes an engine controller, a vehicle controller, and an automatic transmission electronic control unit; the method includes: The vehicle controller obtains the current vehicle status; Determine whether the current vehicle condition meets the preset conditions for opening the exhaust brake switch; When the current vehicle condition meets the conditions for activating the exhaust brake switch, the engine controller responds to the signal command generated by the vehicle and further determines whether the signal command meets the preset downshift conditions. When the signal command meets the downshift condition, a downshift request signal is sent to the automatic transmission electronic control unit. Based on the downshift signal, the automatic transmission electronic control unit applies exhaust braking to the current vehicle; The vehicle controller obtains the current vehicle status including: the current vehicle's slope and speed; The step of determining whether the current vehicle condition meets the preset conditions for opening the exhaust brake switch includes: When the slope is greater than the preset slope setting value and the vehicle speed is greater than the preset vehicle speed setting value, it is determined that the current vehicle condition meets the preset condition for opening the exhaust brake switch. The signal commands include: Exhaust brake enable signal, exhaust brake switch signal, fuel supply signal, engine speed signal, anti-lock braking system flag signal, brake caliper pressure signal, and AT controller lockout signal; The method further includes: When the exhaust brake enable signal appears, the fuel supply signal does not appear, the engine speed signal indicates an engine speed greater than a preset engine setting value, the exhaust brake switch signal indicates an open signal, the anti-lock braking system flag signal indicates an active signal, the brake caliper pressure signal indicates a caliper pressure greater than a preset first pressure setting value, and the AT controller lockout signal indicates a locked state, the engine controller sends a downshift request signal to the automatic transmission electronic control unit and outputs a high level to the exhaust brake solenoid valve; The exhaust brake solenoid valve responds to a high-level output to initiate exhaust braking for the current vehicle. The method further includes: When the exhaust brake enable signal appears, the fuel supply signal does not appear, the engine speed signal indicates an engine speed greater than a preset engine setting value, the exhaust brake switch signal appears, the anti-lock braking system flag signal appears, and the AT controller lockout signal shows a locked state, the engine controller sends a downshift request signal to the automatic transmission electronic control unit and outputs a high level to the exhaust brake solenoid valve. The exhaust brake solenoid valve responds to a high-level output to initiate exhaust braking for the current vehicle. The engine controller is further configured to: When the brake caliper pressure signal represents a caliper pressure greater than a preset second pressure setting value, and the AT controller lockout signal shows a locked state, the engine controller sends a downshift request signal to the automatic transmission electronic control unit and outputs a high level to the exhaust brake solenoid valve, wherein the second pressure setting value is greater than the first pressure setting value. The exhaust brake solenoid valve responds to a high-level output to initiate exhaust braking for the current vehicle. The method further includes: When the exhaust brake enable signal is not present, the engine controller automatically switches to the exhaust brake control strategy in manned driving mode.

2. A vehicle, characterized in that, The vehicle is configured to implement the off-road vehicle exhaust braking method for unmanned driving mode as described in claim 1.

3. A computer storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the exhaust braking method for an off-road vehicle in unmanned driving mode as described in claim 1.

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