Vehicle speed limit control method and system and all-terrain vehicle

Abstract

The invention relates to the technical field of vehicle speed control, in particular to a vehicle speed limiting control method and system and an all-terrain vehicle, and the vehicle speed limiting control method comprises an ECU used for monitoring a vehicle gear, an engine rotating speed N and a throttle opening theta, and if the vehicle gear is in a reverse gear, and the engine rotating speed N is lower than a preset rotating speed or the throttle opening theta is lower than a preset opening, vehicle speed limiting control is not carried out. According to the scheme, the speed limiting strategy can be flexibly adjusted according to the actual operation working condition of the vehicle, flameout of the engine under the reversing idling working condition is effectively prevented, the overall performance and stability of the vehicle are greatly improved, the problem that the engine flames out when a user backs up on a ramp at a low speed when a reverse gear is engaged is solved, and the user experience is improved. The commodity and user satisfaction of the vehicle are improved, and the market competitiveness of the vehicle is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle speed control, and in particular to a vehicle speed limit control method, system and all-terrain vehicle. Background Art

[0002] For safety reasons, four-wheeled motorcycles equipped with mechanical CVT (continuously variable transmission) automatic transmissions, including all-terrain vehicles (ATV) and multi-purpose all-terrain vehicles (UTV / SSV), usually have a speed limit of about 10-20km / h for the reverse gear speed. At present, the vehicle speed limit method adopted is that the ECU collects gear information and vehicle speed information. When the reverse gear signal is detected, the difference between the actual vehicle speed and the speed limit target speed is compared, and the engine is controlled to intermittently cut off the fuel and adjust the engine torque output to achieve vehicle speed limit. Once the actual speed exceeds the speed limit target speed by a certain value, the engine will completely cut off the fuel. The above speed limit method is applicable to all four-wheeled motorcycles equipped with a mechanical throttle body system.

[0003] The mechanical CVT automatic transmission used in four-wheel motorcycles is mainly composed of two sets of pulleys and belts; among them, the driving pulley is connected to the engine crankshaft, and the driven pulley is connected to the wheel transmission system. The engine speed determines the speed of the driving pulley. When the speed of the driving pulley is greater than about 2000 revolutions, due to the centrifugal force, the V-groove of the driving pulley is clamped by the centrifugal shoe, causing friction between the belt and the driving pulley, thereby transmitting power to the driven wheel and the wheel system; and when the speed of the driving pulley is less than this value, the driving pulley cannot transmit power to the driven wheel and the wheel system through the belt. In other words, the engine speed determines the power decoupling state of the engine and the wheel transmission system, and this engine speed is the clutch disengagement speed of the mechanical CVT automatic transmission.

[0004] Based on the existing vehicle speed limit strategy and the inherent characteristics of the mechanical CVT automatic transmission, when a user drives a four-wheel motorcycle and stops on a slope and needs to shift into reverse gear to reverse back to the bottom of the slope, or shift into reverse gear to reverse uphill from the bottom of the slope and then forward back to the bottom of the slope, the user will control the throttle handle to make the throttle valve at a small opening or idle position, the engine at a low speed or idle, and then operate the brake system and direction control system to control the vehicle. If the engine speed is lower than the clutch disengagement speed of the mechanical CVT automatic transmission, and the vehicle speed exceeds a certain value of the speed limit target speed, the engine will be completely cut off from fuel. Because the wheel transmission system is in a decoupled state from the engine, the wheels cannot reverse the engine to run, which will eventually cause the engine to shut down, and the user has to restart the engine to continue driving, which seriously affects the user experience and the practicality of the vehicle. Summary of the invention

[0005] One of the purposes of the present invention is to provide a vehicle speed limit control method, which can flexibly adjust the speed limit strategy according to the actual operating conditions of the vehicle, effectively prevent the engine from stalling under the reverse idling condition, greatly improve the overall performance and stability of the vehicle, so as to solve the problem of the engine stalling when the user shifts into reverse gear and reverses at a low speed on a slope, improve the commercial value and user satisfaction of the vehicle, and enhance the market competitiveness of the vehicle.

[0006] The present invention provides a basic solution 1: a vehicle speed limit control method, comprising the following contents:

[0007] The vehicle gear position, engine speed N and throttle opening θ are monitored. If the vehicle gear position is in reverse gear and the engine speed N is lower than a preset speed or the throttle opening θ is lower than a preset opening, the vehicle speed limit control is not performed.

[0008] Furthermore, the engine speed N and the throttle opening θ are directly collected and acquired;

[0009] Preset the opening, query the throttle opening threshold MAP according to N, and obtain the corresponding throttle opening threshold θthreshold as the preset opening; wherein the throttle opening threshold MAP is a relationship table between N and θthreshold;

[0010] Preset the speed, query the engine speed threshold MAP according to the ambient temperature and the mileage in a specific period, and obtain the corresponding engine speed threshold N1;

[0011] According to the ambient temperature and the downtime, query the engine speed threshold correction MAP to obtain the corresponding engine speed threshold correction value NΔ;

[0012] According to N1 and NΔ, the engine speed threshold Nthreshold=N1+NΔ is modified as the preset speed;

[0013] The engine speed threshold MAP is a relationship table of the ambient temperature, the mileage within a specific period and the engine speed threshold N1; the engine speed threshold correction MAP is a relationship table of the ambient temperature, the downtime and the engine speed threshold correction value NΔ.

[0014] Further, the downtime is calculated by obtaining relevant time information; wherein the relevant time information includes: the time ton read and recorded when the vehicle key is turned on and the time toff read and recorded when the vehicle key is turned off;

[0015] Stop time tstop = toff-ton.

[0016] Furthermore, when the vehicle is turned on, the ambient temperature is determined to determine whether tstop is greater than a preset time threshold. If so, the ambient temperature is updated to the currently measured temperature to obtain the ambient temperature Tair;

[0017] If not, the ambient temperature Tair is obtained, which is the temperature measured when the vehicle was turned on after tstop was greater than the preset time threshold last time.

[0018] Furthermore, the mileage within the specific period is calculated and obtained by obtaining mileage information, including:

[0019] When the vehicle is turned on, determine whether tstop is greater than the preset time threshold. If so, update the mileage information S0 to the current mileage obtained;

[0020] If not, no update is performed and S0 remains unchanged;

[0021] Get mileage information in real time S1;

[0022] The mileage of the vehicle in a specific cycle SΔ=S1-S0.

[0023] The second purpose of the present invention is to provide a vehicle speed limit control system, which can flexibly adjust the speed limit strategy according to the actual operating conditions of the vehicle, effectively prevent the engine from stalling under reverse idling conditions, greatly improve the overall performance and stability of the vehicle, and solve the problem of engine stalling when the user engages reverse gear and reverses at a low speed on a slope, improve the commercial value and user satisfaction of the vehicle, and enhance the market competitiveness of the vehicle.

[0024] The present invention provides a second basic solution: a vehicle speed limit control system, comprising: an ECU;

[0025] The ECU is used to monitor the vehicle gear position, engine speed N and throttle opening θ. If the vehicle gear position is in reverse gear and the engine speed N is lower than a preset speed or the throttle opening θ is lower than a preset opening, the vehicle speed limit control is not performed.

[0026] Further, it also includes: a sensor and a travel monitoring device;

[0027] The ECU is connected to the sensor and the travel monitoring device, and is used to obtain gear information through the sensor to determine whether the vehicle is in reverse gear. If so, it is determined that the vehicle is in reverse gear;

[0028] It is also used to obtain the engine speed N and the throttle opening θ through sensors;

[0029] It is also used to obtain the engine speed N through the sensor, query the pre-stored throttle opening threshold MAP, and obtain the corresponding throttle opening threshold θthreshold as the preset opening; wherein the throttle opening threshold MAP is a relationship table between N and θthreshold;

[0030] It is also used to obtain the ambient temperature through the sensor, obtain the mileage within a specific period through the travel monitoring device, and query the pre-stored engine speed threshold MAP according to the ambient temperature and the mileage within the specific period to obtain the corresponding engine speed threshold N1;

[0031] It is also used to obtain the ambient temperature through the sensor, obtain the downtime through the travel monitoring device, and query the pre-stored engine speed threshold correction MAP according to the ambient temperature and the downtime to obtain the corresponding engine speed threshold correction value NΔ;

[0032] It is also used to correct the engine speed threshold Nthreshold=N1+NΔ according to N1 and NΔ to serve as a preset speed;

[0033] The engine speed threshold MAP is a relationship table of the ambient temperature, the mileage within a specific period and the engine speed threshold N1; the engine speed threshold correction MAP is a relationship table of the ambient temperature, the downtime and the engine speed threshold correction value NΔ.

[0034] Further, the sensors include: a reverse gear sensor, a rotation speed sensor, a throttle position sensor, a temperature sensor and a vehicle speed sensor;

[0035] The reverse gear sensor is used to collect gear information, so that the ECU can accurately determine whether the vehicle is in reverse gear.

[0036] Speed ​​sensor, used to collect engine speed N;

[0037] The throttle position sensor is used to collect the throttle opening θ;

[0038] Temperature sensor, used to collect ambient temperature;

[0039] Vehicle speed sensor, used to collect vehicle speed.

[0040] Furthermore, the downtime is calculated and obtained by the ECU by obtaining relevant time information from a travel monitoring device of the vehicle;

[0041] The relevant time information includes: the time ton read and recorded by the ECU when the vehicle key is turned on, and the time toff read and recorded when the vehicle key is turned off;

[0042] ECU calculates the stop time tstop = toff-ton;

[0043] When the vehicle key is turned on, the ECU determines whether tstop is greater than a preset time threshold. If so, the ambient temperature is updated to the temperature measured by the current temperature sensor to obtain the ambient temperature Tair;

[0044] If not, then obtain the ambient temperature Tair, which is the temperature measured by the temperature sensor when the vehicle key is turned on after the last tstop is greater than the preset time threshold;

[0045] The mileage within the specific period is calculated by the ECU by obtaining mileage information from the vehicle's travel monitoring device, including:

[0046] When the vehicle key is turned on, the ECU determines whether tstop is greater than the preset time threshold. If so, the mileage information S0 is updated to the current mileage obtained by the ECU from the travel monitoring device;

[0047] If not, no update is performed and S0 remains unchanged;

[0048] The ECU obtains mileage information S1 from the travel monitoring device in real time;

[0049] The ECU calculates the vehicle's mileage SΔ=S1-S0 within a specific period.

[0050] The third purpose of the present invention is to provide an all-terrain vehicle that can flexibly adjust the speed limit strategy according to the actual operating conditions of the vehicle, effectively prevent the engine from stalling under reverse idling conditions, greatly improve the overall performance and stability of the vehicle, and solve the problem of engine stalling when the user engages reverse gear and reverses at a low speed on a slope, thereby improving the commercial value and user satisfaction of the vehicle and enhancing the market competitiveness of the vehicle.

[0051] The present invention provides basic solution three: an all-terrain vehicle adopting the above-mentioned vehicle speed limit control system.

[0052] Beneficial effect: Compared with the traditional vehicle speed limit control, the present solution adds the judgment of the engine speed and the throttle opening. It can be that when the vehicle gear is in the reverse gear, it is judged whether the engine speed N is lower than the preset speed or whether the throttle opening θ is lower than the preset opening. If either or both of the two judgment conditions are met, the vehicle speed limit control will not be performed. It can also be that it is first judged whether the engine speed N is lower than the preset speed or whether the throttle opening θ is lower than the preset opening. If either or both of the two judgment conditions are met, it is judged whether the vehicle gear is in the reverse gear. If so, the vehicle speed limit control will not be performed; or it can be judged whether the vehicle gear is in the reverse gear at the same time, and whether the engine speed N is lower than the preset speed or whether the throttle opening θ is lower than the preset opening. If either or both of the two judgment conditions are met, if so, the vehicle speed limit control will not be performed. Taking into account the existing vehicle speed limit strategy and the inherent characteristics of the mechanical CVT automatic transmission, when a user drives a four-wheel motorcycle and stops on a slope and needs to shift into reverse gear to reverse back to the bottom of the slope or shift into reverse gear to reverse uphill from the bottom of the slope and then forward back to the bottom of the slope, the user will control the throttle handle to make the throttle at a smaller opening or idle position, the engine at a lower speed or idle, and then operate the brake system and the direction control system to control the vehicle's driving. After the engine speed N is lower than the preset speed or the throttle opening θ is lower than the preset opening, the vehicle speed limit control is not performed, thereby avoiding the engine speed being lower than the clutch disengagement speed of the mechanical CVT automatic transmission, and the vehicle speed exceeds a certain value of the speed limit target speed, the engine will be completely cut off from fuel, the wheel transmission system and the engine are in a decoupled state, the wheels cannot reverse and drag the engine to run, and eventually the engine will stall.

[0053] This solution accurately determines whether vehicle speed limit control is suitable. Through this multi-parameter comprehensive judgment method, vehicle speed limit control is more intelligent and precise, and can flexibly adjust the speed limit strategy according to the actual operating conditions of the vehicle, effectively preventing the engine from stalling under reverse idling conditions, greatly improving the overall performance and stability of the vehicle, and solving the problem of engine stalling when users engage reverse gear and reverse at a low speed on a slope, thereby improving the commerciality and user satisfaction of the vehicle and enhancing the market competitiveness of the vehicle.

[0054] In addition, in particular, the preset speed and preset opening for comparison of the engine speed and throttle opening in the present solution are not directly set fixed values, but threshold values ​​applicable to the current operating conditions are retrieved in consideration of the current operating conditions of the vehicle. Specifically, the preset opening is queried according to N, and the corresponding throttle opening threshold MAP is obtained as the preset opening; wherein the throttle opening threshold MAP is a relationship table between N and θthreshold; during the actual operation of the vehicle, the ECU implements the vehicle speed limit by limiting the output power of the engine, but the engine does not output power to the outside under certain specific working conditions, so the vehicle speed limit control is not performed under these specific working conditions, and these specific working conditions need to be tested and calibrated to obtain the corresponding throttle opening threshold MAP, so that the throttle opening threshold MAP can be queried according to the current situation N to obtain the minimum opening threshold as the preset opening;

[0055] Similarly, for a preset speed, the engine speed threshold MAP is queried according to the ambient temperature and the mileage within a specific period to obtain the corresponding engine speed threshold N1; the engine speed threshold correction MAP is queried according to the ambient temperature and the downtime to obtain the corresponding engine speed threshold correction value NΔ; according to N1 and NΔ, the engine speed threshold Nthreshold=N1+NΔ is corrected as the preset speed; wherein the engine speed threshold MAP is a relationship table between the ambient temperature, the mileage within a specific period and the engine speed threshold N1; the engine speed threshold correction MAP is a relationship table between the ambient temperature, the downtime and the engine speed threshold correction value NΔ; the clutch disengagement speed of the mechanical CVT automatic transmission is closely related to factors such as the belt friction coefficient and the elastic force of the spring in the transmission system, and the temperature of components such as the belt and spring has a greater impact on their performance, and these temperature changes are closely related to the ambient temperature and the transmission after power coupling. There is a correlation between the power time (which can be approximately replaced by the vehicle mileage, defined as the mileage within a specific period) and the downtime; generally, the lower the ambient temperature, the higher the clutch disengagement speed; conversely, the lower the clutch disengagement speed; similarly, the longer the mileage within a specific period, the higher the temperature of the transmission system will be, and the clutch disengagement speed will decrease accordingly; conversely, the clutch disengagement speed will increase; in addition, after the vehicle stops, the temperature of the transmission system will gradually decrease, and the longer the downtime, the higher the clutch disengagement speed correction value will be; conversely, the clutch disengagement speed will be lower; therefore, it is necessary to establish a corresponding mathematical model or calibrate MAP (engine speed threshold MAP and engine speed threshold correction MAP) through testing and analysis based on the above-mentioned parameters such as ambient temperature, mileage and downtime, so that the ECU can accurately determine or correct the clutch disengagement speed during actual driving, and further improve the accuracy and reliability of vehicle speed limit control. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 A schematic diagram of a flow chart of throttle opening determination in an embodiment of a vehicle speed limit control method of the present invention;

[0057] Figure 2 It is a partial schematic diagram of a throttle opening threshold MAP diagram in an embodiment of a vehicle speed limit control method of the present invention;

[0058] Figure 3 It is a flow chart of engine speed determination in a vehicle speed limit control method embodiment of the present invention;

[0059] Figure 4 It is a partial schematic diagram of an engine speed threshold MAP diagram in an embodiment of a vehicle speed limit control method of the present invention;

[0060] Figure 5 It is a partial schematic diagram of an engine speed threshold correction MAP diagram in an embodiment of a vehicle speed limit control method of the present invention;

[0061] Figure 6 A logic block diagram of an embodiment of a vehicle speed limit control system of the present invention;

[0062] Figure 7 The figure is a curve diagram of vehicle speed and engine speed change in deceleration coasting state. DETAILED DESCRIPTION

[0063] The following is further described in detail through specific implementation methods:

[0064] In the description of this application, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0065] Embodiment 1

[0066] This embodiment provides a vehicle speed limit control method, including the following contents:

[0067] Monitor the vehicle gear position, engine speed N and throttle opening θ. If the vehicle gear position is in reverse gear, and the engine speed N is lower than a preset speed or the throttle opening θ is lower than a preset opening, the vehicle speed limit control is not performed; if the vehicle gear position is in reverse gear, and the engine speed N is greater than or equal to the preset speed or the throttle opening θ is greater than or equal to the preset opening, the vehicle speed limit control is performed;

[0068] In a specific implementation process, when the vehicle gear is in the reverse gear, it can be determined whether the engine speed N is lower than the preset speed or whether the throttle opening θ is lower than the preset opening. If either or both of the two judgment conditions are met, the vehicle speed limit control will not be performed. Alternatively, it can be determined whether the engine speed N is lower than the preset speed or whether the throttle opening θ is lower than the preset opening first. If either or both of the two judgment conditions are met, it can be determined whether the vehicle gear is in the reverse gear. If so, the vehicle speed limit control will not be performed. It can also be determined whether the vehicle gear is in the reverse gear and whether the engine speed N is lower than the preset speed or whether the throttle opening θ is lower than the preset opening at the same time. If either or both of the two judgment conditions are met, the vehicle speed limit control will not be performed. In this embodiment, the vehicle gear is first determined;

[0069] The engine speed N is directly acquired through the set engine speed sensor;

[0070] The throttle opening θ is directly acquired through the throttle position sensor;

[0071] According to the current N, the throttle opening threshold MAP is queried to obtain the corresponding throttle opening threshold θthreshold as the preset opening, so as to determine whether the throttle opening θ is lower than the preset opening, as shown in the attached figure. Figure 1 As shown;

[0072] The throttle opening threshold MAP is a relationship table between N and θthreshold, as shown in the attached figure. Figure 2 As shown, a partial schematic diagram of the relationship table between N and θthreshold; during the actual operation of the vehicle, the ECU realizes the vehicle speed limit by limiting the output power of the engine, but the engine does not output power to the outside under certain specific working conditions, so the vehicle speed limit control is not performed under these specific working conditions. These specific working conditions need to be obtained through testing and calibration, and then the throttle opening threshold MAP is formulated. In this embodiment, the process of formulating the throttle opening threshold MAP is as follows: fix the whole vehicle on the chassis dynamometer, control the chassis dynamometer speed to reversely drag the wheels, the wheels are connected to the engine, so controlling the dynamometer speed can control the engine speed. For example, the engine speed is controlled to 5000rpm by the dynamometer, and the rear wheel output or output power test parameters of the chassis dynamometer are observed; control the throttle body opening change, when the throttle body changes from small to large, the rear wheel output or output power will gradually change from a negative value to a positive value, when the rear wheel output or output power is 0, it is the critical point of the engine outputting power to the outside, and the throttle body opening corresponding to this critical point is used as a theoretical threshold. In engineering, considering the dispersion between individual vehicles, about 2% will be subtracted from the above theoretical threshold as the final threshold, and so on, to complete the threshold calibration of all speed points.

[0073] Preset the speed, query the engine speed threshold MAP according to the ambient temperature and the mileage in a specific period, and obtain the corresponding engine speed threshold N1;

[0074] According to the ambient temperature and the downtime, query the engine speed threshold correction MAP to obtain the corresponding engine speed threshold correction value NΔ;

[0075] According to N1 and NΔ, the engine speed threshold Nthreshold=N1+NΔ is modified as the preset speed, so as to judge, as shown in the attached figure Figure 3 As shown;

[0076] The engine speed threshold MAP is a relationship table of the ambient temperature, the mileage within a specific period and the engine speed threshold N1, as shown in the attached figure. Figure 4 As shown, a partial schematic diagram of a relationship table of ambient temperature, mileage within a specific period and engine speed threshold value N1;

[0077] The engine speed threshold correction MAP is a relationship table of ambient temperature, downtime and engine speed threshold correction value NΔ, as shown in the attached figure. Figure 5 As shown, a partial schematic diagram of a relationship table between ambient temperature, downtime and engine speed threshold correction value NΔ;

[0078] The clutch disengagement speed of the mechanical CVT automatic transmission is closely related to factors such as the belt friction coefficient and the elastic force of the spring in the transmission system, while the temperature of components such as the belt and spring has a great influence on their performance, and these temperature changes are related to the ambient temperature, the time for power transmission after power coupling (which can be approximately replaced by the vehicle mileage, defined as the mileage within a specific period) and the downtime. In general, the lower the ambient temperature, the higher the clutch disengagement speed; conversely, the lower the clutch disengagement speed. Similarly, the longer the mileage within a specific period, the higher the temperature of the transmission system, and the clutch disengagement speed will decrease accordingly; conversely, the clutch disengagement speed will increase. In addition, after the vehicle stops, the temperature of the transmission system will gradually decrease. The longer the downtime, the higher the clutch disengagement speed correction value will be; conversely, the lower the clutch disengagement speed. Therefore, it is necessary to establish a corresponding mathematical model or calibrate MAP through testing and analysis based on the above parameters such as ambient temperature, mileage and downtime, so that the ECU can accurately determine or correct the clutch disengagement speed, and further improve the accuracy and reliability of vehicle speed limit control. In this embodiment, the process of establishing a corresponding mathematical model or calibrating MAP through testing and analysis is as follows:

[0079] There are obvious characteristics when the CVT clutch is disengaged. Take the deceleration coasting condition as an example of a typical condition. When the driver drives at a certain speed (such as 20km / h), the accelerator is completely released and the engine stops injecting fuel. Because the engine speed is high at this time, the CVT clutch is in a state of engagement, and the engine speed slowly decreases with the vehicle speed. When the engine speed drops to a certain value, the clutch is disengaged, the vehicle is decoupled from the engine, and the speed curve decreases more slowly, and the curve tends to be stable; but the speed of the engine speed decreases faster, and the curve tends to change steeply. Combined with the above obvious characteristics, the corresponding engine speed when the clutch is disengaged can be calibrated by analyzing the data.

[0080] Examples include Figure 7 As shown, the circled position represents the clutch disengagement speed;

[0081] First, the clutch disengagement speed is calibrated under different ambient temperatures and mileages. At the corresponding ambient temperature Tair, such as 20°C, the corresponding mileage SΔ, such as 5km, is driven, and the clutch disengagement speed is calibrated according to the above method. Then, when the mileage is continued to be a certain, such as 10km, the clutch disengagement speed N1 is calibrated again until all the parameters in the MAP table are calibrated.

[0082] Then, the correction calibration of the disengagement speed is carried out according to the downtime. The corresponding mileage stop in the MAP table, such as 3600s, is used to calibrate the disengagement speed of the clutch according to the above method, and the difference is calculated with the disengagement speed before the stop. The correction value is then calculated. The stop is continued for 7200s, and the correction value NΔ is calibrated until the calibration of all parameters in the MAP table is completed.

[0083] After the calibration is completed, multiple sample vehicles are tested to determine the final calibration parameters, and N1 and N△ are both the minimum values ​​among multiple vehicles.

[0084] The downtime is calculated by obtaining relevant time information from the vehicle's travel monitoring device through CAN communication;

[0085] The relevant time information includes: the time ton read and recorded when the vehicle key is turned on, and the time toff read and recorded when the vehicle key is turned off;

[0086] Stop time tstop = toff - ton; accurate stop time data plays a key role in judging the thermal state of the vehicle and the performance changes of the transmission system, and helps to more accurately control the vehicle speed limit and engine operating status.

[0087] The ambient temperature is obtained through a temperature sensor, which can be directly obtained through the vehicle's ambient temperature sensor or directly collected and obtained through a set intake temperature sensor; however, the temperature sensor is generally installed on the intake pipe or throttle body. Since its temperature will affect the intake temperature when the engine is running, the temperature measured by the temperature sensor when the engine is running cannot be completely equal to the ambient temperature.

[0088] Therefore, in this solution, when the vehicle key is turned on, it is determined whether tstop is greater than the preset time threshold. If so, the ambient temperature is updated to the temperature measured by the current temperature sensor, and the ambient temperature Tair is obtained accordingly. In this embodiment, the preset time threshold is 6 hours.

[0089] If not, then obtain the ambient temperature Tair, that is, the temperature measured by the temperature sensor when the vehicle key was turned on after the last tstop>6h, so as to ensure that the ambient temperature data used reflects the actual environmental conditions of the vehicle as accurately as possible.

[0090] The mileage within a specific period is calculated by obtaining mileage information from the vehicle's travel monitoring device through the ECU;

[0091] Specifically, when the vehicle key is turned on, it is determined whether tstop is greater than a preset time threshold. If so, the mileage information S0 is updated to be the current mileage obtained by the ECU from the travel monitoring device;

[0092] If not, no update is performed and S0 remains unchanged;

[0093] The ECU obtains mileage information S1 from the travel monitoring device in real time;

[0094] The mileage of the vehicle within a specific period SΔ=S1-S0; through the accurate calculation and monitoring of the vehicle's mileage, we can better understand the working status and temperature change trend of the vehicle's transmission system, providing an important basis for the subsequent determination and correction of the clutch disengagement speed.

[0095] Among the above parameters, the unit related to mileage is km, the unit related to time is s, the unit related to temperature is ℃, and the unit related to speed is rpm.

[0096] The above-mentioned travel monitoring device includes but is not limited to: one or more of an instrument, a T-BOX, and a mileage sensor; in this embodiment, an instrument is used to obtain the mileage and downtime, which is adaptively adjusted according to the number of component interfaces. In other embodiments, it can also be obtained through an ECU or other external devices such as a T-BOX, or a device with a timing function and receiving sensor signals can be used.

[0097] Compared with the traditional vehicle speed limit control, this solution adds the judgment of engine speed and throttle opening. When the vehicle is in reverse gear, it is judged whether the engine speed is lower than the preset speed or the throttle opening is lower than the preset opening. If either or both of the two judgment conditions are met, the vehicle speed limit control will not be performed. Taking into account the existing vehicle speed limit strategy and the inherent characteristics of the mechanical CVT automatic transmission, when the user drives a four-wheeled motorcycle and stops on a slope and needs to shift into reverse gear to reverse back to the bottom of the slope or shift into reverse gear to reverse uphill from the bottom of the slope and then move forward back to the bottom of the slope, the user will control the throttle. The door handle makes the throttle valve at a smaller opening or idle position, the engine is at a lower speed or idle speed, and then the brake system and the direction control system are operated to control the vehicle's driving. After the engine speed is lower than the preset speed or the throttle valve opening is lower than the preset opening, the vehicle speed limit control is not performed, thereby avoiding the engine speed being lower than the clutch disengagement speed of the mechanical CVT automatic transmission, and the vehicle speed exceeds a certain value of the speed limit target speed, the engine will be completely cut off from fuel, the wheel drive system and the engine are in a decoupled state, the wheels cannot drag the engine to run, and will eventually cause the engine to stall.

[0098] This solution accurately determines whether vehicle speed limit control is suitable. Through this multi-parameter comprehensive judgment method, vehicle speed limit control is more intelligent and precise, and can flexibly adjust the speed limit strategy according to the actual operating conditions of the vehicle, effectively preventing the engine from stalling under reverse idling conditions, greatly improving the overall performance and stability of the vehicle, and solving the problem of engine stalling when users engage reverse gear and reverse at a low speed on a slope, thereby improving the commerciality and user satisfaction of the vehicle and enhancing the market competitiveness of the vehicle.

[0099] Embodiment 2

[0100] This embodiment is basically as shown in the attached Figure 6 As shown: A vehicle speed limit control system, comprising: an ECU, a sensor and a travel monitoring device;

[0101] The ECU monitors the vehicle gear position, the engine speed N and the throttle opening θ. If the vehicle gear position is in the reverse gear, and the engine speed N is lower than the preset speed or the throttle opening θ is lower than the preset opening, the vehicle speed limit control is not performed; if the vehicle gear position is in the reverse gear, and the engine speed N is greater than or equal to the preset speed or the throttle opening θ is greater than or equal to the preset opening, the vehicle speed limit control is performed;

[0102] Specifically, the ECU is connected to the sensor and the travel monitoring device, and is used to obtain gear information through the sensor to determine whether the vehicle is in reverse gear. If so, it is determined that the vehicle is in reverse gear;

[0103] It is also used to obtain the engine speed N and the throttle opening θ through sensors;

[0104] It is also used to obtain the engine speed N through the sensor, query the pre-stored throttle opening threshold MAP, and obtain the corresponding throttle opening threshold θthreshold as the preset opening; wherein the throttle opening threshold MAP is a relationship table between N and θthreshold; during the actual operation of the vehicle, the ECU achieves vehicle speed limit by limiting the output power of the engine, but the engine does not output power to the outside under certain specific working conditions, so the vehicle speed limit control is not performed under these specific working conditions. These specific working conditions need to be obtained through testing and calibration, and then the throttle opening threshold MAP is formulated.

[0105] It is also used to obtain the ambient temperature through the sensor, obtain the mileage within a specific period through the travel monitoring device, and query the pre-stored engine speed threshold MAP according to the ambient temperature and the mileage within the specific period to obtain the corresponding engine speed threshold N1;

[0106] It is also used to obtain the ambient temperature through the sensor, obtain the downtime through the travel monitoring device, and query the pre-stored engine speed threshold correction MAP according to the ambient temperature and the downtime to obtain the corresponding engine speed threshold correction value NΔ;

[0107] It is also used to correct the engine speed threshold Nthreshold=N1+NΔ according to N1 and NΔ to serve as a preset speed;

[0108] The engine speed threshold MAP is a relationship table between the ambient temperature, the mileage within a specific period, and the engine speed threshold N1;

[0109] The engine speed threshold correction MAP is a relationship table of the ambient temperature, the downtime and the engine speed threshold correction value NΔ;

[0110] The clutch disengagement speed of the mechanical CVT automatic transmission is closely related to factors such as the belt friction coefficient and the elastic force of the spring in the transmission system, while the temperature of components such as the belt and spring has a great influence on their performance, and these temperature changes are related to the ambient temperature, the time for power transmission after power coupling (which can be approximately replaced by the vehicle mileage, defined as the mileage within a specific period) and the downtime. In general, the lower the ambient temperature, the higher the clutch disengagement speed; conversely, the lower the clutch disengagement speed. Similarly, the longer the mileage within a specific period, the higher the temperature of the transmission system, and the clutch disengagement speed will decrease accordingly; conversely, the clutch disengagement speed will increase. In addition, after the vehicle stops, the temperature of the transmission system will gradually decrease. The longer the downtime, the higher the clutch disengagement speed correction value will be; conversely, the lower the clutch disengagement speed. Therefore, it is necessary to establish a corresponding mathematical model or calibrate MAP through testing and analysis based on the above parameters such as ambient temperature, mileage and downtime, so that the ECU can accurately determine or correct the clutch disengagement speed, and further improve the accuracy and reliability of vehicle speed limit control.

[0111] If the sensor and the travel monitoring device are connected to the ECU, the detection electrical signal (i.e., the sensor signal) is directly sent to the ECU. In other embodiments, the ECU is connected to the sensor and the travel monitoring device via a CAN bus, so that the sensor and the travel monitoring device upload CAN information to the ECU via the CAN bus;

[0112] The sensors include: reverse gear sensor, speed sensor, throttle position sensor, temperature sensor, and vehicle speed sensor;

[0113] The reverse gear sensor is used to collect gear information, so that the ECU can accurately determine whether the vehicle is in reverse gear.

[0114] Speed ​​sensor, used to collect engine speed N;

[0115] The throttle position sensor is used to collect the throttle opening θ;

[0116] Temperature sensor, used to collect ambient temperature;

[0117] Vehicle speed sensor, used to collect vehicle speed;

[0118] The downtime is calculated by the ECU by obtaining relevant time information from the vehicle's travel monitoring device;

[0119] The relevant time information includes: the time ton read and recorded by the ECU when the vehicle key is turned on, and the time toff read and recorded when the vehicle key is turned off;

[0120] The ECU calculates the stop time tstop = toff - ton; accurate stop time data plays a key role in determining the thermal state of the vehicle and the performance changes of the transmission system, and helps to more accurately control the vehicle speed limit and engine operating status.

[0121] The ambient temperature is obtained through a temperature sensor. The ECU can obtain it directly through the vehicle's ambient temperature sensor, or it can be directly collected and obtained through a set intake temperature sensor. However, the temperature sensor is generally installed on the intake pipe or throttle body. Since its temperature will affect the intake temperature when the engine is running, the temperature measured by the temperature sensor when the engine is running cannot be completely equal to the ambient temperature.

[0122] Therefore, in this solution, when the vehicle key is turned on, the ECU determines whether tstop is greater than the preset time threshold. If so, the ambient temperature is updated to the temperature measured by the current temperature sensor, and the ambient temperature Tair is obtained accordingly. In this embodiment, the preset time threshold is 6 hours.

[0123] If not, then obtain the ambient temperature Tair, that is, the temperature measured by the temperature sensor when the vehicle key was turned on after the last tstop>6h, so as to ensure that the ambient temperature data used reflects the actual environmental conditions of the vehicle as accurately as possible.

[0124] The mileage within a specific period is calculated by the ECU by obtaining mileage information from the vehicle's trip monitoring device;

[0125] Specifically, when the vehicle key is turned on, the ECU determines whether tstop is greater than a preset time threshold. If so, the mileage information S0 is updated to be the current mileage obtained by the ECU from the travel monitoring device;

[0126] If not, no update is performed and S0 remains unchanged;

[0127] The ECU obtains mileage information S1 from the travel monitoring device in real time;

[0128] The ECU calculates the vehicle's mileage within a specific cycle SΔ=S1-S0; through accurate calculation and monitoring of the vehicle's mileage, it can better understand the working status and temperature change trend of the vehicle's transmission system, providing an important basis for the subsequent determination and correction of the clutch disengagement speed.

[0129] Among the above parameters, the unit related to mileage is km, the unit related to time is s, the unit related to temperature is ℃, and the unit related to speed is rpm.

[0130] The above-mentioned travel monitoring device includes but is not limited to: one or more of an instrument, a T-BOX, and a mileage sensor; in this embodiment, an instrument is used to obtain the mileage and downtime, which is adaptively adjusted according to the number of component interfaces. In other embodiments, it can also be obtained through an ECU or other external devices such as a T-BOX, or a device with a timing function and receiving sensor signals can be used.

[0131] Compared with the traditional vehicle speed limit control, this scheme adds the judgment of engine speed and throttle opening. When the vehicle is in reverse gear, if the engine speed is lower than the preset speed or the throttle opening is lower than the preset opening, the vehicle speed limit control will not be performed. Taking into account the existing vehicle speed limit strategy and the inherent characteristics of the mechanical CVT automatic transmission, when the user drives a four-wheeled motorcycle and stops on a half slope and needs to shift into reverse gear to reverse back to the bottom of the slope or shift into reverse gear to reverse uphill from the bottom of the slope and then forward back to the bottom of the slope, the user will control the throttle handle to make the throttle at a smaller opening or idle position, the engine is at a lower speed or idle, and then operate the brake system and the direction control system to control the vehicle's driving. After the engine speed is lower than the preset speed or the throttle opening is lower than the preset opening, the vehicle speed limit control will not be performed, thereby avoiding the situation where the engine speed is lower than the clutch disengagement speed of the mechanical CVT automatic transmission, and the vehicle speed exceeds a certain value of the speed limit target speed, the engine will be completely cut off from fuel, the wheel transmission system and the engine are in a decoupled state, the wheels cannot reverse and drag the engine to run, and eventually the engine will be shut down.

[0132] This solution accurately determines whether vehicle speed limit control is suitable. Through this multi-parameter comprehensive judgment method, vehicle speed limit control is more intelligent and precise, and can flexibly adjust the speed limit strategy according to the actual operating conditions of the vehicle, effectively preventing the engine from stalling under reverse idling conditions, greatly improving the overall performance and stability of the vehicle, and solving the problem of engine stalling when users engage reverse gear and reverse at a low speed on a slope, thereby improving the commerciality and user satisfaction of the vehicle and enhancing the market competitiveness of the vehicle.

[0133] This embodiment also provides an all-terrain vehicle, which adopts the above-mentioned vehicle speed limit control system.

[0134] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A vehicle speed limit control method, characterized in that: It includes the following: The vehicle gear position, engine speed N and throttle opening θ are monitored. If the vehicle gear position is in reverse gear and the engine speed N is lower than a preset speed or the throttle opening θ is lower than a preset opening, the vehicle speed limit control is not performed.

2. A vehicle speed limit control method according to claim 1, characterized in that: The engine speed N and throttle opening θ are directly collected and obtained; Preset opening: according to N, query the throttle opening threshold MAP, and obtain the corresponding throttle opening threshold θthreshold as the preset opening; The throttle opening threshold MAP is a relationship table between N and θthreshold; Preset the speed, query the engine speed threshold MAP according to the ambient temperature and the mileage in a specific period, and obtain the corresponding engine speed threshold N1; According to the ambient temperature and the downtime, query the engine speed threshold correction MAP to obtain the corresponding engine speed threshold correction value NΔ; According to N1 and NΔ, the engine speed threshold Nthreshold=N1+NΔ is modified as the preset speed; The engine speed threshold MAP is a relationship table between the ambient temperature, the mileage within a specific period, and the engine speed threshold N1; The engine speed threshold correction MAP is a relationship table of the ambient temperature, the downtime, and the engine speed threshold correction value NΔ.

3. A vehicle speed limit control method according to claim 2, characterized in that: The downtime is calculated and obtained by obtaining relevant time information; The relevant time information includes: the time ton read and recorded when the vehicle key is turned on, and the time toff read and recorded when the vehicle key is turned off; Stop time tstop=toff-ton.

4. A vehicle speed limit control method according to claim 3, characterized in that: The ambient temperature, when the vehicle is turned on, determines whether tstop is greater than a preset time threshold, and if so, updates the ambient temperature to the currently measured temperature to obtain the ambient temperature Tair; If not, the ambient temperature Tair is obtained, which is the temperature measured when the vehicle was turned on after tstop was greater than the preset time threshold last time.

5. A vehicle speed limit control method according to claim 3, characterized in that: The mileage within the specific period is calculated and obtained by obtaining mileage information, including: When the vehicle is turned on, determine whether tstop is greater than the preset time threshold. If so, update the mileage information S0 to the current mileage obtained; If not, no update is performed and S0 remains unchanged; Get mileage information in real time S1; The mileage of the vehicle in a specific cycle SΔ=S1-S0.

6. A vehicle speed limit control system, characterized in that: include: ECU; The ECU is used to monitor the vehicle gear position, engine speed N and throttle opening θ. If the vehicle gear position is in reverse gear and the engine speed N is lower than a preset speed or the throttle opening θ is lower than a preset opening, the vehicle speed limit control is not performed.

7. The vehicle speed control system according to claim 6, characterized in that: Also included: sensors and travel monitoring devices; The ECU is connected to the sensor and the travel monitoring device, and is used to obtain gear information through the sensor to determine whether the vehicle is in reverse gear. If so, it is determined that the vehicle is in reverse gear; It is also used to obtain the engine speed N and the throttle opening θ through sensors; It is also used to obtain the engine speed N through the sensor, query the pre-stored throttle opening threshold MAP, and obtain the corresponding throttle opening threshold θthreshold as the preset opening; wherein the throttle opening threshold MAP is a relationship table between N and θthreshold; It is also used to obtain the ambient temperature through the sensor, obtain the mileage within a specific period through the travel monitoring device, and query the pre-stored engine speed threshold MAP according to the ambient temperature and the mileage within the specific period to obtain the corresponding engine speed threshold N1; It is also used to obtain the ambient temperature through the sensor, obtain the downtime through the travel monitoring device, and query the pre-stored engine speed threshold correction MAP according to the ambient temperature and the downtime to obtain the corresponding engine speed threshold correction value NΔ; It is also used to correct the engine speed threshold Nthreshold=N1+NΔ according to N1 and NΔ to serve as a preset speed; The engine speed threshold MAP is a relationship table between the ambient temperature, the mileage within a specific period, and the engine speed threshold N1; The engine speed threshold correction MAP is a relationship table of the ambient temperature, the downtime, and the engine speed threshold correction value NΔ.

8. The vehicle speed limit control system according to claim 7, characterized in that: The sensors include: a reverse gear sensor, a rotation speed sensor, a throttle position sensor, a temperature sensor and a vehicle speed sensor; The reverse gear sensor is used to collect gear information, so that the ECU can accurately determine whether the vehicle is in reverse gear. Speed ​​sensor, used to collect engine speed N; The throttle position sensor is used to collect the throttle opening θ; Temperature sensor, used to collect ambient temperature; Vehicle speed sensor, used to collect vehicle speed.

9. The vehicle speed limit control system according to claim 8, characterized in that: The downtime is calculated and obtained by the ECU by obtaining relevant time information from the vehicle's travel monitoring device; The relevant time information includes: the time ton read and recorded by the ECU when the vehicle key is turned on, and the time toff read and recorded when the vehicle key is turned off; ECU calculates the stop time tstop = toff-ton; When the vehicle key is turned on, the ECU determines whether tstop is greater than a preset time threshold. If so, the ambient temperature is updated to the temperature measured by the current temperature sensor to obtain the ambient temperature Tair; If not, then obtain the ambient temperature Tair, which is the temperature measured by the temperature sensor when the vehicle key is turned on after the last tstop is greater than the preset time threshold; The mileage within the specific period is calculated by the ECU by obtaining mileage information from the vehicle's travel monitoring device, including: When the vehicle key is turned on, the ECU determines whether tstop is greater than the preset time threshold. If so, the mileage information S0 is updated to the current mileage obtained by the ECU from the travel monitoring device; If not, no update is performed and S0 remains unchanged; The ECU obtains mileage information S1 from the travel monitoring device in real time; The ECU calculates the vehicle's mileage SΔ=S1-S0 within a specific period.

10. An all-terrain vehicle, characterized in that: A vehicle speed control system using any one of claims 6 to 9.

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