Control module and method for preventing engine stall and machine readable storage medium

Abstract

The present application provides a control module and a control method for preventing engine stall of a vehicle. The control module comprises a measuring unit configured to measure at least one operating parameter of the vehicle, and a judging unit configured to obtain a variation trend of the at least one operating parameter based on a parameter value of the at least one operating parameter measured by the measuring unit, and determine whether the engine is in danger of stall according to the variation trend of the at least one operating parameter. The present application also provides an engine control unit comprising the control module and a vehicle comprising the engine control unit. The present application also provides a control method for preventing engine stall of a vehicle by using the control module. The present application also relates to an engine control unit comprising the control module and a machine readable storage medium storing a control method which can be executed when executed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of off-road vehicles, in particular to the field of construction vehicles, and more particularly to a control module and method for preventing engine stall when a construction vehicle encounters an excessive load. The present application also relates to an engine control unit comprising such a control module and to a machine-readable storage medium storing instructions for carrying out the method described above. BACKGROUND

[0002] Large off-road vehicles, in particular construction vehicles, are often required to excavate, transport, lift and move heavy loads such as sand, earth, bricks or other cargo. Such vehicles are usually powered by a high-power diesel engine, which provides power to action mechanisms such as buckets, shovels or the like through a transmission system and a hydraulic system to act on the load.

[0003] For such construction machines, it is easy to encounter an excessive load or overloading. In particular, when the load is excessive at idle speed, the engine can stall. Frequent stalling and restarting of the engine not only shortens the life of the engine-related components, but also reduces the operating efficiency and wastes time.

[0004] Therefore, anti-stall control is an important part of the control of construction machines such as excavators. For example, providing maximum engine power to the hydraulic system in the full speed range, reducing the flow of the pump to prevent the engine from stalling when the load is excessive, which undoubtedly causes the waste of engine power in most cases. For another example, when the load exceeds the maximum power of the engine and the engine speed is lower than the set load speed, the engine is not stalled by reducing the flow of the motor. However, this anti-stall control method uses the engine speed to reflect the load of the excavator and is performed only when the engine speed is found to be lower than the load speed, which has a lag in control.

[0005] Controlling the flow of the motor of the engine is also a commonly used control method. When the instantaneous load is large, the engine speed drops too quickly, and if the control parameters are not appropriate, it may directly lead to engine stall, which does not prevent the engine from stalling. SUMMARY

[0006] The purpose of the present application is to provide a control module and method that uses the trend of changes in the operating parameters of the construction machine vehicle to determine in advance whether the engine is at risk of stalling, which not only accurately determines the possibility of engine stall, but also effectively avoids the problem of response and control delay.

[0007] The first aspect of the present application provides a control module for preventing engine stall of a vehicle, comprising a measuring unit configured to measure at least one operating parameter of the vehicle, and a judging unit configured to obtain a variation trend of the at least one operating parameter based on a parameter value of the at least one operating parameter measured by the measuring unit, and determine whether the engine is at risk of stall according to the variation trend of the at least one operating parameter.

[0008] The second aspect of the present application provides an engine control unit comprising the above control module.

[0009] The third aspect of the present application provides a control method for preventing engine stall of a vehicle by using the above control module, comprising:

[0010] a measuring step of measuring at least one operating parameter of the vehicle;

[0011] a calculating step of obtaining a variation trend of the at least one operating parameter based on a parameter value of the at least one operating parameter measured;

[0012] a judging step of determining whether the engine is at risk of stall based on the variation trend of the operating parameter.

[0013] The fourth aspect of the present application provides a machine readable storage medium having stored thereon executable instructions that, when executed, cause a machine to perform the above control method.

[0014] The control module constructed according to the principles of the present application and the control method for preventing engine stall by using the control module can determine whether the engine is at risk of stall based on the variation trend or rate of the operating parameter of the vehicle, instead of the real-time measured value of the operating parameter itself. More preferably, this determination by comprehensively considering the variation trends of multiple operating parameters can maximize the elimination of the possibility of lagging determination result, failing to prevent or stop engine stall in time, while greatly improving the accuracy of determination and prevention. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A simplified schematic diagram of a excavator comprising the control module according to the present application is shown.

[0016] Figure 2 A flowchart of the control method for preventing engine stall by using the control module according to the present application is shown. DETAILED DESCRIPTION

[0017] The present application is mainly applied to off-road vehicles, such as construction machines, for example, excavators, loaders, cranes, etc. These vehicles dig, carry or move, lift or rotate heavy loads such as sand, bricks, earth, etc. in operation.

[0018] The principle of the present application will be described in detail below with an example of an excavator. However, those skilled in the art will understand that the present application is not only applicable to excavators, but also to any construction vehicle or construction machine that operates a load by means of a power source, for example, a diesel engine, and is prone to engine stall when the load is too heavy.

[0019] Figure 1 A simplified schematic diagram of an excavator is shown.

[0020] A construction vehicle, such as an excavator, that operates on heavy loads mostly includes a power system 10 with a high-power diesel engine 12. When the operator steps on the accelerator pedal (also known as the throttle pedal or foot pedal) of the excavator, fuel, for example, diesel, is injected into the cylinder of the engine 12 to combust, and the engine 12 of the power system 10 outputs power and torque. The power system 10 transmits the power and torque to a hydraulic system 20, for example, via a transmission system including a reducer. The hydraulic system 20 generates a force and transmits the force to an action mechanism 30 of the construction vehicle, for example, a bucket or shovel of the excavator, to act on the load. Of course, the hydraulic system 20 can also actuate other action mechanisms of the excavator, including, but not limited to, a travel mechanism for traveling on the ground, a swing mechanism for rotating the vehicle body, etc. Among them, the change of the load will react on and thus cause the change of the pressure in the hydraulic system 20.

[0021] An engine control unit 40 is communicatively connected with the power system 10 and the hydraulic system 20, for example, for receiving: operating or parameter information of the engine 12, for example, the speed and torque of the engine; pressure information of the hydraulic system 20 (as a representation of the load), operating parameters of the hydraulic system 20, for example, the speed of the pump, in order to control the operation of the engine 12 and the hydraulic system 20 according to the feedback.

[0022] When the excavator operates a heavy load, the operator (or the driver of the excavator) will usually step on the accelerator pedal deeply to increase the amount of fuel injection of the engine, in order to increase the engine speed and increase the output torque of the engine, and thus increase the lifting force acting on the load through the hydraulic system 20. However, when the load exceeds the preset load threshold of the excavator, the excavator cannot operate this load at all. At this time, if the operator further steps on the accelerator pedal deeply, not only will the engine speed not increase, on the contrary, due to the heavy load acting on the hydraulic system, the engine speed will not only not increase, but will decrease, eventually leading to engine stall.

[0023] Accordingly, the engine control unit 40 of the excavator in the present embodiment is configured to comprise a control module for preventing the engine from stalling in this case. Although the control module is described herein as a constituent part of the engine control unit 40, this is not essential and the control module of the present application can be provided independently or partially independently of the engine control unit 40.

[0024] The control module of the present embodiment determines and prevents the occurrence of engine stall events in advance by measuring at least one, for example, a plurality of operating parameters of the vehicle, for example, the excavator, determining the trend of the measured operating parameters, and further determining whether the engine is at risk of stalling. The control module for preventing engine stall of the present embodiment generally comprises a measurement unit 50, a determination unit 60 and a memory 70.

[0025] The measurement unit 50 comprises at least one sensor for measuring at least one operating parameter of the excavator, including but not limited to an engine speed sensor 52 for measuring the engine speed of the excavator; an accelerator pedal position sensor 54 for measuring the accelerator pedal position of the excavator; and a fuel injection amount sensor 56 for measuring the fuel injection amount of the excavator engine 12. These sensors can be provided separately or can be configured as a combined sensor capable of simultaneously measuring these operating parameters.

[0026] The determination unit 60 is in communication with the measurement unit 50 and is configured to obtain the measurement results or parameter values of the operating parameters from the measurement unit 50 as needed, determine the trend of the operating parameters, and determine whether the engine is at risk of stalling from the trend of the operating parameters.

[0027] Specifically, for example, the determination unit 60 can calculate the rate of change of the accelerator pedal position, i.e. the acceleration of the accelerator pedal when it is depressed downward, from the accelerator pedal positions measured at two different times by the accelerator pedal position sensor 54. The change in the accelerator pedal position can be inferred from the demand of the operator of the excavator. If the rate of change of the accelerator pedal position exceeds the preset rate of change threshold (or range) of this parameter, it indicates that the operator is trying to obtain greater operating force to operate larger loads by urgently and sharply depressing the accelerator pedal, and the engine can be at risk of stalling. Here, since the change in the accelerator pedal position directly leads to a change in the engine 12 throttle opening, the operating parameter "accelerator pedal position" can be replaced by "engine throttle opening", and accordingly, the accelerator pedal position sensor 54 of the measurement unit 50 can be replaced by an engine throttle opening sensor.

[0028] For another example, the judging unit 60 can calculate the rate of change of the engine speed, i.e. the acceleration or deceleration of the engine speed, according to the engine speed values measured at two different time instants by the engine speed sensor 52. If the rate of change of the engine speed, in particular the deceleration, exceeds the threshold value of the rate of change of the engine speed of the excavator, i.e. the maximum deceleration, it indicates that the engine speed is rapidly decreasing and the engine is in danger of stalling.

[0029] For another example, the judging unit 60 can calculate the rate of change of the fuel injection amount, i.e. the acceleration value of the increase of the fuel injection amount, according to the fuel injection amount values measured at two different time instants by the fuel injection amount sensor 56. If the rate of change of the fuel injection amount, i.e. the acceleration value of the increase, exceeds the threshold value of the acceleration of the fuel injection amount of the engine of the excavator, it also indicates that the operator is trying to make the hydraulic system 20 generate a larger load lifting force by increasing the fuel injection amount to operate a larger load, and the engine is also in danger of stalling.

[0030] As described above, the judging unit 60 can draw a conclusion on whether the engine is in danger of stalling by judging the trend of change of at least one of the above-mentioned operating parameters of the excavator. Here, the judging unit 60 judges whether the engine is in danger of stalling according to whether the rate of change of the operating parameter exceeds the preset threshold value of the rate of change, rather than whether the real-time measured value of the operating parameter of the excavator exceeds the preset threshold value, which to some extent solves the technical problem that the conclusion that the engine is in danger of stalling is drawn too late and preventive measures cannot be taken in time.

[0031] According to the principles of the present application, the applicant further envisages an optimized judging algorithm that takes more than one operating parameter, for example the above-mentioned three operating parameters, as a basis at the same time, which can be expressed by the following optimized equation:

[0032] H = ax a1+ β x a2+ γ x a3

[0033] where H is referred to as the optimization coefficient, a1 represents the rate of change of the position of the excavator's accelerator pedal, which is calculated from the measured value or parameter value measured by the accelerator pedal position sensor 54; a2 represents the rate of change of the engine speed of the excavator (acceleration or deceleration value), which is calculated from the measured value measured by the engine speed sensor 52; a3 represents the rate of change of the fuel injection amount of the excavator engine (acceleration or deceleration value), which is calculated from the measured value measured by the fuel injection amount sensor 56. a, β, and γ respectively represent the optimization factors for the three operating parameters, and their values depend on the type, model, and / or operating condition of the construction machine, such as the excavator, and are constant for excavators of a particular machine type, a particular machine model, and a particular operating condition, and are stored in the memory 70 of the control module as predetermined parameters together with the above optimization equation at the time of vehicle delivery. For example, a, β, and γ are each between 0.1 and 0.9. As an example, for a particular model of excavator, a, β, and γ can be 0.8, 0.1, and 0.1, respectively.

[0034] The determination unit 60 first calculates the rate of change a1 of the position of the excavator's accelerator pedal, the rate of change a2 of the engine speed of the excavator, and the rate of change a3 of the fuel injection amount of the excavator engine using the measured values measured by the sensors of the measurement unit 50, and then calculates the optimization coefficient H according to the above optimization determination algorithm. Next, the determination unit 60 obtains the optimization coefficient threshold value (or range) preset for this type, this model, and this operating condition from the memory 70, and determines that the engine has the risk of stalling when the calculated optimization coefficient H exceeds the preset optimization coefficient threshold value or range. Otherwise, the determination unit 60 determines that the engine does not have the risk of stalling.

[0035] This method takes into account the trends (rates of change) of multiple operating parameters related to engine stall events of the excavator and the influence of each operating parameter on vehicles of different machine types, different machine models, and different operating conditions, and ultimately determines whether the engine has the risk of stalling, not only achieving the purpose of early determination and prevention, but also greatly improving the accuracy of the determination and reducing the probability of false determination. Of course, based on this principle, other operating parameters related to engine stall events can also be similarly considered, and the number of operating parameters involved in the equation is not limited to the three in the above example.

[0036] The combination of the plurality of operating parameters for the determination can preferably reduce or eliminate the probability of determination delay and misjudgment. For example, when the engine speed is used as the operating parameter for the determination, because the change of the engine speed is delayed relative to the change of the accelerator pedal position of the excavator and the change of the engine fuel injection amount of the excavator, there is a possibility of determination delay. For another example, when the vehicle is jolted, the driver can unconsciously step on the accelerator pedal hard due to the jolt, in which case the driver usually lifts the foot off the accelerator pedal immediately after stepping on it hard, and the change of the accelerator pedal can cause the engine fuel injection amount to increase suddenly and then decrease rapidly, in which case the change rate of the fuel injection amount alone can also cause misjudgment of whether the engine is in danger of stalling.

[0037] As described above, the change rate of the accelerator pedal position of the excavator, the change rate of the engine speed of the excavator, and the change rate of the fuel injection amount of the engine of the excavator can all be used as the operating parameters for determining whether the engine is in danger of stalling. Those skilled in the art should understand that these operating parameters are only exemplary and are not exclusive, and any other operating parameter that can reflect the engine state or the load size, such as the pressure in the hydraulic system, can be used. According to the principles of the present application, in order to avoid determination delay as much as possible, the basis for determining whether the engine is in danger of stalling is the change trend of the operating parameter, rather than the measured value of the parameter itself.

[0038] The memory 70 of the control module is in communication connection with the determination unit 60, and the change rate threshold or range of the operating parameter related to determining whether the engine is in danger of stalling is pre-stored in the memory 70, and the optimization determination algorithm and the optimization factor values for the operating parameters are also pre-stored in the memory 70.

[0039] According to the control module of the present application, the control module is also in communication connection with the hydraulic system 20, and can be configured to automatically disconnect the hydraulic relay of the hydraulic system 20 to release or loosen the load to avoid the occurrence of the engine stalling event when it is determined that the engine is in danger of stalling. Alternatively, the control module can also indirectly control the hydraulic relay of the hydraulic system 20 via the engine control unit 40 to release or loosen the load when it is determined that the engine is in danger of stalling.

[0040] In addition, according to the present application, the engine control unit can include a mode selector 80 for the driver or operator to select whether to enable or disable the control module. The mode selector 80 can be in the form of a button or a knob.

[0041] Figure 2 A control method for determining whether the engine of the excavator is in danger of stalling according to the principles of the present application is shown. The control method includes:

[0042] a measuring step S1 of measuring at least one operating parameter of the excavator;

[0043] a deriving step S2 of deriving a trend of variation of said at least one operating parameter based on the measured values of said at least one operating parameter measured in the measuring step S1 ;

[0044] a judging step S3 of judging whether the engine has a risk of stalling based on the trend of variation of said at least one operating parameter derived in the deriving step S2.

[0045] The measuring step S1 of measuring at least one operating parameter can comprise steps of measuring a position of an accelerator pedal of the excavator, a rotational speed of an engine of the excavator and a fuel injection amount of the engine. The deriving step S2 can comprise steps of deriving a trend of variation of each of the above-mentioned operating parameters, and deriving a trend of variation of an operating parameter can comprise calculating a rate of variation of the operating parameter, such as an acceleration of an increase of the operating parameter or a deceleration of a decrease of the operating parameter, from measured values of the operating parameter at two different times measured in the measuring step S1.

[0046] The judging step S3 can comprise a step of judging that the engine has a risk of stalling when a rate of variation of one of the operating parameters exceeds a threshold value of the rate of variation of the operating parameter. Alternatively, the judging step S3 can comprise a step of judging that the engine has a risk of stalling when rates of variation of all of the operating parameters exceed threshold values of the rates of variation of the respective operating parameters. Further alternatively, the judging step S3 can comprise a step of calculating an optimization coefficient based on the rates of variation of each of said at least one operating parameter, and judging that the engine has a risk of stalling when the calculated optimization coefficient exceeds a preset threshold value or range of the optimization coefficient. The optimization coefficient is derived by the aforementioned optimization equation, i.e. performing a multiplication operation of a rate of variation of each of the three operating parameters with a preset optimization factor for the operating parameter, and then summing the products obtained from the multiplication operations for each of the three operating parameters.

[0047] Alternatively, the present control method can comprise a selecting step S0 of starting the control module before the measuring step S1.

[0048] Alternatively, the present control method can further comprise a step S4 of releasing a load of the vehicle in the case where it is judged that the engine has a risk of stalling. Alternatively, the step S4 is automatically performed.

[0049] Alternatively, the present control method can comprise a step of storing the measured values of the operating parameters measured in the measuring step S1 and the rates of variation of the operating parameters calculated in the deriving step S2, for the purpose of generating a report and subsequent analysis.

[0050] The application can also provide a machine readable storage medium, which stores executable instructions, and the executable instructions, when executed, cause a machine to perform the control method described in the above embodiments. The application is described above in combination with specific embodiments, and it should be understood that these embodiments are only used to illustrate the application and not to limit the scope of the application. In addition, it should be understood that after reading the content of the application, those skilled in the art can make various modifications or changes to the application, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A control module for preventing a vehicle engine from stalling, comprising a measuring unit and a determining unit, wherein the measuring unit is configured to measure a plurality of operating parameters of the vehicle, and the determining unit is configured to: calculating a change rate of each operating parameter based on a measurement value of each operating parameter among the plurality of operating parameters measured by the measuring unit at two different times; Calculate the optimization coefficient based on the rate of change of each operating parameter, and When the calculated optimization coefficient exceeds a preset optimization coefficient threshold, it is determined that the engine is in danger of stalling. in, The optimization coefficient is obtained by the following calculation: performing a multiplication operation on each of the multiple operating parameters by multiplying its change rate by a preset optimization factor for the operating parameter, and then summing the products obtained by the multiplication operation on each of the multiple operating parameters.

2. The control module according to claim 1, wherein: The determining unit is further configured to: determining that the engine is at risk of stalling when a rate of change of one or more operating parameters of the at least one operating parameter exceeds a respective rate of change threshold; or The engine is determined to be at risk of stalling when a rate of change of each of the at least one operating parameter exceeds a respective rate of change threshold.

3. The control module according to claim 1, wherein: The optimization factor depends on the type, model and / or operating conditions of the vehicle.

4. The control module according to claim 1, wherein: The at least one operating parameter includes an accelerator pedal position of the vehicle, an engine speed of the vehicle, and a fuel injection amount of the vehicle engine.

5. The control module according to claim 4, wherein: The optimization factors of the three operating parameters of the vehicle's accelerator pedal position, the vehicle's engine speed, and the vehicle's engine fuel injection amount are all between 0.1 and 0.

9.

6. The control module according to any one of claims 1 to 5, further comprising a memory storing a rate of change threshold of at least one operating parameter, an optimization factor for the at least one operating parameter, and an optimization coefficient threshold or range for the vehicle.

7. An engine control unit comprising the control module according to any one of claims 1 to 6.

8. The engine control unit of claim 7, further comprising a mode selector selectable to enable or disable the control module.

9. The engine control unit according to claim 7 or 8, wherein: The engine control unit is used in an excavator, a forklift or a crane.

10. A control method for preventing a vehicle engine from stalling using a control module according to any one of claims 1 to 6, comprising: measuring a plurality of operating parameters of the vehicle; Calculating a rate of change of each operating parameter based on measured values ​​of each operating parameter at two different moments; Calculating an optimization coefficient based on the rate of change of each operating parameter; and When the calculated optimization coefficient exceeds the preset optimization coefficient threshold, it is determined that the engine is in danger of stalling. The optimization coefficient is obtained by the following calculation: performing a multiplication operation on each of the multiple operating parameters by multiplying its change rate by a preset optimization factor for the operating parameter, and then summing the products obtained by the multiplication operation on each of the multiple operating parameters.

11. The control method according to claim 10, wherein: The determining step further includes determining that the engine is at risk of stalling when the calculated change rate of one or more of the plurality of operating parameters exceeds a respective change rate threshold.

12. The control method according to claim 10 or 11, further comprising at least one of the following steps: the step of removing the vehicle load when it is determined that the vehicle engine is in danger of stalling; a selecting step of enabling said control module before the measuring step; A step of storing the parameter values ​​of the operating parameters measured in the measuring step and the change rates of the operating parameters calculated in the acquiring step.

13. A machine-readable storage medium having executable instructions stored thereon, wherein when the executable instructions are executed, the machine is caused to perform the control method according to any one of claims 10 to 12.

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