A method for accurately calculating the weight of a whole vehicle

Abstract

The application discloses a kind of whole vehicle weight accurate calculation methods, belong to automobile technical field.The whole vehicle weight accurate calculation method includes the following steps: S1: measured engine output torque;S2: establish engine dynamics model;S3: stop vehicle weight estimation;S4: correct vehicle weight;When using, stop vehicle weight estimation, since the driving force in braking process cannot be measured, when ECU detects that driving is braking state, stop vehicle weight estimation, correct vehicle weight, subtract the actual vehicle speed collected from the model estimated vehicle speed, if the deviation of both is 0, then prove that the vehicle weight used by current vehicle dynamics model is correct value;If the deviation of both is not 0, then input to integrator, correct vehicle weight;Until the deviation is 0, the vehicle weight of model is the real vehicle weight at this time, the whole vehicle weight accurate calculation method can obtain the real vehicle weight without installing expensive vehicle weight sensor, reduce the production cost of whole vehicle.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automobiles, and more particularly to a method for accurately calculating the weight of a whole vehicle. BACKGROUND

[0002] An automobile is a vehicle powered by a combustible gas, also a vehicle powered by its own equipment, generally having four or more wheels, traveling on land, not relying on tracks or wires, and usually used to carry passengers and cargo and tow passenger and cargo trailers. There are also special vehicles that have been modified or equipped with special equipment to complete specific transportation tasks or work tasks, but agricultural special machinery, all trailers and semi-trailers do not have their own power devices, and they only belong to the category of automobiles when they form a train of automobiles with the traction automobile. The automobile is driven by its own power and is equipped with a driving control device.

[0003] Regulations require vehicles to monitor vehicle weight, predictive control algorithms, etc. Vehicle weight is needed, and current vehicle weight data acquisition requires the installation of a vehicle weight sensor. Since the vehicle weight sensor is expensive, it increases the production cost of the whole vehicle. SUMMARY

[0004] To solve the defects in the above-mentioned technology, the application provides a method for accurately calculating the weight of a whole vehicle, which is essentially to improve the problem that current vehicle weight data acquisition requires the installation of a vehicle weight sensor, which is expensive and increases the production cost of the whole vehicle.

[0005] To achieve the above-mentioned purpose, the application provides a method for accurately calculating the weight of a whole vehicle, comprising the following steps:

[0006] S1: Measure the engine output torque, and the engine controller ECU obtains the engine output torque by dividing the test measured combustion efficiency by the circulating fuel injection amount, and obtains the actual vehicle speed through a sensor;

[0007] S2: Establish an engine dynamics model, model the vehicle dynamics of the vehicle, input the output torque of the engine to the model, estimate the speed of the vehicle from the model, and correct the vehicle speed used in the model until the deviation is eliminated by combining the deviation between the actual speed and the model estimated speed;

[0008] S3: Stop the vehicle weight estimation, since the driving force during braking cannot be measured, when the ECU detects that the vehicle is in the braking state, stop the vehicle weight estimation;

[0009] S4: correcting the vehicle weight, subtracting the model-estimated vehicle speed from the collected actual vehicle speed, if the deviation between the two is 0, it proves that the vehicle weight used by the current vehicle dynamics model is the correct value; if the deviation is not 0, it is input to the integrator to correct the vehicle weight; until the deviation is 0, at this time the vehicle weight of the model is the real vehicle weight.

[0010] In the above implementation process, the engine controller ECU in step S1 is an electronic control unit, which is composed of a microcontroller, a memory, an input / output interface, an analog-to-digital converter, and a shaping and driving large-scale integrated circuit. The voltage working range of the ECU is 6.5-16V, the working current is 0.015-0.1A, the working temperature is -40℃-80℃, and it can withstand vibration below 1000Hz. The CPU is the core part of the ECU. When the engine is running, it collects signals from various sensors, performs calculations, and converts the results of the calculations into control signals to control the operation of the controlled object. It also implements control over the memory, input / output interface, and other external circuits. The program stored in the memory ROM is written based on data obtained through precise calculation and a large number of experiments. This inherent program continuously compares and calculates with the signals collected from various sensors when the engine is operating.

[0011] In the above implementation process, the cycle injection quantity in step S1 is controlled by the engine controller ECU. The ECU calculates according to various operating parameters such as engine intake air quantity, speed, throttle opening, water temperature, and intake air temperature measured by various sensors, and sends an electric pulse to the injector according to the calculation results. By changing the width of each electric pulse, the duration of each injection of the injector is controlled, thereby achieving the purpose of controlling the injection quantity. The wider the width of the electric pulse, the longer the injection duration, and the larger the injection quantity. The engine operates under different conditions, and the requirements for the mixture concentration are also different, especially under some special conditions such as starting, rapid acceleration, and rapid deceleration, which have special requirements for the mixture concentration. The ECU controls the injection quantity in different ways according to the operating conditions measured by the relevant sensors. The control mode of the injection quantity can be roughly divided into starting control, operating control, fuel cut control, and feedback control.

[0012] In the above implementation process, the combustion efficiency in step S1 also refers to the combustion chamber efficiency, which is the ratio of the actual heat available to heat combustion products when the quantitative fuel is combusted in the combustion chamber to the low heat of combustion released when the fuel is completely combusted under adiabatic conditions. It is a main indicator for evaluating the operation economy of various combustion chambers. The combustion efficiency mainly depends on the characteristics of the combustion device and the fuel itself, and is related to environmental factors. This indicator is meaningful only for a certain combustion device and a certain fuel, that is, it is an indicator for evaluating a specific combustion device burning a specific fuel. In the following cases, this indicator often differs: a specific combustion device burning different fuels, and a specific fuel burning in different combustion devices.

[0013] In the above implementation process, the engine output torque in step S1 is a specific indicator of the engine acceleration capability, which refers to the reciprocating motion of the piston in the cylinder, and a certain work is done once. Its unit is newton-meter. In the case of constant angular velocity, the greater the torque, the greater the power, and the greater the driving force of the engine to the wheels, that is, the stronger the acceleration capability of the automobile.

[0014] In the above implementation process, the actual vehicle speed in step S1 is measured by a vehicle speed sensor. The vehicle speed sensor is controlled by the ECU. The ECU can measure the actual vehicle speed of the vehicle in real time through the vehicle speed sensor and input it into the engine dynamics model.

[0015] In the above implementation process, the engine dynamics model in step S2 can predict its driving state in the future period of time, and then generate an optimal motion trajectory that meets various safety constraints, which can greatly improve the feasibility of the planning result. In the tracking control process, the motion characteristics, handling performance, and actuator constraints of the vehicle are comprehensively considered, which can more effectively track the planning result, reduce or avoid traffic accidents, and the engine dynamics model. Vehicle dynamics modeling studies the motion law of the vehicle from the perspective of geometry, including the spatial pose, speed, and change of vehicle weight with time. When the vehicle is driving at low speed on good road surface, the handling stability dynamics of the vehicle does not need to be considered. At this time, the path tracking controller designed based on the kinematics model has reliable control performance.

[0016] In the above implementation process, the vehicle dynamics model in step S2 is Fx=m*g*f+0.5*Cd*A*v^2+mgθ+m*dv / dt, the driving force Fx=T*r, T is the engine torque, which can be obtained in real time by the ECU, r is the transmission ratio, the design parameter is known, g: gravitational acceleration, known, f: rolling resistance coefficient, known, Cd: wind resistance coefficient, known, A: windward area, known, V: actual vehicle speed, sensor collection, θ: slope, which is 0 on flat road, m: vehicle weight, which is a parameter to be estimated.

[0017] In the implementation process, the integrator in step S4 is an element whose output signal is the integral of the input signal with respect to time, and the input can be accumulated and then output. The integrator is an important part of many engineering and scientific applications. For example, a mechanical integrator can be used to measure electrical energy, an analog electronic integrator is the basis of an analog computer, and an electronic integrator is a first-order low-pass filter that can be implemented in an analog circuit or a discrete circuit. The integrator has a low-pass filtering effect, but if there is a non-zero bias, the output of the integrator will continuously rise or fall until the output reaches the system limit. A voltage integrator is an electronic device that integrates voltage with respect to time and finally measures the accumulated voltage-seconds. A current integrator is an electronic device that integrates current with respect to time and finally measures the accumulated coulombs. A charge amplifier is a current integrator, and a current integrator is also used to measure the charge of a Faraday cup on a residual gas analyzer to measure the partial pressure of a gas in a vacuum. Another application of a current integrator is in ion beam deposition.

[0018] In the implementation process, the actual vehicle speed in step S1 is measured in real time by a vehicle speed sensor. The vehicle speed sensor is a device used to detect the speed of an electronically controlled vehicle. The control computer uses this input signal to control the engine idle speed, the automatic transmission torque converter lock, the automatic transmission shift, the engine cooling fan opening and closing, and other functions such as cruise control. The output signal of the vehicle speed sensor can be a magneto alternating current signal, a Hall digital signal, or an optical digital signal. The vehicle speed sensor is usually installed in the drive axle housing or the transmission housing. The vehicle speed sensor signal line is usually installed in a shielded jacket to eliminate electromagnetic and radio frequency interference generated by high-voltage electrical wires and vehicle-mounted telephones or other electronic devices, to ensure that electronic communication does not interrupt and prevent driving performance from deteriorating or causing other problems. Magneto and optical sensors are the most commonly used vehicle speed sensors on vehicles.

[0019] Compared with the prior art, the present application has the following advantages:

[0020] In use, the engine output torque is measured, the engine controller ECU obtains the engine output torque by dividing the test measured combustion efficiency by the cycle fuel injection quantity, the actual vehicle speed is obtained through a sensor, an engine dynamics model is established, the engine output torque is input to the model by modeling the vehicle dynamics, the vehicle speed is estimated by the model, the vehicle speed used in the model is corrected by combining the deviation between the actual vehicle speed and the model estimated vehicle speed until the deviation is eliminated, the vehicle weight is re-estimated, since the driving force during braking cannot be measured, when the ECU detects that the vehicle is in a braking state, the vehicle weight re-estimation is stopped, the vehicle weight is corrected, the model estimated vehicle speed is subtracted from the collected actual vehicle speed, if the deviation between the two is 0, it is proved that the vehicle weight used in the current vehicle dynamics model is the correct value; if the deviation between the two is not 0, the vehicle weight is input to the integrator for correction; until the deviation is 0, at this time the vehicle weight of the model is the true vehicle weight, the whole vehicle weight accurate calculation method can obtain the true vehicle weight without installing expensive vehicle weight sensors, thereby reducing the production cost of the whole vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a system block diagram of a whole vehicle weight accurate calculation method provided by the embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below in combination with embodiments.

[0023] It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0024] In the embodiments, unless otherwise specified, the means used are conventional means in the art.

[0025] Please refer to Figure 1 The present application provides a whole vehicle weight accurate calculation method, comprising the following steps:

[0026] S1: measured engine output torque, engine controller ECU by the cycle injection quantity divided by the test measured combustion efficiency of engine output torque, by sensor to get the actual vehicle speed, step S1 in the engine controller ECU for electronic control unit, by microcontroller, memory, input / output interface, analog to digital converter and shaping, drive large scale integrated circuit is composed of, ECU voltage working range in 6.5-16V, working current in 0.015-0.1A, working temperature in-40℃ ~ 80℃, can withstand 1000Hz below the vibration, in the ECU CPU is the core part, engine in operation, it collects the signal of each sensor, carries on the operation, and the result of operation is changed into control signal, control the work of controlled object, it also implements the control to the memory, input / output interface and other external circuit, the program stored in the memory ROM is based on the data obtained by accurate calculation and a large number of experiments, this inherent program in engine operation, constantly compared with the signal collected from each sensor, step S1 in the cycle injection quantity is controlled by engine controller ECU, ECU according to various sensors measured engine intake, speed, throttle opening, water temperature, intake temperature and many other operating parameters, according to the set program for calculation, and according to the calculation results to the injector sends out electric pulse, by changing the width of each electric pulse to control each injector each time the duration of injection, so as to achieve the purpose of controlling the injection quantity, the greater the width of the electric pulse, the longer the injection duration, the greater the injection quantity, engine in different operating conditions, the requirement of the mixture concentration is also different, especially in some special conditions such as starting, rapid acceleration, rapid deceleration, the mixture concentration has special requirements, ECU according to the operating conditions measured by the relevant sensor, according to different ways to control the injection quantity, the control mode of injection quantity can be divided into starting control, running control, cut-off control and feedback control several kinds;

[0027] The combustion efficiency in step S1 also refers to the combustion chamber efficiency, which is the ratio of the actual heat available to heat the combustion products when the quantitative fuel is combusted in the combustion chamber to the low heat of combustion released when the fuel is completely combusted under adiabatic conditions. It is a main index for evaluating the operation economy of various combustion chambers. The combustion efficiency mainly depends on the combustion device and the characteristics of the fuel itself, and is related to environmental factors. The index of combustion efficiency is meaningful only for a certain combustion device and a certain fuel, that is, it is an index for evaluating a specific combustion device combusting a specific fuel. The index is often different in the following cases: a specific combustion device combusting different fuels, and a specific fuel combusting in different combustion devices. The engine output torque in step S1 is a specific index of the acceleration capacity of the engine, which refers to the reciprocating motion of the piston in the cylinder, and a certain work is done once. Its unit is newton-meter. In the case where the angular velocity is constant, the greater the torque, the greater the power, and the greater the driving force of the engine to the wheels, that is, the stronger the acceleration capacity of the automobile. The actual vehicle speed in step S1 is measured by a vehicle speed sensor. The vehicle speed sensor is controlled by the ECU. The ECU can measure the actual vehicle speed of the vehicle in real time through the vehicle speed sensor and input it into the engine dynamics model. The actual vehicle speed in step S1 is measured in real time by a vehicle speed sensor. The vehicle speed sensor is a device for detecting the speed of an electronically controlled vehicle. The control computer uses this input signal to control the engine idle speed, the automatic transmission torque converter lock, the automatic transmission gear shifting, the opening and closing of the engine cooling fan, and other functions such as cruise control. The output signal of the vehicle speed sensor can be a magnetic AC signal, a Hall digital signal, or an optical digital signal. The vehicle speed sensor is usually installed in the drive axle housing or the transmission housing. The vehicle speed sensor signal line is usually installed in a shielded jacket to eliminate electromagnetic and radio frequency interference generated by high-voltage electric wires and vehicle-mounted telephones or other electronic devices, to ensure that electronic communication does not interrupt and prevent driving performance from deteriorating or causing other problems. The magnetic and optical sensors are the most commonly used vehicle speed sensors on automobiles.

[0028] S2: Establishing engine dynamics model, through vehicle dynamics modeling, input the engine output torque to the model, estimate the vehicle speed by the model, combine the deviation between actual speed and model estimated speed, correct the speed used in the model until the deviation is eliminated, the engine dynamics model in step S2 can predict its driving state in the future, and then generate optimal motion trajectory that meets various safety constraints in advance, which can greatly improve the feasibility of the planning result, and in the tracking control process, the motion characteristics, handling performance and actuator constraints of the vehicle are considered comprehensively, which can more effectively track the planning result, reduce or avoid traffic accidents, the engine dynamics model, vehicle dynamics modeling studies the motion law of the vehicle from the perspective of geometry, including the spatial pose, speed and weight of the vehicle changing with time, when the vehicle is driving at low speed on good road, the handling stability dynamics of the vehicle does not need to be considered, at this time the path tracking controller designed based on the kinematics model has reliable control performance, the vehicle dynamics model in step S2 Fx=m*g*f+0.5*Cd*A*v^2+mgθ+m*dv / dt, driving force Fx=T*r, T is engine torque, which can be obtained in real time by ECU, r is transmission ratio, design parameters, known, g: gravitational acceleration, known, f: rolling resistance coefficient, known, Cd: wind resistance coefficient, known, A: windward area, known, V: actual vehicle speed, sensor collection, θ: slope, this item is 0 on flat road, m: vehicle weight, parameter to be estimated;

[0029] S3: Stop estimating vehicle weight, since the driving force during braking cannot be measured, when ECU detects that the vehicle is in braking state, stop estimating the vehicle weight;

[0030] S4: correcting the vehicle weight, subtracting the actual vehicle speed collected from the model-estimated vehicle speed, if the deviation between the two is 0, it proves that the vehicle weight used by the current vehicle dynamics model is the correct value; if the deviation between the two is not 0, it is input to the integrator to correct the vehicle weight; until the deviation is 0, at this time the vehicle weight of the model is the real vehicle weight, the integrator in step S4 is an element, the output signal of which is the integral of the input signal with respect to time, the input can be accumulated and then output, the integrator is an important part in many engineering and scientific applications, such as mechanical integrator which can be used to measure electric energy, analog electronic integrator is the basis of analog computer, electronic integrator is a first-order low-pass filter, which can be realized by analog circuit or discrete circuit, the integrator has the effect of low-pass filtering, but if there is a non-zero bias, the output of the integrator will continue to rise or fall until the output reaches the system limit, the voltage integrator is an electronic device that integrates voltage with respect to time, and finally measures the accumulated voltage-second, the current integrator is an electronic device that integrates current with respect to time, and finally measures the accumulated coulomb, the charge amplifier is a current integrator, the current integrator is also used to measure the charge of the Faraday cup on the residual gas analyzer to measure the partial pressure of the gas in the vacuum, another application of the current integrator is in ion beam deposition.

[0031] Specifically, the working principle of the method for accurately calculating the whole vehicle weight is as follows: in use, the engine output torque is measured, the engine controller ECU obtains the engine output torque by dividing the circulating fuel injection amount by the test-measured combustion efficiency, the actual vehicle speed is obtained through a sensor, an engine dynamics model is established, the engine output torque is input to the model, the speed of the vehicle is estimated by the model, the vehicle speed used in the model is corrected in combination with the deviation between the actual vehicle speed and the model-estimated vehicle speed, until the deviation is eliminated, the vehicle weight estimation is stopped, since the driving force during braking cannot be measured, when the ECU detects that the driving is in the braking state, the vehicle weight estimation is stopped, the model-estimated vehicle speed is subtracted from the actual vehicle speed collected, if the deviation between the two is 0, it proves that the vehicle weight used by the current vehicle dynamics model is the correct value; if the deviation between the two is not 0, it is input to the integrator to correct the vehicle weight; until the deviation is 0, at this time the vehicle weight of the model is the real vehicle weight, the method for accurately calculating the whole vehicle weight can obtain the real vehicle weight without installing expensive vehicle weight sensors, thereby reducing the production cost of the whole vehicle.

[0032] The above embodiments only express several embodiments of the present application, which are more specific and detailed, but cannot be understood as limiting the patentable scope of the application.

[0033] It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A method for accurately calculating the weight of a whole vehicle, characterized by, The method and system comprise the following steps: S1: measure the engine output torque, the engine controller ECU obtains the engine output torque by dividing the test measured combustion efficiency by the circulating fuel injection quantity, and obtains the actual vehicle speed through a sensor; S2: establish an engine dynamics model, input the engine output torque into the model by modeling the vehicle dynamics, estimate the vehicle speed from the model, correct the vehicle speed used in the model by combining the deviation between the actual vehicle speed and the model estimated vehicle speed until the deviation is eliminated; the vehicle dynamics model in step S2 is Fx=m*g*f+0.5*Cd*A*v^2+mgθ+m*dv / dt, the driving force Fx=T*r, T is the engine torque, which is obtained in real time by the ECU, r is the transmission ratio, which is a design parameter and is known, g is the gravitational acceleration, which is known, f is the rolling resistance coefficient, which is known, Cd is the wind resistance coefficient, which is known, A is the windward area, which is known, V is the actual vehicle speed, which is collected by a sensor, θ is the slope, which is 0 on a flat road, m is the vehicle weight, which is a parameter to be estimated; S3: stop the vehicle weight estimation, since the driving force during braking cannot be measured, when the ECU detects that the vehicle is in a braking state, stop the vehicle weight estimation; S4: correct the vehicle weight, subtract the model estimated vehicle speed from the collected actual vehicle speed, if the deviation between the two is 0, it is proved that the vehicle weight used in the current vehicle dynamics model is the correct value; if the deviation is not 0, input it to the integrator to correct the vehicle weight; until the deviation is 0, the vehicle weight of the model at this time is the true vehicle weight.

2. The method for accurately calculating the weight of a whole vehicle according to claim 1, characterized in that, The engine controller ECU in step S1 is an electronic control unit composed of a microcontroller, a memory, an input / output interface, an analog-to-digital converter, and a shaping and driving large-scale integrated circuit, the voltage working range of the ECU is 6.5-16V, the working current is 0.015-0.1A, the working temperature is -40℃-80℃, and it can withstand vibrations below 1000Hz, the CPU is the core part in the ECU, when the engine is running, it collects signals from various sensors, performs calculations, and converts the calculation results into control signals to control the working of the controlled object, it also controls the memory, input / output interface, and external circuit, the program stored in the memory ROM is written based on the data obtained through accurate calculation and a large number of experiments, this inherent program continuously compares and calculates the signals collected from various sensors when the engine is working.

3. The method for accurately calculating the weight of a whole vehicle according to claim 1, characterized in that, The cycle injection quantity in the step S1 is controlled by the engine controller ECU, which calculates according to various operating parameters such as engine intake volume, speed, throttle opening, water temperature, intake temperature measured by sensors, and sends electric pulses to the injectors according to the calculation results, and controls the duration of each injection by changing the width of each electric pulse, so as to control the injection quantity, the wider the electric pulse, the longer the injection duration, and the larger the injection quantity, the engine operates under different conditions, and the requirements for the mixture concentration are different, the ECU controls the injection quantity in different ways according to the operating conditions measured by the relevant sensors, and the control modes of the injection quantity include start control, operation control, fuel cut control and feedback control.

4. The method for accurately calculating the weight of a whole vehicle according to claim 1, characterized in that, The engine output torque in the step S1 is a specific index of the engine acceleration capacity, which refers to the reciprocating motion of the piston in the cylinder, and the unit is newton-meter.

5. The method of claim 1, wherein, The engine actual vehicle speed in the step S1 is measured by a vehicle speed sensor, which is controlled by the ECU, and the ECU can measure the actual vehicle speed of the vehicle in real time through the vehicle speed sensor and input it into the engine dynamics model.

6. The method for accurately calculating the weight of a vehicle according to claim 1, wherein, The engine dynamics model in the step S2 can predict its driving state in the future, and then generate an optimal motion trajectory that meets various safety constraints, which can greatly improve the feasibility of the planning result, and comprehensively consider the motion characteristics, handling performance and actuator constraints of the vehicle in the tracking control process, the engine dynamics model, and the vehicle dynamics modeling studies the motion law of the vehicle from the geometric point of view, including the spatial pose, speed and weight of the vehicle changing with time.

7. The method of claim 1, wherein, The integrator in the step S4 is an element whose output signal is the integral of the input signal with respect to time, which can accumulate the input and then output, the integrator is an important part of many engineering and scientific applications, such as mechanical integrator which can be used to measure electric energy, analog electronic integrator is the basis of analog computer, electronic integrator is a first-order low-pass filter, which can be realized by analog circuit or discrete circuit, the integrator has the effect of low-pass filter, but if there is a non-zero bias, the output of the integrator will continue to rise or fall until the output reaches the system limit, the voltage integrator is an electronic device that integrates voltage with respect to time, and finally measures the cumulative voltage-second, the current integrator is an electronic device that integrates current with respect to time, and finally measures the cumulative coulomb, the charge amplifier is a current integrator, and the current integrator is also used to measure the charge of the Faraday cup on the residual gas analyzer to measure the partial pressure of the gas in the vacuum, another application of the current integrator is in ion beam deposition.

8. The method of claim 5, wherein, The actual vehicle speed in the step S1 is measured in real time by a vehicle speed sensor, which is a device for detecting the vehicle speed of an electronically controlled vehicle, and the output signal of the vehicle speed sensor can be a magneto-electric alternating current signal, a Hall type digital signal or an optical digital signal. The vehicle speed sensor is installed in a drive axle housing or a transmission housing, and the vehicle speed sensor signal line is installed in a shielded sheath. The magneto-electric and optical sensors are the two most commonly used vehicle speed sensors on vehicles.

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