Excavator constant power control method and system for improving volume efficiency of oil pump

Abstract

The invention belongs to the technical field of excavator power control, and particularly relates to an excavator constant power control method and system for improving the volume efficiency of an oil pump. The method comprises the steps that when the excavator enters a constant power mode, the current pump pressure and the current required displacement of a hydraulic oil pump under the target rotating speed of an engine are obtained, and required power is obtained through calculation; the ratio of the set power to the required power of the hydraulic oil pump serves as a first input value, and the calibrated minimum displacement of the hydraulic oil pump serves as a second input value; taking the ratio of the second input value to the first input value as an output value; calculating a final request rotating speed according to the ratio of the target rotating speed to the first output value, and adjusting the rotating speed of the engine to the calculated final request rotating speed; and the pump displacement of the hydraulic oil pump is adjusted in real time according to the set adjusting coefficient so as to adjust the actual flow of the pump. The pump displacement is improved by reducing the target rotating speed, the volume efficiency is improved by improving the pump displacement, and the purpose of reducing oil consumption is finally achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of excavator power control, and in particular relates to an excavator constant power control method and system for improving the volumetric efficiency of an oil pump. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] At present, most excavators are controlled by constant power, which can keep the power output of the machine constant under various working conditions. The constant power control technology of excavators is an advanced technology based on load sensors and electronic controllers. The load sensor detects the load of the excavator in real time, and the electronic controller automatically adjusts the engine speed and pump displacement according to the load changes, so that the excavator maintains a constant power output under different working conditions. The core of this technology is to improve the working efficiency of the machine as much as possible while ensuring constant power, so as to achieve the purpose of energy saving and emission reduction.

[0004] When the excavator is under constant power control, power = current pump pressure * displacement * target speed. The target speed is a constant value. When the pump pressure is high, the displacement will be reduced due to constant power control.

[0005] The volumetric efficiency reflects the proportional relationship between the actual amount of fluid that the oil pump can transport during operation and the theoretical maximum amount of fluid, that is, the volumetric efficiency of the oil pump = actual useful displacement / current displacement; therefore, the smaller the overall displacement of the pump, the greater the leakage, resulting in a lower volumetric efficiency of the pump; and the volumetric efficiency is directly related to the energy conversion efficiency of the pump and the operating efficiency of the system. Therefore, the current constant power control method for excavators has the problem of low energy utilization. Summary of the invention

[0006] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a method and system for controlling constant power of an excavator for improving the volumetric efficiency of an oil pump.

[0007] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0008] A first aspect of the present invention provides a constant power control method for an excavator for improving the volumetric efficiency of an oil pump, comprising:

[0009] When the excavator enters the constant power mode, the current pump pressure and the current required displacement of the hydraulic oil pump at the target engine speed are obtained, and the required power is calculated according to the target engine speed, the current pump pressure and the current required displacement;

[0010] The ratio of the set power of the hydraulic oil pump to the calculated required power is used as the first input value, and the calibrated minimum displacement of the hydraulic oil pump is used as the second input value; it is determined whether the first input value is less than 1, and if so, the ratio of the second input value to the first input value is used as the output value;

[0011] Determine whether the output value is greater than 1, if so, calculate a final requested speed according to the ratio of the target speed and the first output value, and adjust the engine speed to the calculated final requested speed;

[0012] At the same time, the pump displacement of the hydraulic oil pump is adjusted in real time according to the set adjustment coefficient, and the actual flow of the pump is ensured to remain unchanged by adjusting the engine speed and pump displacement.

[0013] A second aspect of the present invention provides an excavator constant power control system for improving the volumetric efficiency of an oil pump, comprising:

[0014] The required power calculation module is configured to: when the excavator enters the constant power mode, obtain the current pump pressure and the current required displacement of the hydraulic oil pump at the target engine speed, and calculate the required power according to the target engine speed, the current pump pressure and the current required displacement;

[0015] The output value calculation module is configured to: use the ratio of the set power of the hydraulic oil pump to the calculated required power as the first input value, and use the calibrated minimum displacement of the hydraulic oil pump as the second input value; determine whether the first input value is less than 1, and if so, use the ratio of the second input value to the first input value as the output value;

[0016] The engine speed regulating module is configured to: determine whether the output value is greater than 1, and if so, calculate a final requested speed according to a ratio of the target speed and the first output value, and regulate the engine speed to the calculated final requested speed;

[0017] The actual flow rate regulation module of the pump is configured to: simultaneously adjust the pump displacement of the hydraulic oil pump in real time according to the set regulation coefficient, and ensure that the actual flow rate of the pump remains unchanged by adjusting the engine speed and pump displacement.

[0018] The third aspect of the present invention provides a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the steps of a constant power control method for an excavator for improving the volumetric efficiency of an oil pump as described in the first aspect of the present invention.

[0019] The fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, the steps in a constant power control method for an excavator for improving the volumetric efficiency of an oil pump as described in the first aspect of the present invention are implemented.

[0020] One or more of the above technical solutions have the following beneficial effects:

[0021] The present invention adaptively adjusts the target engine speed according to the current pump pressure, which can reduce the target speed and thus increase the pump displacement. By increasing the pump displacement, its volumetric efficiency is increased, and ultimately the purpose of reducing fuel consumption is achieved, and the working efficiency of the pump can be guaranteed.

[0022] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 This is a flow chart of a constant power control method for an excavator for improving the volumetric efficiency of an oil pump according to a first embodiment. DETAILED DESCRIPTION

[0025] Embodiment 1

[0026] This embodiment discloses a constant power control method for an excavator to improve the volumetric efficiency of an oil pump. Figure 1 As shown, including:

[0027] Step 1: When the excavator enters the constant power mode, the current pump pressure and the current required displacement of the hydraulic oil pump at the target engine speed are obtained, and the required power is calculated according to the target engine speed, the current pump pressure and the current required displacement.

[0028] Step 2: Take the ratio of the set power of the hydraulic oil pump to the calculated required power as the first input value, and take the calibrated minimum displacement of the hydraulic oil pump as the second input value; determine whether the first input value is less than 1, and if so, take the ratio of the second input value to the first input value as the output value. Therefore, the output value is actually the calibrated minimum displacement of the pump / (set power / required power).

[0029] In this embodiment, the determination threshold is set to 1, because only when it is less than 1 does it represent entering the constant power state.

[0030] Step 3: Determine whether the output value is greater than 1. If so, calculate the final requested speed according to the ratio of the target speed and the output value, and adjust the engine speed to the calculated final requested speed;

[0031] Step 4: At the same time, the pump displacement of the hydraulic oil pump is adjusted in real time according to the set adjustment coefficient, and the actual flow of the pump is ensured to remain unchanged by adjusting the engine speed and pump displacement.

[0032] In step 1, the current pump pressure and current required flow rate of the hydraulic oil pump at the target engine speed are obtained, and the specific steps of calculating the current required displacement according to the current required flow rate and speed are as follows:

[0033] Step 101: Obtain the current pump pressure and current required displacement of the oil pump at the target engine speed, including:

[0034] A pressure sensor is installed on the oil pump, and the outlet pressure of the oil pump (i.e., the current pump pressure) is obtained through the pressure sensor;

[0035] The target speed of the engine is a set value, and the target speed range of the engine is usually between 1000 and 3500 rpm; this range is suitable for most engines and ensures that the engine can work in the best condition and provide maximum power output.

[0036] The required displacement at each point is obtained according to the calibration of the handle pressure sensor.

[0037] In this embodiment, the required displacement is a calibration quantity, the horizontal axis is the handle signal, and the vertical axis is the required displacement. The less the handle is pulled, the smaller the required displacement is; the more the handle is pulled, the larger the required displacement is.

[0038] According to the operator's operating handle stroke, the handle pressure sensor will collect a pressure value, and the pressure value of each point is calibrated to obtain the required displacement of each point.

[0039] Step 102: Calculate the current required power based on the obtained current pump pressure, the current required displacement and the set target speed.

[0040] Among them, power = pump pressure * speed * displacement = pump pressure * flow. Calculate the required flow according to the required displacement, flow = displacement * current speed, and further calculate the current required power.

[0041] The current required power calculation formula is:

[0042] P = n × v × p.

[0043] Where P represents the current required power, n represents the initial target speed, v represents the current required displacement, and p represents the current pump pressure.

[0044] The greater the pump pressure, the greater the current required power, and the smaller the ratio of set power / required power; and the ratio range is 0-1, and is not allowed to exceed 1. If it exceeds 1, it is overpower.

[0045] In step 2, the power is set to the power of the input shaft of the main pump, not the actual output power. The actual output power will be reduced due to losses such as volumetric efficiency. The engine and the pump are connected by splines and gears for transmission, so the speed of the shaft is equivalent to the speed of the engine shaft. This embodiment adjusts the speed of the engine by adjusting the speed of the shaft.

[0046] The second input value is the minimum calibrable displacement value, which can be calibrated on-site according to the pump brand and type, or an empirical value of 30 can be used.

[0047] The larger the second input value of the calibration is, the larger the output value is, that is, the larger the target speed adjustment is; this means that when the pump displacement calibration value is set to a smaller value, that is, when the volumetric efficiency is lower, the larger the target speed adjustment is, that is, the lower the target speed value is, and the overall trend is linear.

[0048] It also includes: judging whether the first input value is less than 1, if not, not adjusting the speed. Wherein, less than 1 means the required power > set power. It means that the constant power limit has been entered. Only when the constant power limit is entered will the displacement decrease, and the adjustment will be meaningful at this time;

[0049] Specifically: the larger the first input value is, the smaller the ratio (output value) of the two is, and the ratio range is 0-1, and is not allowed to exceed 1. When it exceeds 1, it is overpower.

[0050] The smaller the first input value obtained, that is, the higher the pump pressure at this time, the larger the output value, that is, the larger the target speed adjustment; its meaning is that when the pump pressure is higher, the displacement is smaller, and the volumetric efficiency is lower, the output value is larger, and the target speed adjustment is larger, that is, the target speed value is lower, and the overall trend is linear.

[0051] In step 3, the second input value / the first input value is used as the output value, and the output value is used as the divisor of the basic target speed, and the obtained value is output as the final requested speed.

[0052] The method further includes: determining whether the output value is less than 1, and if not, not performing speed regulation.

[0053] Among them, the output value ≥ 1 indicates that the calibrated minimum displacement value is not allowed to be less than the first input value. If it is less than the first input value, the engine speed adjustment cannot be triggered and this function has no practical significance.

[0054] In step 4, the pump displacement of the hydraulic oil pump is adjusted in real time according to the set adjustment coefficient, including:

[0055] The pump displacement is corrected by multiplying the adjustment coefficient, where the adjustment coefficient is a value between 0 and 1, and its specific value can be customized according to actual conditions.

[0056] Specifically: the adjustment of the pump displacement is "follow-up", which avoids the vibration caused by the rapid change of the pump swing angle caused by the linkage adjustment of the pump displacement and the pump pressure.

[0057] The horizontal axis of the follow-up is the displacement, and the vertical axis is the corresponding adjustment coefficient, which is the on-site calibration value. The larger the horizontal axis, the smaller the coefficient is relatively, that is, in the first half, when the pump pressure is larger, the adjustment is faster; when the displacement exceeds a certain value, the adjustment is relatively slower. That is, fast response is guaranteed and jitter caused by excessively frequent adjustments is avoided.

[0058] The present invention adopts a control strategy that can reduce the target speed and thus increase the pump displacement when the vehicle enters a constant power and high pump pressure state. Target speed*pump displacement=actual flow, and the actual flow remains unchanged, so its working efficiency can be guaranteed.

[0059] Embodiment 2

[0060] This embodiment discloses an excavator constant power control system for improving the volumetric efficiency of an oil pump, comprising:

[0061] The required power calculation module is configured to: when the excavator enters the constant power mode, obtain the current pump pressure and the current required displacement of the hydraulic oil pump at the target engine speed, and calculate the required power according to the target engine speed, the current pump pressure and the current required displacement;

[0062] The output value calculation module is configured to: use the ratio of the set power of the hydraulic oil pump to the calculated required power as the first input value, and use the calibrated minimum displacement of the hydraulic oil pump as the second input value; determine whether the first input value is less than 1, and if so, use the ratio of the second input value to the first input value as the output value;

[0063] The engine speed regulating module is configured to: determine whether the output value is greater than 1, and if so, calculate a final requested speed according to a ratio of the target speed and the first output value, and regulate the engine speed to the calculated final requested speed;

[0064] The actual flow rate regulation module of the pump is configured to: simultaneously adjust the pump displacement of the hydraulic oil pump in real time according to the set regulation coefficient, and ensure that the actual flow rate of the pump remains unchanged by adjusting the engine speed and pump displacement.

[0065] Among them, obtaining the current pump pressure and current required displacement of the hydraulic oil pump at the target engine speed includes:

[0066] A pressure sensor is installed on the hydraulic oil pump, and the outlet pressure of the oil pump is obtained through the pressure sensor as the current pump pressure;

[0067] The required displacement at each point is obtained according to the calibration of the handle pressure sensor.

[0068] It also includes: determining whether the first input value is less than 1, and if not, not adjusting the engine speed;

[0069] The method further includes: determining whether the output value is less than 1, and if so, not adjusting the engine speed.

[0070] Embodiment 3

[0071] The purpose of this embodiment is to provide a computer-readable storage medium.

[0072] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in a constant power control method for an excavator for improving the volumetric efficiency of an oil pump as described in Example 1 of the present disclosure.

[0073] Embodiment 4

[0074] The purpose of this embodiment is to provide an electronic device.

[0075] An electronic device includes a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, the steps in a constant power control method for an excavator for improving the volumetric efficiency of an oil pump as described in Example 1 of the present disclosure are implemented.

[0076] The steps involved in the apparatuses of the above embodiments 2, 3 and 4 correspond to the method embodiment 1, and the specific implementation methods can refer to the relevant description part of embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood to include any medium that can store, encode or carry an instruction set for execution by a processor and enable the processor to execute any method in the present invention.

[0077] Those skilled in the art should understand that the modules or steps of the present invention described above can be implemented by a general-purpose computer device, or alternatively, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0078] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A constant power control method for an excavator for improving the volumetric efficiency of an oil pump, characterized in that: include: When the excavator enters the constant power mode, the current pump pressure and the current required displacement of the hydraulic oil pump at the target engine speed are obtained, and the required power is calculated according to the target engine speed, the current pump pressure and the current required displacement; The ratio of the set power of the hydraulic oil pump to the required power is used as the first input value, and the calibrated minimum displacement of the hydraulic oil pump is used as the second input value; it is determined whether the first input value is less than 1, and if so, the ratio of the second input value to the first input value is used as the output value; Determine whether the output value is greater than 1, if so, calculate a final requested speed according to the ratio of the target speed and the first output value, and adjust the engine speed to the calculated final requested speed; At the same time, the pump displacement of the hydraulic oil pump is adjusted in real time according to the set adjustment coefficient, and the actual flow of the pump is ensured to remain unchanged by adjusting the engine speed and pump displacement.

2. The method for controlling constant power of an excavator for improving the volumetric efficiency of an oil pump as claimed in claim 1, characterized in that: The obtaining of the current pump pressure and the current required displacement of the hydraulic oil pump at the target engine speed includes: A pressure sensor is installed on the hydraulic oil pump, and the outlet pressure of the oil pump is obtained through the pressure sensor as the current pump pressure; The required displacement at each point is obtained according to the calibration of the handle pressure sensor.

3. The method for controlling constant power of an excavator for improving the volumetric efficiency of an oil pump as claimed in claim 1, characterized in that: Also includes: It is determined whether the first input value is less than 1. If not, the engine speed is not adjusted.

4. The method for controlling constant power of an excavator for improving the volumetric efficiency of an oil pump as claimed in claim 1, characterized in that: Also includes: It is determined whether the output value is less than 1. If so, the engine speed is not adjusted.

5. The method for controlling constant power of an excavator for improving the volumetric efficiency of an oil pump as claimed in claim 1, characterized in that: The real-time adjustment of the pump displacement of the hydraulic oil pump according to the set adjustment coefficient includes: The pump displacement of the hydraulic pump is multiplied by the adjustment coefficient to correct the pump displacement, wherein the adjustment coefficient is a value between 0-1.

6. A constant power control system for an excavator for improving the volumetric efficiency of an oil pump, characterized in that: include: The required power calculation module is configured to: when the excavator enters the constant power mode, obtain the current pump pressure and the current required displacement of the hydraulic oil pump at the target engine speed, and calculate the required power according to the target engine speed, the current pump pressure and the current required displacement; The output value calculation module is configured to: use the ratio of the set power of the hydraulic oil pump to the calculated required power as the first input value, and use the calibrated minimum displacement of the hydraulic oil pump as the second input value; determine whether the first input value is less than 1, and if so, use the ratio of the second input value to the first input value as the output value; The engine speed regulating module is configured to: determine whether the output value is greater than 1, and if so, calculate a final requested speed according to a ratio of the target speed and the first output value, and regulate the engine speed to the calculated final requested speed; The actual flow rate regulation module of the pump is configured to: simultaneously adjust the pump displacement of the hydraulic oil pump in real time according to the set regulation coefficient, and ensure that the actual flow rate of the pump remains unchanged by adjusting the engine speed and pump displacement.

7. The excavator constant power control system for improving the volumetric efficiency of the oil pump as claimed in claim 6, characterized in that: The obtaining of the current pump pressure and the current required displacement of the hydraulic oil pump at the target engine speed includes: A pressure sensor is installed on the hydraulic oil pump, and the outlet pressure of the oil pump is obtained through the pressure sensor as the current pump pressure; The required displacement at each point is obtained according to the calibration of the handle pressure sensor.

8. The excavator constant power control system for improving the volumetric efficiency of the oil pump as claimed in claim 6, characterized in that: Also includes: Determining whether the first input value is less than 1, if not, not adjusting the engine speed; Preferably, the method further includes: determining whether the output value is less than 1, and if so, not adjusting the engine speed.

9. A computer-readable storage medium having a program stored thereon, characterized in that: When the program is executed by a processor, the steps of a constant power control method for an excavator for improving the volumetric efficiency of an oil pump as described in any one of claims 1 to 5 are implemented.

10. An electronic device comprising a memory, a processor, and a program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps in the constant power control method for an excavator for improving the volumetric efficiency of an oil pump as described in any one of claims 1 to 5 are implemented.

Images