A control system and method for a transmission of a construction machine

Abstract

This invention discloses a control system and method for a transmission in engineering machinery. The system includes a shift control electronic unit, a vehicle operating condition and vehicle condition detection unit, a driver intention acquisition unit, a gear drive unit, a shift monitoring unit, and a communication unit. The vehicle operating condition and vehicle condition detection unit, driver intention acquisition unit, gear drive unit, shift monitoring unit, and communication unit are all connected to the shift control electronic unit. The shift control electronic unit includes a power supply circuit and a gear solenoid valve drive signal output circuit. The power supply circuit includes a power conversion chip U8 for converting +24V power to 5V and a chip isolation power module U9. This invention avoids the damage to the shift controller caused by voltage pulses generated during operation and uses oil filling and discharging time and pressure control to solve the shift shock problem.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a control system and control method for an engineering machinery transmission. Background Technology

[0002] Construction machinery operations are characterized by high starting torque requirements, large load variations, frequent changes in operating conditions, and high operational efficiency demands. To meet these requirements, construction machinery power transmission systems often employ hydraulic-mechanical transmissions. A hydraulic-mechanical transmission consists of a hydraulic torque converter connected in series with a mechanical transmission. Hydraulic transmission devices offer high low-speed torque, smooth transmission, good and stable performance, and automatic speed adjustment capabilities. This improves the vehicle's passability on special road surfaces such as mud, sand, snow, and other soft surfaces. Vehicles equipped with this transmission experience smooth starts and rapid, even acceleration.

[0003] The fluid medium used in the transmission can be compatible with the oil supply system and the hydraulic shifting control system. Most multi-gear hydraulic mechanical transmissions achieve automatic or semi-automatic shifting through a transmission control device, thereby adapting to constantly changing working conditions, simplifying operation, and improving work efficiency. Shock is an important indicator for evaluating the shifting quality of a hydraulic mechanical transmission. During shifting, the timing of oil filling and releasing in the wet clutch drum of the transmission, as well as the control of the oil filling pressure, are important factors affecting the shock. However, currently there is no technology to solve the shifting shock problem through oil filling and releasing timing and oil filling pressure control. Summary of the Invention

[0004] The technical problem to be solved by this invention is: in view of the technical problems existing in the prior art, this invention provides a control system and control method for engineering machinery transmissions that solves the shift shock problem.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0006] A transmission control system for engineering machinery includes a shift control electronic unit, a vehicle operating condition and vehicle condition detection unit, a driver intention acquisition unit, a gear drive unit, a shift monitoring unit, and a communication unit. The vehicle operating condition and vehicle condition detection unit, driver intention acquisition unit, gear drive unit, shift monitoring unit, and communication unit are all connected to the shift control electronic unit. The shift control electronic unit includes a power supply circuit and a gear solenoid valve drive signal output circuit. The power supply circuit includes a power conversion chip U8 for converting +24V power to 5V. The chip-isolated power supply module U9; pin 1 of the power conversion chip U8 is connected to a polarized capacitor CP9, pin 2 is connected to a Zener diode D10, and this pin is also connected to one end of an inductor L1. The other end of the inductor L1 is a 5V voltage output terminal, which is connected to a polarized capacitor CP10; the negative terminal of the light-emitting diode DS1 is grounded, the positive terminal is connected to one end of a resistor R96, and the other end is connected to pin 4 of the power conversion chip U8 and the other end of the inductor L1. The light-emitting diode DS1 and the resistor R96 work together to detect whether there is voltage at the output terminal;

[0007] Pins 2 and 3 of the chip-isolated power supply module U9 are connected to the negative terminal of the polarized capacitor and the power ground. Pins 22 and 23 of the chip-isolated power supply module U9 are connected to the 24V power supply. Pin 16 of the chip-isolated power supply module U9 is connected to the signal power ground. Pin 14 of U9 is connected to the positive terminal of the polarized capacitor CP13, one end of resistor R99, and one end of resistor R97. Pin 14 outputs power supply VDD_3.3V, and the other end of R97 outputs power supply VCC_3.3V. VCC_3.3V is filtered and regulated by capacitor C6 and 10uF tantalum capacitor CP11.

[0008] Preferably, the gear position solenoid valve drive signal output circuit includes a chip U11. Pin 3 of chip U11 is connected to one end of resistor R84, and the other end of resistor R84 is connected to the processor solenoid valve control output signal. Pin 4 of chip U11 is connected to one end of resistor R96, and pin 6 of U11 is connected to one end of resistor R80. One end of resistor R80 is connected to power ground and one end of resistor R97, and the other end of R97 is connected to the other end of resistor R96 to form a signal feedback terminal, which provides feedback on whether there is an open circuit or short circuit fault at the gear position solenoid valve drive output terminals of pins 18 and 17 of chip U11. Pin 18 of chip U11 is connected to one end of resistor R68 and the negative terminal of freewheeling diode D7.

[0009] Preferably, it also includes a DC / DC isolated regulated power supply M1, a neutral relay J1, and a reverse relay J2; the positive input terminal of the DC / DC isolated regulated power supply M1 is connected to the positive terminal of a vehicle battery through a fuse FUSE, and the negative input terminal of M1 is connected to the vehicle ground; the output ground of M1 is connected to the power ground of the shift control electronic unit through lines 3-5 and 3-6, and the output power of M1 is connected to the positive power supply terminal of the shift control electronic unit through lines 3-1 and 3-2; one end of the coil of the neutral relay J1 is connected to the neutral control terminal of the shift control electronic unit, and the other end is connected to the output ground of M1; the vehicle ground is connected in sequence through the key start switch, the normally open contact of the neutral relay J1, and one end of the vehicle start coil RL1; the other end of the vehicle start coil RL1 is connected to the positive terminal of the battery; one end of the reverse relay J2 is connected to the reverse control terminal of the shift control electronic unit, and the other end is connected to the output ground of M1; the positive terminal of the battery is connected to the reverse light L1 through the normally open contact of the reverse relay J2.

[0010] Preferably, the vehicle operating condition and vehicle condition detection unit includes one or more of the following: vehicle speed sensor, pump wheel speed sensor, turbine speed sensor, gear oil pressure sensor, and oil temperature sensor.

[0011] Preferably, the vehicle speed sensor, pump wheel speed sensor, and turbine speed sensor are all magnetoelectric or Hertz pulse wave sensors, and the gear oil pressure sensor and oil temperature sensor are all analog signal output sensors.

[0012] Preferably, the driver intent acquisition unit includes a mode handle information acquisition module, a brake signal acquisition module, and an accelerator pedal signal acquisition module.

[0013] Preferably, the gear drive unit includes a gear solenoid valve and a vehicle signal output module; the monitoring unit includes a transmission status LCD monitoring information module; and the communication unit includes a calibration interface and a vehicle CAN communication interface.

[0014] This invention also discloses a control method based on the above-described engineering machinery transmission control system, comprising the following steps:

[0015] Obtain the shift boost curve and the oil filling and draining overlap time of the gear;

[0016] When the vehicle reaches a point where a gear shift is required, the target gear is determined. If the conditions for shifting are not met, the vehicle remains in its current gear and the target gear is determined again. If the conditions for shifting are met, it is determined whether to upshift.

[0017] If so, the upshift logic is invoked, and the upshift release and fill times are controlled. The fill and release times overlap to reduce the torque output interruption time and reduce the impact.

[0018] If not, the downshifting logic is invoked, and the timing of downshifting, releasing fuel, and refueling is controlled. Fuel is released after refueling to reduce the impact on the vehicle caused by backward acceleration.

[0019] Compared with the prior art, the advantages of the present invention are as follows:

[0020] This invention automatically or semi-automatically switches to the target gear based on the vehicle's operating process by collecting vehicle speed, engine speed, braking, and lever signals reflecting the driver's intentions through the Electronic Control Unit (ECU). It adopts electro-hydraulic proportional control technology and controls the timing of oil filling and releasing of the wet clutch drum, as well as the oil filling pressure, according to different gears of the transmission, which can reduce the shifting shock of the hydraulic mechanical transmission. Attached Figure Description

[0021] Figure 1 This is a block diagram of the transmission control system of the present invention in an embodiment.

[0022] Figure 2 This is a circuit schematic diagram of the power supply circuit of the present invention in an embodiment.

[0023] Figure 3 This is a circuit diagram of the gear position solenoid valve drive signal output circuit in an embodiment of the present invention.

[0024] Figure 4 This is a circuit diagram of the shift protection unit of the present invention in an embodiment.

[0025] Figure 5 This is a flowchart of the control method of the present invention in an embodiment.

[0026] Figure 6 This is a schematic diagram of the continuous current principle of the present invention.

[0027] Figure 7 This is a graph showing the effect of the upshifting overlap parameters in this invention on the output torque of the transmission.

[0028] Figure 8 This is a graph showing the effect of the downshifting overlap parameters in this invention on the output torque of the transmission. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1As shown, the engineering machinery transmission control system of this embodiment includes a shift control electronic unit (ECU), a vehicle operating condition and vehicle condition detection unit, a driver intention acquisition unit, a gear drive unit, a shift monitoring unit, and a communication unit. The vehicle operating condition and vehicle condition detection unit, driver intention acquisition unit, gear drive unit, shift monitoring unit, and communication unit are all connected to the shift control electronic unit (ECU). The vehicle operating condition and vehicle condition detection unit is used to detect vehicle operating information, providing input conditions for automatic shifting and a basis for calculating the target gear. The driver intention acquisition unit is used to collect whether the driver operates the vehicle forward and backward, whether braking is performed, and accelerator pedal signals indicating whether the vehicle needs continuous power output. The gear drive unit is used to drive the gear solenoid valve. The monitoring unit is used to display transmission operating status information. Specifically, the vehicle operating condition and vehicle condition detection unit includes a vehicle speed sensor PI1, a pump wheel speed sensor PI2, a turbine speed sensor PI3, a gear position oil pressure sensor AI1, and an oil temperature sensor AI2. Among them, the vehicle speed sensor PI1, pump wheel speed sensor PI2, and turbine speed sensor PI3 are all magnetoelectric or Hertz pulse sensors, while the gear position oil pressure sensor AI1 and oil temperature sensor AI2 are both analog signal output sensors. When receiving signals from the above sensors, the vehicle operating condition and vehicle condition detection unit also acquires engine speed, throttle opening, and torque output information. The driver intention acquisition unit includes a mode lever information acquisition module DI1, a brake signal acquisition module DI2, and an accelerator pedal signal acquisition module AI3. The gear drive unit includes a gear position solenoid valve DO1 and a vehicle signal output module DO2. The monitoring unit includes a transmission status LCD monitoring information module BUS1. The communication unit includes a calibration interface BUS2 and a vehicle CAN communication interface BUS3-SAE1939.

[0031] like Figure 2 and Figure 3 As shown, the shift control electronic unit includes a power supply circuit and a gear position solenoid valve drive signal output circuit. The power supply circuit is as follows: Figure 2As shown, the power supply needs to provide VCC_5V for the external controller and VCC_3.3V and VDD_3.3V for the chip. The power supply circuit includes a power conversion chip U8, which converts +24V to 5V to power the 5V chip and the external controller. Pin 1 of the chip is connected to a 680uF polarized capacitor CP9. Pin 2 is connected to a 5V Zener diode D10 and also to one end of a 33uH inductor L1. The other end of inductor L1 outputs 5V, and the 5V output terminal is connected to a 220uF polarized capacitor CP10. Pin 4 of chip U8 is connected to the output terminal of inductor L1. A resistor R96 and an LED DS1 are connected to the 5V output terminal to detect whether there is voltage at the output terminal. Pins 2 and 3 of the isolation power supply module U9 are connected to the negative terminal of a 47uF polarized capacitor and the power ground. Pins 22 and 23 of module U9 are connected to the 24V power supply, and pin 16 of U9 is connected to the signal power ground. Pin 14 of U9 is connected to the positive terminal of polarized capacitor CP13, resistor R99, and resistor R97. Pin 14 outputs the power supply VDD_3.3V for the digital chip, and the other pin of R97 outputs the power supply VCC_3.3V for the analog chip. VCC_3.3V is filtered and regulated by a 0.1uF ceramic capacitor C6 and a 10uF tantalum capacitor CP11.

[0032] like Figure 3 As shown, the gear shift solenoid valve drive signal output circuit includes chip U11. Pin 3 of chip U11 is connected to a 12kΩ resistor R84, the other end of which is connected to the processor's solenoid valve control output signal. Pin 4 of U11 is connected to a 15kΩ resistor R96, and pin 6 is connected to a 75Ω resistor R80. The other end of resistor R80, besides being connected to power ground, is also connected to a 15kΩ resistor R97. R97 and R96 form a signal feedback terminal, which provides feedback on whether there is an open circuit or short circuit at pins 18 and 17 of chip U11, the gear shift solenoid valve drive output terminal. Pin 18 of chip U11 is also connected to a 51kΩ resistor R68 and the negative terminal of freewheeling diode D7. Figure 6 As shown in the freewheeling principle, the solenoid valve is not in a momentary cutting-off state, but rather in a steady-state operation. Since the negative terminal of diode D7 is connected to pin 18 (positive terminal), diode D7 is in a cut-off state. At this time, pin 18 of the U11 chip and the solenoid valve coil L2 form a closed loop TL1. When pin 18 of U11 cuts off the output under the action of the control signal, the reverse high voltage energy generated by the inductive load of the solenoid valve coil L2 at the moment of cutting off, that is, the end connected to pin 18 of L2 becomes negative. The principle is that at the moment of cutting off, the freewheeling diode D7 and the solenoid valve form a current loop TL1, thereby preventing the reverse voltage energy generated at the moment of cutting off the solenoid valve from being loaded onto pin 18, causing a short circuit and overcurrent protection of the chip, and affecting the normal operation of U11.

[0033] like Figure 4 As shown, it also includes a shift protection unit, which comprises a DC / DC isolated regulated power supply M1, a neutral relay J1, and a reverse relay J2. The DC / DC isolated regulated power supply M1 is required to have an isolation voltage of not less than 500V and a power of not less than 100W. The positive input terminal of M1 is connected to the positive terminal of the battery via a fuse (FUSE), and the negative input terminal of M1 is connected to the vehicle ground. The output ground of M1 is connected to the ground of the shift controller via lines 3-5 and 3-6, and the output power of M1 is connected to the positive power supply terminal of the shift controller via lines 3-1 and 3-2. One end of the neutral relay J1 coil is connected to the neutral control terminal of the shift controller, and the other end is connected to the output ground of the M1 module. The vehicle ground is connected to the normally open contact of the neutral relay J1 via the key start switch, and finally to the vehicle start coil RL1. The other end of the RL1 coil is connected to the positive DC24V_H terminal of the battery. One end of the reverse relay J2 is connected to the reverse control terminal of the shift controller, and the other end is connected to the output ground of the M1 module. The positive DC24V_H terminal of the battery is connected to the reverse light L1 via the normally open contact of the reverse relay J2. Because the vehicle is constantly charging and discharging during operation, and the generator itself is an inductive load, the charging and discharging process generates voltage pulses. These pulses can couple into the shift controller through the vehicle ground (before the invention was implemented, the shift controller shared the same ground as other vehicle electrical equipment), posing a risk of damaging the processor chip on the controller. This can be addressed by... Figure 4 The isolated regulated power supply M1 in the controller forms its own loop (such as...) Figure 4 In the diagram, 3-1 and 3-2 are the controller power supply, and 3-5 and 3-6 are the controller ground. These are isolated from the vehicle body ground, preventing voltage pulses generated by the vehicle generator from coupling into the controller and achieving a good protection effect. Furthermore, the coil power supply of the neutral relay J1 and reverse relay J2 is the controller power supply, and the grounds of J1 and J2 are the controller ground. The grounds of high-power loads connected to their contacts, such as the reverse horn, reverse light, and neutral starting current load, are shared with the vehicle power supply, which can also effectively isolate these loads from damaging the shift controller.

[0034] like Figure 5 As shown, this embodiment of the invention also provides a control method based on the above-described engineering machinery transmission control system, including the following steps:

[0035] First, read the shift boost curve, the fuel filling and releasing time of the gear, and store them in the processor memory;

[0036] When the vehicle reaches the point where it needs to shift gears, the target gear is first determined; if the conditions for shifting gears are not met, the vehicle remains in its current gear state, and the determination of the target gear continues.

[0037] If the conditions for shifting gears are met, determine whether to upshift.

[0038] If so, the upshift logic is invoked, and the timing of upshifting fuel release and refueling is controlled; for example... Figure 7 As shown, when the oil charging and discharging overlaps appropriately by a time t1 (generally 100-500 milliseconds), the torque Tout output interruption time can be reduced. Combined with the hydraulic control of the charging through the clutch friction plates, the vehicle shock caused by the interruption of output torque can be significantly improved. However, the overlap should not be too long, otherwise it will accelerate the wear of the clutch drum friction plates. Control the transmission clutch pressure and judge whether the control is completed in real time. If completed, return to the target gear for judgment; this step can solve the problem that when the transmission is upshifting, if the oil charging of the clutch drum corresponding to the gear engagement and the oil discharging of the clutch drum corresponding to the gear disengagement are carried out simultaneously, or if the oil charging is delayed by the oil discharging, the current gear has already cut off the power while the target gear has not yet established the power, thus causing the output torque Tout to be interrupted and causing shock.

[0039] If not, the downshifting logic is invoked, and the downshifting fuel release and refueling time are controlled; for example... Figure 8 As shown, by appropriately delaying the oil filling and releasing, the impact on the vehicle caused by rearward acceleration can be reduced, the transmission clutch pressure can be controlled, and the control can be judged in real time to determine whether the control is complete. If complete, the system returns to the target gear for judgment. This step solves the problem that when the transmission downshifts, if the oil filling and releasing of the clutch drum corresponding to the gear position is carried out simultaneously, or if the oil filling and releasing overlap, it will create reverse torque and cause the vehicle to experience a rearward impact.

[0040] This invention automatically or semi-automatically switches to the target gear based on the vehicle's operating process by collecting vehicle speed, engine speed, braking, and lever signals reflecting the driver's intentions through the Electronic Control Unit (ECU). It adopts electro-hydraulic proportional control technology and controls the timing of oil filling and releasing of the wet clutch drum, as well as the oil filling pressure, according to different gears of the transmission, which can reduce the shifting shock of the hydraulic mechanical transmission.

[0041] As shown in this disclosure and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "comprising" or "including" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. The terms "connected" or "linked" are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect.

[0042] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A transmission control system for engineering machinery, characterized in that, The system includes a shift control electronic unit, a vehicle operating condition and vehicle condition detection unit, a driver intention acquisition unit, a gear drive unit, a shift monitoring unit, and a communication unit. These units are all connected to the shift control electronic unit. The shift control electronic unit includes a power supply circuit and a gear solenoid valve drive signal output circuit. The power supply circuit includes a power conversion chip U8 and a chip-isolated power module U9 for converting +24V power to 5V. Pin 1 of the power conversion chip U8 is connected to a polarized capacitor CP9, and pin 2 is connected to a Zener diode D10. Pin 2 is also connected to one end of an inductor L1, the other end of which is the 5V voltage output terminal, connected to the polarized capacitor CP10. The negative terminal of an LED DS1 is grounded, and its positive terminal is connected to one end of a resistor R96. The other end of the LED DS1 is connected to pin 4 of the power conversion chip U8 and the other end of the inductor L1. The LED DS1 and resistor R96 work together to detect whether there is voltage at the output terminal. Pins 2 and 3 of the chip-isolated power supply module U9 are connected to the negative terminal of the polarized capacitor and the power ground. Pins 22 and 23 of the chip-isolated power supply module U9 are connected to the 24V power supply. Pin 16 of the chip-isolated power supply module U9 is connected to the signal power ground. Pin 14 of U9 is connected to the positive terminal of the polarized capacitor CP13, one end of resistor R99, and one end of resistor R97. Pin 14 outputs power supply VDD_3.3V, and the other end of R97 outputs power supply VCC_3.3V. VCC_3.3V is filtered and regulated by capacitor C6 and 10uF tantalum capacitor CP11. The gear shift solenoid valve drive signal output circuit includes chip U11. Pin 3 of chip U11 is connected to one end of resistor R84, and the other end of resistor R84 is connected to the processor solenoid valve control output signal. Pin 4 of chip U11 is connected to one end of resistor R96, and pin 6 of U11 is connected to one end of resistor R80. One end of resistor R80 is connected to power ground and one end of resistor R97. The other end of R97 is connected to the other end of resistor R96 to form a signal feedback terminal, which provides feedback on whether there is an open circuit or short circuit fault at the gear shift solenoid valve drive output terminals of pins 18 and 17 of chip U11. Pin 18 of chip U11 is connected to one end of resistor R68 and the negative terminal of freewheeling diode D7.

2. The engineering machinery transmission control system according to claim 1, characterized in that, It also includes a DC / DC isolated regulated power supply M1, a neutral relay J1, and a reverse relay J2; the positive input terminal of the DC / DC isolated regulated power supply M1 is connected to the positive terminal of a vehicle battery through a fuse FUSE, and the negative input terminal of M1 is connected to the vehicle ground; the output ground of M1 is connected to the power ground of the shift control electronic unit through lines 3-5 and 3-6, and the output power of M1 is connected to the positive power supply terminal of the shift control electronic unit through lines 3-1 and 3-2; one end of the coil of the neutral relay J1 is connected to the neutral control terminal of the shift control electronic unit, and the other end is connected to the output ground of M1; the vehicle ground is connected in sequence through the key start switch, the normally open contact of the neutral relay J1, and one end of the vehicle start coil RL1; the other end of the vehicle start coil RL1 is connected to the positive terminal of the battery; one end of the reverse relay J2 is connected to the reverse control terminal of the shift control electronic unit, and the other end is connected to the output ground of M1; the positive terminal of the battery is connected to the reverse light L1 through the normally open contact of the reverse relay J2.

3. The engineering machinery transmission control system according to claim 1 or 2, characterized in that, The vehicle operating condition and vehicle condition detection unit includes one or more of the following: vehicle speed sensor, pump wheel speed sensor, turbine speed sensor, gear oil pressure sensor, and oil temperature sensor.

4. The engineering machinery transmission control system according to claim 3, characterized in that, The vehicle speed sensor, pump wheel speed sensor, and turbine speed sensor are all magnetoelectric or Hertz pulse wave sensors, while the gear position oil pressure sensor and oil temperature sensor are all analog signal output sensors.

5. The engineering machinery transmission control system according to claim 1 or 2, characterized in that, The driver intent acquisition unit includes a mode handle information acquisition module, a brake signal acquisition module, and an accelerator pedal signal acquisition module.

6. The engineering machinery transmission control system according to claim 1 or 2, characterized in that, The gear drive unit includes a gear solenoid valve and a vehicle signal output module; the monitoring unit includes a transmission status LCD monitoring information module; and the communication unit includes a calibration interface and a vehicle CAN communication interface.

7. A control method for a transmission control system of engineering machinery according to any one of claims 1-6, characterized in that, Including the following steps: Obtain the shift boost curve and the oil filling and draining overlap time of the gear; When the vehicle reaches a point where a gear shift is required, the target gear is determined. If the conditions for shifting are not met, the vehicle remains in its current gear and the target gear is determined again. If the conditions for shifting are met, it is determined whether to upshift. If so, the upshift logic is invoked, and the upshift release and fill times are controlled. The fill and release times overlap to reduce the torque output interruption time and reduce the impact. If not, the downshifting logic is invoked, and the timing of downshifting, releasing fuel, and refueling is controlled. Fuel is released after refueling to reduce the impact on the vehicle caused by backward acceleration.

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