阅读说明：本技术 一种大功率液力缓速器的控制方法 (Control method of high-power hydraulic retarder ) 是由 陆应骅 谢嘉 廖安强 田世杰 于 2020-11-28 设计创作，主要内容包括：本发明公开了一种大功率液力缓速器的控制方法,属于汽车制动设备技术领域。该方法包括以下步骤：控制器判断缓速器应急开关信号是否有效；控制器根据发动机转速决定是否打开缓速器,再根据是否接收到缓速器档位手柄硬线或CAN开关信号尝试打开缓速器；控制器进一步判断是否满足缓速器打开条件；控制器打开子程序,并根据缓速器被尝试打开时的输入条件,给出相应缓速器电磁阀的初始电流；控制器根据缓速器油温高低,控制变速箱的扭矩和档位,及缓速器的制动扭矩；结束,继续重复步骤(1)至步骤(5)。能够挽回损失,最大限度保障车辆及乘车人员的安全；避免发动机持续超速而损坏发动机；避免缓速器因高温而损坏。(The invention discloses a control method of a high-power hydraulic retarder, and belongs to the technical field of automobile braking equipment. The method comprises the following steps: the controller judges whether the retarder emergency switch signal is effective or not; the controller determines whether to open the retarder according to the rotating speed of the engine, and tries to open the retarder according to whether a retarder gear handle hard line or a CAN switch signal is received; the controller further judges whether a retarder opening condition is met; the controller opens the subprogram, and gives the initial current of the corresponding retarder electromagnetic valve according to the input condition when the retarder is tried to be opened; the controller controls the torque and the gear of the gearbox and the braking torque of the retarder according to the oil temperature of the retarder; and (5) ending, and continuing to repeat the steps (1) to (5). Loss can be recovered, and the safety of vehicles and passengers can be guaranteed to the maximum extent; the damage to the engine caused by continuous overspeed of the engine is avoided; the retarder is prevented from being damaged due to high temperature.)

1. A control method of a high-power hydraulic retarder is characterized by comprising the following steps: the method comprises the following steps:

(1) the controller judges whether the retarder emergency switch signal is effective or not, if so, the retarder is completely opened and then is ended, and the next cycle is entered, and if not, the next step is directly entered;

(2) the controller determines whether to open the retarder according to the rotating speed of the engine, if the retarder is opened, the controller directly enters the next step, otherwise, the controller tries to open the retarder according to whether a retarder gear lever hard line or a CAN switch signal is received, so as to determine whether to open the retarder, if one signal is received, the controller tries to open the retarder, the controller directly enters the next step, and if not, the controller closes the retarder and enters the next cycle;

(3) the controller further judges whether a retarder opening condition is met, if yes, the retarder is continuously opened, the next step is directly carried out, and if not, the retarder is closed, and the next cycle is carried out;

(4) the controller opens the subprogram, and gives the initial current of the corresponding retarder electromagnetic valve according to the input condition when the retarder is tried to be opened;

(5) the controller controls the torque and the gear of the gearbox and the braking torque of the retarder according to the oil temperature of the retarder;

(6) and (5) ending, and continuing to repeat the steps (1) to (5).

2. The control method of the high-power hydraulic retarder according to claim 1, characterized in that: and (2) if the controller detects that the signal of the retarder emergency switch is effective in the step (1), immediately starting the retarder emergency pneumatic valve, instantly injecting oil in the storage tank into the retarder cavity, keeping the current of the retarder electromagnetic valve unchanged at the maximum value, and keeping the maximum braking torque and the best braking effect of the retarder.

3. The control method of the high-power hydraulic retarder according to claim 1, characterized in that: the specific process of the step (2) is as follows: the controller judges whether the rotating speed of the engine is greater than a set value A or not, if so, the value of the state quantity B is set to be 1, and the retarder is opened and the next step is directly carried out; if the value is not greater than the set value A, the controller judges whether a retarder gear handle hard line or a CAN switch signal is received to try to open the retarder, if one signal is received to try to open the retarder, the value of the state quantity B is set to be 2, the retarder is opened and directly enters the next step, otherwise, the retarder is closed, the value of the state quantity B is set to be 0 and then the next cycle is finished, and the next cycle is started.

4. The control method of the high-power hydraulic retarder according to claim 3, characterized in that: and when the rotating speed of the engine is greater than the set value A, the retarder is opened by the controller, and the rotating speed of the engine is continuously judged.

5. The control method of the high-power hydraulic retarder according to claim 4, characterized in that: the method for continuously judging the engine speed by the controller comprises the following steps:

a. if the engine speed is greater than a threshold value C (C < A), the retarder is kept in an open state, and if the engine speed is reduced below the threshold value C, the retarder is closed;

b. in the process that the engine speed is increased to the threshold value C from below the threshold value C and is continuously increased to the set value A, the retarder is not tried to be opened, and the step a is not executed until the engine speed is further increased and is larger than the set value A.

6. The control method of the high-power hydraulic retarder according to claim 1, characterized in that: and (4) the condition that the retarder is opened in the step (3) comprises that the output rotating speed of the gearbox is more than 200rpm, the throttle signal is 0, and the ABS does not work.

7. The control method of the high-power hydraulic retarder according to claim 1, characterized in that: and (4) after the retarder is closed in the step (3), setting the value of the state quantity B to be 0, and entering the next cycle.

8. The control method of the high-power hydraulic retarder according to claim 1, characterized in that: the input conditions in the step (4) comprise retarder handle gear information, CAN switch signal content and engine overspeed information.

9. The control method of the high-power hydraulic retarder according to claim 1, characterized in that: the method for controlling the torque and the gear of the gearbox and the braking torque of the retarder by the controller according to the oil temperature of the retarder in the step (5) comprises the following steps:

step one, when the oil temperature of a retarder is less than or equal to D, the current braking torque of the gearbox is kept unchanged;

step two, when the oil temperature E is larger than or equal to the oil temperature D of the retarder, the gearbox downshifts according to a forced downshifting rule set by the controller;

step three, when the temperature F is more than or equal to the oil temperature E of the retarder, the controller adaptively adjusts the braking torque according to the temperature rising or falling trend of the retarder, so that the braking torque is between I and II, and I is less than II;

step four, when G is larger than or equal to the oil temperature of the retarder and is larger than F, the controller adaptively adjusts the braking torque to enable the braking torque to be between III and II, wherein I is larger than III and smaller than II, and the over-temperature alarm lamp of the retarder is turned on;

and step five, when the oil temperature of the retarder is greater than G, the controller directly reduces the braking torque of the retarder to 516Nm, wherein 516Nm is less than I.

10. The method for controlling a high power hydrodynamic retarder according to claim 9, characterized in that: the I is the initial input request torque value, II is 800Nm, and III is 600 Nm.

Technical Field

The invention relates to a control method of a high-power hydraulic retarder, and belongs to the technical field of automobile braking equipment.

Background

The hydraulic retarder is an auxiliary braking device for automobiles, and is mainly applied to large buses, urban buses and heavy trucks. The device is installed between automobile transmission shaft and gearbox, drives hydraulic rotation and strikes the stator through the rotor, and the stator also can produce a reaction force through hydraulic and act on the rotor this moment to hinder the rotor to rotate, realize contactless braking. A high power hydrodynamic retarder is usually provided with 4 gears: 100%, 75%, 50% and 25%, different gears are through different retarder solenoid valve control current, and the driver can select required gear according to particular case.

Chinese patent publication No. CN101837738A discloses a hydrodynamic retarder drive controller and a control method thereof, the control method includes the following steps: the signal processing module receives and processes temperature sensing signals of a oil temperature sensor and a water temperature sensor in the hydraulic retarder; and the control unit receives or reads a gear input by a user, and controls the electromagnetic control valve of the hydraulic retarder to downshift and adjust the pressure of the output corresponding gear according to the condition that the oil temperature or the water temperature corresponding to the temperature sensing signal exceeds the respective temperature threshold through the output control unit. The method fills the blank of the driving controller of the hydraulic retarder.

However, this control method does not provide the engine continuous overspeed protection, and the risk of the engine having a shortened service life due to the continuous overspeed is high; secondly, the hydraulic retarder can not be quickly opened under emergency and special conditions, so that serious consequences of vehicle damage and people death are avoided; finally, only a single threshold value is used for judging whether the oil temperature of the hydraulic retarder per se exceeds the temperature, and the implementation is not strong for a dynamically running vehicle.

Disclosure of Invention

In order to solve the technical problem, the invention provides a control method of a high-power hydraulic retarder.

The invention is realized by the following technical scheme:

a control method of a high-power hydraulic retarder comprises the following steps:

(1) the controller judges whether the retarder emergency switch signal is effective or not, if so, the retarder is completely opened and then is ended, and the next cycle is entered, and if not, the next step is directly entered;

(2) the controller determines whether to open the retarder according to the rotating speed of the engine, if the retarder is opened, the controller directly enters the next step, otherwise, the controller tries to open the retarder according to whether a retarder gear lever hard line or a CAN switch signal is received, so as to determine whether to open the retarder, if one signal is received, the controller tries to open the retarder, the controller directly enters the next step, and if not, the controller closes the retarder and enters the next cycle;

(3) the controller further judges whether a retarder opening condition is met, if yes, the retarder is continuously opened, the next step is directly carried out, and if not, the retarder is closed, and the next cycle is carried out;

(4) the controller opens the subprogram, and gives the initial current of the corresponding retarder electromagnetic valve according to the input condition when the retarder is tried to be opened;

(5) the controller controls the torque and the gear of the gearbox and the braking torque of the retarder according to the oil temperature of the retarder;

(6) and (5) ending, and continuing to repeat the steps (1) to (5).

And (2) if the controller detects that the signal of the retarder emergency switch is effective in the step (1), immediately starting the retarder emergency pneumatic valve, instantly injecting oil in the storage tank into the retarder cavity, keeping the current of the retarder electromagnetic valve unchanged at the maximum value, and keeping the maximum braking torque and the best braking effect of the retarder.

The specific process of the step (2) is as follows: the controller judges whether the rotating speed of the engine is greater than a set value A or not, if so, the value of the state quantity B is set to be 1, and the retarder is opened and the next step is directly carried out; if the value is not greater than the set value A, the controller judges whether a retarder gear handle hard line or a CAN switch signal is received to try to open the retarder, if one signal is received to try to open the retarder, the value of the state quantity B is set to be 2, the retarder is opened and directly enters the next step, otherwise, the retarder is closed, the value of the state quantity B is set to be 0 and then the next cycle is finished, and the next cycle is started.

And when the rotating speed of the engine is greater than the set value A, the retarder is opened by the controller, and the rotating speed of the engine is continuously judged.

The method for continuously judging the engine speed by the controller comprises the following steps:

a. if the engine speed is greater than a threshold value C (C < A), the retarder is kept in an open state, and if the engine speed is reduced below the threshold value C, the retarder is closed;

b. in the process that the engine speed is increased to the threshold value C from below the threshold value C and is continuously increased to the set value A, the retarder is not tried to be opened, and the step a is not executed until the engine speed is further increased and is larger than the set value A.

And (4) the condition that the retarder is opened in the step (3) comprises that the output rotating speed of the gearbox is more than 200rpm, the throttle signal is 0, and the ABS does not work.

And (4) after the retarder is closed in the step (3), setting the value of the state quantity B to be 0, and entering the next cycle.

The input conditions in the step (4) comprise retarder handle gear information, CAN switch signal content and engine overspeed information.

The method for controlling the torque and the gear of the gearbox and the braking torque of the retarder by the controller according to the oil temperature of the retarder in the step (5) comprises the following steps:

step one, when the oil temperature of a retarder is less than or equal to D, the current braking torque of the gearbox is kept unchanged;

step two, when the oil temperature E is larger than or equal to the oil temperature D of the retarder, the gearbox downshifts according to a forced downshifting rule set by the controller;

step three, when the temperature F is more than or equal to the oil temperature E of the retarder, the controller adaptively adjusts the braking torque according to the temperature rising or falling trend of the retarder, so that the braking torque is between I and II, and I is less than II;

step four, when G is larger than or equal to the oil temperature of the retarder and is larger than F, the controller adaptively adjusts the braking torque to enable the braking torque to be between III and II, wherein I is larger than III and smaller than II, and the over-temperature alarm lamp of the retarder is turned on;

and step five, when the oil temperature of the retarder is greater than G, the controller directly reduces the braking torque of the retarder to 516Nm, wherein 516Nm is less than I.

The I is the initial input request torque value, II is 800Nm, and III is 600 Nm.

The invention has the beneficial effects that:

1. the retarder can be completely opened under emergency and special conditions, so that the current of the electromagnetic valve of the retarder is kept unchanged to the maximum value, the maximum braking torque and the best braking effect of the retarder are kept, loss can be saved, and the safety of vehicles and passengers is guaranteed to the maximum extent.

2. When the controller detects that the rotating speed of the engine is greater than the overspeed set value of the engine, the hydraulic retarder can be automatically started to provide braking, and the damage to the engine caused by continuous overspeed of the engine is avoided.

3. Divide into 4 intervals with the overtemperature range of hydraulic retarber, the controller can be according to the interval that hydraulic retarber temperature was located, and the braking torque of automatically regulated hydraulic retarber carries out overtemperature protection to hydraulic retarber under the condition that satisfies hydraulic retarber braking torque as far as possible, avoids the retarber to damage because of the high temperature.

Drawings

FIG. 1 is a flow chart of a hydrodynamic retarder control according to the present invention;

FIG. 2 is a diagram of the operating region of the retarder when the engine speed is reduced from above the set value A to below the threshold value C according to the present invention;

fig. 3 is a diagram of the retarder operating region when the engine speed rises from below the threshold C to above the set value a according to the present invention.

Detailed Description

The technical solution of the present invention is further described below, but the scope of the claimed invention is not limited to the described.

As shown in fig. 1 to fig. 3, the control method for the high-power hydraulic retarder according to the present invention includes the following steps:

(1) the controller judges whether the retarder emergency switch signal is effective or not, if so, the retarder is completely opened and then is ended, and the next cycle is entered, and if not, the next step is directly entered;

(2) the controller determines whether to open the retarder according to the rotating speed of the engine, if the retarder is opened, the controller directly enters the next step, otherwise, the controller tries to open the retarder according to whether a retarder gear lever hard line or a CAN switch signal is received, so as to determine whether to open the retarder, if one signal is received, the controller tries to open the retarder, the controller directly enters the next step, and if not, the controller closes the retarder and enters the next cycle;

(3) the controller further judges whether a retarder opening condition is met, if yes, the retarder is continuously opened, the next step is directly carried out, and if not, the retarder is closed, and the next cycle is carried out;

(4) the controller opens the subprogram, and gives the initial current of the corresponding retarder electromagnetic valve according to the input condition when the retarder is tried to be opened;

(5) the controller controls the torque and the gear of the gearbox and the braking torque of the retarder according to the oil temperature of the retarder;

(6) and (5) ending, and continuing to repeat the steps (1) to (5).

And (2) if the controller detects that the signal of the retarder emergency switch is effective in the step (1), immediately starting the retarder emergency pneumatic valve, instantly injecting oil in the storage tank into the retarder cavity, keeping the current of the retarder electromagnetic valve unchanged at the maximum value, and keeping the maximum braking torque and the best braking effect of the retarder.

The specific process of the step (2) is as follows: the controller judges whether the rotating speed of the engine is greater than a set value A or not, if so, the value of the state quantity B is set to be 1, and the retarder is opened and the next step is directly carried out; if the value is not greater than the set value A, the controller judges whether a retarder gear handle hard line or a CAN switch signal is received to try to open the retarder, if one signal is received to try to open the retarder, the value of the state quantity B is set to be 2, the retarder is opened and directly enters the next step, otherwise, the retarder is closed, the value of the state quantity B is set to be 0 and then the next cycle is finished, and the next cycle is started. When in use, the state quantity B is 1, which indicates that the engine overspeed tries to open the retarder; b ═ 2 means that the retarder gear lever hard wire signal or the CAN switch signal tries to open the retarder, and another reason for assigning the state quantity B is: in order to carry out hysteresis control on a rotating speed value interval of engine overspeed.

And when the rotating speed of the engine is greater than the set value A, the retarder is opened by the controller, and the rotating speed of the engine is continuously judged.

The method for continuously judging the engine speed by the controller comprises the following steps:

a. if the engine speed is greater than a threshold value C (C < A), the retarder is kept in an open state, and if the engine speed is reduced below the threshold value C, the retarder is closed;

b. in the process that the engine speed is increased to the threshold value C from below the threshold value C and is continuously increased to the set value A, the retarder is not tried to be opened, and the step a is not executed until the engine speed is further increased and is larger than the set value A. When the retarder is used, the overspeed hysteresis control of the engine defines the overspeed interval and the speed change direction of the engine, and the problem that the retarder is opened by mistake due to the fluctuation of the rotating speed of the engine can be solved.

And (4) the condition that the retarder is opened in the step (3) comprises that the output rotating speed of the gearbox is more than 200rpm, the throttle signal is 0, and the ABS does not work.

And (4) after the retarder is closed in the step (3), setting the value of the state quantity B to be 0, and entering the next cycle.

The input conditions in the step (4) comprise retarder handle gear information, CAN switch signal content and engine overspeed information.

The method for controlling the torque and the gear of the gearbox and the braking torque of the retarder by the controller according to the oil temperature of the retarder in the step (5) comprises the following steps:

step one, when the oil temperature of a retarder is less than or equal to D, the current braking torque of the gearbox is kept unchanged;

step two, when the oil temperature E is larger than or equal to the oil temperature D of the retarder, the gearbox downshifts according to a forced downshifting rule set by the controller; in use, the downshift point for the kick-down law may be slightly higher than the downshift point for the normal downshift law.

Step three, when the temperature F is more than or equal to the oil temperature E of the retarder, the controller adaptively adjusts the braking torque according to the temperature rising or falling trend of the retarder, so that the braking torque is between I and II, and I is less than II; when the temperature-controlled brake device is used, the braking torque can be reduced by continuous temperature rise, the temperature rise speed and the braking torque reduction amplitude are in a proportional relation, similarly, the braking torque can be improved by continuous temperature fall, the temperature fall speed and the braking torque increase amplitude are in a proportional relation, the temperature is stabilized in a certain range, and the braking torque is not changed any more.

Step four, when G is larger than or equal to the oil temperature of the retarder and is larger than F, the controller adaptively adjusts the braking torque to enable the braking torque to be between III and II, wherein I is larger than III and smaller than II, and the over-temperature alarm lamp of the retarder is turned on; when the retarder overtemperature warning lamp is used, the retarder overtemperature warning lamp is lightened to remind a driver of noticing that the oil temperature of the retarder is overtemperature, and the risk of damaging a gearbox is caused.

And step five, when the oil temperature of the retarder is greater than G, the controller directly reduces the braking torque of the retarder to 516Nm, wherein 516Nm is less than I.

The I is the initial input request torque value, II is 800Nm, and III is 600 Nm.

The control method of the high-power hydraulic retarder provided by the invention has three purposes:

the method is realized by providing a method for realizing 100% braking torque immediately by the hydraulic retarder under emergency and special conditions. When the controller receives the emergency switch signal of the retarder, the controller can enable the emergency pneumatic valve of the retarder to inject the oil stored in the storage box into the cavity of the hydrodynamic retarder instantly, the current of the electromagnetic valve of the retarder is kept unchanged to the maximum value, after the emergency switch signal of the retarder is closed, the oil flows into the storage box again, and the electromagnetic valve of the retarder is closed. The design can recover the loss at the emergency and critical moment, and the safety of the vehicle and passengers is ensured to the maximum extent;

and secondly, when the engine is overspeed, the hydraulic retarder tries to be automatically opened to protect the engine. When the controller detects that the rotating speed of the engine is greater than an engine overspeed set value, the hydraulic retarder can be automatically started to provide braking, the situation that the engine is damaged due to continuous overspeed of the engine is avoided, and when the rotating speed of the engine is reduced to a specified rotating speed, the retarder is closed;

and thirdly, performing overtemperature protection on the hydraulic retarder under the condition of meeting the braking torque of the hydraulic retarder as much as possible. If the hydraulic retarder blade stirs oil for a long time at a high speed, the retarder can be damaged due to high temperature. The invention divides the overtemperature range of the hydraulic retarder into 4 intervals, and the controller can automatically adjust the braking torque of the hydraulic retarder according to the interval in which the temperature of the hydraulic retarder is positioned.