CN103075441B - Automatic transmission clutch controlling method - Google Patents

Abstract

The invention discloses a clutch control method of an automatic transmission, which is used for adjusting the pre-fill oil pressure value of the clutch to adaptively detect the linkage point position of the clutch. The method includes: step a: according to the current pre-fill oil pressure value of the clutch Control the clutch for pre-filling oil; step b: control the clutch for a second oil filling with a predetermined fixed oil filling time, and obtain the engine output torque increase value during the second oil filling process; step c: judge the engine Whether the difference between the output torque increase value and a preset torque increase calibration value is within the preset error range; if yes, maintain the current pre-charge oil pressure value; if not, proceed to step d; step d: change the The above-mentioned pre-fill pressure value, use the changed pre-fill pressure value as the current pre-fill pressure value, and repeat the steps a to c.

Description

Automatic transmission clutch control method

technical field

The invention relates to the technical field of vehicle automatic control, in particular to an automatic transmission clutch control method.

Background technique

The linkage point of the clutch is the position where the driving part and the driven part are just in contact after the clutch overcomes the idle travel, but the torque has not been transmitted or the torque is very small (the torque is not enough to overcome the driving resistance of the vehicle to drive the vehicle), at this time The driving and driven parts of the clutch create sliding friction. Before the vehicle is running, if the clutch is controlled at the linkage point, when the brake is released, the vehicle can start quickly, reducing the response time of the vehicle. The clutch linkage point detection has an important influence on the quick response of the vehicle starting. If the clutch linkage point detection is inaccurate, it will cause serious clutch wear, increased fuel consumption of the vehicle, and shocks at the start of the vehicle.

The automatic transmission clutch does not have a clutch position sensor, so the clutch linkage point cannot be directly detected. In addition, due to factors such as the wear and tear of the clutch of the automatic transmission, the position of the clutch linkage point is not fixed, and the oil pressure of the clutch will also change. Therefore, the detection and adaptive adjustment of the clutch linkage point of the automatic transmission need to be solved urgently.

Contents of the invention

According to one aspect of the present invention, a clutch control method of an automatic transmission is provided for controlling the clutch to reach a linkage point. The automatic transmission clutch control method includes:

Pre-filling step: pre-filling the clutch according to the pre-filling pressure value;

The second oil filling step: for the clutch after the pre-oil filling, the clutch is filled with oil for the second time, so that the clutch reaches the state of the linkage point;

Wherein, in the second oil filling process, the clutch pressure is used as the control amount, so that the clutch pressure is increased by a fixed clutch pressure increase value; or, the clutch oil filling time is used as the control amount, and the clutch is filled with oil for a fixed duration . Preferably, the pre-charge oil pressure value is adjustable.

The method may further include an adjusting step, by adjusting the pre-charge oil pressure value to obtain the pre-charge oil pressure value corresponding to the current use condition of the clutch.

Specifically, the adjustment step includes:

Step a: controlling the clutch to perform pre-filling according to the current pre-filling pressure value;

Step b: controlling the clutch for the second oil filling with the fixed duration, and obtaining the engine output torque increase value during the second oil filling process;

Step c: judging whether the difference between the engine output torque increase value and a preset torque increase calibration value is within a preset error range; if yes, end the adjustment step; if not, proceed to step d;

Step d: changing the pre-fill pressure value, using the changed pre-fill pressure value as the current pre-fill pressure value, and repeating steps a to c.

Wherein, in step d:

When the engine output torque increase value is less than the torque increase calibration value, the pre-charge oil pressure value is increased by a predetermined step value to change the pre-charge oil pressure value; or,

When the engine output torque increase value is greater than the torque increase calibration value, the pre-charge oil pressure value is decreased by a predetermined step value, so as to change the pre-charge oil pressure value.

Specifically, the preset step size is 0.1 bar.

Specifically, the preset error range is ±10%.

Preferably, said adjusting step is performed each time the vehicle's transmission control unit is powered on.

According to another aspect of the present invention, a clutch control method of an automatic transmission is provided for adjusting a pre-charge oil pressure value of a clutch to adapt to a current use condition of the clutch. The methods include:

Step a: Control the clutch to perform pre-filling according to the current pre-filling pressure value of the clutch;

Step b: controlling the clutch for a second oil filling with a predetermined fixed oil filling time, and obtaining the engine output torque increase value during the second oil filling process;

Step c: judging whether the difference between the engine output torque increase value and a preset torque increase calibration value is within a preset error range; if yes, then maintain the current pre-fill pressure value; if not, proceed to step d;

Step d: changing the pre-fill pressure value, using the changed pre-fill pressure value as the current pre-fill pressure value, and repeating steps a to c.

Wherein, in step d:

When the engine output torque increase value is less than the torque increase calibration value, the pre-charge oil pressure value is increased by a predetermined step value to change the pre-charge oil pressure value; or,

When the engine output torque increase value is greater than the torque increase calibration value, the pre-charge oil pressure value is decreased by a predetermined step value, so as to change the pre-charge oil pressure value.

Specifically, the preset step size is 0.1 bar.

Specifically, the preset error range is ±10%.

Preferably, the method is performed each time the transmission control unit of the vehicle is powered on.

The automatic transmission clutch control method is especially suitable for controlling DCT transmission clutches.

By controlling the clutch pressure or clutch oil filling time to control the clutch to quickly reach the linkage point, the vehicle can be started quickly when starting, which can greatly reduce clutch wear for an automatic transmission without a clutch position sensor, thereby reducing unnecessary Necessary fuel consumption. In addition, the pre-charge oil pressure of the clutch is automatically adjusted according to the actual wear and tear of the clutch to ensure that the clutch can reach the linkage point according to the predetermined control steps, and reduce the aging speed of the clutch caused by clutch wear.

Description of drawings

Fig. 1 shows the pressure change diagram before and after the automatic transmission clutch pre-fill oil provided by an embodiment of the present invention;

Fig. 2 shows the pressure change diagram before and after the automatic transmission clutch pre-fill oil that another embodiment of the present invention provides;

Fig. 3 is a diagram showing the pressure change before and after pre-filling of the automatic transmission clutch provided by another embodiment of the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

During the working process of the vehicle clutch, the clutch completes three oil filling processes: the clutch is pre-filled with oil, so that the control oil circuit of the clutch is filled with oil when the clutch is in the pre-filled state, and the active part and the driven part are not in contact; the second charge After the brake is released, the clutch is filled with oil for the third time, so that the clutch completes the engagement process and starts to transmit the engine torque. In the present invention, it is necessary to control the clutch from the non-linked state to the linked point, so it is necessary to control the clutch pre-fill pressure value and the second oil-fill pressure value.

In the case that the clutch is not worn, the acquisition and calibration of the following parameters can be carried out first, and this work can be carried out, for example, before the vehicle leaves the factory. Firstly, the unworn clutch pre-fill oil pressure value P1 can be calibrated, so that when the clutch is in the pre-fill oil state, its control oil circuit is filled with oil, and the driving part and the driven part are not in contact, and the output torque of the engine remains unchanged for idling operation. , record the engine output torque at this time as T1. Then charge the clutch a second time to bring it to the linkage point. During the second oil filling process of the clutch, as the clutch pressure value continues to increase, the driving part and the driven part of the clutch begin to contact to generate sliding friction, and the engine will increase the output torque accordingly in order to continue to run at idle speed. Record the time t consumed by the process, the clutch pressure value P2 when the clutch reaches the linkage point, and the second output torque value T2 of the engine, so as to calibrate the clutch pressure increase value DeltaP=P2-P1 when the clutch reaches the linkage point from the pre-filled state , clutch pressure change rate GradP=(P2-P1)/t and engine output torque increase calibration value DeltaT=T2-T1.

In fact, the engine output torque increase calibration value DeltaT when the clutch reaches the linkage point position from the non-linkage state can be regarded as a constant fixed value, so it can be judged whether the clutch reaches the linkage point position according to the engine output torque increase calibration value DeltaT.

For the clutch oil filling process, if the clutch pressure changes too fast, the engine will stall, and if the clutch pressure changes too slowly, the clutch slip friction will be serious. Therefore, in the actual design of the vehicle, the clutch pressure change rate GradP is usually set to a Well-calibrated fixed values to avoid the above problems. Therefore, the clutch pressure change rate GradP=DeltaP/t can actually be regarded as a substantially constant quantity, so that the required clutch pressure increase value DeltaP=GradP can be obtained by controlling the time t of the second oil filling *t, so as to obtain the required clutch pressure value P2=P1+DeltaP.

The transmission control unit records the clutch pre-fill pressure value P1 and the time t for the second oil filling, so that when the clutch is controlled from non-linkage to the state of the linkage point, the pre-fill pressure value P1 Control the clutch to complete the pre-filling, and then control the clutch to perform the second oil filling with the clutch pressure change rate GradP for a period of t, so that the clutch reaches the linkage point. Of course, in another embodiment, the transmission control unit can also directly record the clutch pressure increase value DeltaP, and control the clutch pressure to reach P2=P1+DeltaP during the second oil filling process, so that the clutch reaches the linkage point.

After the clutch wears out during use, the clutch pressure value P2 required for the clutch to reach the linkage point state will change. The inventors of the present application have found through research that although the clutch pressure value P2 may vary, the influence of clutch wear or other factors on the clutch pressure is actually mainly reflected in the pre-fill pressure value P1. That is to say, if a new appropriate pre-fill pressure value P1 can be accurately determined as the clutch wears, then after the clutch pre-fill is completed, in the second oil filling process, as long as the clutch pressure value Increasing DeltaP can make the clutch reach the linkage point state.

Figure 1 shows the pressure change diagram of the unworn automatic transmission clutch from the non-linkage state to the linkage point. In Figure 1, the pre-filling of the clutch is completed from -0.5s to 0s, so that the control oil circuit of the clutch is filled with oil at 0s; and then from 0s to 0.5s (that is, the aforementioned second filling time t) Fill the clutch a second time to make it reach the linkage point. It can be seen from Figure 1 that since the pre-fill pressure value is appropriate, the engine output torque value also increases with the increase of the clutch pressure value at the beginning of the second oil charge. As shown in Figure 1, the engine output torque value is 2Nm when the pre-filling is completed, the engine output torque value is 10Nm after the second oil filling, and the engine output torque increase value is 8Nm during the second oil filling process. When the clutch is in the linkage point state, the active part and the driven part of the clutch can be quickly engaged after the brake is released, so that the vehicle can be started quickly.

With the increase in the number of times the clutch is used, the position of the clutch linkage point changes after the clutch wears out. After pre-filling the clutch with the pre-fill oil pressure value P1, the control oil circuit of the clutch may not be filled with oil. It may have already been filled with oil and the contact between the driving part and the driven part has already begun, which will result in that after the second oil filling of the clutch with the stated time period t (ie from 0s to 0.5s in Figures 2 and 3), there will be The clutch may not have reached the linkage point position as shown in Figure 2, or it may have already passed the linkage point position as shown in Figure 3. Therefore, after each time the transmission control unit is powered on, adjust the pre-charge oil pressure value P1 of the clutch by performing the following adjustment steps, so that it can adapt to the current use status of the clutch:

Step a, controlling the clutch to prefill oil according to the current clutch prefill oil pressure value P1;

Step b, control the clutch for the second oil filling with the time length t, and obtain the engine output torque increase value DeltaT2 during the second oil filling process;

Step c, comparing whether DeltaT2 is equal to the preset engine output torque increase calibration value DeltaT, if they are equal or the error is within the predetermined error range, then the adjustment step is ended; otherwise, the pre-filling pressure value P1 is changed; specifically, the difference between DeltaT2 and DeltaT is judged size, if DeltaT2<DeltaT, proceed to step d; if DeltaT2>DeltaT, proceed to step e;

Step d, increase the pre-fill oil pressure value P1 by a predetermined step value as the new pre-fill oil pressure value P1, and then repeat steps a to c;

Step e, reducing the pre-charging pressure value P1 by a predetermined step value as a new pre-charging pressure value P1, and then repeating steps a to c.

Wherein, the preset step value may specifically be 0.1 bar. The preset error range is specifically ±10%. Certainly, both the preset step size value and the preset error range can be other values to adapt to different adjustment precisions.

Taking Fig. 1 to Fig. 3 as an example, the preset engine output torque increase calibration value DeltaT=8Nm, then the engine output torque increase value shown in Fig. 1 is equal to DeltaT, and there is no need to adjust the pre-charge pressure value P1. The increase in engine output torque shown in Figure 2 is less than 8Nm, and it is necessary to increase the pre-charge oil pressure value P1 so that the clutch can reach the linkage point after the second oil charge with a fixed time length t, so that the clutch can reach the linkage point after Panasonic brakes Quick engagement reduces engine idle time. The increase in engine output torque shown in Figure 3 is greater than 8Nm. It is necessary to reduce the pre-fill pressure value P1 to avoid excessive engine output torque due to excessive clutch engagement, waste of energy, and further aggravate clutch wear.

Record the adjusted clutch pre-fill oil pressure value P1 through the transmission control unit, and use the adjusted pre-fill oil pressure value P1 to control the clutch to complete the pre-fill oil, so that the control oil circuit of the clutch is just full after the pre-fill oil is completed. Oil, which in turn can control the clutch to reach the linkage point position. Since the wear state of the clutch during the operation of the vehicle is unpredictable, it is impossible to adapt to various states with the preset pre-fill oil pressure value, and adjust the clutch pre-fill oil pressure value at any time according to the above adjustment steps It is possible to obtain the clutch pre-charge oil pressure value suitable for the current state, reduce wear and improve the service life of the clutch.

It should be understood that the method for adjusting the clutch pre-fill oil pressure value P1 described above is not only applicable to the automatic transmission clutch control method in the present invention, but also applicable to adjusting the clutch pre-fill oil pressure value in other clutch control methods .

The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the protection scope of the present invention. Those skilled in the art may make modifications or equivalent replacements to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims (4)

1. An automatic transmission clutch control method for adjusting a pre-charge pressure value of a clutch to adaptively detect a linkage point position of the clutch, the method comprising:

step a: controlling the clutch to pre-charge oil according to the current pre-charge oil pressure value of the clutch;

step b: controlling the clutch to carry out secondary oil filling according to a preset fixed oil filling duration, and obtaining an engine output torque increment value in the secondary oil filling process;

step c: judging whether the difference between the output torque increment value of the engine and a preset torque increment calibration value is within a preset error range or not; if so, keeping the current pre-filling oil pressure value; if not, performing the step d;

step d: changing the pre-charging oil pressure value, taking the changed pre-charging oil pressure value as the current pre-charging oil pressure value, and repeating the steps a to c;

in step d:

when the output torque increment value of the engine is smaller than the torque increment calibration value, increasing the pre-charge pressure value by a preset step value so as to change the pre-charge pressure value; or,

and when the output torque increment value of the engine is greater than the torque increment calibration value, reducing the pre-oil charge pressure value by a preset step value so as to change the pre-oil charge pressure value.

2. The automatic transmission clutch control method according to claim 1, characterized in that the predetermined step value is 0.1 bar.

3. The automatic transmission clutch control method according to claim 1, characterized in that the preset error range is ± 10%.

4. An automatic transmission clutch control method according to any one of claims 1-3, characterized in that the method is performed each time a transmission control unit of a vehicle is powered on.