JPH06100271B2 - Controller for continuously variable transmission - Google Patents

Description

Description: (a) Technical Field The present invention relates to a control device for a continuously variable transmission.

(B) Prior Art As a conventional control device for a continuously variable transmission, for example, Japanese Patent Laid-Open No.
There is one shown in -90450. This control device for a continuously variable transmission detects a throttle opening and an engine rotation speed by a throttle opening sensor and an engine rotation speed sensor, and sets the relationship between them to a preset relationship. It was designed to control the gear ratio. However, since the control device for the continuously variable transmission does not take measures against the abnormality in the throttle opening sensor, the target gear ratio cannot be determined when the abnormality in the throttle opening sensor occurs. Or, there is a problem that the gear ratio is set to an inappropriate value. If the gear ratio is set to an inappropriate value, for example, the gear ratio becomes too small to make the vehicle unable to run, or if the gear ratio becomes small while traveling with a large gear ratio, a sudden change in the running state occurs. May cause a dangerous condition.

In the case of an automatic transmission having a stepwise gear ratio, as shown in JP-A-56-49447 and JP-A-56-49448, when abnormality occurs, the gear is fixed to the third speed. However, there is one that makes the line pressure the highest, but since no control is performed in the process of shifting from the gear ratio before the abnormality occurred to the third speed at the time of abnormality, the running state immediately before the abnormality occurred is ignored. Then, it is not always appropriate to fix the third speed. For example, if an abnormality occurs during uphill traveling, overtaking traveling, or the like, there is a possibility that a traveling impossible state or a dangerous state may occur.

(C) Object of the Invention The present invention is a continuously variable transmission that is capable of continuing to run even when an engine output sensor (throttle opening sensor, intake pipe negative pressure sensor, etc.) is abnormal, and is less dangerous. The purpose is to obtain a control device.

(D) Structure of the Invention The present invention normally operates the shift control mechanism of the continuously variable transmission by the normal gear ratio control signal, and switches to the abnormal gear ratio control signal when an abnormality occurs in the engine output sensor. The gear shift control mechanism is operated to determine the delay time according to the operating state immediately before the abnormality occurs, and during this delay time, the gear ratio control during abnormality from the value of the normal gear ratio control signal immediately before the abnormality occurs to a constant value is controlled. The signal is changed gradually. That is, the present invention comprises, as shown in FIG. 1, normal gear ratio control signal determining means, sensor abnormality detecting means, abnormal gear ratio control signal determining means, and gear ratio control signal selecting means. , The gear ratio control signal selection means,
When the sensor abnormality detecting means does not detect an abnormality, the normal gear ratio control signal from the normal gear ratio control signal determining means is sent to the gear shift control mechanism, and when the sensor abnormality detecting means detects an abnormality, the abnormal gear ratio control signal is determined. It has a function of sending a gear ratio control signal from the means to the gear shift control mechanism at the time of abnormality. The abnormal speed ratio control signal can be gradually changed from the value of the normal speed ratio control signal immediately before the abnormal condition to a constant value during the delay time determined according to the operating condition immediately before the abnormal condition occurs. ing.

(E) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

(First Embodiment) FIG. 2 shows a first embodiment of the present invention as a block diagram.
The normal target gear ratio determining means 10 has an engine output signal,
An operating condition signal 12 such as an engine speed signal and a vehicle speed signal is input, and the normal target gear ratio determining means 10 determines a normal target gear ratio signal 14 indicating a target gear ratio based on these signals. Then, it outputs to the target gear ratio selecting means 16. The sensor abnormality detecting means 18 includes an engine output sensor (throttle opening sensor or intake pipe negative pressure sensor).
The engine output signal 20 from the engine output sensor 20 is input, and the sensor abnormality detecting means 18 detects the abnormality of the engine output sensor based on the engine output signal 20. The abnormality of the engine output sensor is detected when the value of the engine output signal 20 is out of the normal range. Sensor abnormality detection means
When the sensor 18 detects an abnormality, the sensor abnormality signal 22 is sent to the abnormal target gear ratio determination means 24, the sensor abnormality alarm / storage means 26, and the target gear ratio selection means 16. The operating condition signal 28 indicating the operating state of the vehicle and the selected target gear ratio signal 32 described later are input to the abnormal target gear ratio determining means 24. The operating condition signal 28 is obtained by removing the engine output signal from the operating condition signal 12 described above. The abnormal target gear ratio determining means 24 determines an abnormal gear ratio control signal 30 based on the operating condition signal 28 and the selected target gear ratio signal 32 and sends it to the target gear ratio selecting means 16. Target gear ratio selection means 16
When the sensor abnormality signal 22 is not input from the sensor abnormality detecting means 18, the gear shift command signal calculating means 34 uses the normal target gear ratio signal 14 as the selected target gear ratio signal 32.
Send to. On the other hand, the target gear ratio selecting means 16 receives the abnormal target gear ratio signal 30 when the sensor abnormality signal 22 is input.
Is selected as the target gear ratio signal 32
Send to 34. The selected target gear ratio signal 32 is also sent to the abnormal target gear ratio determining means 24. The gear change command signal calculating means 34 calculates a gear change command signal 40 based on the selected target gear ratio signal 32 from the target gear ratio selecting means 16 and an actual gear ratio signal 38 from an actual gear ratio detecting means 36 described later, This is sent to the shift control mechanism 42. The shift control mechanism 42 operates based on the shift command signal 40, and the gear ratio of the continuously variable transmission mechanism 44 changes. The continuously variable transmission mechanism 44 is a V-belt type continuously variable transmission mechanism in which the pulley groove spacing is variable by hydraulic pressure, and the transmission control mechanism 42 operates a hydraulic valve by a step motor or a DC motor to operate the pulley hydraulic pressure. Is to control. The gear ratio of the continuously variable transmission mechanism 44 is the actual gear ratio detecting means 36.
Have been detected by. The actual gear ratio detecting means 36 calculates the actual gear ratio from the rotational speed of the pulley or a member that rotates in a predetermined relationship with the pulley.

With the above configuration, the following effects can be obtained.
First, when the sensor abnormality detecting means 18 has not detected an abnormality, normal gear shift control is performed based on the normal target gear ratio signal 14 from the normal target gear ratio determining means 10. That is, the normal gear ratio determining means 10 determines the normal gear ratio signal 14 based on the engine output signal and the vehicle speed signal from the predetermined gear ratio table set in advance.
To decide. The speed change ratio table indicates that when the speed change is controlled based on this speed change ratio table, the engine is always driven along a predetermined operation line (for example, a minimum fuel consumption rate operation line connecting points at which the fuel consumption rate becomes the smallest). Driving is done. The normal target gear ratio signal 14 is input to the gear change command signal calculating means 34 as the selected target gear ratio signal 32 via the target gear ratio selecting means 16, and the gear change command signal calculating means 34 and the actual gear ratio signal 38 The shift command signal 40 for reducing the difference between the two based on
Send to. By doing so, the actual gear ratio matches the target gear ratio.

When the sensor abnormality detecting means 18 detects an abnormality, it operates as follows. First, the sensor abnormality detecting means 18 detects an abnormality of the engine output sensor from the value of the engine output signal 20. That is, for example, assuming that the range of the normal value of the engine output signal 20 is 0 to 1, if an abnormality occurs in the engine output sensor and the open or short circuit state occurs, the engine output signal 20 becomes 0 or It will be a value of 1 or more. When the engine output signal 20 has a value outside the normal range, the sensor abnormality detecting means 18 outputs a sensor abnormality signal 22. When the sensor abnormality signal 22 is input from the sensor abnormality detecting means 18 to the abnormal target gear ratio determining means 24, the abnormal target gear ratio determining means 24 operates as follows. That is, the abnormal target gear ratio determining means 24 is configured to gradually change the abnormal target gear ratio signal from the value of the selected target gear ratio signal 32 immediately before the occurrence of the abnormality to a constant value (for example, a value corresponding to the maximum gear ratio). Raise 30. As for the time for gradually changing the target gear ratio, that is, the delay time, for example, as shown in FIG.
Alternatively, as shown in FIG. 4, the delay time is made longer as the difference between the above-mentioned constant value of the target gear ratio signal 30 at the time of abnormality and the value of the selected target gear ratio signal 32 immediately before the occurrence of the abnormality increases, or The delay time is set based on both the difference between the vehicle speed and the target gear ratio signal. The target gear ratio selecting means 16 receives the selected target gear ratio signal as soon as the sensor abnormality signal 22 is input.
As 32, the abnormal target gear ratio signal 30 is output instead of the normal target gear ratio signal 14. Therefore, the continuously variable transmission mechanism 44 is controlled by the shift control mechanism 42 so that the abnormal target gear ratio determined by the abnormal target gear ratio determination means 24 is reached, and the actual gear ratio matches the abnormal target gear ratio. . Therefore,
The actual speed ratio of the continuously variable transmission mechanism 44 gradually changes during the delay time from the state before the occurrence of the abnormality to the constant speed ratio (the speed ratio corresponding to the above-mentioned constant value), and then the constant speed ratio It will be fixed in the state. After all, even if an abnormality occurs in the engine output sensor, the operating state does not change suddenly and it is possible to avoid the occurrence of a dangerous state.
Further, after the delay time has elapsed, it becomes possible to continue traveling at a constant gear ratio. The sensor abnormality alarm / storage means 26 displays the occurrence of the abnormality with an alarm lamp, a buzzer, etc. when the abnormality of the engine output sensor occurs. Further, since an abnormality of the engine output sensor may occur temporarily, in order to easily find the failure location, the sensor abnormality alarm / storage unit 26 stores the occurrence of the abnormality in the nonvolatile storage device. deep.

Each of the above means is composed of a microcomputer. The function of the microcomputer will be described with reference to the flowchart shown in FIG. First, a driving condition signal indicating the driving state of the vehicle is read (step 500), then it is determined whether or not there is an abnormality in the engine output sensor (step 510), and if normal, the process proceeds to step 520a and the shift lever is moved. It is determined whether it is in the D range or the L range. Step 530 according to D range and L range
Then, the process proceeds to step 540 to read out the normal target gear ratio signal in the D range and the L range, respectively. Step
If the 510 detects an abnormality in the sensor, it issues a sensor abnormality alarm and stores it (step 60).
0), proceed to step 520b, determine whether it is the D range or the L range, proceed to step 550 and step 560 depending on the case of the D range and the L range, respectively, and output the target gear ratio signal at the time of abnormality of the D range and the L range. read out. Next, in step 570, the actual gear ratio is read, gear change control is calculated based on the target gear ratio and the actual gear ratio from any of steps 530, 540, 550 and 560 (step 580), and then the gear change control mechanism. Output a signal to drive (step 59
0). It is obvious that the functions of the respective means shown in FIG. 2 are achieved by the action of the microcomputer shown in this flowchart.

In this embodiment, the normal target speed ratio determining means 10 is a normal speed ratio control signal determining means, and the abnormal target speed ratio determining means 24 is an abnormal speed ratio control signal determining means.
The target gear ratio selecting means 16 is a gear ratio control signal selecting means, and the normal target gear ratio signal 14 and the abnormal target gear ratio signal 30 correspond to normal and abnormal gear ratio control signals, respectively.

Second Embodiment Next, a second embodiment shown in FIGS. 6 and 7 will be described.
In this embodiment, the gear shift command signal in the normal state and the gear shift command signal in the abnormal state are selected by the gear shift command signal selecting means 16 '. That is, in the embodiment shown in FIG. 2, the normal target gear ratio signal 14 from the normal target gear ratio determining means 10 and the abnormal target gear ratio signal 30 from the abnormal target gear ratio determining means 24 are provided. The target gear ratio selecting means 16 is selected, but in the embodiment shown in FIG. 6, the gear ratio command signal calculating means 34 is immediately changed from the normal target gear ratio signal 14 of the normal target gear ratio determining means 10. The normal speed shift command signal 40 'is calculated by the abnormal speed shift command determining means 24', and the abnormal speed shift command signal 40 'is determined by the abnormal speed shift command calculating means 34 and the abnormal speed shift command determining means 24'. The normal speed shift command signal 40 'and the abnormal speed shift command signal 40 "are selected by the shift command signal selecting means 16'. After all, the difference between the first embodiment and the second embodiment is based on whether the normal speed or the abnormal time is selected at the stage of the target gear ratio (first embodiment) or based on the target gear ratio and the actual gear ratio. It is obvious that the same operation can be obtained, except that whether the normal operation or the abnormal operation is selected after the shift command signal is calculated (second embodiment). The flowchart of the program of the microcomputer is also shown in FIG. 7 according to the above difference.

In this second embodiment, the normal target gear ratio determining means is used.
10 and the gear shift command signal calculation means 34 are normal gear ratio control signal determining means, and the abnormal gear command determining means 24 'are abnormal gear ratio control signal determining means, and the gear command signal selecting means.
Reference numeral 16 'is a gear ratio control signal selecting means, and the normal gear change command signal 40' and the abnormal gear change command signal 40 "correspond to the normal gear ratio control signal and the abnormal gear ratio control signal, respectively.

(F) Effects of the Invention As described above, according to the present invention, a control device for a continuously variable transmission equipped with a gear shift control mechanism capable of continuously controlling a gear ratio based on an input gear ratio control signal. At
When the engine output sensor is in a normal state, the normal gear ratio control signal determining means determines the normal gear ratio control signal, the sensor abnormality detecting means that detects an abnormal output signal of the engine output sensor, and the engine output sensor is abnormal. In addition to determining the value of the gear ratio control signal during abnormal conditions, calculate the delay time according to the operating condition immediately before the engine output sensor malfunctions, and during this delay time, From the abnormal speed ratio control signal determining means for gradually changing the abnormal speed ratio control signal from the value to the value determined above, and from the normal speed ratio control signal determining means when the sensor malfunction detecting means detects no abnormality. When the normal gear ratio control signal is input to the gear change control mechanism and the sensor abnormality detection means detects an abnormality, the abnormal gear ratio control signal is input. When there is an abnormality in the engine output sensor (throttle opening sensor or intake pipe negative pressure sensor), since there is a gear ratio control signal selecting means for inputting the gear ratio control signal at the time of abnormality from the determining means to the gear shift control mechanism. In addition, a smooth transition from the operating state immediately before the occurrence of an abnormality to a predetermined operating state in which the vehicle can continue to run, and since there is no sudden change in the operating state, safety is increased, and it is possible to continue traveling even after the abnormality occurs. The effect of being able to be obtained is obtained.

[Brief description of drawings]

1 is a block diagram showing the configuration of the first embodiment of the present invention, FIGS. 3 and 4 are diagrams showing the characteristics of delay time, and FIG. 5 is the first embodiment. 6 is a block diagram showing the configuration of the second embodiment of the present invention, and FIG. 7 is a diagram showing the flow chart of the second embodiment. 10 …… Target speed ratio determining means for normal operation, 12 …… Operating condition signal, 14 …… Target speed ratio signal for normal operation, 16 …… Target speed ratio selecting means, 16 ′ …… Shift command signal selecting means, 18 …… Sensor abnormality detection means, 20 ... Engine output signal, 22 ... Sensor abnormality signal, 24 ... Abnormal target gear ratio determination means, 24 '
…… Abnormal gear change command determination means, 26 …… Sensor abnormality alarm / storage means, 28 …… Operating condition signal, 30 …… Abnormal target gear ratio signal, 32 …… Selected target gear ratio signal, 34 …… Gear change Command signal calculating means, 36 ... actual gear ratio detecting means, 38 ... actual gear ratio signal, 40 ... shift command signal, 40 '... normal shift command signal, 40 "... abnormal shift command signal, 42 ...... Shift control mechanism, 44 …… Stepless speed change mechanism.

Claims (3)

[Claims] 1. A controller for a continuously variable transmission equipped with a shift control mechanism capable of continuously controlling a gear ratio on the basis of an input gear ratio control signal, wherein the engine output sensor is in a normal state. The normal gear ratio control signal determining means for determining the ratio control signal, the sensor abnormality detecting means for detecting an abnormality of the output signal of the engine output sensor, and the value of the abnormal gear ratio control signal when the engine output sensor is in an abnormal state Determine and calculate the delay time according to the operating condition immediately before the engine output sensor abnormality occurs, and during this delay time from the value of the normal gear ratio control signal immediately before the abnormality occurs to the value determined above Abnormal gear ratio control signal determining means for gradually changing the control signal, and normal gear ratio control signal determining means when the sensor abnormality detecting means detects no abnormality. When the normal gear ratio control signal from the setting means is input to the gear shift control mechanism, and when the sensor abnormality detecting means detects an abnormality, the abnormal gear ratio control signal from the abnormal gear ratio control signal determining means is input to the gear shift control mechanism. A control device for a continuously variable transmission, comprising: input gear ratio control signal selection means. 2. The control device for a continuously variable transmission according to claim 1, wherein the delay time is determined to be longer as the vehicle speed is higher. 3. The delay time is determined so as to become longer as the difference between the constant value of the target gear ratio signal at the time of abnormality and the selected gear ratio signal before occurrence of the abnormality becomes larger. A control device for a continuously variable transmission according to claim 1.