JPH04151068A - Fail safe device for automatic transmission control system employing rotation sensor - Google Patents

Abstract

PURPOSE:To provide the fail safe device of an automatic transmission control system through which reliable control is practicable by executing decision of a trouble through majority decision of a car speed sensor and fail safe, in an automatic transmission to effect control by using three or more rotation sensors. CONSTITUTION:An engine rotation sensor 1A is arranged to the vicinity of an engine output shaft 8, a transmission input rotation sensor 1B is arranged to the vicinity of a drum 64 of a first clutch C1, and a transmission output rotation sensor 1C is arranged to the vicinity of a differential drive pinion 73. Data equivalent to a car speed is calculated by means of a sensor signal according to the state of the number of revolutions obtained from one sensor signal. A value equivalent to a present car speed is calculated from input rotation, differential gear rotation, and engine rotation. An accurate car speed is calculated from the remaining two car speed signals of three or more car speed signals through a method of a majority decision redundant system even when one of the three car speed signals effects an extremely delicate change of, for example, 5-10km/h.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a fail-safe device that guarantees failure of a rotation sensor that detects information for controlling an automatic transmission, and particularly relates to a fail-safe device that guarantees failure of a rotation sensor that detects information for controlling an automatic transmission. The present invention relates to a fail-safe device for a control system using a rotation sensor installed in a rotary sensor.

[Conventional technology]

The vehicle speed signal is used as an important signal for electronic control of automatic transmissions for vehicles. Therefore, backup means is provided for detecting the vehicle speed signal.

Conventionally, a fair roof device for a vehicle speed sensor compares the number of pulses of two signals indicating sensor information corresponding to vehicle speed, that is, the speedometer and the transmission output shaft rotation speed, and the number of pulses detected from one reaches a predetermined number. If not a single pulse is detected from the other sensor when this occurs, the sensor that does not output a signal pulse during that time is determined to be malfunctioning, and a fail-safe device is installed that uses the vehicle speed calculated from the other sensor signal to control the automatic transmission. be.

[Problem to be solved by the invention]

However, in the above-mentioned device, if a disturbance such as noise occurs in one sensor, the number of output pulses increases significantly in a short period of time, which may cause a normal sensor with a smaller number of pulses to malfunction. There is a possibility that an erroneous determination will be made.

In addition, since it is impossible to determine a failure when a tooth gapping signal occurs in one sensor, the vehicle speed data of that sensor will fluctuate, which may lead to, for example, an unintended downshift of the automatic transmission controlled by the sensor. be.

By the way, recent trends in the control of automatic transmissions include the rotation of rotating members, that is, engine rotation, transmission input rotation, transmission output rotation,
There is a movement to install rotation sensors that detect rotation at many parts of an automatic transmission, such as differential gear rotation and clutch rotation, to pick up the rotation of various parts and perform fine control.

In view of these circumstances, the present invention attempts to provide redundancy to the vehicle speed signal itself by using these sensors, and is an object of the present invention to provide an automatic transmission system that uses three or more rotation sensors to perform control. An object of the present invention is to provide a fail-safe device for an automatic transmission control system, which enables reliable control by determining failure and implementing fail-safe by majority decision of vehicle speed sensors.

[Means to solve the problem]

In order to solve the above problems, the present invention provides three automatic transmissions.
A vehicle speed calculation/judgment means that calculates the vehicle speed based on the output signals of rotation sensors disposed at more than one location, and determines the vehicle speed by a majority decision among the calculated values; sensor failure determination means that determines that a rotation sensor that has obtained an output outside the range is malfunctioning; and vehicle speed selection means that prioritizes the signals of each rotation sensor and selects a vehicle speed to be used for control according to the priority order. Become.

[Action and effect of invention]

In the fail-safe device for an automatic transmission control system according to the present invention having such a configuration, the vehicle speed calculation/judgment means calculates a value equivalent to the vehicle speed from the output signal of the rotation sensor of each part, and makes a majority decision between these calculated values. The vehicle speed is determined by Then, the presence or absence of a failure in each rotation sensor is determined based on whether the difference between the result determined by the sensor failure determination means and the calculated value obtained from the output signal of each sensor is within a predetermined standard tolerance. Ru. Further, the vehicle speed selection means sequentially selects priority signals in accordance with the priority order of the signals depending on the failure status of each rotation sensor, thereby performing control.

In this way, according to the failsafe device of the present invention,
The automatic transmission control system can be controlled reliably by detecting the rotations of various parts of the automatic transmission, determining a malfunction based on a majority vote of the vehicle speed sensor, and implementing a failsafe.

Furthermore, by using this device, it becomes possible to perform various fail-safe controls such as speed change, lockup, and oil pressure.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram of a fail-safe device showing an embodiment of the present invention.

As shown in Fig. 1, this system includes various sensors lA
, IB, IC, ID...IX, electronic control unit (hereinafter referred to as ECU), various solenoids operated by it, 2A, 2B, 2C... and alarm lamp 2L...
It also includes appropriate control elements 2X and the like. The engine rotation sensor IA is an electromagnetic pickup type sensor that detects the rotation of the engine crankshaft, etc. and outputs a pulse signal, and is an interface circuit (abbreviated as I/F in the figure. The same applies to the reference symbols in parentheses below). It is connected to a microprocessor (μP) 4 via 3A. The transmission (T/M) input rotation sensor IB is the second
Drum 64 of the first clutch CI, which will be described later with reference to the figure.
It is also an electromagnetic pickup type sensor that detects the rotational speed of and outputs a pulse, and is connected to the microprocessor 4 via an interface circuit 3B. The transmission output rotation sensor IC is an electromagnetic pickup type sensor that detects the rotation speed of the differential drive pinion 73, and is also connected to the interface circuit 3C.
The microprocessor 4 is connected to the microprocessor 4 via the microprocessor 4. Note that this sensor may be one that detects the rotation speed of a differential driven gear, a parking gear, or the like. A throttle position sensor (hereinafter referred to as throttle sensor) LD is a sensor that detects the throttle opening of the engine, and is also connected to the microprocessor 4 via an interface circuit 3D. Although not shown in the figure, the ECU includes a ROM (read only memory) that fixedly stores a control program and various data connected to the microprocessor 4, and a ROM.
R for storing read data and -temporal input/output data.
Needless to say, AM (Random Access Memory) is also provided.

The ECU includes a solenoid drive circuit 5 that drives the first solenoid (solenoid Nα1) of the hydraulic control device.
A. Also provided are a solenoid drive circuit 5B that drives the second solenoid (solenoid Nα2), a solenoid drive circuit 5C that drives the lock-up solenoid, and a lamp drive that turns on and off a failure lamp as a failure warning device. A circuit 5L is also provided.

Next, FIG. 2 is a skeleton diagram showing an example of a transmission mechanism of an automatic transmission to which the above-mentioned failsafe device is applied.

As shown in Fig. 2, this transmission has a main transmission mechanism section (3
6, an auxiliary transmission mechanism 7, an engine output shaft 8 connected to the crankshaft of an engine (not shown), a hydraulic torque converter 9A, a lock-up clutch 9B, and a main transmission mechanism. Input shaft 60, single planetary gear unit 61, dual planetary gear unit 62, counter drive gear 6
3. The sub-transmission mechanism includes a counter driven gear 71, a counter shaft 70, a planetary gear unit 72, and a differential drive pinion 73. In addition, as shift control elements, a first clutch C1, a second clutch C1 (
direct) clutch C2, first brake B1, first
One-way clutch F1, second brake B2, third
brake B3, second one-way clutch F2, third
A one-way clutch F3, a third (underdrive direct) clutch C3, and a fourth (underdrive brake) B4 are provided.

An engine rotation sensor IA is arranged close to the engine output shaft 8 to detect the rotation of the engine output shaft 8 of the transmission mechanism, and a transmission input rotation sensor IB is arranged close to the engine output shaft 8 to detect the rotation of the input shaft 60. Further, a transmission output rotation sensor IC is arranged close to the differential drive pinion 73 to detect the output rotation of the transmission.

Next, the control flow of the fail-safe device will be explained according to the flowcharts in FIGS. 3(a) to (C). The basic concept of this control is that the rotation speed obtained from one sensor signal Calculates data equivalent to vehicle speed from sensor signals according to each situation, such as gear ratio for input rotation, differential ratio and gear ratio for differential gear rotation, and gear ratio and torque converter slip rate for engine rotation. The current vehicle speed equivalent value is calculated from the input rotation, differential gear rotation, and engine rotation, respectively. Then, by using a majority vote redundancy method to program from three or more vehicle speed signals, even if one of them makes a very subtle change such as 5 to 10 km/h, the correct vehicle speed can be determined by the other two. It is something to calculate.

As shown in FIG. 3(a), the first processing step involves input processing of the input signal system, that is, input of engine rotation NE, input of transmission input rotation SP■, calculation of input rotation speed N5PI, and output shaft rotation SPO. , calculation of the output rotational speed N5PO, and input of the throttle opening TH are performed. In the next process, a vehicle speed equivalent value VIP+ is calculated by multiplying the input rotation SPI by a gear ratio G that is determined according to the gear position. In the next step after the decision lockup flag check, there is a slip in the torque converter depending on whether it is locked up or not, so if it is not locked up, the slip rate of the torque converter is checked. Throttle opening TH and engine speed NE from the ROM table
It is brought out by Its slip ratio RC and gear ratio G
A process for calculating the vehicle speed VWZ is performed. On the other hand, when lockup is in progress, the vehicle speed equivalent value vN is calculated directly from the engine rotation NE and gear ratio G! is calculated. In the final process, the vehicle speed vsp is determined from the transmission output rotation N5PO. is calculated.

The next flowchart in FIG. 3(b) is as shown in FIG.
Three cars 1i1 each calculated by the flow shown in
Vsp1. It is determined whether the difference between two values in Vspo and Vyz is larger than a predetermined tolerance d.

It should be noted that although a constant value may be used for this tolerance d for convenience, it is also possible to set a different value depending on each gear stage for more fine-grained control. In the first decision of this flow, the output vehicle speed Vs
It is determined whether or not the difference between po and input vehicle speed VSP+ is large, and based on this, it is selected whether or not to set the flag Fl. In the second decision, a flag F is set depending on whether the vehicle speed value vspo calculated from the output rotation and the vehicle speed value VIE calculated from the engine rotation are larger than the tolerance d.

is standing. The third decision sets a flag F3 based on the relationship between input rotation and engine rotation. Each of the above flags becomes 1 if the difference is large, and 0 otherwise. Based on the combination of flags F+, Fz, and Fs, it is determined which sensor is malfunctioning. next third
This determination is made in the flowchart in Figure (C1).

The first decision, shown in FIG. 3fc), is to check the code W of the warning lamp indicating a fault. The −th cycle passes with code W=0, and the next flag F +
, F! , enter the Fs check. By the way, W=
0 represents a no-failure situation. Here, the flags F+, Ft
, Fs, different warning codes W are set depending on the situation. That is, W=0: No failure W=1: SPO failure W=2: SPI failure W=3: NE failure W=4=Unable to identify.

On the other hand, as can be seen from the flowchart, priorities are determined for the sensors that output the respective speed calculation values V, in other words, the signals that are the basis thereof. This is intended to give priority to the signals of the sensors closer to the output shaft, which would make the calculated values more accurate. That is, the priority is vs
p. has the highest priority, followed by Vsp+ and Vyz. Therefore, the speed calculation value V selected in response to the warning code W is specified as shown for each process.

In these processes, warning code W=417)
In the case where the vehicle speed cannot be specified, the vehicle speed calculation value is set to the maximum value without using it, and the fourth gear is automatically selected as a fail-safe. Warning code W after the second round
is not 0 but is 1 to 4, the flow for turning on the fault lamp based on W is shown on the right side of the above flow. In this flow, after the failure lamp ON input processing, the value of V is selected according to the value of W, as described above. By the way, in the past, the output rotation was used as the vehicle speed data used to change the transmission gear, but in this embodiment, this can be changed to the input rotation in response to a failure, or the maximum speed value can be input to control the speed. It's a failsafe. And in the final process, the vehicle speed V selected in this way
and the gear position g of the shift selected by the throttle opening TH.
Alternatively, the on/off state of the lock-up clutch is determined, and then the solenoid drive signal SL is output to the corresponding shift solenoid Nα1, solenoid drive signal SL, shift solenoid Nα2, solenoid drive signal S2, or lock-up solenoid. This flow completes the cycle and returns to the steps after initial setting shown in FIG. 3(a).

In this way, in this fail-safe device, in the event of a failure of the full rotation sensor, the highest speed gear, which is the safest side, is selected by switching the vehicle speed used for control to the max value on the shift diagram in the ROM. This allows you to avoid unexpected downshifts due to changes in the vehicle speed signal. At that time, the line pressure of the hydraulic control device is also regulated to the maximum pressure, so the pressure required to engage the frictional engagement elements of the transmission mechanism is maintained at a sufficiently high pressure, and the frictional engagement Prevents elements from slipping.

Finally, some application examples of the failsafe device will be explained.

First, FIG. 4 is a configuration diagram when the vehicle speed information obtained as described above is applied to line pressure control of a hydraulic control device, and in this example, a solenoid drive circuit for hydraulic control provided in the ECU is used. Output from 5E is linear solenoid 2
D and is configured to operate the linear solenoid valve IO. In this example, according to the shift position information from the neutral start switch, which is provided as a separate input means and detects the shift position, and the shift gear stage g information obtained from the operating state information of the shift solenoids N (Ll, Nα2), it is fixed in the ROM in advance. A reference is made to the stored line pressure table.Following the line pressure information corresponding to each transmission gear stage g read from the fixed memory, the hydraulic control solenoid drive circuit 5E controls the linear solenoid valve 10, and the primary regulator valve 11 back pressure is adjusted to control the oil pressure in the line pressure oil path PL leading to the manual valve.As mentioned above, if the warning code W=4 is "unspecified", the calculated vehicle speed value is max without using (
max) value so that the 4th gear is automatically selected, and the linear solenoid valve I
By turning off the O-glue solenoid 2D, the oil pressure of the line pressure oil passage PL regulated by the primary regulator valve 11 is maximized, and the engagement pressure of the friction engagement elements of the transmission mechanism such as the clutch and brake is increased. , control is performed to prevent the occurrence of slips, etc. In Fig. 4, reference numeral 12 indicates a secondary regulator valve, 13 indicates a solenoid modulator valve, and 14 indicates a pressure relief valve, and there is no particular difference in their arrangement, functions, etc. from conventional ones. Therefore, the explanation will be omitted.

Next, FIG. 5 is a configuration diagram when applied to lock-up control, and in this example, lock-up solenoid 2C
By operating the lock-up relay valve 20, which is switched on and off, the flow direction of the pressure oil leading to the lock-up clutch 9B is switched and controlled. As a result, the lock-up clutch is controlled on and off. As mentioned above, the warning code W=4 is "Unable to identify.

In this case, the fourth gear is automatically selected and the lock-up clutch 9B is turned off.

The rotation sensor failure determination described above is applied to the control of the shift solenoids Nα1 and Nα2 shown in FIG. 1, the lock-up solenoid, and the hydraulic control solenoid shown in FIG.
Shift solenoid Nα1. The control of Nα2 is shifted to timer control, and the lock-up clutch is released by turning off the lock-up solenoid to prevent the occurrence of shift shock, and the line pressure is maximized by turning off the hydraulic control solenoid to prevent slipping of the friction engagement element. It is also possible to use it for preventive control.

Finally, in each of the above-mentioned embodiments, modifications were mainly explained on the output side of the present device, but the rotation sensor as an input means can also be disposed in various locations. For example, FIG. 6 shows an example in the form of a skeleton. In this transmission 100, 111 is a lock-up clutch;
110 is a torque converter, 120 is a planetary transmission gear mechanism, 121 is an overdrive planetary gear unit, 122 is a main transmission unit, 122a is a front planetary gear unit, 122b is a planetary gear unit, 101 and 102 are input shafts, and 103 is an output axis, P
I~3 are planetary binions, CR1~3 are carriers,
SL-3 is a sun gear, R1-3 are ring gears, CO is an overdrive direct clutch, FO-3 is a one-way clutch, BO is an overdrive brake, C1 is a forward clutch, C2 is a direct clutch, and the second coast brake consists of a B1 band brake. ,B2
is the second brake, and B3 is the first and reverse brake. In this example, sun gears Sl and B
Rotation sensors IF and IG for detecting the rotation of the sun gear S1 and the drum of the direct clutch C2 that rotate together with the shaft of the sun gear S1 and the sun gear S2, respectively, are arranged close to each other.

Although the present invention has been described in detail based on the examples above, the present invention is not limited to the contents disclosed in the above examples, but can be implemented by specific configurations according to the implementation situation within the scope of the claims. Needless to say, this does not preclude changes to the .

[Brief explanation of drawings]

FIG. 1 is a system diagram of a fail-safe device according to an embodiment of the present invention, FIG. 2 is a skeleton diagram of the transmission mechanism showing the rotation sensor arrangement position, FIG. 3 is a flowchart showing its control flow, and FIG. Figure 5 is a configuration diagram showing its application to line pressure control, Figure 5 is a configuration diagram showing its application to lock-up control, and Figure 6 is the arrangement position of the rotation sensor in a transmission mechanism of a different type from Figure 2. FIG. IA...Engine rotation sensor (rotation sensor), IB・
・・Transmission input rotation sensor (rotation sensor)
, IC...Transmission output rotation sensor (rotation sensor), 2A...Shift solenoid Nα112B・
...Shift solenoid Nα2.2C...Lock-up solenoid, 2L...Failure lamp, 4...Microprocessor (vehicle speed calculation judgment means, failure judgment means, vehicle speed selection means) Agent: Patent attorney Yukihiro Abe Figure (a) Figure (b) Country 9th Figure

Claims (1)

[Claims] (1) A vehicle speed calculation/judgment means that calculates the vehicle speed based on the output signals of rotation sensors disposed at three or more parts of the automatic transmission, and determines the vehicle speed by a majority decision among the calculated values; a sensor failure determination means that sets a standard tolerance and determines that a rotation sensor that obtains an output outside the standard tolerance is a failure; and a sensor failure determination means that prioritizes the signals of each rotation sensor and determines the vehicle speed to be used for control according to the priority. A fail-safe device for an automatic transmission control system, comprising vehicle speed selection means that selects a vehicle speed according to the following.