JP2005172118A - Range position detection device and its control program for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability of a range position detection switch for an automatic transmission. <P>SOLUTION: Four switch bodies S1 to S4 of the range position detection switch 12 are divided into a first group provided with three switch bodies S1 to S3, and a second group provided with one switch body S4. 3-bit codes representing four range positions P, R, N, and D, and an intermediate state positions P-R, R-N, and N-D are provided by combining binary signal output from three switch bodies S1 to S3 of the first group. Three switch bodies S1 to S3 of the first group are set to switch signal values only of one switch body between two adjacent positions in the four range positions and three intermediate state positions. The switch body S4 of the second group detects the range positions P and N permitting engine start, and provides to output signals for P and N positions, which are different from other positions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an automatic transmission range position detecting device for detecting a range position selected by operating a shift lever of an automatic transmission and a control program therefor.

  In the automatic transmission range position detection device, for example, as described in Patent Document 1 (Japanese Patent Laid-Open No. 2003-294134), it is turned on / off in response to the movement of a shift lever operated by the driver 4. Equipped with an inhibitor switch with 4 contacts S1 to S4, the combination pattern of 4 contacts S1 to S4 on / off, parking range (P), reverse range (R), neutral range (N), drive range There is a configuration in which the range position is detected on the basis of the on / off combination pattern of the four contacts S1 to S4 by being configured to change for each range position of (D).

  Such an inhibitor switch may output an error signal different from the original range position when an abnormality such as failure of the individual contacts S1 to S4 or disconnection of the wire harness occurs.

Therefore, in Patent Document 1 (Japanese Patent Laid-Open No. 2003-294134), when the inhibitor switch fails and outputs an error signal different from the original range position, erroneous determination of the N range and the P range is prevented. For the N range, even if any one contact in the N range outputs an error signal different from the original range position, the combination pattern of ON / OFF of the four contacts S1 to S4 in the N range is the P range. The on / off combination pattern of the four contacts S1 to S4 is set so as not to coincide with the on / off combination pattern of the four contacts S1 to S4. Furthermore, a failure is determined when the on / off combination pattern of the four contacts S1 to S4 does not match any range position pattern.
JP 2003-294134 A (pages 1 to 4 etc.)

  However, in the technique of the above-mentioned Patent Document 1, a failure is determined when the combination pattern of the four contacts S1 to S4 of the inhibitor switch does not match any of the range position patterns. When the on / off combination pattern of the four contacts S1 to S4 matches the pattern of the range position different from the actual one, there is a defect that not only the failure cannot be detected but also erroneously determined as another range position. .

  SUMMARY OF THE INVENTION An object of the present invention is to provide a range position detection device for an automatic transmission and a control program therefor that can improve the reliability against a failure of a range position detection switch.

  In order to achieve the above object, the invention according to claim 1 is a pattern in which states of a plurality of binary signal generating means are set for each binary signal generating means in accordance with the operation position of the shift lever of the automatic transmission. And a range position detection switch that outputs a plurality of binary signals and a control unit that reads the plurality of binary signals output from the range position detection switch and determines the operation position of the shift lever. In the range position detecting device for an automatic transmission, the range position detecting switch divides the plurality of binary signal generating means into two groups, and information on the operation position of the shift lever for each group based on the binary signal of each group. The control unit determines the operation position of the shift lever based on a combination of binary signals of the two groups of the range position detection switch. Beauty / or to perform a fault diagnosis of the range position detecting switch is characterized in. In this way, if the plurality of binary signal generating means of the range position detection switch are divided into two groups and the information regarding the operation position of the shift lever is expressed for each group by the binary signal of each group, the shift is performed. The operating position of the lever can be determined with higher accuracy than before, and more faults can be detected than before.

  In this case, as in claim 2, the combination of the binary signals of at least one group of the range position detection switch includes at least the parking range, reverse range, neutral range, and drive range as the operation position of the shift lever. It is preferable to set so that the intermediate state position can be identified. Thereby, all the positions with high use frequency of a driver are detectable.

  According to a third aspect of the present invention, the binary signal generation means of at least one group of the range position detection switches generates one binary signal between two adjacent positions at each of the range positions and the intermediate state position. It is good to comprise so that only a means can be switched. In this way, erroneous determination of the range position can be reliably prevented when any one of the binary signal generating means fails (disconnection or short circuit).

  According to a fourth aspect of the present invention, the binary signal generating means of at least one group of the range position detection switches includes at least one binary signal generating means at any of the range positions and intermediate state positions. It is preferable that an active signal (active signal) is output from. In short, if all the binary signal generating means are in an inactive state (inactive state) at any position between each range position and its intermediate state position, it becomes impossible to distinguish between disconnection and normal state. At any position, if at least one binary signal generating means is configured to be in an active state (active state), it is possible to distinguish between disconnection and normal operation.

  Further, as in claim 5, the binary signal generating means of at least one group of the range position detection switches may be configured so that all signals are switched to active signals in the drive range. In this way, when a failure occurs, it is possible to avoid erroneously determining that the backup lamp is erroneously lit due to a reverse range at an intermediate state position between the neutral range and the drive range.

  As a preferred embodiment of the present invention, as in claim 6, a combination of binary signals of one group of range position detection switches (hereinafter referred to as “first group”) is at least parked as an operation position of the shift lever. The binary signal generating means of the other group (hereinafter referred to as “second group”) is set so as to identify each range position of the range, reverse range, neutral range, and drive range and the intermediate state position thereof. The control unit determines the operation position of the shift lever based on the binary signal combination of the first group based on the combination of the binary signals of the first group. The range position detection switch based on the determination result and the binary signal of the second group May to perform the failure diagnosis. In this way, it is possible to detect more failures than in the past while accurately detecting all positions where the frequency of use of the driver is high.

  More specifically, as in claim 7, the first group of range position detection switches is composed of three binary signal generating means, and the two binary signal generating means are active at the intermediate state position. It may be configured to output a signal. This configuration is an optimum configuration for identifying the four range positions of the parking range, reverse range, neutral range, and drive range and their intermediate state positions.

  Further, as in claim 8, the control unit reads the binary signal of the first group by interrupt processing every time one of the binary signals of the first group changes, and performs the second group at a predetermined sampling period. It is better to read the binary signal. In this way, even when the operation speed of the driver's shift lever is high, all the positions switched by the operation of the shift lever can be detected in the order of operation, and the detection position skips (misses). It can be surely prevented.

  Further, as described in claim 9, every time any one of the binary signals of the first group changes, the control unit changes the binary signal combination after the change (detected position after the change) to the binary value before the change. It is preferable to provide a function for determining whether or not the combination of signals (detected position before change) and a binary signal at a position adjacent to each other is a combination of the binary position signals and diagnosing the range position detection switch. In this way, even if failure diagnosis cannot be performed based on the binary signal combination of the first group and the binary signal of the second group, whether or not the detection position skips (misses) occurs. Fault diagnosis can be performed with.

  Further, the control program for controlling the range position detecting device of the present invention includes a process of reading binary signals output from the binary signal generating means of two groups as information on the operation position of the shift lever for each group, and 2 It may include processing for determining the operation position of the shift lever and / or performing failure diagnosis of the range position detection switch based on a combination of binary signals of two groups.

  Further, the combination of binary signals of one group of the range position detection switches (hereinafter referred to as “first group”) includes at least the parking position, the reverse range, the neutral range, and the drive range as the operation position of the shift lever. The intermediate state position is set so that it can be identified, and the binary signal generating means of the other group (hereinafter referred to as “second group”) has a signal different from other positions only in the parking range and the neutral range. A control program for controlling a system configured to output a process for determining an operation position of the shift lever based on a combination of binary signals of the first group, and a determination result of the operation position of the shift lever The range position detection switch based on the binary signal of the second group As long as it contains a process to perform fault diagnosis may (claim 11).

  Further, the control program includes an interrupt process for reading the binary signal of the first group every time one of the binary signals of the first group changes, and the binary signal of the second group at a predetermined sampling period. It is preferable to include a time synchronization process for reading in (claim 12).

  Further, every time one of the binary signals in the first group changes, this control program includes a binary signal combination at a position adjacent to the binary signal combination after the change. It is preferable to include a process of determining whether or not the range is a combination and performing a failure diagnosis of the range position detection switch (claim 13).

  Hereinafter, examples embodying the best mode for carrying out the present invention will be described. First, the configuration of the entire system will be described with reference to FIG.

  The automatic transmission according to the present embodiment is switched to four range positions including a parking range (P), a reverse range (R), a neutral range (N), and a drive range (D) by operating the shift lever 11. A range position detection switch 12 is provided in the vicinity of the shift lever 11 of the automatic transmission, and a sliding lever 13 of the range position detection switch 12 is connected to the shift lever 11 via a link 10. Thereby, the sliding lever 13 slides in conjunction with the operation of the shift lever 11.

  The range position detection switch 12 of the present embodiment is composed of four switch bodies S1 to S4 (binary signal generating means), and these four switch bodies S1 to S4 are provided on the sliding lever 13 4. Each of the sliders 15 and a conductor 16 arranged in a pattern to be described later on the insulator 14, and the slider 15 is integrally formed on the insulator 14 by operating the shift lever 11. The slider 15 comes into contact with the conductor 16 at a predetermined position. The sliders 15 of the four switch bodies S1 to S4 are connected to the four input ports of the control unit 17 by signal lines Ls1 to Ls4, respectively, and each conductor 16 is connected to the GND of the control unit 17 by the GND wiring Lgnd. Connected to the terminal.

  The control unit 17 includes a CPU, a ROM, a RAM, an input / output interface circuit, and the like. The signal value when the slider 15 comes into contact with the conductor 16 becomes logic 1 (hereinafter simply referred to as “1”), and the control unit 17 is slid. Signal processing is performed by the input interface circuit so that the signal value when the moving element 15 is not in contact with the conductor 16 becomes logic 0 (hereinafter simply referred to as “0”). The control unit 17 reads the output signal of the range position detection switch 12, determines the operation position of the shift lever 11 by a method described later, and performs failure diagnosis of the range position detection switch 12.

  Next, the configuration of the range position detection switch 12 will be described in detail with reference to FIGS. Since the automatic transmission of this embodiment is configured to sequentially switch to the four range positions of the P range, R range, N range, and D range by operating the shift lever 11, the position to be detected by the range position detection switch 12 Are four range positions of P range, R range, N range and D range, PR range (intermediate state position between P range and R range), RN range (R range and N range) Intermediate state position) and ND range (intermediate state position between N range and D range), and therefore, the range position detection switch 12 detects seven positions. There is a need.

  Therefore, in this embodiment, these seven positions are expressed by a 3-bit code, and for this purpose, the four switch bodies S1 to S4 of the range position detection switch 12 are composed of three switch bodies S1 to S3. A combination of binary signals ("0", "1") output from the three switch bodies S1 to S3 of the first group, divided into a first group and a second group consisting of one switch body S4 Thus, a 3-bit code expressing the seven positions is configured.

In the 3-bit code, 2 ³ = 8 patterns can be expressed, but since there are 7 positions to be detected by the combination of the output signals of the three switch bodies S1 to S3 of the first group, 8 of the 3-bit code One pattern is not used. In this embodiment, in order to enable disconnection detection, a pattern in which the signal values of the three switch bodies S1 to S3 are all inactive signal values “0” is not used, and the other seven patterns are used. Shall be used. As a result, the active signal “1” is output from at least one switch body at any of the range positions and the intermediate state positions. Thereby, disconnection detection becomes possible.

  In addition, when only one switch body failure (disconnection or short circuit) occurs, the four range position patterns of P range, R range, N range, and D range match the patterns of other range positions. In order not to erroneously determine the position, the pattern of the seven positions is composed of a gray code. Specifically, the three switch bodies S1 to S3 are configured such that only the signal value of one switch body is switched between two adjacent positions at four range positions and three intermediate state positions.

  In this case, there are 3 patterns in which only 1 bit is “1”, 3 patterns in which 2 bits are “1”, and 1 pattern in which all 3 bits are “1”. Will be assigned to one position. Due to the restrictions of the Gray code, a pattern in which 2 bits are all “1” is assigned to the three intermediate state positions. Therefore, three patterns in which only 1 bit is “1” and one pattern in which all 3 bits are “1” are assigned to the four range positions of P range, R range, N range, and D range. . In this case, if a pattern in which all 3 bits are “1” is assigned to the P range or the N range, a failure can be detected only at an intermediate position when the switch bodies S1 to S3 are short-circuited, and the number of patterns that can be detected is reduced. To do.

If a pattern in which all three bits are “1” is assigned to the R range, it is inevitable that the ND range is erroneously determined as the R range and the backup lamp is erroneously lit.
From these viewpoints, a pattern in which all three bits are “1” is optimally assigned to the R range.

  On the other hand, the switch body S4 of the second group detects the P range and the N range, which are range positions permitting engine start, and a signal different from the other positions is output only by the P range and the N range. It is comprised so that. In the present embodiment, as shown in FIG. 3A, the signal value of the second group of switch bodies S4 is “1” only in the P range and the N range, and the signal value is “0” in other positions. It goes without saying that the logic may be the opposite of this.

  With the method as described above, the signal values of the four switch bodies S1 to S4 are assigned to the seven positions to be detected by the range position detection switch 12, as shown in FIG. As shown in FIG. 2, the conductor 16 of each switch body S1-S4 is comprised so that the slider 15 may be contacted in the position allocated to "1".

  As shown in FIG. 3A, a 3-bit code expressed by a combination of output signals from the three switch bodies S1 to S3 of the first group has a P range of “100” and a PR range when normal. Is “110”, the R range is “010”, the RN range is “011”, the N range is “001”, the ND range is “101”, and the D range is “111”.

  Next, a code pattern when the range position detection switch 12 fails will be examined with reference to FIGS. The failure will be considered when any one of the four switch bodies S1 to S4 is disconnected or short-circuited. In FIG. 3 and FIG. 4, the “discrimination” column at the bottom indicates the discrimination results based on the signal values of the first group of switch bodies S1 to S3, and “X” represents the signal of the first group of switch bodies S1 to S3. The value represents a pattern in which all values are “0”, the subscript (S) represents that engine start is permitted, that is, the signal value of the switch body S4 is “1”, and the subscript (I) is engine start prohibited, that is, the switch body. It represents that the signal value of S4 is “0”.

[When switch body S1 is disconnected]
As shown in FIG. 3B, when the switch body S1 of the first group is disconnected, the signal value of the switch body S1 becomes “0” at all positions.

  As a result, in the P range, the signal value of the switch body S1 to S3 of the first group is “000”, but the signal value of the switch body S4 of the second group is “1”. The In this case, since the signal value of the switch body S4 is “1”, the engine start is permitted.

In the PR range, since the signal values of the first group of switch bodies S1 to S3 are “010”, it is erroneously determined as “R range” (a failure detection method in this case will be described later).
In the ND range, the signal value of the switch body S1 to S3 of the first group is “001”, which is the same as that of the N range, but the signal value of the switch body S4 of the second group is “0”. Is determined, and engine start is prohibited.
In the D range, since the signal value of the first group of switch bodies S1 to S3 is “011”, it is erroneously determined as the “RN range”.

[When switch body S2 is disconnected]
As shown in FIG. 3C, when the switch body S2 of the first group is disconnected, the signal value of the switch body S2 becomes “0” at all positions.

  As a result, in the PR range, the signal values of the first group of switch bodies S1 to S3 are “100”, which is the same as that of the P range, but the signal value of the second group of switch bodies S4 is “0”. Therefore, it is determined that there is a failure, and engine start is prohibited.

  In the R range, the signal value of the switch body S1 to S3 of the first group is “000”, and the signal value of the switch body S4 of the second group is also “0”. Is prohibited.

In the RN range, the signal values of the first group of switch bodies S1 to S3 are “001”, which is the same as that of the N range, but the signal value of the second group of switch bodies S4 is “0”, so that the failure occurs. Is determined, and engine start is prohibited.
In the D range, since the signal values of the switch bodies S1 to S3 are “101”, it is erroneously determined as “ND range”.

[When switch body S3 is disconnected]
As shown in FIG. 3D, when the switch body S3 of the first group is disconnected, the signal value of the switch body S3 becomes “0” at all positions.

As a result, in the RN range, since the signal values of the first group of switch bodies S1 to S3 are “010”, it is erroneously determined as “R range”.
In the N range, the signal value of the first group of switch bodies S1 to S3 is “000”, but since the signal value of the second group of switch bodies S4 is “1”, it is determined to be a failure. In this case, since the signal value of the switch body S4 is “1”, the engine start is permitted.

In the ND range, the signal value of the switch body S1 to S3 of the first group is “100” which is the same as that of the P range, but the signal value of the switch body S4 of the second group is “0”. Is determined, and engine start is prohibited.
In the D range, since the signal value of the switch bodies S1 to S3 is “110”, it is erroneously determined as the “PR range”.

[When switch body S4 is disconnected]
As shown in FIG. 3E, when the switch body S4 of the second group is disconnected, the signal value of the switch body S4 becomes “0” at all positions. In this case, since the switch bodies S1 to S3 of the first group are normal, all positions can be correctly determined based on their signal values. However, even if it is determined as “P range” or “N range”, the signal value of the switch body S4 does not become “1” at the range position, so that engine start is prohibited and a failure (switch body S4 is disconnected). ).

[When switch body S1 is short-circuited]
As shown in FIG. 4B, when the first group of switch bodies S1 is short-circuited, the signal value of the switch body S1 becomes “1” at all positions.

As a result, in the R range, since the signal value of the first group of switch bodies S1 to S3 is “110”, it is erroneously determined as “PR range”.
In the RN range, since the signal value of the first group of switch bodies S1 to S3 is “111”, it is erroneously determined as the “D range” (a failure detection method in this case will be described later).

  In the N range, the signal value of the first group of switch bodies S1 to S3 is “101”, which is the same as that of the ND range. However, since the signal value of the second group of switch bodies S4 is “1”, a failure occurs. It is determined that the engine starts.

[When switch body S2 is short-circuited]
As shown in FIG. 4C, when the first group of switch bodies S2 is short-circuited, the signal value of the switch body S2 becomes “1” at all positions.

  As a result, in the P range, since the signal value of the first group of switch bodies S1 to S3 is “110”, the signal value of the second group of switch bodies S4 is erroneously determined as “PR range”. Is “1”, it is determined that there is a failure, and the engine start is permitted.

In the N range, since the signal values of the first group of switch bodies S1 to S3 are “011”, it is erroneously determined as “RN range”, but the signal value of the second group of switch bodies S4 is “1”. Therefore, it is determined that there is a failure and the engine start is permitted.
In the ND range, since the signal value of the first group of switch bodies S1 to S3 is “111”, it is erroneously determined as “D range”.

[When switch body S3 is short-circuited]
As shown in FIG. 4D, when the switch body S3 of the first group is short-circuited, the signal value of the switch body S3 becomes “1” at all positions.

  As a result, in the P range, since the signal value of the first group of switch bodies S1 to S3 is “101”, the signal value of the second group of switch bodies S4 is erroneously determined as “ND range”. Is “1”, it is determined that there is a failure, and the engine start is permitted.

In the PR range, since the signal value of the first group of switch bodies S1 to S3 is “111”, it is erroneously determined as the “D range”.
In the R range, since the signal values of the first group of switch bodies S1 to S3 are “011”, it is erroneously determined as the “RN range”.

[When switch body S4 is short-circuited]
As shown in FIG. 4 (e), when the switch body S4 of the second group is short-circuited, the signal value of the switch body S4 becomes “1” at all positions. In this case, since the switch bodies S1 to S3 of the first group are normal, all positions can be correctly determined based on their signal values. However, since the signal value of the switch body S4 is “1” even at positions other than “P range” and “N range”, engine start is permitted, but at those positions, a failure (short circuit of the switch body S4) occurs. Determined.

  As described above, erroneous determination may not be avoided only by a combination of the signal values of the four switch bodies S1 to S4. Therefore, in this embodiment, every time the signal value of any of the first group of switch bodies S1 to S3 changes, the combination of the signal values after the change (detected position after the change) is the combination of the signal values before the change. It is determined whether or not it is a combination of signal values at adjacent positions (detected position before change), and if it is not a combination of signal values at adjacent positions, it is determined as a failure.

  For example, when the switch body S1 shown in FIG. 3B is disconnected, the range determination result is “X (unknown)” → “R range in the process of operating the shift lever 11 from P range → PR range → R range. ”And the detection position jump (miss) occurs that jumps over the PR range. A failure can be detected by detecting this phenomenon.

  By the way, when the signal value of the switch bodies S1 to S3 of the first group is configured to be read by the control unit 17 at a constant sampling period, the switch bodies S1 to S3 are increased when the operation speed of the driver's shift lever 11 is increased. There is a possibility that the signal value change interval becomes shorter than the signal value sampling interval, whereby the signal value may be missed and the detection position may be skipped.

  Therefore, in this embodiment, every time the signal value of any one of the switch bodies S1 to S3 of the first group changes, the signal value of the switch bodies S1 to S3 of the first group is read by the control unit 17 by interrupt processing. I am doing so. As a result, even when the operation speed of the driver's shift lever 11 is high, all signal values that change due to the operation of the shift lever 11 can be read in the order of operation, and the detection position skips (misses). It can be surely prevented.

  On the other hand, the signal value of the switch body S4 of the second group is “1” only in the P range and the N range that allow the engine start, and “0” in other positions. Even when the operation speed is high, the signal value does not change so fast that the signal value of the switch body S4 is missed. Therefore, in this embodiment, the signal value of the switch body S4 of the second group is read by the control unit 17 at a predetermined sampling period (for example, 10 msec period).

  The range position determination / failure diagnosis of the present embodiment described above is executed by each program shown in FIGS. In the following description, the signal value of the switch body S1 is represented as “S1”, the signal value of the switch body S2 is represented as “S2”, the signal value of the switch body S3 is represented as “S3”, and the switch body S4. Is expressed as “S4”.

  When the control unit 17 is powered on by turning on the ignition switch, the control unit 17 starts the main routine of FIG. When this routine is started, first, in step 101, a predetermined initialization process is executed to reset each flag, stored value, and the like, which will be described later, to an initial value. The previous storage value SS40 and the current storage value SS4 of the signal value are updated. Specifically, the current storage value SS4 at the time of the previous processing is stored as the previous storage value SS40, and the signal value “S4” read this time is stored as the current storage value SS4.

  Thereafter, the process proceeds to step 103, where it is determined whether or not the current stored value SS4 matches the previous stored value SS40. If not, the process proceeds to step 104, and the S4 signal change flag Flag is set to the signal value “S4”. Is set to “1” which means that there is a change, and the process proceeds to step 109 and waits until, for example, 10 msec which is the sampling period of the signal value “S4” elapses. Thereafter, when 10 msec elapses, the process returns to step 102, the signal value “S4” is read, and the previous storage value SS40 and the current storage value SS4 are updated. Thereafter, the process proceeds to step 103, where it is determined whether or not the current stored value SS4 matches the previous stored value SS40. If they match, the process proceeds to step 105, where the S4 signal change flag Flag has the signal value “S4”. It is determined whether or not it is set to “1” which means that there is a change. Only when it is determined “Yes”, the process proceeds to step 106, the previous stored value SS40 is set to the S4 signal detection value FS4, and the next In step 107, the S4 signal change flag Flag is reset to “0”, and the process proceeds to step. If “No” is determined in step 105, the process skips step 106 and step 107 and proceeds to step 108.

  In short, the process of steps 102 to 107 is repeated at the sampling period (for example, 10 msec) of the signal value “S4”, so that the S4 signal detection value FS4 is updated every time a change in the signal value “S4” is detected.

  Then, except when the signal value “S4” changes, the range position determination routine of FIG. 7 described later is executed at the sampling period (for example, 10 msec) of the signal value “S4” to perform range position determination / failure diagnosis. Is called.

  The interrupt processing routine of FIG. 6 is started each time the signal value of any of the first group of switch bodies S1 to S3 changes. When this routine is started, first, in step 201, the signal values of the first group of switch bodies S1 to S3 are read, and the previous storage value SS13 and the current storage value SS130 of the 3-bit code formed by the signal values are updated. . Specifically, the current storage value SS13 at the time of the previous processing is stored as the previous storage value SS130, and the 3-bit code “S13” read this time is stored as the current storage value SS13.

  Thereafter, the process proceeds to step 202, where the current stored value SS13 (detected position after change) and the previous stored value SS130 (detected position before change) are compared to determine whether or not they are adjacent transitions. As a result, if it is determined that the transitions are not adjacent to each other, the process proceeds to step 203, the failure determination flag FlagS is set to “1” indicating that there is a failure, and this routine is terminated.

  On the other hand, if it is determined in step 202 that the current storage value SS13 and the previous storage value SS130 are adjacent transitions, the process proceeds to step 204, where the current storage value SS13 is set as the code detection value FS13. Thereafter, the process proceeds to step 205, where the failure determination flag FlagS is maintained or reset to “0” meaning normal (no failure), and this routine is terminated.

  The range position determination routine of FIG. 7 is executed at the sampling period (eg, 10 msec) of the signal value “S4” except when the signal value “S4” changes in step 108 of the main routine of FIG. When this routine is started, first, in step 301, it is determined whether or not the failure determination flag FlagS is set to “0” which means normal (no failure), and the failure determination flag FlagS means that there is a failure. If it is set to “1”, the process proceeds to step 308, it is determined that there is a failure, and this routine is terminated.

  On the other hand, if the failure determination flag FlagS is set to “0” meaning normal (no failure), the process proceeds to step 302, and the S4 signal detection value FS4 is “1” meaning the P range or the N range. If “Yes” is determined, the process proceeds to step 303 to determine whether or not the code detection value FS13 is “100” meaning the P range. As a result, if it is determined that the code detection value FS13 is “100” meaning the P range, the process proceeds to step 304, where the current range position is determined to be the P range, and this routine is terminated.

  If it is determined in step 302 that the S4 signal detection value FS4 is not “1” meaning the P range or the N range, the process proceeds to step 305, where the code detection value FS13 is “100” meaning the P range. It is determined whether or not it is “001” meaning the N range. If “Yes” is determined in step 305, the process proceeds to step 308, where it is determined that there is a failure, and this routine is terminated. In short, although it is determined from the S4 signal detection value FS4 that it is neither the P range nor the N range, the code detection value FS13 is determined to be the P range or the N range, and the determinations of both are contradictory. Therefore, it is determined as a failure.

  If “No” is determined in step 305, the S4 signal detection value FS4 and the code detection value FS13 are consistent with each other, so the process proceeds to step 309, and the range position or the intermediate state position is determined based on the code detection value FS13. . Specifically, if the code detection value FS13 is “110”, it is determined as the PR range, if “010”, it is determined as the R range, and if “011”, it is determined as the RN range. If it is “101”, it is determined as the ND range, and if it is “111”, it is determined as the D range.

  If it is determined in step 303 that the code detection value FS13 is not “100” indicating the P range, the process proceeds to step 306 to determine whether the code detection value FS13 is “001” indicating the N range. If “Yes” is determined, the process proceeds to step 307, where it is determined that the current range position is the N range, and this routine is terminated.

  On the other hand, if “No” is determined in step 306, that is, the P4 range or the N range is determined from the S4 signal detection value FS 4, the P detection range is determined from the code detection value FS 13. Alternatively, if it is determined that neither of the N ranges is satisfied, the determinations of the two contradict each other, so that the process proceeds to step 308, where it is determined that there is a failure, and this routine is terminated.

  In the present embodiment described above, the four switch bodies S1 to S4 of the range position detection switch 12 are divided into a first group composed of three switch bodies S1 to S3 and a second group composed of one switch body S4. A three-bit code expressing the seven positions is configured by a combination of binary signals (“0”, “1”) output from the three switch bodies S1 to S3 of the first group, The switch body S4 of the second group is configured so that a signal different from the other positions is output only in the P range and the N range that allow the engine start, so that the operation position of the shift lever 11 is more accurate than before. This makes it possible to make a good determination and detect more failures than in the past.

  In addition, in the present embodiment, the three switch bodies S1 to S3 of the first group switch only the signal value of one switch body between two adjacent positions at the four range positions and the three intermediate state positions. When a single switch failure (disconnection / short circuit) occurs, the four range position patterns of P range, R range, N range, and D range become patterns of other range positions. And an erroneous determination of the range position can be prevented.

  Further, in this embodiment, the active signal “1” is output from at least one switch body at any of the range positions and the intermediate state position, so it is determined that there is a failure upon disconnection. be able to.

  In addition, since the pattern in which all 3 bits are “1” is assigned to the R range, it is possible to increase the number of patterns that can be detected in failure, and to make a backup by misjudging the ND range as the R range. It is possible to prevent the lamp from being turned on erroneously.

  In this embodiment, every time the signal value of any of the first group of switch bodies S1 to S3 changes, the control unit 17 is caused to read the signal value of the first group of switch bodies S1 to S3 by interrupt processing. As a result, even when the operation speed of the driver's shift lever 11 is high, all signal values that change due to the operation of the shift lever 11 can be read in the order of operation, and detection position skips (misses) occur. This can be surely prevented.

  The automatic transmission of this embodiment can be switched to four range positions of P range, R range, N range, and D range by operating the shift lever 11, but the switchable range position is 5 When the present invention is applied to two or more automatic transmissions, the number of switch bodies is increased to 5, for example, a first group including four switch bodies and a second group including one switch body. The 4-bit code may be configured by dividing into groups and combining binary signals (“0”, “1”) output from the four switch bodies of the first group. Further, the second group may be composed of a plurality of switch bodies. In this case, in the second group, the P range and the N range may be detected separately, or other range positions may be detected.

  Further, in this embodiment, the switch bodies S1 to S4 (binary signal generating means) of the range position detection switch 12 are configured by contact type switches, but may be configured by non-contact type switches (sensors). As the non-contact type switch (sensor), for example, a magnetic sensor such as a Hall element or an optical sensor may be used. Specifically, a magnetic sensor is attached to the sliding lever 13 instead of the slider 15, a magnetic material is provided instead of the conductor 16, and the magnetic moves integrally with the sliding lever 13 by operating the shift lever 11. A configuration may be adopted in which the output of the magnetic sensor changes when the sensor faces the magnetic body. Alternatively, an optical sensor is attached to the sliding lever 13 instead of the slider 15 and a slit or the like is provided instead of the conductor 16 so that the optical sensor moves integrally with the sliding lever 13 by operating the shift lever 11. A configuration in which the output of the optical sensor changes when facing a slit or the like may be adopted. If a non-contact type switch (sensor) is used, there is an advantage that the durability of the range position detection switch 12 can be improved.

It is a schematic block diagram of the range position detection apparatus of the automatic transmission which shows one Example of this invention. It is a figure which shows the arrangement pattern of the conductor of each switch body S1-S4 of a range position detection switch. (A) is a figure explaining the relationship between each range position at the time of normal and the signal value of switch body S1-S4, (b) is each range position at the time of disconnection of switch body S1, and the signal value of switch body S1-S4 (C) is a diagram for explaining the relationship between each range position when the switch body S2 is disconnected and the signal values of the switch bodies S1 to S4, and (d) is a diagram when the switch body S3 is disconnected. The figure explaining the relationship between each range position and the signal value of switch body S1-S4, (e) is the figure explaining the relationship between each range position at the time of disconnection of switch body S4, and the signal value of switch body S1-S4. It is. (A) is a figure explaining the relationship between each range position at the time of normal and the signal value of switch body S1-S4, (b) is each range position at the time of short circuit of switch body S1, and the signal value of switch body S1-S4 (C) is a diagram illustrating the relationship between each range position when the switch body S2 is short-circuited and the signal values of the switch bodies S1 to S4, and (d) is a diagram when the switch body S3 is short-circuited. The figure explaining the relationship between each range position and the signal value of switch body S1-S4, (e) is the figure explaining the relationship between each range position at the time of short circuit of switch body S4, and the signal value of switch body S1-S4. It is. It is a flowchart which shows the flow of a process of a main routine. It is a flowchart which shows the flow of a process of an interruption process routine. It is a flowchart which shows the flow of a process of a range position determination routine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Link, 11 ... Shift lever, 12 ... Range position detection switch, 13 ... Sliding lever, 14 ... Insulator, 15 ... Slider, 16 ... Conductor, 17 ... Control part, S1-S4 ... Switch body (2 Value signal generation means)

Claims (13)

A range position detection switch for outputting a plurality of binary signals by switching the state of the plurality of binary signal generating means in a pattern set for each binary signal generating means in accordance with the operation position of the shift lever of the automatic transmission; ,
A range position detection device for an automatic transmission comprising: a control unit that reads the plurality of binary signals output from the range position detection switch and determines an operation position of the shift lever;
The range position detection switch divides the plurality of binary signal generating means into two groups and expresses information on the operation position of the shift lever for each group by a binary signal of each group,
The control unit performs determination of the operation position of the shift lever and / or failure diagnosis of the range position detection switch based on a combination of binary signals of the two groups of the range position detection switch. Range position detector for automatic transmission.   The combination of binary signals of at least one group of the range position detection switch can identify at least the parking position, reverse range, neutral range, and drive range as the operation position of the shift lever and the intermediate state position thereof. The range position detecting device for an automatic transmission according to claim 1, wherein   The binary signal generating means of at least one group of the range position detecting switch is configured such that only one binary signal generating means is switched between two adjacent positions at each range position and its intermediate state position. The range position detecting device for an automatic transmission according to claim 2, wherein the range position detecting device is used.   The binary signal generation means of at least one group of the range position detection switch outputs an active signal from at least one binary signal generation means at any of the range positions and intermediate state positions. The range position detecting device for an automatic transmission according to claim 2, wherein the range position detecting device is configured as described above.   5. The binary signal generation means of at least one group of the range position detection switch is configured so that all signals are switched to active signals in the drive range. A range position detecting device for an automatic transmission according to claim 1. The combination of binary signals of one group of the range position detection switches (hereinafter referred to as “first group”) includes at least each of the range positions of the parking range, reverse range, neutral range, and drive range as the operation position of the shift lever. The binary signal generating means of the other group (hereinafter referred to as “second group”) is set so as to be able to identify the intermediate state position, and the signal different from the other positions only in the parking range and the neutral range. Configured to output,
The control unit determines an operation position of the shift lever based on a combination of binary signals of the first group, and based on a result of the determination and a binary signal of the second group, the range position detection switch 6. A range position detecting device for an automatic transmission according to claim 1, wherein failure diagnosis is performed.   The first group of the range position detection switches is constituted by three binary signal generating means, and an active signal is output from the two binary signal generating means at the intermediate state position. The range position detecting device for an automatic transmission according to claim 6.   The control unit reads the binary signal of the first group by an interrupt process every time one of the binary signals of the first group changes, and reads the binary signal of the second group at a predetermined sampling period. The range position detecting device for an automatic transmission according to claim 6 or 7.   Whenever one of the binary signals of the first group changes, the control unit is a combination of binary signals at positions adjacent to the combination of binary signals after the change. 9. The range position detection device for an automatic transmission according to claim 1, further comprising a function of determining whether or not there is a failure diagnosis of the range position detection switch. Range of automatic transmission having range position detection switch for switching states of binary signal generating means of two groups in a pattern set for each binary signal generating means according to the operation position of shift lever of automatic transmission A control program for controlling a position detection device,
A process of reading the binary signal output from the binary signal generating means of the two groups as information on the operation position of the shift lever for each group;
A control program comprising: a process of determining an operation position of the shift lever and / or a failure diagnosis of the range position detection switch based on a combination of binary signals of the two groups. The combination of binary signals of one group of the range position detection switches (hereinafter referred to as “first group”) includes at least each of the range positions of the parking range, reverse range, neutral range, and drive range as the operation position of the shift lever. The binary signal generating means of the other group (hereinafter referred to as “second group”) is set so as to be able to identify the intermediate state position, and the signal different from the other positions only in the parking range and the neutral range. Configured to output,
A process of determining an operation position of the shift lever based on a combination of binary signals of the first group;
The control program according to claim 10, further comprising: a process of performing a failure diagnosis of the range position detection switch based on a determination result of an operation position of the shift lever and a binary signal of the second group. An interrupt process for reading the binary signal of the first group each time one of the binary signals of the first group changes;
The control program according to claim 11, further comprising a time synchronization process of reading the second group of binary signals at a predetermined sampling period.   Whether each combination of binary signals in the first group changes is a combination of binary signals after the change is a combination of binary signals at positions adjacent to the combination of binary signals before the change The control program according to claim 11, further comprising a process of determining and diagnosing a failure of the range position detection switch.

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