JPH0258500B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for an automatic transmission, and particularly to control when changing gears of an auxiliary transmission.

BACKGROUND ART In order to improve driving performance, there is an automatic transmission that is equipped with an auxiliary transmission that can be manually switched between a high gear and a low gear. In such automatic transmissions, there is no auxiliary transmission, and in order to reduce the number of changes to the automatic transmission and make it advantageous in manufacturing, the auxiliary transmission has the output of the main transmission that can automatically change gears. It is often placed on the side. In this case, even though the driver switched the operation position of the sub-transmission from a high gear position (high gear) to a low gear position (low gear) in order to increase the drive torque, the main transmission The main transmission may be upshifted due to the increase in the output shaft rotational speed, and the driving force intended by the driver may not be obtained. vice versa,
Even though the driver switched the operating position of the auxiliary transmission from the low gear position to the high gear position, the main transmission was downshifted due to a decrease in the output shaft rotation speed of the main transmission due to this switching. As a result, the engine rotational speed does not decrease, which may cause discomfort and shift shock. In particular, even when an auxiliary transmission is added, the vehicle speed sensor detects the rotation speed of the output shaft of the main transmission, and therefore the rotation speed of the input shaft of the auxiliary transmission. Since the rotational speed of the output shaft of the main transmission is significantly increased and decreased by switching and switching to a high gear, respectively, the main transmission is likely to shift in the direction intended by the driver.

In the transmission disclosed in Japanese Patent Publication No. 56-73251, a manual transmission and an automatic transmission are connected in series, and when the manual transmission is in a low gear, that is, when the torque fluctuation of the engine is large, Automatic transmissions are prohibited from changing gears to avoid excessive gear shock. Furthermore, in the transmission disclosed in Japanese Patent Publication No. 56-73252, a manual transmission and an automatic transmission are similarly connected in series, and downshifting of the automatic transmission is prohibited when the engine speed is above a predetermined value. , which prevents engine overruns. However, neither publication mentions special control of the gear position of the automatic transmission when the gear position of the manual transmission is manually changed.

Purpose of the Invention It is an object of the present invention to provide an automatic transmission in which a sub-transmission capable of manually switching gears is provided on the output side of the main transmission. An object of the present invention is to provide a control device that prevents inappropriate gear shifting.

Means for achieving the object In order to achieve this object, the invention provides a main transmission that can be automatically switched into a plurality of gears;
an auxiliary transmission connected to the output side of the main transmission and capable of manually switching between a high speed gear and a low gear; A control device for an automatic transmission configured to change the gear position of an auxiliary transmission, comprising: a shift detection means for detecting that an operating position for determining a gear position of an auxiliary transmission has been switched from a high gear position to a low gear position; A limiting means is provided for limiting upshifting of the main transmission based on a signal output from the means.

Further, in the present invention, the limiting means is configured to hold the gear of the main transmission immediately before the operating position changes from the high gear position to the low gear position; It can be configured to prohibit upshifting to a gear position two or more higher speeds than the gear position of the main transmission, or to maintain the main transmission at the lowest gear position that can avoid engine overrun. .

Functions and Effects of the Invention When the driver switches the operating position from the high gear position to the low gear position, the auxiliary transmission switches from the high gear to the low gear, and this causes the vehicle speed sensor attached to the output shaft of the main transmission to Although the detected vehicle speed increases, the limiting means restricts upshifting of the main transmission despite the increase in vehicle speed, thereby preventing the main transmission from shifting against the intention of the driver.
Appropriate driving torque can be obtained.

If the vehicle speed sensor is located on the output shaft of the auxiliary transmission, it is necessary to provide separate shift patterns for H and L, but even in such a case, the manual When the shift pattern of the transmission is adopted, skip shifting of two or more gears occurs.

The limiting means maintains the gear position of the main transmission immediately before the operation position is changed, or changes the gear position from the previous gear position.
It is preferable to prohibit shifting to a gear position that is more than one gear position apart. If an upshift of two or more gears to the high speed side is prevented and an upshift of only one gear is allowed, it is possible to prevent engine overrun and appropriately suppress a decrease in drive torque.

The limiting means for limiting upshifting of the main transmission may maintain the main transmission at the lowest gear position at which engine overrun can be avoided.

Example The present invention will be described with reference to the embodiments shown in the drawings.

FIG. 1 shows an automatic transmission and its control device, including an engine 10, a fluid torque converter 12,
A main transmission 14 and a sub-transmission 16 are provided in series in a power transmission path of the engine. The lock-up clutch 18 is provided in parallel with the fluid torque converter 12, and the main transmission 14 has first to fourth gears that are automatically switched depending on vehicle speed and throttle opening, and a sub-shift. Machine 16
has a high speed gear and a low gear that can be switched by manual operation. The shift position sensor 20 detects a shift position such as D (drive), N (neutral), or R (reverse) range selected by the driver, and the L/H position sensor 22 detects a shift position selected by the driver. The L (low gear) and H (high gear) of the auxiliary transmission 16 are detected, the throttle opening 24 detects the intake throttle opening, and the pattern select switch 26 detects the economy (economical driving) selected by the driver. The water temperature sensor 28 detects the cooling water temperature of the engine, the brake switch 30 detects the depression of the foot brake, and the vehicle speed sensor 32 detects the driving pattern such as power (acceleration driving).
detects the rotational speed of the output shaft 34 of the main transmission 14, and therefore the vehicle speed. The CPU 36 operates the solenoid valves 42, 44 of the main transmission control hydraulic circuit 38 and the sub-transmission control hydraulic circuit 40 based on input signals from these sensors and switches.
Solenoid valves 42, 4 that control 46, 48
4 is used to control the first to fourth speeds of the main transmission 14, the solenoid valve 46 is used to control the lock-up clutch 18, and the solenoid valve 48 is used to control the high speed and high speed of the auxiliary transmission 16. It is used to control the low speed gear.

FIG. 2 is a flowchart of a shift control routine when the operating position of the sub-transmission 16 is switched from H (high gear) to L (low gear). As soon as the ignition switch is turned on (step
60), graph F showing the change from H→L is assigned 0 as an initial value (step 62). In the main routine of step 64, the gear position of the main transmission 14 is calculated as the commanded gear position based on the intake throttle opening θ, the vehicle speed V, and the like. If there is no change from H→L, it is determined in step 66 that F=0, and H→L is determined to be N0 in step 70, so that the indicated gear position calculated in step 64 is not corrected and the shift is continued. 86 is executed,
The main transmission 14 is set to that gear.

When there is a change from H to L, the indicated gear position calculated in step 64 before the change from H to L is substituted into M1 (step 68), flag F is set (step 72), and the main shift in step 64 is again set. In the routine, the commanded gear position is calculated. The indicated gear position calculated after the change from H to L is assigned to M2 (step 74), and the indicated gear position M2 after the change from H to L is changed from H to L.
If the gear position is lower than or equal to the commanded gear M1 before the change (M2M1 in step 76), that is, the main transmission 1
If an instruction to downshift 4 is issued, the instructed gear is set to M2 (step 82), flag F is reset (step 84), and step 86 is executed. However, if an instruction to upshift the main transmission 14 is issued even after the change from H to L (M2>M1 in step 76), the commanded gear is set to M1, which is the gear before the change from H to L, and step 86 is performed. is executed. The instructed gear position=M1 is held until the upshift permission condition is satisfied (YES in step 80). The upshift permission conditions include, for example, that the driver has switched the operating position of the auxiliary transmission 16 from L to H, vehicle speed = 0 km/h,
and a sudden decrease in intake throttle opening.

FIG. 3 shows a partially modified version of the routine shown in FIG. When there is a change from H to L, upshifting of the main transmission 14 to a higher gear by two or more gears than the gear before the change from H to L is prohibited. Since an upshift of only one gear is allowed, engine overrun can be appropriately suppressed. That is, in step 76b, M2 and M1+1 are compared, and M2
>M1+1, M1+1 in step 78b
However, if M2M1+1, M2 is assigned to the instructed gear in step 82.

FIG. 4 shows another embodiment of the shift routine when changing from H to L. When flag F is set in step 72c, the program proceeds to step 66 without recalculating the designated gear position in step 64. When there is a change from H to L, upshifting of the main transmission is prohibited until the upshift permission condition for the main transmission 14 is satisfied (YES in step 80), but if engine overrun is unavoidable,
Allows upshifts to the lowest gear where overrun can be avoided. That is, read the rotational speed Nout of the output shaft 34 of the main transmission 14 (step
94), coefficient related to the gear ratio corresponding to the indicated gear position
Ki is calculated (steps 92, 96), the engine rotational speed Ne occurring at the indicated gear is calculated (step 98), and if Ne is greater than or equal to the overrun rotational speed Nc (NeNc at step 100), the engine rotational speed Ne occurring at the indicated gear is calculated (step 98). with only one gear on the high speed side (step
102), find the lowest gear position where Ne<Nc. The gear position corresponding to the gear position determined in this way is set as the designated gear position (step 104), and the routine of step 86 is executed.

Although the present invention has been described with reference to embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit of the invention.

[Brief explanation of the drawing]

Fig. 1 is an overall view of the automatic transmission and its control device, and Figs. 2, 3, and 4 show various speed changes of the main transmission when the operating position of the sub-transmission is changed from H to L. 3 is a flowchart of a control routine. 14...Main transmission, 16...Sub-transmission, 22...
...L/H position sensor, 32...Vehicle speed sensor, 36...CPU.

Claims (1)

[Scope of Claims] 1. A main transmission that can automatically change to a plurality of gears, and a sub-transmission that is connected to the output side of the main transmission and that can be manually switched between high and low gears. In a control device for an automatic transmission configured to change the gear position of the main transmission in relation to the vehicle speed based on the rotational speed of the output shaft of the main transmission, the operating position that determines the gear position of the sub-transmission is at high speed. The main transmission is characterized by comprising a shift detection means for detecting a shift from a gear position to a low gear position, and a restriction means for limiting upshifting of the main transmission based on a signal output from the shift detection means. automatic transmission control device. 2. The automatic transmission according to claim 1, wherein the limiting means is a means for holding the gear position of the main transmission immediately before the operation position is changed from the high gear position to the low gear position. Control device. 3. The limiting means is configured to move the gear position of the main transmission from the gear position immediately before the operating position changes from the high gear position to the low gear position.
2. The control device for an automatic transmission according to claim 1, further comprising means for inhibiting upshifting to a higher speed gear. 4. The control device for an automatic transmission according to claim 1, wherein the limiting means maintains the main transmission at the lowest gear position at which engine overrun can be avoided.