JP2829775B2 - Electronically controlled automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to an electronically controlled automatic transmission that automatically switches the transmission (T / M) gear ratio. In the electronically controlled automatic transmission that transmits the rotation of the transmission to the transmission via the torque converter and automatically determines the transmission gear ratio from the relationship between the vehicle speed and the throttle opening, means for detecting the drive state of the transmission, Means for detecting that the throttle is off, and when the transmission is in a driving state when the throttle is off and an upshift is required,
Means for extending the shift time until the transmission is in the reverse drive state.

[Industrial Application Field] The present invention relates to an electronically controlled automatic transmission that automatically switches a T / M speed ratio.

When automatically switching the gear ratio of T / M based on the relationship between the vehicle speed and the throttle opening, a large gear shift shock occurs if an upshift is performed at a stage where the engine generated torque is large, so it is desirable to reduce this. .

[Conventional technology]

The automatic transmission is equipped with a diagram for upshifts and downshifts, and the vehicle speed rises above the upshift line,
When the throttle opening falls below the upshift line, an upshift is performed. This upshift is from P1 to P2 in FIG.
If the operation is performed immediately due to the throttle-off (power-off) in which the throttle is suddenly returned, a large shift shock occurs because the generated torque of the engine is large.

In order to improve this point, there is a method of starting a delay timer when the throttle is off, prohibiting (postponing) the shift output within the set time of the timer, and waiting for a decrease in torque.

[Problems to be solved by the invention]

However, since the delay time is constant in the above-described delay timer method, there is a disadvantage that it cannot cope with variations in T / M characteristics, aging, and the like.

The present invention seeks to reduce the shift shock at the time of an upshift due to a throttle off by determining the optimal shift timing at which the torque has decreased from the state of T / M.

[Means for solving the problem]

FIG. 1 is a block diagram of the present invention, wherein 1 is an engine (E / G),
2 is a torque converter (hereinafter abbreviated as torque converter),
Reference numeral 3 denotes a transmission (T / M), and reference numeral 4 denotes a shift control device using a microcomputer.

[Action]

The shift control device 4 determines T / T based on the relationship between the vehicle speed and the throttle opening.
The change ratio of M3 is determined, and usually, a speed change output for setting the speed ratio of T / M3 is immediately transmitted. In general, the gear ratio is set stepwise so as to be a shift position such as the first to fourth gears. The torque converter 2 fluidly couples the output of the E / G1 and the input of the T / M3. However, in the type having a built-in lock-up (L / U) clutch, the transmission control device 4 controls the on / off of the clutch also at vehicle speed and throttle opening. Control from the relationship. in this case,
L / U on (direct connection) can realize an intermediate shift position of L / U off (fluid coupling), so upshift is 3rd speed L / U off → 3rd speed L / U on → 4th speed L / U off → In the order of 4-speed L / U ON.

When the rotational speed of the E / G1 is NE and the input rotational speed of the T / M3 is NI, NE = NI... (1) always holds when the L / U is on.

On the other hand, when L / U is off, if T / M3 is in the driving state to rotate the wheels, then NE> NI ... (2), and if T / M3 is in the reverse driving state to be rotated by the wheels, NE <NI ... (3) If the gear ratio of T / M3 is i (T / M) and the output rotational speed is NO, the following formula always holds.

NI = i (T / M) · NO (4) In the driving state of T / M3 described above, the torque generated by E / G1 is large. Therefore, if an upshift is performed at this time, a shift shock is large. On the other hand, in the reverse drive state of the T / M3, the generated torque of the E / G1 is reduced. Therefore, if the upshift is performed in this state, the shift shock can be reduced. However, if the shift timing is postponed too much, the torque is excessively reduced and the vehicle speed is reduced. Therefore, in the present invention, the time when the T / M3 changes from the driving state to the reverse driving state is defined as the shift timing.

At this time, when L / U is off, either of equations (2) and (3) holds, so that it is easy to determine.

On the other hand, when L / U is on, equation (1) holds, so that the state of T / M3 cannot be determined. However, when the NE decreases with the throttle off, control is performed to switch from L / U on to L / U off, so that the state of T / M3 can be determined at this point. For this reason, when L / U is on when the throttle is off, the following equations (2) 'and (3)' are used.

NE + α> NI (2) ′ NE + α <NI (3) ′ α is an offset of about 100 rpm, and if L / U is on, equation (1) holds, so equation (2) ′ holds. I do. On the other hand, when the NE decreases and the L / U turns off, the equation (3) 'is eventually established. Therefore, this point is defined as a shift time. The offset α is a delay factor of the shift timing, but does not have much effect if it is about 100 rpm.

〔Example〕

FIG. 3 is a flowchart showing one embodiment of the present invention.
The details of the driving state detection processing A, the throttle-off processing B, the guide processing C, and the shift inhibition processing D are shown.

In the drive state detection processing A, NI and NE are calculated in step A1. The input rotation speed NI when the output rotation speed NO is detected is calculated by the above-mentioned equation (4). In addition, there is a method of directly detecting NI. Next, at step A2, NE and NI are compared by the above equation (3) '). Where NE ≧ NI
If -α is established, the driving state is established (the L / U on / off state is not distinguished here), and the driving state flag XDRiVE is set to 1 in step A3. In contrast, in step A2
If NE ≧ NI−α is not satisfied, the driving state is the reverse driving state, so that the driving state flag XDRiVE is cleared to 0 in step A4 and the delay flag XDELAY is cleared to 0 in step A5.

In the processing B at the time of throttle off, throttle off (idle SW on) is detected in step B1. When the throttle changes from on to off, the throttle ON → OFF detection flag XTHOF is set to 1 in steps B2 and B3. Then, the drive state at the time when the throttle is turned off in step B4 is checked, and if XDRiVE = 1, XDELAY is set to 1 in step B5 to inhibit shifting. In order to forcibly release the shift prohibition, the guard timer CGD is set to 1 in step B6.
Start by setting about s. On the other hand, step B1
If it is determined that the throttle is not off in Steps B7 and B
XDELAY, CGD, XTHOF are all cleared to 0 in 8, B9.

In the guard process C, the value of the guard timer CGD is determined in step C1, and if it is not 0, nothing is done, but if it becomes 0 (after 1s has elapsed), XDELAY is set to 0 in step C2 to forcibly cancel the shift inhibition. .

In the shift prohibition process D, XDELAY is determined in step D1, and while this is 1, the shift determination in step D2 and the shift output in step D3 are prohibited. In contrast, XDELAY in step D1
When it is determined that = 0, the processing of steps D2 and D3 is permitted. This is a case where 0 has been cleared in any of steps A4, B7, and C2.

〔The invention's effect〕

As described above, according to the present invention, there is an advantage that the shift shock at the time of an upshift caused by the throttle off can always be effectively reduced even if the T / M characteristics vary or change over time.

[Brief description of the drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 is an explanatory diagram of an upshift diagram, and FIG. 3 is a flowchart of an embodiment of the present invention. In the figure, 1 is an engine, 2 is a torque converter, 3 is a transmission, and 4 is a shift control device.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (1)

(57) [Claims] 1. An electronically controlled automatic transmission for transmitting the rotation of an engine (1) to a transmission (3) via a torque converter (2) and automatically determining a transmission ratio of the transmission from a relationship between a vehicle speed and a throttle opening. In the transmission, means (A) for detecting the driving state of the transmission, means (B) for detecting that the throttle is off, and if the transmission is in the driving state when the throttle is off and an upshift is required. Means (D) for delaying the shift time until the transmission is in the reverse drive state.