JPS5943666B2 - Lock-up control device for lock-up automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lockup control device for a lockup automatic transmission, and more particularly to an electronic lockup control device.

Automatic transmissions generally include a torque converter in a power transmission line for the purpose of increasing transmission torque or absorbing fluctuations in transmission torque to reduce vibration.

However, since the torque converter is configured to transfer power between the input element (pump inverter) and output element (turbine runner) via hydraulic oil, slip between these input and output elements is unavoidable, resulting in poor power transmission efficiency. .

For this reason, a lock-up torque converter has been proposed that can directly connect the input and output elements in a relatively high vehicle speed range where no torque increase is required and torque fluctuations are not a problem. A lock-up automatic transmission equipped with a transmission is used in some vehicles as a measure to reduce fuel consumption.

The lock-up region of such an automatic transmission is shown on the shift pattern as shown in FIG. 4, for example, and v
1. V2. The lock-up vehicle speeds of the V3 cars in 1st, 2nd, and 3rd gear are A, B, and C (hatched respectively).

) are the lock-up areas for 1st, 2nd, and 3rd gears based on the 1→2 upshift line and 2→3 upshift line (based on the 1←2 downshift line and 2←3 downshift line). (The lock-up region has been omitted to maintain the clarity of the drawing), and v,', V2', and V3' are the first gear, V2', and V3', respectively.
This is the lock-up release vehicle speed for 2nd and 3rd speeds.

The lock-up control device controls the torque converter to obtain such a lock-up mode, and at each shift position, the vehicle speed or the lock-up vehicle speed v1. V2. Lockup areas A and B beyond V3.

When shifting to running in C, the torque converter is brought into a lock-up state in which its input and output elements are directly connected.

In addition, the torque converter in the lock-up state has the vehicle speed at each shift position set to the lock-up release vehicle speed v1', ■2', ■3, which is set slightly lower than the lock-up vehicle speed by the amount of hysteresis for preventing bunching. In the region where the input and output elements are less than

However, with conventional devices that perform only such lock-up control, there is a risk that the engine will stall when sudden braking is applied while the vehicle is running in a lock-up state, as will be explained below.

Figure 3 shows the decrease in vehicle speed during braking, where α is the decrease in vehicle speed during braking when the brake pedal is depressed at normal speed,
β is the reduction in vehicle speed when the brake pedal is pressed at a faster speed than normal during sudden braking.

In other words, when the brake pedal is depressed at instant t1, the brakes will start operating with a response delay Tβ, and the vehicle speed will start to decrease from this time, but during normal braking, it will correspond to the depression speed of the brake pedal as shown by α. During sudden braking, the vehicle speed decreases rapidly in response to the strong depression of the brake pedal, as shown by β.

If these brakes are applied while driving in third gear, the moment t2. At t3, lock-up release is instructed, but
The lock amplifier is actually released from T1 due to the delay in response of the lock-up control hydraulic system. That's when it was too late.

This response delay is not a problem during normal braking because the lock-up is released while the vehicle speed is still above the vehicle speed value v1 corresponding to the engine's idling speed, but during sudden braking, the vehicle speed is still above the above value. The lockup is released after the voltage drops below v1, and the above response delay induces engine stalling.

In order to solve this problem, it is conceivable to set the lock-up release vehicle speed high in anticipation of the above response delay TL, but in this case, the lock-up vehicle speed must also be increased in response to the delay, and as a result, the lock-up region As the distance becomes narrower, the fuel efficiency reduction effect due to lockup is reduced.

The present invention is a lock-up control device that is designed to prevent the engine from stalling as described above even if the lock-up release vehicle speed remains the same as before.Specifically, the vehicle speed is set to be higher than the lock-up release vehicle speed within a set time after braking. It is an object of the present invention to provide a lock-up control device that can put a torque converter into a converter state regardless of normal lock-up control when braking suddenly such that the torque becomes lower than the torque limit.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows an electronic circuit diagram of a lock-up control device according to a first embodiment of the present invention. In this embodiment, the device is configured to prevent the engine from stalling when sudden braking is applied while driving in third gear, which is the most problematic. be.

In the figure, 1 and 2 indicate a 1-2 shift switch and a 2-3 shift switch, respectively, and these switches are incorporated in, for example, a 1-2 shift valve and a 2-3 shift valve of an automatic transmission, respectively, and are connected to the respective valve spools. is closed when is in the downshift position,
Configure to open when in upshift position.

These shift switches 1 and 2 are connected to the power supply +Vc via resistors 3 and 4, respectively, and a 1-2 shift signal 812 and a 2-3 shift signal 823 are output from these switches in response to opening and closing of both switches 1 and 2, respectively. Make it output.

Therefore, the switches 1 and 2 have the opening/closing combinations shown in the table below at each shift position, and the shift signals 812 j S23 have the combinations of levels shown in the table below at each shift position.

Note that H in the following table represents a high signal level or a low signal level, respectively.

In addition, 5 in the figure is the lock-up solenoid of the lock-up control valve that controls whether the torque converter is in the converter state or lock-up state, and when this solenoid is deenergized, the torque converter is in the converter state, It is assumed that the torque converter is placed in a lock-up state when the engine is activated.

The shift signal SI2+823 is input to the shift position determination circuit 6 and the shift detection circuit 7.

The shift position determination circuit 6 determines the current shift position from the combination of the levels of both shift signals S1□ and S23 according to the above table. Only the output 51 (1 serial number) from a is set to [], and only the level of the shift signal S12 is (-(), and only the output 52 (2 stray signals) from the gate stone is set to (t). None, output 53 from gate c at 3rd speed when the level of shift signal S23 is also H (3 stray signals)
Let's sing only H.

The shift detection circuit 7 is an edge trigger circuit that detects the rising and falling edges of the shift signal S12. , the corresponding shift signal 5121823 changes from L level to H level.
When switching to L level or from H level to L level, that is, when the valve spool of the corresponding shift valve moves from the downshift position or upshift position to the upshift position or downshift position to perform automatic gear shifting, the negative polarity A tri-force pulse P1 is output, and its pulse width is made to correspond to the time required for the automatic transmission to operate at an actual rabbit speed.

The vehicle speed sensor 8 supplies a vehicle speed signal (■) corresponding to the vehicle speed to the vehicle speed ratio soft circuit 9.

When the torque/7 converter is in the converter state, the vehicle speed ratio soft circuit 9 converts the vehicle speed signal V into the lock-up vehicle speed V1 of the first series.
, compared with the lock-up vehicle speed v2 for the second series and the lock-up vehicle speed v3 for the third series (see Fig. 4 for both),
When V 2 V 1, from Kate a', ■? It is assumed that when v2, a 1 level signal is outputted from the gate 'V, and a 1 level signal is outputted from the gate gate/2 at the samurai gate of V3.

If the torque converter is already in the lock-up state, the vehicle speed ratio soft circuit 9 also uses the lock-up vehicle speed V1. ■2. It is assumed that the lock-up release vehicle speed is switched from (3) to the lock-up release vehicle speeds V1', (2), and (3) (see FIG. 4), and the vehicle speed signal is compared with these lock-up release vehicle speeds to function in the same manner.

In order to determine whether the torque converter is in the converter state or the lock-up state, a signal from an OR gate 26, which will be described in detail later, is input to the vehicle speed ratio soft circuit 9.

In the present invention, a brake switch 10 is provided as a braking detection means for detecting braking of the vehicle, and this brake switch is linked to the brake pedal, closes when the brake pedal is depressed (during braking), and outputs a 17-level brake signal SB. ,
It shall open when released and set the brake signal SB to [Level 5].

Note that as the brake switch 10, one that senses changes in brake oil pressure may also be used.

The brake signal SB is supplied to a delay circuit composed of a NoT gate 12, a resistor 13, a capacitor 14, and a NOR gate 15.

In this delay circuit, since the brake signal SB during driving with the brake pedal released is at <1 level and 0 as described above, in response to this H level signal, the NOR gate 15 is set to 1 and level is set to 0. An AND gate 16 that outputs the brake holding signal SH and receives this 17-level signal
supplies an L level signal to the OR gate 18 of the sudden braking memory circuit 17.

Thus, the sudden braking memory circuit 17 receives the 1. A level signal will be output, and this signal will be N
OT gate 19? This is reversed to F Lebel, l\N
I) Gate 20 (This is supplied, and while the vehicle is running with the brake pedal released, normal lock-up control (shown in FIG. 4), which will be described below, is executed in accordance with the signal levels of other inputs to the AND gate 20.

The signals from the shift position discrimination circuit 6 and the vehicle speed ratio soft circuit 9 are sent to AND gates 23 to 2 of the lockup judgment circuit 21.
5 and these ANI) gates 23 to 25
is a two-man AND operation with lock-up head A, B, or C (see Figure 4) in the 1st, 2nd, and 3rd gear ranges tζ.
and outputs an H level signal.

In this way, when an H level, small signal is output from one of the AND gates 23 to 25, this signal is output to the OR gate 26.
The signal is supplied to the AND gate 20 via the .

At this time, if the speed change operation is not in progress and the pulse signal P1 from the speed change detection circuit 7 is not supplied to the AND gate 20,
ANI) All three gates 20 become H level, and the F level lock-up signal S1. is applied to the base of transistor 28, and this transistor 28
By making the lock-up solenoid 5 conductive and energizing the lock-up solenoid 5 by the power supply V, the torque converter can be brought into the lock-up state as required.

On the other hand, while the automatic transmission is shifting and the pulse signal P1 is present, this is input to the AND gate 20 and causes the AND gate 20 to output an L level signal (the lockup signal SL disappears). ) Therefore, even in the lock-up region, the lock-up solenoid 5 is deenergized by the non-conduction of the transistor 28.

Therefore, the torque converter is temporarily released from the lock-up state during the gear shifting operation and enters the converter state, thereby preventing the occurrence of gear shifting shock.

Note that the lock-up area A in FIG. While driving in modes other than B and C, both AND gates 23 to 25 output L level signals because the two human power inputs do not reach H level, and in this case, lock-up solenoid 5 is deenergized. This allows the torque converter to function as required in the converter state.

Note that once the torque converter enters the lock-up state, the vehicle speed comparison circuit 9 changes the comparison target of the vehicle speed signal V to the lock-up vehicle speed V1. Since the lockup release vehicle speed is switched from V2°v3 to the lockup release vehicle speed V1', ■2', and ■3', the lockup state is maintained at each shift position until the vehicle speed decreases to these lockup release vehicle speeds.
The lockup control shown in FIG. 4 is obtained.

By the way, when the brake pedal is depressed while the vehicle is running in the lock-up state where the third speed is selected, the brake switch 10 linked therewith closes, and the brake signal SB is switched to the L level at instant t1 in FIG. 2.

This L level signal is supplied to one input terminal of the NOR gate 15, is inverted to H level by the NOT gate 12, and is used to charge the capacitor 14.

However, the time required to charge the capacitor 14 (resistor 13
An L level signal is also supplied to the other input terminal of the NOR gate 15 for a time constant (time constant determined by the capacitor 14) T (see FIG. 2), and as a result, the NOR gate 15 outputs the brake holding signal SH for the set time T1. As shown in Fig. 2, the voltage is set to H level, and then returned to L level.

On the other hand, in the present invention, the vehicle speed comparison circuit 9 is also used as a comparison means for detecting that the vehicle speed has become lower than a set value VB (illustrated in FIGS. 3 and 4) which is higher than the vehicle speed V3'. For this purpose, a vehicle speed comparison circuit 9 is used.
A game 1-d' is provided.

This gate 10' is the vehicle speed (in the lock-up state, there is no slip of the torque converter, so the engine speed may be used) signal V is the vehicle speed setting value VB (engine speed setting corresponding to the vehicle speed VB set in anticipation of the 3rd gear ratio). value) or more, and when it drops below this level, the signal is L.
It is assumed that a level signal is output.

Now, considering sudden braking that causes a decrease in vehicle speed as shown by β in FIG. 3, at instant t4 when the vehicle speed has decreased to the set value VB, the vehicle speed comparator circuit 9 outputs an L level signal from the gate d'.
This is inverted to H level by NOT gate 29, and vehicle speed comparison signal Sv rises as shown in FIG.

By the way, during sudden braking as described above, the vehicle speed comparison signal Sv rises within the set time T1 as shown in FIG.
When both of the ND game 116 are supplied with H level signals, the ND game 116 supplies the H level signal to the OR gate 18, causing the game H to output an H level signal.

However, since this H level signal is inverted to L level by NOT gate 19 and then supplied to AND gate 20, the output of lockup signal SL is blocked regardless of the above-mentioned normal lockup control, and when the torque converter is suddenly braked. It is possible to issue a command to quickly return to the converter state at instant t4, thereby preventing the engine from stalling due to the response delay TL.

However, during normal braking accompanied by a decrease in vehicle speed as shown by α in FIG. An H level signal cannot be output, and the normal lock-up control described above with reference to FIG. 4 is performed.

Note that in such a braking state, the engine will not stall even due to the response delay TL as described above.

Once the sudden braking lock-up is released in this way, the brake hold signal SH is set to the second level after the set time T1.
As shown in the figure, even if the AND gate 16 supplies an L level signal to the OR gate 18 when the signal becomes L level, the brake switch 10 closes when the brake pedal is depressed and the brake signal SB is output. As long as is maintained at the L level, the release of the lockup is maintained as follows.

That is, the L level brake signal SB is applied to the NOT gate 3C.
A of the braking memory circuit 17 is inverted from H to H level.
N I) is supplied to the gate 31.

Further, the output of the OR gate 18 is also supplied to the AND gate 31, and when this output is once set to the H level as described above to release the lock-up during sudden braking, this output is then set to the L level. However, the AND gate 31 indicates that the brake signal sB is I (level (release of brake pedal)).
It continues to output an H level signal until the
After passing through gate 18 and being inverted to L level by NOTOR gate 35, it is supplied to AND gate 20.

Therefore, once the lock-up is released as described above during sudden braking, this release continues as long as the brake pedal is depressed, thereby avoiding the inconvenience of the torque converter being locked up again after the set time T1 has elapsed and causing the engine to stall. can do.

When the brake pedal is released and braking is stopped, the brake signal SB becomes H level, but this is NOT game 1-3.
0, it is inverted to L level and supplied to AND gate 31, and as a result of causing this AND gate to output a 17 level signal, the NOR gate 15 also receives H level brake signal SB.

A level signal is supplied to AND'7'-to 16, and this
I) As a result of causing the gate to output an L level signal, the OR gate 18 outputs an L level signal since both meat inputs are at the L level.

Therefore, even though the lock-up is released as described above during sudden braking, the release of the lock-up is interrupted at the same time as the brake pedal is released, and the normal lock-up control is returned to, without interfering with normal operation.

FIG. 5 shows a circuit diagram of a second embodiment according to the present invention, and the same parts as in the first embodiment described in detail with respect to FIGS. 1 to 4 are given the same reference numerals and detailed explanations are omitted. and explain the differences.

In this example, in addition to the gate 1, the vehicle speed comparison circuit 9 also detects the vehicle speed (of course, the engine rotational speed may also be used).

) When the signal V is higher than the lock-up release vehicle speed v2', ■V1', the H level signal is maintained at the vehicle speed set value (one engine speed may be sufficient considering each gear ratio), and when the signal V is lower than these, the L level signal is maintained. Added a gate function that outputs all signals.

Furthermore, each of these gates, 3/, 7', and 7' has a NOTE
AND gates 32, 33, and 34 are connected to the other input terminals of which the 3rd speed signal, 2nd speed signal, and 1st speed signal are respectively inputted via R gates 356.37.

One of these AN L) gates 32 to 34 outputs an H level signal when the vehicle speed is lower than the vehicle speed setting value at each shift position.

The outputs of AND gates 32 to 34 are all output to OR gate 35.
As is clear from the above explanation, this O
The output of the R gate 35 can be used as the vehicle speed ratio soft signal Sv.

According to this embodiment, even when driving with the torque converter locked up in the second and first gears, the vehicle speed ratio soft signal Sv switches from the L level to the H level, thereby preventing engine stalling during sudden braking. Can be prevented.

Thus, as described above, the lock-up control device of the present invention determines that the vehicle speed (or the engine rotation) is higher than the normal lock-up release vehicle speed within the set time T1 after the brake pedal is depressed (or the corresponding engine rotation speed setting value). ) When the vehicle speed (engine speed) decreases to the above set value during sudden braking, the lock-up release command is issued as soon as the vehicle speed (engine rotation) drops to the above-mentioned setting value. The output can be made earlier by the time indicated by T2 in FIG. 3, and it is possible to avoid problems such as the engine stalling due to the lockup being released too late due to the response delay TL of the lockup control system.

[Brief explanation of the drawing]

Fig. 1 is an electronic circuit diagram of the lock-up control device of the present invention, Fig. 2 is an operation time chart of the device, and Fig. 3 is a diagram used to explain the reason for engine stalling due to delay in releasing lock-up during sudden braking. , FIG. 4 is a shift pattern diagram of an automatic transmission illustrating a lock-up region, and FIG. 5 is an electronic circuit diagram similar to FIG. 1 showing another example of the present invention. 1...1-2 shift switch, 2...
2-3 Shift switch, 5...Lock-up solenoid, 6...Shift position determination circuit, T...
...speed change detection circuit, 8...vehicle speed sensor, 9.
...Vehicle speed comparison circuit (comparison means), 10...
・Brake switch (braking detection means χ12...
to OT gate, 13... Resistor, 14...
・Capacitor, 15...NOR gate, 16,
20゜31...AND gate, 17...
・Brake memory circuit, 18...OR gate, 19,
30...NOT gate, 21...Lock-up determination circuit, 28...Transistor.

Claims (1)

[Scope of Claims] 1. A power transmission system includes a torque converter, and the torque converter is brought into a lockup state in which input and output elements of the torque converter are directly connected by an electric lockup signal outputted at a lockup vehicle speed or higher, and the lockup release vehicle speed is set. In a lock-up automatic transmission that can return the torque converter to the converging state by eliminating the lock-up signal, the brake detecting means detects braking of the vehicle and the vehicle speed is lower than or equal to a set value higher than the lock-up release vehicle speed. and a comparison means for detecting the lock-up signal, and is configured to prevent the output of the lock-up signal during sudden braking such that the vehicle speed falls below the set value within a set time after braking. lockup control device. 2. The lock-up control device for a lock-up type automatic transmission according to claim 1, wherein the output of the lock-up signal continues for one week during braking.