JPS6346301B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic transmission control system for an automobile, and more particularly to a safety device for detecting disconnection in an output signal line for a vehicle speed response signal.

A conventional automatic shift control system has a control circuit that receives a vehicle speed response signal and a signal corresponding to engine output torque or a throttle opening response signal as input signals, compares these two signals, and outputs a transmission shift operation control signal. . This vehicle speed response signal is supplied, for example, by a known reed switch type vehicle speed sensor that detects the rotation speed of the drive shaft. This reed switch type vehicle speed sensor is turned on by a magnet that rotates according to the rotation of the drive shaft.
-OFF is activated, and a constant voltage is applied between both terminals, emitting constant voltage pulses at a frequency that corresponds to the drive shaft rotation speed. This vehicle speed sensor is placed near the drive shaft or inside the speedometer, and the output signal line leading to the control circuit may be disconnected. In this case, the same output signal as when the vehicle is stopped is usually generated. For example, in the case of a reed switch with one end connected to the body ground and the other end connected to a constant voltage circuit, a constant voltage non-pulse continuous signal is generated, which is the same signal as when the vehicle is stopped.
In such a case, the control circuit of the automatic transmission control system determines that the vehicle has stopped and issues a transmission control signal to shift the transmission to a low speed shift position (for example, 1st gear). If the vehicle is traveling at high speed, a sudden downshift will result in sudden and sudden engine braking, which is dangerous due to the large shock, and may cause transmission or engine failure. The present invention aims to provide a disconnection detection safety device for a control circuit of an automatic transmission system that can prevent such a danger.

That is, the present invention firstly provides a control method that uses a vehicle speed response signal and an engine output torque corresponding signal or a throttle opening response signal as input signals, compares and calculates these two input signals, and outputs a transmission shift operation control signal. In an automatic speed change control system for an automobile, the system has a switch which has a constant voltage applied to both ends of the switch as means for detecting the vehicle speed response signal and generates a constant pressure pulse by opening and closing the switch in response to the vehicle speed, one terminal of the switch is connected. The second resistor is connected to one end of the first resistor via a cable, the other end of the first resistor is connected to a constant voltage circuit, and one terminal of the second resistor is connected to a terminal of the switch connected to the first resistor. The other terminal is connected to the terminal on the opposite side of the first resistor of the switch, so that the second resistor is placed in parallel with the switch, and a voltage is applied to the end of the first resistor connected to the switch. A disconnection detection safety device for an automatic transmission control system is provided, which is characterized by being provided with an output terminal. The present invention also has a second control circuit which uses a vehicle speed response signal and an engine output torque corresponding signal or a throttle opening response signal as input signals, compares and calculates these two input signals, and outputs a transmission shift operation control signal. In an automatic speed change control system for an automobile, the vehicle speed response signal is detected by a switch that has a constant voltage applied to both ends and generates a constant pressure pulse by opening or closing in response to the vehicle speed. is connected to one end of the first resistor, the other end of the first resistor is connected to a constant voltage circuit, one terminal of the second resistor is connected to the terminal of the switch connected to the first resistor, and the other terminal of the second resistor is connected to the terminal of the switch connected to the first resistor. By connecting the terminal to the terminal on the opposite side of the first resistor of the switch, the second resistor is placed in parallel with the switch, and the voltage output terminal is connected to the end of the first resistor on the side connected to the switch. a safety circuit that is connected to the voltage output terminal and switches the transmission shift operation control signal to the high speed side or maintains it at the high speed side when the voltage of the voltage output terminal is a voltage other than when the switch is operated on or off; The present invention also provides a disconnection detection safety device for an automatic transmission system, which is characterized by being equipped with the following.

The present invention will be explained in detail below.

FIG. 1 shows a control circuit of an automatic transmission control system according to an embodiment of the present invention. The reed switch LSW of the reed switch type vehicle speed sensor 31 has its + side connected to the input terminal of an FV conversion circuit that forms part of the control circuit, and its - terminal connected to the vehicle body ground.
Magnet MG rotates according to the rotation of the drive shaft, reed switch LSW turns ON and OFF at a frequency that responds to vehicle speed, and resistor R1 (first resistor)
Resistors R2, R3, R4 and resistor R connected in series with
With a circuit configuration in which a reed switch LSW is connected in parallel to 2, R3, and R4, _a constant voltage pulse signal _V'L1 as shown in FIG. terminal). When a resistor R _L (second resistor) is connected in parallel to both terminals of the reed switch LSW, the voltage at terminal L in Fig. 2 drops below V' _L1 because it is connected in parallel to resistors R2, R3, and R4. A voltage pulse signal voltage V _L1 is generated. Disconnection here
When BR occurs in the signal line between the reed switch LSW and the control circuit input terminal, the voltage at the terminal L becomes V _L2 in the same figure. On the other hand, under normal conditions, when the vehicle is in a stopped state ST, the voltage at the terminal L becomes V _L1 (ST) or 0 depending on the position of the reed switch LSW.

According to the present invention, by connecting the resistor RL in parallel with the reed switch LSW in this way, a disconnection abnormality output signal different from that when the vehicle is stopped can be obtained as a vehicle speed response signal. This disconnection abnormality output signal can be detected by a known method not shown, and can be used as an output signal for activating an alarm circuit or taking other safety measures.

The present invention further provides a wire breakage detection safety device listed as the above-mentioned second feature, which effectively uses the abnormal output signal at the time of wire breakage from the vehicle speed response signal detection circuit 31 consisting of the reed switch LSW to which the above-mentioned parallel resistor RL is connected. do.

That is, the terminal L of the FV conversion circuit 32 is connected to the resistor R41.
is connected to the + input terminal of comparator IC2, which is maintained in an operating state by a predetermined power supply circuit, through
On the other hand, the - input terminal is a constant voltage circuit (constant voltage V _S2 )
It is connected to a voltage dividing point that divides the voltage between the voltage and the ground using resistors R43 and R44, and is supplied with a set voltage Vo.
This set voltage Vo is, for example, a voltage between the above-mentioned V _L1 and V' _L1 or V _L2 . The output terminal of the comparator IC2 is connected to the base of the emitter-grounded transistor T _r41 via the resistor R42, and the collector of the transistor T _r41 is connected to the constant voltage circuit (+, V _S2 ) via the resistor R45 on the one hand and the other side. It is connected via a diode D41 (reverse) and a resistor R46 to a terminal (transistor T _r 6 base) M which passes from a comparator IC1 output terminal G of a control circuit, which will be described in detail later, through diodes D12 and D13 in reverse order and in series. This terminal M is the first stage voltage regulator V _S1
The resistor R32 and the diode D13 (in this order) are connected in series.

Disconnection detection safety circuit 40 configured in this way
is the set voltage Vo and the input signal pressure V _L (= V _L1 or
When the input signal pressure V _L = _{V L1} <V ₀ , the output signal V _AL of the comparator IC 2 is output as L level. When V _L =V' _L1 >Vo, V _AL issues an H level abnormal signal, causes the transistor T _r 41 to be grounded, and the output signal pressure V _M becomes 0. When the terminal M is grounded, transistor T _r 6 is turned OFF, transistor T _r 7 is turned OFF, and the shift solenoid SSV is kept de-energized. As a result, the shift solenoid SSV, which is the transmission speed change operating means, is brought to the speed position and thereafter maintained at the speed position. In this way, in the event of a wire breakage, the speed position is secured regardless of the previous state, protecting the engine and transmission system, and preventing sudden downshift impacts during high-speed driving. At the same time, the driver who receives a disconnection or failure indication from an alarm circuit (not shown) can ensure safety by switching to a predetermined manual operation.

In the present invention, this disconnection detection safety circuit 40
Although this can be applied to various control circuits, the structure and operation of a preferred embodiment of the control circuit will be described in detail below.

The control circuit of this embodiment includes an FV conversion circuit 32 for the vehicle speed response signal _Ev (pulse signal), a signal forming circuit 33 for the engine output torque corresponding signal (or throttle opening response signal), and a vehicle speed response signal _Ev A comparator IC1 forming a comparison circuit for comparison calculation between the output torque signal and the output torque corresponding signal;
It basically consists of a circuit (hysteresis circuit) that _positively feeds back the output signal of the output torque corresponding signal E to the output torque corresponding signal E〓 formation circuit via the resistor R17, R24 or R28 each time. Operation control means (shift solenoid valve SSV)
It has an additional circuit for providing a control signal E _s for the control signal E s .

The output torque corresponding signal E=forming circuit 33 generates signal pressures V _B , V C , and V _C corresponding to the three throttle opening degrees, respectively.
for selectively supplying V _D to the comparator IC1 via diodes D9, D8, and D7, respectively.
It has an OR circuit on its output side, and each signal voltage V _B ,
V _C and V _D are connected between the second stage voltage regulator V _S2 and the ground terminal using two resistors R25 and R26, R21 and R2, respectively.
2. The pressure is divided by R14 and R15. Each voltage dividing terminal voltage V B , V C , V _D at voltage dividing terminals _B , _C , and D
is formed as. However, each of these voltage dividing terminals is connected to the output terminal G of the comparator IC1 via resistors R17, R24, and R28 (positive feedback).
Therefore, each divided voltage terminal voltage V _B , V _C , V _D is determined by three resistors R25, R26, R28; R21, R22, R
24; Generates three different signal pressures of V _B < V _C < V _D basically defined by R14, R15, and R17.

Of these three throttle opening response pressure output terminals B, C, and D, terminal B is only connected to ground via resistor R26, but terminal C (throttle opening second stage) is composed of transistor TR5. The switch circuit SW1 is grounded through the switch circuit SW1, which conducts to ground when closed, and the bias voltage input terminal C' of the switch circuit SW1 is connected to the throttle opening detection switch.
Grounded via VSW (e.g. vacuum switch for negative pressure detection in engine intake system), and constant voltage circuit (hereinafter referred to as + side) via resistor R18.
Connected to V _S2 . Terminal D, like terminal C, is connected to ground via switch circuit SW2.
Switch circuit SW consisting of 4 transistors T _r
The bias voltage input terminal D' of No. 2 is connected to ground via another throttle opening detection switch ASW (for example, an accelerator position detection switch or a switch with a different operating point of the same type as VSW), and is connected to the ± side via the other resistor R11. Connected to V _S2 . A Zener diode DZ (reverse direction) is connected to the ground on the + side V _S2 of the output torque corresponding signal E=forming circuit 33 in the same way as the capacitor C5.

Switch circuit SW1 is the npn type transistor
The emitter of T _r 5 is grounded, and the collector is connected to the voltage dividing terminal C. Base is diode D6
(in the opposite direction), the capacitor C7 and the resistor R20 are connected in parallel to ground, and on the other hand, the resistor R19 is connected to the terminal C', and then the resistor R18 is connected to the +
Connect to side V _S2 . The switch circuit SW2 uses an npn type transistor T _r 4, the collector is connected to the voltage dividing terminal D, the base is connected to the terminal D' through R12,
While connected to the + side V _S2 via resistor R11,
Diode D5, capacitor C6 and resistor R13
earthed through a parallel connection of

A known circuit can be used as the FV conversion circuit 32, and detailed explanation will be omitted, but a transistor
T _r 1 to T _r 3, diode D1 to D4, resistor R1
~R10, capacitors C1 to C4, and has shaping, differentiation, integration, and buffer circuits sequentially from the signal input terminal side, and its output terminal is connected to the + side V _S2 terminal, which is common to the control circuit, via resistor R10. It consists of the emitter terminal A of a pnp type transistor T _r 3 (for buffer, collector grounded). Note that the negative terminal of the FV conversion circuit 32 is grounded to the body. + of the reed switch of the vehicle speed sensor 31
The terminal (output terminal) is connected to the diode D1 terminal in the FV conversion circuit 32 as an input terminal.

The output terminal A of the FV conversion circuit 32 is then connected to the - input terminal of the comparator IC1 of the comparison circuit, and a capacitor C is connected between it and the + input terminal.
8. + of comparator IC1
The input terminal is the output torque corresponding signal E〓formation circuit 33
It is connected to the output terminal of the OR circuit (diodes D9, D8, D7), and is grounded via a resistor R29. The power supply circuit of the comparator IC1 is formed by connecting between the + side V _S2 of the control circuit and the ground.

The output terminal G of the comparator IC1 is connected to the + side V _S2 via the resistor R30 (the second stage + side
V _S2 ), this second stage + side V _S2 is further connected in series to the first stage + side V _S1 via a resistor R31, and on the other hand, a diode D12 and a resistor R32 are connected in series to a resistor R31.
30, connected in parallel with R31 to the + side (first stage) V _S1 .

Note that the conventional + side or constant voltage circuit V _S2 is connected to the output terminal K of this resistor R31. Further, this first stage + side V _S1 is connected to a + constant voltage power supply via a diode D16. Diode D16
The collector terminal of the npn transistor T _r6 is connected to the output side of the first stage (+ side) through series resistors R33 and R34, the emitter terminal is grounded, and the base terminal is connected to the resistor R32 through a diode D13. It is connected to a terminal between diode D12. The base terminal of the transistor T _r 6 is also grounded via a resistor R35, and from its collector terminal an npn transistor is connected via a resistor R34.
Connected to the base terminal of T _r7 . transistor
The emitter terminal of T _r 7 is connected to the first stage + side V _S1 , and the collector terminal is connected in parallel with the diode D17 and the coil of the shift solenoid valve SSV, and the other ends of these are grounded.

The operation of the control circuit of the present invention will be explained below. The throttle opening detection switch VSW is connected to the throttle valve 21 and intake manhold 22.
The ASW uses a negative pressure response switch connected to the engine intake system 20 through the communication pipe 4, and an accelerator position detection switch is used as an example of the ASW, but other throttle detection means may also be used.

The speed change characteristic diagram shown in FIG. 4 is realized by the control circuit shown in FIG. That is, the vehicle speed response signal E _V as a pulse frequency signal detected by the vehicle speed sensor 31 is supplied to the FV conversion circuit 32 and output to the terminal A as an output voltage V _A corresponding to the vehicle speed V _V.
is generated and input to the - terminal of comparator IC1.
On the other hand, the negative pressure response switch VSW of the intake system 20, which responds to the throttle opening θ, operates ON and OFF depending on the magnitude of the negative pressure with respect to the set pressure.
Switching circuit SW1 consisting of TR5 is turned off.
ON operates. Accelerator position detection switch (however, it can also be a negative pressure response switch)
ASW turns ON in response to 90% accelerator opening.
Switching circuit consisting of transistor TR4
Turn SW2 OFF. Switching circuit SW1,
SW2 is connected to each resistor R2 from the constant voltage circuit (+ side).
1 and R14 to ground, and when turned off, predetermined voltage signals V _C and V _D are generated at terminals C and D, respectively. On the other hand, a voltage V _B is generated at a terminal B which is divided between the constant voltage circuit V _S2 and the ground by R25 and R26 in order from the + side. these
V _B , V _C , and V _D correspond to each stage of the throttle opening θ, for example, V _B is 0 θ < 30%, and V _C is
30θ<90%, V _D corresponds to θ90% (corresponds to Figure 4). V _B , V _C , V _D are diode D7,
It is input to the + input terminal of comparator IC1 via an OR circuit consisting of D8 and D9.

On the other hand, the vehicle speed response signal pressure V _A is input to the - input terminal of the comparator IC1 as described above, and the H level is output to the comparator output terminal G (V _A < V+ ), an output voltage of L level (when VA>V+) is generated. In response to the H-L change of the voltage V _G at the terminal G, the switching circuit consisting of the transistor TR6 turns OFF-ON.
As a result, the transistor TR7 turns on and off between the constant voltage circuit and the shift solenoid valve SSV whose one end is grounded (GND). In this way, a predetermined voltage is applied to the shift solenoid valve SSV, which constitutes the transmission speed change operation control means, in accordance with the ON/OFF of TR7, and the transmission changes from speed to speed in response to the ON/OFF of the SSV, usually via hydraulic pressure. Be manipulated.

At this time, the voltages V _B , V _C , and V _D , which are the throttle opening corresponding signals mentioned above, respectively determine the switching point (shift point) of speed → speed change, and V _A is outputted each time through the OR circuit. When the vehicle speed is greater than any one of _B , V _C, or V _D (when the vehicle speed is greater than the shift point corresponding to the predetermined throttle opening), a shift up (from speed to speed) is performed. That is, in FIG. 4, shift point vehicle speeds V _VB , V _VC , and V _VD corresponding to V _B , V _C , and V _D are defined, respectively.

On the other hand, once the + terminal input voltage _V of comparator IC1 is any one of V _B , V _C , and V _D , for example, V _B
When V _A becomes large compared to (i.e., SSV is OFF,
output voltage V _G of output terminal G of comparator IC1 becomes L level, until then R28 and R25 were connected in parallel between terminal B and the constant voltage circuit (+ side), and R26 was connected to terminal B. The voltage connected between the ground and the terminal B that was dividing the voltage V _B (when the terminal G is at H level) is now the voltage V G of the terminal _G = O (L
According to the change in level), terminal B will be connected to ground through parallel resistances R26 and R28, resulting in a potential of terminal B V' _B < V _B
becomes. This relationship also applies to the resistance R2 for terminal C.
1, R22, R24 in the same manner, and terminal D
The same holds true for resistors R14, R15, and R17. In this way, once V _A exceeds the set V _B , V _C or V _D each time (speed → speed shift up), V _B → V′ _B , V _C → V′ _C , V _D →
V′ _D becomes lower each time, and the speed →
The speed shift point shifts to the low speed side. Thus, the electrical hysteresis consisting of the B, C, and D terminal voltages V _B , V _C , and V _D that defines the vehicle speed difference (hysteresis) at both shift points during up-shifting and down-shifting is △V _B = V _B − V′ _B , △V _C = V _C −V′ _C , △V _D = V _D −
It is formed as V′ _D.

The width of this hysteresis △V _B etc. are the characteristics of the transmission,
Although it is determined appropriately according to the vehicle type, desired shift characteristic diagram, etc., in the present invention, the resistors R25, R26, R2
8 (for V _B ) etc. can be easily set. Note that the hysteresis width needs to have at least enough margin to prevent chattering.

In addition, the shift solenoid is energized and OFF.
per hour, but this depends on the solenoid itself when driving (especially when driving at a constant high speed).
This is because it is safer to set it to OFF.

It should be noted that the terminal L may have a polarity opposite to that of the above embodiment.

As described above, in this embodiment, a special method was used to form hysteresis in the control circuit, but hysteresis may be formed using a known method, for example, by changing the slope of the gain of FV conversion and changing V _A to V′ _A. The disconnection detection safety device of the present invention can also be applied to a control circuit using a method or the like. Furthermore, the present invention can of course be applied to a control circuit using a known potentiometer linked to a throttle valve as a signal forming circuit corresponding to the output torque of the engine by adding an appropriate auxiliary adaptive circuit.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a graph schematically showing the relationship between the terminal voltage (reed switch LSW output signal) at terminal L in Fig. 1 and time, and Fig. 3 is a block diagram showing an embodiment of the present invention, FIG. 4 is a shift characteristic diagram according to an embodiment of the present invention, and FIG. 5 is a diagram showing electrical hysteresis, vehicle speed V _V , and signal for FIG. FIG. 6 is a graph showing the relationship with voltage, and FIG. 6 is a schematic diagram of the engine intake system negative pressure detection means.

Claims (1)

[Scope of Claims] 1. A control circuit which uses a vehicle speed response signal and an engine output torque response signal or a throttle opening response signal as input signals, compares and calculates these two input signals, and outputs a transmission shift operation control signal. In an automatic speed change control system for an automobile, the switch has a constant voltage applied to both ends as a means for detecting the vehicle speed response signal and generates a constant pressure pulse by opening and closing the switch in response to the vehicle speed, one terminal of the switch is connected to a connecting cable. connected to one end of the first resistor through the first resistor;
The other end of the resistor is connected to a constant voltage circuit, and the second
One terminal of the resistor is connected to the terminal of the switch on the side connected to the first resistor, and the other terminal is connected to the terminal of the switch opposite to the first resistor, so that the second resistor is connected in parallel to the switch. It is arranged in
A disconnection detection safety device for an automatic transmission control system, characterized in that a voltage output terminal is provided at the end of the first resistor connected to the switch. 2. A control circuit that takes as input signals a vehicle speed response signal and an engine output torque corresponding signal or a throttle opening response signal, compares and calculates these two input signals, and outputs a transmission shift operation control signal, and the vehicle speed response signal In an automatic transmission control system for an automobile, the automatic transmission control system for an automobile has a switch which is applied with a constant voltage to both ends and generates a constant pressure pulse by opening or closing in response to the vehicle speed as a detection means.One terminal of the switch is connected to one end of a first resistor via a connecting cable. The other end of the first resistor is connected to a constant voltage circuit, one terminal of the second resistor is connected to the terminal connected to the first resistor of the switch, and the other terminal is connected to the first resistor of the switch.
the second by being connected to the terminal opposite the resistor.
A resistor is arranged in parallel with the switch, and a voltage output terminal is provided at the end of the first resistor connected to the switch, and the voltage at the voltage output terminal is connected to this voltage output terminal so that the voltage of the voltage output terminal can be applied to turn on/off the switch. A disconnection detection safety device for an automatic transmission control system, comprising a safety circuit that switches the transmission speed change operation control signal to a high speed side or maintains it at a high speed side when the voltage is other than that during off operation. 3. The safety circuit includes a comparator circuit that compares and calculates the voltage of the voltage output terminal with a preset voltage, and a switch that switches the transmission shift operation control signal to the high speed side or maintains it at the high speed side in accordance with the output of the comparison circuit. A disconnection detection safety device for an automatic transmission control system according to claim 2, further comprising a holding circuit.