JPH0475420B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a shift shock reduction device for a vehicle equipped with an automatic transmission that is driven by power from an engine via the automatic transmission. (Prior art) Automatic transmissions selectively operate internal friction elements (clutches, brakes, etc.) depending on the vehicle state while the vehicle is running, and automatically select the optimum gear position to match the engine power to the driving state. However, when changing gears, the output shaft torque suddenly changes, causing a shift shock. This shift shock is used when changing from a low gear to a high gear, that is, when changing from 1st gear to 2nd gear (1→2 upshift shifting), and from 2nd gear to 3rd gear (2→3 upshift shifting). ), or when shifting from 3rd to 4th gear (3→4 upshift), this becomes noticeable as these shifts are often performed while driving with the engine's accelerator pedal fully depressed. . For example, as shown in Fig. 6, when there is a shift command from 2nd speed to 3rd speed at instant t ₁ , the corresponding friction element starts operating at instant t ₂ after a response delay ΔT ₁ . (shift starts), and then this friction element is activated instantaneously after the operation delay ΔT ₂ .
The operation is completed (speed change is completed) at t ₃ . Then, the effective gear ratio of the automatic transmission is ΔT.As the operation of the friction element progresses during ₂ hours, the 2nd gear gear ratio R _L (for example, 1, 4) changes to the 3rd gear gear ratio R _H (for example, 1, 0).
Changes to. Also, during this period, the input rotation speed N _i of the automatic transmission decreases in accordance with the change in the gear ratio between instants t ₂ and t ₃ , and becomes equal to the output rotation speed N _O of the automatic transmission (the engine rotation speed is also the same). change with a tendency). Theoretically, the input torque T _i (approximately the same as the engine output torque T _e ) of the automatic transmission will be the input rotational speed if the engine throttle opening is not changed.
The output torque T _p of the automatic transmission, which is approximately inversely proportional to the above change in N _i and is expressed by multiplying this input torque by the effective gear ratio, remains approximately constant. However, in reality, while the input rotation speed N _i decreases during the ΔT ₂ period, the engine inertia acts to prevent this rotation reduction, and applies inertia mode torque to the input shaft of the automatic transmission, resulting in Output torque T _p is a solid line during gear shifting operation (during ΔT ₂ period)
It has a change as shown by T _p ′. Therefore, during the period ΔT _{2 ,} a torque T _n due to inertial force is generated as shown by the solid line, which causes a shift shock. Therefore, the applicant of the present application previously disclosed in Japanese Patent Application Laid-Open No. 58-207556 that based on the fact that the transmission shock is based on the rapid T _p ' of the transmission output shaft torque T _p as described above, We have already proposed a technology that slows down the ignition timing compared to normal in order to reduce output, thereby alleviating sudden changes in transmission output shaft torque and reducing shift shock. The same publication also introduced the technical idea of matching the start timing of the ignition timing control with the actual shift start timing using timer control. However, the response delay from the shift command that switches the shift valve to when the automatic transmission starts the actual shift, and the operation delay from the start of the shift to the end of the shift are caused by variations in the hydraulic system, wear and tear over time of friction elements, and operational delays. It varies depending on the oil temperature (viscosity), and with the above-mentioned timer control, it is not possible to always match the start timing of ignition timing control with the actual shift start timing.
Furthermore, the end timing of ignition timing control cannot be matched with the actual shift end time. If the start and end of ignition timing control are not synchronized with the start and end of the shift, not only will the desired reduction effect of the shift shock not be obtained, but there will also be an unnecessary drop in engine output before or after the start of the shift. This results in new deceleration shocks and greatly reduces the commercial value of the vehicle. On the other hand, Japanese Patent Application Laid-Open No. 59-97350 focuses on the fact that the engine speed changes in response to gear shifting, and immediately reduces the engine output from the shift start point when the engine speed starts to change. A technique has been proposed in which the output of the engine is gradually restored from the end of the shift at which the change in the rotational speed is completed. According to this configuration, the start and end of a shift is determined while monitoring the engine speed, and the start and end of engine output control is determined according to the determination result for reducing shift shock, so the above-mentioned problem is generally solved. It is possible. (Problem to be Solved by the Invention) However, in reality, the waveform of the output torque fluctuation T _p ' (therefore, the torque T _n due to inertial force) during gear shifting becomes a rectangle as shown by the solid line in FIG. Immediately after the start of the shift and immediately before the end of the shift due to interference of friction elements within the transmission involved in the shift, etc.
In particular, it is absorbed by the latter, and becomes gradual as shown by the two-dot chain line in FIG. Other possible causes of such a torque waveform include a change in the friction coefficient due to the rotation of the friction element, a change in the input torque due to a change in the state of the torque converter, and the like. Further, the reason why the above-mentioned tendency becomes particularly large immediately before the end of the shift is also because the change in the torque ratio of the torque converter is large immediately after the start of the shift, and gradually converges just before the end of the shift. In response to such an actual torque fluctuation waveform, the above-mentioned conventional engine output control for reducing shift shock gradually returns the engine output to the original level until the end of the shift. First, the engine output control for reducing shift shock becomes excessive in the region immediately before the end of shift, and
This may cause new deceleration shocks or deteriorate driving performance. The present invention is based on the fact that it is possible to determine that the torque fluctuation begins to converge near the end of the shift by reversing the direction of increase/decrease in the time rate of change of the engine speed or transmission input speed. The object of the present invention is to gradually reduce engine output control for reducing shift shock so that the control matches the torque fluctuation waveform at the end of shift, thereby solving the above problem. (Means for Solving the Problems) For this purpose, the present invention, as conceptually shown in FIG. A rotation speed change rate detection means for detecting a time change rate of the rotation speed; a shift command detection means for detecting a shift command of an automatic transmission; a shift start timing determining means for detecting the shift start time and determining that the shift has started; an engine output reducing means for reducing the engine output to a value required to prevent shift shock from the shift start time; A rotation speed change rate increase/decrease direction reversal timing determining means for detecting the moment when the change rate increase/decrease direction is reversed; and the engine output reducing means so as to gradually reduce the engine output reduction amount from this reversal instant to zero at the end of the shift. This configuration includes an engine output return means for issuing a command to the engine output. (Function) After the shift command is detected by the shift command detection means, when the time rate of change of the engine speed or transmission input revolution detected by the rotation speed change rate detection means exceeds a set value, the shift start timing determining means It is determined that the shift has started. The engine output reducing means reduces the engine output to a value required to prevent a shift shock from the time of detecting the shift start. On the other hand, the rotation speed change rate increase/decrease direction reversal timing determining means detects the moment when the rotation speed change rate increase/decrease direction changes in the opposite direction after detecting the shift start, and the engine output return means detects the moment when the rotation speed change rate increase/decrease direction reverses. The engine output reducing means is commanded to gradually reduce the amount and make it zero at the end of the shift. Therefore, the engine output reduction control for reducing shift shock is started in time with the start of the shift, and at the end of the shift, the engine output reduction amount by the control is adjusted to match the torque fluctuation waveform that starts to converge slightly before the end of the shift. It gradually decreases to zero, which reliably prevents shift shock, and prevents the engine output from decreasing too much in the area just before the shift ends, causing new deceleration shock or deteriorating driving performance. You can do it like this. (Example) Hereinafter, an example of the present invention will be described in detail based on the drawings. Fig. 2 shows the entire system of the shift shock reducing device of the present invention, in which 1 is the engine, 2 is its intake manifold, 3 is a flow meter for measuring the engine intake air amount, 4 is an air cleaner, and 5 is the automatic transmission. A converter housing that houses a torque converter; 6 a transmission case that houses a power transmission gear train of an automatic transmission and various friction elements that determine its power transmission path; 7 a transmission case that houses various friction elements that determine the gear position by selectively operating the various friction elements; 8 is the rear extension. The engine 1 includes a distributor 10 for distributing high voltage to the ignition plugs 9 of each cylinder in synchronization with engine operation. The secondary high voltage generated by intermittent primary current at predetermined times determined by S _I is individually applied to the spark plugs 9 to enable the engine 1 to operate. The intake air amount of the engine 1 is increased as the accelerator pedal 12 is depressed, and the output of the engine 1 is increased by increasing the amount of fuel injection from an injector (not shown). The power is then input to the power transmission gear train in the transmission case 6. Automatic transmission has 1-2 shift valves 13, 2-2
The shift valve 14 and the 3-4 shift valve 15 automatically select an appropriate gear from 1st to 4th gear according to the vehicle running condition, and change the engine power at a gear ratio corresponding to the selected gear. The information is transmitted to the drive wheels of the vehicle (not shown) and the vehicle runs. In the present invention, the ignition timing control device 11 is controlled by the controller 16 to control the ignition timing of the engine 1. For this purpose, the controller 16 is driven by a power supply +V, and receives a signal S _TH from a throttle opening sensor 17 that detects the amount of depression of the accelerator pedal 12 (engine load).
Signals S ₁₂ , S ₂₃ , S ₃₄ from the 1-2 shift switch 18, 2-3 shift switch 19, and 3-4 shift switch 20, which open and close according to the spool positions of the shift valves 13 to 15, and the intake from the flow meter 3. Signal S _Q corresponding to air volume, distributor 1
Signal from crank angle sensor 21 built into 0
S _C , a signal S _T from the engine coolant temperature sensor 21 that detects the engine coolant temperature, and a signal S from the engine rotation speed sensor 23 (which may also be a sensor that detects the automatic transmission input rotation speed) that detects the engine rotation speed. It is assumed that the ignition timing control device 11 is controlled by the output (ignition timing control signal) S _I based on the calculation result of _N. Note that the 1-2 shift switch 18 and the 2-3 shift switch 19 are each disclosed in, for example, Japanese Patent Application Laid-Open No. 56-127856.
As described in the publication, the 1-2 shift valve 13
When the spool of the 2-3 shift valve 14 is in the downshift position, it closes and outputs an L level signal, and when in the upshift position, it opens and outputs an H level signal, and the 3-4 shift switch 20 similarly outputs a 3-4 shift valve 14.
It is assumed that the spool of the 4-shift valve 15 closes to output an L level signal when in the downshift position, and opens to output an H level signal when in the upshift position. Thus, the shift signals S ₁₂ , S ₂₃ , and S ₃₄ have the combinations of levels shown in the following table at each gear stage.

[Table] Specifically, as shown in FIG. 3, the controller 16 includes a central processing unit (CPU) 24, a random access memory (RAM) 25, a read-only memory (ROM) 26, and an input interface circuit 27. and an output interface circuit 28,
It is composed of a waveform shaping circuit 29, an A/D converter 30, a drive circuit 31, and a power supply circuit 32, and the power supply circuit 32 sets the voltage of the power supply +V to a predetermined value and controls the CPU 24,
RAM25, ROM26, circuits 27-29, 31
and the A/D converter 30 to enable them to be driven. It is assumed that the CPU 24 executes the control program shown in FIG. 4 stored in the ROM 26 to perform normal ignition timing control and the ignition timing control (engine output reduction control for reducing shift shock) which is the object of the present invention. This control program is started when the engine is started by turning on the ignition switch, and is repeatedly executed at step 40 by a regular interrupt from a timer (not shown). First step 41
In this step, it is determined whether or not there is a shift command based on whether there is a level change in the shift signal S ₁₂ , S ₂₃ or S ₃₄ , and if there is no shift command, the control is stepped.
Proceed to 42. In this step 42, as will be described later, when the gear shift command is issued (t ₁ in Fig. 5), it is set to 01 (step 42).
47), at the start of the gear shift (t ₂ in Figure 5), it is set to 11 (step 51), and slightly before the end of the gear shift (t 2 in Figure 5).
The shift flag GSFLG is set to 10 (step 59) at t ₂ ') and returned to 00 at the end of shift (t ₃ in FIG. 5) (step 62). Since GSFLG=00 as long as there is no shift command after the shift is completed,
Control proceeds to step 43 via steps 41 and 42,
Here, the retard amount θ _RET for the ignition timing retard (engine output reduction) control which is the object of the present invention is set to zero. In the next step 56, timer TM ₁ is set to the set time T ₃
Check whether the above is true or not. The timer TM ₁ is activated when a shift command is issued in step 55, and measures the elapsed time since then, and therefore represents the time elapsed since the shift command (t ₁ in FIG. 5). Also, setting time
For example, as shown in FIG. 5, _T3 is set to a length that sufficiently covers the time from the shift command to the end of the shift. Therefore, TM ₁ ≧T ₃ indicates that the time required for shifting has already elapsed, and even if TM ₁ ≧T ₃ , this is a fail-safe measure that eliminates the inconvenience of engine output reduction control to reduce shift shock. ,
According to the settings in step 57, θ _RET =0 is set here, the flag GSFLG is returned to 00, and the timer _TM1 is cleared (reset). During TM ₁ <T ₃ , steps 44 and 45 are executed to perform predetermined ignition timing control as follows. In other words, in step 44, the throttle opening (signal S _TH ), engine speed (signal S _N ),
The fuel injection pulse width (fuel supply amount) calculated based on the engine intake air amount (signal S _Q ), engine cooling water temperature (signal S _T ), etc. is read, and the ROM26 The normal ignition timing is read out from the table data in the table using the table lookup method. Next step 45
After correcting this ignition timing in the retard direction by the retard amount θ _RET , the control is terminated in step 46.
Since θ _RET is now set to 0 in step 43, the ignition timing correction in step 45 is not actually executed.
Therefore, the ignition timing control signal S _I during non-shifting controls the ignition timing control device 11 to the normal ignition timing with respect to the crank angle signal S _C , and does not reduce the engine output during non-shifting. Also, when it is determined in step 56 that T≧T ₃ ,
A similar situation is obtained by executing step 57.
In this way, since the shift is originally completed when TM ₁ ≧ T ₃ , the ignition timing control for reducing shift shock should have been completed, but due to a malfunction due to a failure or noise in the signal system, the shift is not performed as described below. It is possible to prevent the problem of the engine being unable to determine the end of the engine and ignition timing control for reducing shift shock is executed indefinitely, and even when the problem occurs, the driver is forced to drive with reduced engine output. There isn't. By the way, if it is determined in step 41 that there is a shift command, the control proceeds to step 47, where the shift flag GSFLG is set to 01 to correspond to the presence of a shift command, and in the next step 55, the above-mentioned timer is set.
Execute startup of TM ₁ . In the next step 48
GSFLG is checked, but since it is set to 01 at step 47, control proceeds to step 49. In this step, the engine speed N _E (signal
It is determined whether or not the shift has not yet started based on whether the amount of change (temporal change rate) N 〓 _E of S _N ) during one calculation cycle has become negative. This rate of change N– _E is shown in FIG. 5 for a 2->3 shift up shift, and since it becomes negative at _t2 when the shift starts, it is determined that the shift has started. If _N〓E ≧0 and the shift has not started, the control advances to steps 44 and 45, and then
Normal ignition timing control is executed using θ _RET =0 at 43. Note that steps 47 and 55 are executed only once when a shift command is issued, and thereafter step 41 selects step 42, but
Since GSFLG is not 00, step 42 is a step.
48 will be selected. After that, at the start of the shift when N〓 _E < 0, step 49 selects step 50, and here the retardation amount is set so that the engine output decreases to eliminate the sudden change T _p ' in the output torque T _p shown in Fig. 6. Find θ _RET by calculation or table lookup method, and then calculate it in the next step 51.
GSFLG 11 to indicate that gear shifting has started
After setting, control passes to steps 56, 44, and 45. Thus, in step 45, the ignition timing is corrected to be delayed by θ _RET from the normal ignition timing determined in step 44, and the ignition timing control signal S _I is set at the start of the shift.
The ignition timing control device 11 can be controlled so that the ignition timing is delayed by θ _RET with respect to the crank angle signal _SC . Therefore, the engine output is reduced, the fluctuation in the output torque shown by T _p ' in FIG. 6 can be eliminated, and the shift shock caused by this can be alleviated. After the start of this shift, the control proceeds to step 41, since GSFLG is set to 11 in step 51 as described above.
Proceed to step 58 via steps 42 and 48. This step 58
Now, the amount of change in engine rotation during one calculation cycle above.
N〓 Depending on whether _E changes from a decreasing direction to an increasing direction, the moment slightly before the end of the gear shift t ₃ in Fig. 5 is determined.
It is determined whether or not t ₂ ' has been reached, and step 58 advances the control to steps 56, 44, and 45 until the instant t ₂ ', so that the ignition timing is normalized by the retard amount θ _RET determined in step 50. The engine output reduction control for reducing the shift shock is continued with the ignition timing being delayed from the ignition timing of the engine. Note that N〓e may be obtained as N〓e≒ΔNe=Ne−e. [N-e; value after low-pass filter, e=Ne
(n-1)/n+Ne(1/n)] At the instant t2' in FIG. 5, where it is determined in step ₅₈ that _N〓E has turned to an increasing direction, the control proceeds to step 58.
59, where GSFLG is set to 10 to indicate that instant t ₂ ' has been reached, and then the control is stepped.
Proceed to 56, 44, 45. It was set like this
GSFLG=10 causes step 48 to select step 60, where the predetermined value α is sensed from the retard amount θ _RET (the value found at step 50 at first, and the value updated at step 60 from the second time onwards). The value is updated as a new value angle quantity. In the next step 61, it is determined whether or not this updated retard amount θ _RET has reached 0. If it has not reached 0, the control proceeds to steps 56, 44, and 45, and if it has reached it, θ _RET is increased in step 62. After setting GSFLG to 00 and returning it to 00, the control returns to step 56.
Proceed to 44 and 45. Thus, in this example, as shown in FIG. 5, the ignition timing gradually returns to the normal ignition timing by α per calculation cycle after the instant t ₂ '. The above control is performed from 2 to 3 in Fig. 5 corresponding to Fig. 6.
To give a general explanation of the shift-up shift, after the shift command instant t ₁ , the time rate of change in engine speed N〓 _E becomes negative at the start of the shift t ₂ , and then from the instant t ₂ when N〓 _E changes from a decreasing direction to an increasing direction. Until then, the ignition timing is delayed by θ _RET from normal. Since the engine output is thereby reduced, the output torque T _p shown in Fig. 6 can be made almost constant without fluctuation T _p ', and the torque due to inertial force can also be made constant with no fluctuation T _n shown in Fig. 6. It becomes like a dashed-dotted line with no . In the above example, the ignition timing is delayed in order to reduce engine output to reduce shift shock, but in addition to or in place of this, it is also possible to reduce the amount of fuel supplied to the engine or increase the amount of exhaust gas recirculation. It goes without saying that the same objective can also be achieved by adopting a configuration in which the turbocharger supercharging pressure is lowered. When stopping _the ignition timing control for reducing shift shock, the time rate of change in engine speed N〓 _E
The retard amount θ _RET is gradually decreased from the moment t ₂ ′ when the ignition timing starts to increase, and at the end of the shift, t ₃ , it is set to 0 and the ignition timing is returned to the normal ignition timing. The ignition timing control in the region immediately before the end of the shift is based on the torque fluctuations T _p ′, T _n described above with reference to FIG.
This corresponds to the actual convergence waveform shown by the two-dot chain line. Therefore, the ignition timing control (engine output reduction control) for reducing shift shock will not become excessive just before the end of shift, and it is possible to prevent new deceleration shock from occurring and deterioration of driving performance. . (Effects of the Invention) Thus, as described above, the shift shock reducing device of the present invention controls the control by adjusting the time rate of change of the engine speed or automatic transmission input speed to the set value when reducing the engine output to reduce the shift shock. The engine output reduction control is started when the rate of change exceeds the above, and the engine output reduction control is stopped while gradually decreasing the engine output reduction amount from when this rate of change reverses the increase/decrease direction.As a result, the response delay from the shift command to the start of the shift and the shift Even if the delay in operation from the start to the end of the shift changes due to variations in the hydraulic system, wear of friction elements over time, or the temperature (viscosity) of the hydraulic oil, the start and end of the engine output reduction control can always be set to the start and end of the shift. By matching the engine output reduction control mode to the torque fluctuation waveform immediately before the end of the shift, it is possible to reliably achieve the desired shift shock reduction effect, and to prevent the occurrence of new deceleration shocks and improve driving performance. Deterioration can be prevented.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of the shift shock reducing device of the present invention, Fig. 2 is an overall system diagram showing an embodiment of the device of the present invention, Fig. 3 is a block diagram of the controller in the device, and Fig. 4 is the controller. 5 is a flowchart showing the control program of FIG. 5. FIG. 5 is an operation time chart of the apparatus of the same example. FIG. 6 is an operation time chart used to explain the cause of shift shock occurrence. 1...Engine, 2...Intake manifold, 3...
...Flow meter, 4...Air cleaner, 5...
Converter housing, 6...Transmission case, 7
... Valve body, 8 ... Rear extension, 9 ... Spark plug, 10 ... Distributor, 11 ... Ignition timing control device, 12 ... Accelerator pedal, 13 ... 1-2 shift valve, 14 ...
...2-3 shift valve, 15...3-4 shift valve, 16...controller, 17...throttle opening sensor, 18...1-2 shift switch,
19...2-3 shift switch, 20...3-4
Shift switch, 21... Crank angle sensor, 2
2...Engine coolant temperature sensor, 23...Engine rotation sensor, 24...Central processing unit, 25
... Random access memory, 26 ... Read-only memory, 27 ... Input interface circuit, 2
8... Output interface circuit, 29... Waveform shaping circuit, 30... A/D converter, 31... Drive circuit, 32... Power supply circuit.

Claims (1)

[Scope of Claims] 1. In a vehicle that is driven by power from an engine via an automatic transmission, a rotation speed change rate detection means for detecting a time change rate of the engine rotation speed or the input rotation speed of the automatic transmission; and automatic transmission. A shift command detecting means for detecting a shift command of the machine; a shift start timing determining means for detecting that the time rate of change of the rotational speed after the shift command becomes equal to or higher than a set value and determining that the shift has started; engine output reducing means for reducing the engine output to a value required to prevent shift shock; and a rotation speed change rate increase/decrease direction for detecting the moment when the time change rate increase/decrease direction of the rotation speed reverses after the shift start. An automatic gear shift characterized in that it is provided with a reversal timing determination means and an engine output return means for instructing the engine output reduction means to gradually reduce the engine output reduction amount from the instant of the reversal and make it zero at the end of the shift. Gear shift shock reduction device for vehicles equipped with aircraft.