JPH0467058B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a shift shock reduction device for a vehicle equipped with an automatic transmission, which is driven by power from an engine via the automatic transmission. (Prior art) An automatic transmission selectively operates internal friction elements (clutches, brakes, etc.) depending on the vehicle state while the vehicle is running, automatically selects the optimum gear position of the power transmission gear train, and transmits engine power. Although the speed is increased or decelerated to match the driving conditions, a shift shock occurs because the output shaft torque suddenly changes when changing gears. 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 (1st gear to 2nd gear).
→2 upshift), shifting from 2nd gear to 3rd gear (2→3 upshift shifting), or shifting from 3rd gear to 4th gear (3→4 upshift shifting)
This becomes noticeable because these gear changes are often performed during power-on driving with the engine's accelerator pedal depressed significantly. For example, as shown in Fig. 9, 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 . The effective gear ratio of the automatic transmission is ΔT.As the operation of the friction element progresses during ₂ hours, the gear ratio of the second gear R _L (for example, 1.4) changes to the gear ratio of the third gear R _H (for example, 1.0). . Also, during this period, the input rotation speed Ni from the torque converter of the automatic transmission to the power transmission gear train decreases in response to the change in the gear ratio between instants t ₂ and _{t 3} , and matches the output rotation speed No of the automatic transmission ( The engine speed also changes with a similar tendency).
Theoretically, the input torque Ti (approximately the same as the engine output torque Te) from the torque converter of the automatic transmission to the power transmission gear train will approximately correspond to the above change in the input rotation speed Ni, unless the engine throttle opening is changed. The automatic transmission's output torque To is inversely proportional and is expressed by multiplying this input torque by the effective gear ratio.
remains almost constant. However, in reality, while the input rotation speed Ni decreases during the ΔT ₂ period, the engine's inertia acts to prevent this rotation speed decrease, and applies inertia mode torque to the input shaft of the automatic transmission, resulting in The output torque To changes as shown by To' during the gear shifting operation (during the ΔT ₂ period). As a result, a torque T _n due to inertia force is generated during the period ΔT ₂ , which causes a shift shock. Therefore, the applicant of the present application previously disclosed in Japanese Patent Application Laid-Open No. 58-207556 based on the fact that the shift shock is based on a sudden change in the transmission output shaft torque as described above, and in order to reduce the engine output at this time. We have already proposed a technology that reduces shift shock by delaying the ignition timing compared to normal to compensate for sudden changes in transmission output shaft torque. 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. (Problem to be Solved by the Invention) However, the response delay from the shift command for switching the shift valve to the start of the actual shift and the operation delay from the start of shift to the end of shift are caused by the hydraulic system. The timer control described above cannot always match the start time of the ignition timing control with the actual shift start time.
Furthermore, the end timing of the 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 gear shifting shocks and greatly reduces the commercial value of the vehicle. Therefore, according to Japanese Patent Application Laid-open No. 59-97350,
Since the engine speed changes abnormally during a gear shift operation, a technique has been proposed in which this change is determined to indicate that a gear shift operation is in progress, and the engine output is changed during this time. However, since a torque converter is installed between the engine and the automatic transmission, and this causes slip, when the change in the input rotational speed from the torque converter of the automatic transmission to the power transmission gear train due to gear shifting is small, this The change hardly appears as a change in engine speed, and as a result, in such a case, it is impossible to determine whether to start or end a shift. (Means for Solving the Problems) The present invention determines the start and end of a shift based on a specific change in the input revolution from the torque converter of an automatic transmission to a power transmission gear train instead of the engine revolution. As shown in Fig. 1, in a vehicle that is driven by power from engine a via automatic transmission b, power is transmitted from the torque converter of automatic transmission b. an input rotation speed detection means c for detecting the input rotation speed to the gear train; a shift command detection means d for detecting a shift command for the automatic transmission b; a shift type determination means e for discriminating the type of shift command; Input for calculating the input rotation speed for determining the start of a shift and the input rotation speed for determining the end of a shift by multiplying the input rotation speed at the time of the command by coefficients for determining the start of a shift and for determining the end of a gear shift determined for each type of shift. Rotation speed setting means f
and a shift start timing determining means g that detects when the input rotation speed reaches the input rotation speed for determining shift start after the shift command and determines that the shift has started; A shift end timing determining means h that detects when the input rotation speed for end judgment has been reached and determines that the shift is completed, and a value required for the output of the engine to prevent a shift shock from the start of the shift until the end of the shift. The present invention is characterized in that it is provided with an engine output reducing means i for reducing the engine output. (Function) The gear shift start timing determining means g determines, after the input rotational speed from the torque converter of the automatic transmission b to the power transmission gear train detected by the means c detects the gear shift start determined for each type of gear shift by the means f, after the gear shift command. The engine output reducing means i detects that the input rotation speed for shift start judgment, which is obtained by multiplying the judgment coefficient and the automatic transmission input rotation speed at the time of the shift command, is reached and considers the shift start.
Activate. and means h for determining the end of gear shift.
is the input rotation for determining the end of shifting determined by multiplying the coefficient for determining the end of shifting determined by means f for each type of shifting by the automatic transmission input revolution at the time of the shifting command after the input rotational speed starts shifting. The engine output reduction means i
The above-mentioned operation is suppressed. As a result, the output of the engine a is reduced from the start of the shift until the end of the shift, and a shift shock can be prevented. In order to determine the shift start timing and shift end timing based on the change in the input rotational speed from the torque converter of automatic transmission b to the power transmission gear train,
Even when the rotational change due to gear shifting is small, this determination can be made accurately, and the gear shifting shock prevention effect can be reliably achieved under any conditions. (Example) Hereinafter, an example of the present invention will be described in detail based on the drawings. FIG. 2 shows an overall system according to an embodiment of the shift shock reducing device of the present invention, in which 1 is an engine, 2 is its intake manifold, 3 is an air flow meter for measuring the amount of engine intake air, 4 is an air cleaner, 5 is a converter housing that houses the torque converter of the automatic transmission; 6 is a transmission case that houses the power transmission gear train of the automatic transmission and various friction elements that determine its power transmission path; and 7 is a selective operation of various friction elements. Bubble body housing a shift control hydraulic circuit that determines the gear position, 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. As the accelerator pedal 12 is depressed, the intake air amount of the engine 1 is increased, and the fuel injection amount is increased from an injector (not shown) to increase the output. The power is then input to the power transmission gear train in the transmission case 6. Automatic transmission has 1-2 shift valves 13, 2-3
Shift valve 14 and 3-4 shift valve 15
automatically selects an appropriate gear from 1st to 4th gear according to the vehicle running condition, changes the engine power at a gear ratio corresponding to the selected gear, and transmits it to the drive wheels of the vehicle shown in the figure. run. In the present invention, the ignition 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 opens and closes according to the signal S _TH from the throttle opening sensor 17 that detects the amount of depression of the accelerator pedal 12 (engine load), and the spool position of the shift valves 13 to 15. - Signals from 2 shift switch 18, 2-3 shift switch 19, 3-4 shift switch 20
S ₁₂ , S ₂₃ , S ₃₄ , signal S _Q corresponding to the intake air amount from air flow meter 3, distributor 1
Signal from crank angle sensor 21 built into 0
S _C , a signal S _T from the engine coolant temperature sensor 22 that detects the engine coolant temperature, and an output based on the calculation results of the signal S _N from the sensor 23 that detects the automatic transmission input rotation speed (torque converter output rotation speed) (Ignition timing control signal) The ignition timing control device 11 is controlled by S _I. In addition, 1-2 shift switch 18 and 2-3
The shift switches 19 are, for example,
As described in Publication No. 127856, when the spools of the 1-2 shift valve 13 and the 2-3 shift valve 14 are in the downshift position, they close and output an L level signal.
In addition, when the spool of the 3-4 shift valve 15 is in the downshift position, it is opened to output an H level signal, and the 3-4 shift switch 20 similarly closes and outputs an L level signal when the spool of the 3-4 shift valve 15 is in the downshift position. It is assumed that the cap is opened when the cap is open and outputs an H level signal. Thus, the shift signals S ₁₂ , S ₂₃ , S ₃₄
The following table shows the combination of levels for each gear.

[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 ignition timing control (engine output reduction control for reducing shift shock) which is the object of the present invention. This control program is repeatedly started in step 40 when the engine is started by turning on the ignition switch and a regular interrupt from a timer (not shown) occurs. First, in step 41, 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, control is carried out in step 4
Proceed to step 2. In this step 42, as will be described later, it is set to 01 when a shift command is issued, and set to 11 when a shift is started.
Check the shift flag GSFLG, which is returned to 00 at the end of the shift. Since GSFLG=00 as long as the state of no shift command continues after the end of the shift, the control proceeds to step 43, where the retard amount θ is determined for the ignition timing retard (engine output reduction) control which is the object of the present invention. Set _RET to 0. In the next step 44, the throttle opening (signal S _TH ),
Engine rotation speed, engine intake air amount (signal S _Q ), which can be obtained by calculating the input period of crank angle signal S _C ,
In addition to reading the fuel injection pulse width (fuel supply amount) calculated based on the engine cooling water temperature (signal _S is read out using the table lookup method. In the next step 45, this ignition timing is corrected in the retard direction by the retard amount θ _RET , and then the control _is terminated in step 46.
= 0, 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. 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. In the next step 55, the input rotational speed Ni ₁ (signal S _N ) from the torque converter of the automatic transmission to the power transmission gear train at the time of the relevant shift command and which of the shift signals S ₁₂ , S ₂₃ , and S ₃₄ are determined. The input rotation speed change ratio β (coefficient for determining shift start) set for each type of shift command, which can be determined by level change, is multiplied by β ₂ (coefficient for determining shift end). The number N ₁ and the input rotation speed N ₂ for determining the end of shifting are determined. Next step 4
Check GSFLG at step 8, but now step 47
Since this is set to 01, the control is at step 4.
Proceed to step 9. In this step, the automatic transmission input rotation speed Ni (signal S _N ) is the input rotation speed for determining the start of gear shifting.
It is determined whether or not N is less than ₁ , that is, whether the ratio of the input rotation speed Ni to the input rotation speed Ni ₁ at the time of the gear shift command is less than β ₁ , and it is determined whether or not the actual gear shift has started. . When Ni>N ₁ and the shift has not yet started, the control proceeds to steps 44 to 46, and normal ignition timing control is executed using θ _RET =0 in step 43. Note that steps 47 and 55 are executed only once when a shift command is issued, and thereafter, even if step 41 selects step 42, it is no longer executed.
Since GSFLG is not 00, step 42 selects step 48. After the response delay ΔT ₁ (see FIG. 9), at the start of the shift when Ni≦N ₁ , step 49 selects step 50, and here the sudden change T _p ' of the output torque T _p shown in FIG. 9 is calculated. The amount of retardation θ _RET that causes a decrease in engine output is determined by calculation or by a table pull-up method, and in the next step 51 GSFLG is determined.
After setting 11 to indicate that the gear shift has started, control proceeds to steps 44 and 45. Thus, in step 45, the ignition timing is corrected to be delayed by θ _RET from the normal ignition timing θ determined in step 44, and the ignition timing control signal S _I changes the ignition timing control device 11 to the crank angle signal S _C at the start of the shift. On the other hand, it is possible to control the ignition timing to be delayed by θ _RET compared to normal. Therefore, the engine output is reduced, the fluctuation in the output torque shown by T _p ' in FIG. 9 can be eliminated, and the shift shock caused by this can be alleviated. This control after the start of the shift is performed by GSFLG as described above.
= 11, the process proceeds to step 52 via steps 41, 42, and 48, where it is determined whether the automatic transmission input rotation speed Ni is less than or equal to the input rotation speed _N2 for determining the end of the shift, that is, the input at the time of the shift command. It is determined whether the ratio of the input rotational speed Ni to the rotational speed _Ni1 has become equal to or less than _β2 , and it is determined whether or not the shift has been completed. If the gear shift has not been completed, the control proceeds to steps 44 and 45.
As a result, the ignition timing is delayed from normal by the retardation amount θ _RET finally determined in step 50, and the ignition timing control (engine output reduction control) continues to be executed. When the shift is completed, step 52 sequentially selects steps 53 and 54. In step 53, the retard amount θ _RET is set to 0, and in step 54, the shift flag GSFLG is returned to 00. Thereafter, the control proceeds to steps 44 and 45, but since θ _RET =0 as described above, normal ignition timing control is executed and no reduction in engine output occurs. The above control will be briefly explained for the 2→3 shift-up shift corresponding to FIG. _9. As shown in FIG.
The ignition timing remains at the normal θ from time t ₂ at the start of the shift, when Ni becomes less than or equal to the input revolution number N ₁ for determining the start of the shift, until time t ₃ at the end of the shift, when Ni becomes less than the input revolution number N ₂ for determining the end of the shift. is delayed by θ _RET .
This reduces engine output, so
The input torque T _i is lower than the conventional characteristic shown by the virtual line, as shown by the solid line, and the output torque T _p can be kept almost constant without fluctuation T _p ', and the torque due to inertial force is also lower than the conventional characteristic shown by the solid line. Since there is no variation T _n as shown by the imaginary line, the shift shock can be reduced. 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. FIG. 6 shows another example of the control program, in which step 56 is added between steps 47 and 55, and steps 57 and 58 are added before step 44. In step 56, when a shift command is received, the timer _TM1 is activated to measure the time elapsed since the shift command. In step 57, it is determined whether or not this timer has exceeded the set time shown, for example, at _T3 in FIG. 5 (the set time that covers the time from the shift command to the end of the shift). If TM ₁ < T ₃ , control step 44;
In order to proceed to step 45, ignition timing control similar to the example described above is executed. However, if TM ₁ ≧T ₃ , control proceeds to step 58 where GSFLG is reset to 00, timer TM ₁ is cleared, θ _RET is set to 0, and control proceeds to steps 44 and 45. In this way, since the shift is originally completed when TM ₁ ≧ T ₃ , the ignition timing control for reducing the shift shock should have been completed, but due to a malfunction due to a failure or noise in the signal system, the shift is stopped at step 52. It is possible to prevent the problem of the ignition timing control for reducing shift shock being executed forever without being able to determine the end of the shift, and even when the problem occurs, the user is not forced to drive with a reduced engine output. FIG. 7 shows still another example of the control program,
In this example, the second-order differential value N¨i of the input rotational speed N _i changes from negative to positive at the same time t ₂ ′ as the first-order differential value N _{·i of} the input rotational speed N _i shown in FIG. From the moment the ignition timing changes, the ignition timing should be gradually returned to the normal ignition timing. Therefore, in step 55, the input rotation speed N ₃ corresponding to the instant t ₂ ' is multiplied by the input rotation speed change ratio β ₃ set for each type of shift command and the input rotation speed N _i1 at the time of the shift command. Find it by
Although the method for determining N ₁ in this step is the same as in each of the embodiments described above, the input rotational speed N ₂ for determining the end of the shift is not determined in this step. In addition, the shift flag GSFLG is set to 01 when there is a shift command as in each of the above embodiments, and is set to 11 at the start of shifting (when N _i ≦N ₁ ), but when N _i ≦N ₃ , as shown in FIG. It becomes 10 at the middle instant t ₂ ', and the retard amount θ _RET becomes 0 (the ignition timing returns to the normal ignition timing). It is assumed that it returns to 00 at the instant t ₃ (at the end of the shift) in Figure 8. . At the start of the shift (instant t ₂ in FIG. 8) when the input rotation speed N _i after the shift command becomes equal to or less than the input rotation speed N ₁ for determining the shift start, the control in FIG. 42, 48, 49, 50, 5
1, 57, 44, and 45 to perform ignition timing control to prevent shift shock. This control is then carried out in step 59.
This continues until the instant t ₂ ' in FIG. 8 when N _i ≦N ₃ , and the shift shock can be reduced in the same way as in the previous example. Thereafter, in step 60, GSFLG is set to 10 to indicate that the instant t ₂ ' has been reached.
Step 48 selects Step 61, and here the value obtained by subtracting the predetermined value α from the retard amount θ _RET (the value obtained in Step 50 at first, and the value updated in Step 61 from the second time onwards) is determined as a new retard angle. Update as quantity. In the next step 62, it is determined whether the updated retard amount θ _RET has reached 0 or not. If it has not reached 0, the control proceeds to steps 57, 44, and 45, and if it has reached it, the θ _RET is increased in step 63. 0 and set GSFLG to
After returning to 00, the control goes to steps 57, 44, 45.
Proceed to. Thus, in this example, as shown in FIG. 8, the ignition timing gradually returns to the normal ignition timing by α per calculation cycle after the instant t ₂ '. The reason why the ignition timing is controlled in this way is that in reality, due to the characteristics of the friction element, the torque fluctuation T _p ' (see Figures 5 and 9) does not suddenly decrease around the instant _t3 , but gradually decreases. In some cases, the amount of output reduction due to engine output reduction control is smaller than the torque T _n due to inertial force (see Figures 5 and ₉ ). This is to make it smoother and further increase the effect of reducing shift shock. (Effects of the Invention) As described above, the shift shock reducing device of the present invention reduces the engine output to reduce the shift shock by controlling the input rotational speed from the torque converter of the automatic transmission to the power transmission gear train. The configuration starts when the input rotational speed for determining the start of shifting is reached and ends when the input rotational speed reaches the input rotational speed for determining the end of shifting, so there is a response delay from the shifting command to the start of shifting, and an operation delay from the beginning of shifting to the end of shifting. Even if changes occur due to variations in the hydraulic system, wear of friction elements over time, or hydraulic oil temperature (viscosity), the start and end of the engine output reduction control can always be made to coincide with the shift start and end times, so that the desired speed change is achieved. It is possible to reliably achieve the effect of alleviating the shift shock, and also to prevent the occurrence of new deceleration shocks caused by a shift between the above two timings. Furthermore, in the present invention, the start and end of shifting is determined based on changes in the automatic transmission input speed, not the engine speed. Even when changing gears, the start and end can be detected reliably and accurately at all times.
The gear shift shock prevention effect can be reliably achieved under any conditions. In addition, the automatic transmission input rotation speed is the input rotation speed for shift start judgment determined by multiplying the input rotation speed at the time of the shift command by the coefficient for shift start judgment and shift end judgment determined for each type of shift. Since the time when the input rotation speed for determining the end of the shift is reached is determined to be the start of the shift and the end of the shift, the detected value of the input rotation speed can be used as the determination data without being processed for this determination, making the determination quick and easy. It is accurate, and in this respect as well, the above-mentioned shift shock prevention effect can be reliably performed.

[Brief explanation of the drawing]

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 same. FIG. 5 is a flowchart showing a control program of the controller, FIG. 5 is an operation time chart of the apparatus of the present invention, FIGS. 6 and 7 are flowcharts showing other examples of the control program, and FIG. 8 is an example of FIG. 7. FIG. 9 is an operation time chart used to explain the cause of shift shock. 1... Engine, 2... Intake manifold, 3... Air flow meter, 4... Air cleaner, 5... Converter housing, 6... Transmission case, 7... Valve body, 8... Rear extension, 9... Spark plug,
DESCRIPTION OF SYMBOLS 10... Distributor, 11... Ignition timing control device, 112... 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, 22... engine coolant temperature sensor, 23... transmission input rotation speed sensor, 24... central processing unit,
25...Random access memory, 26...Read-only memory, 27...Input interface circuit, 28
...Output interface circuit, 29...Waveform shaping circuit, 30...A/D converter, 31...Drive circuit, 32
...Power circuit.

Claims (1)

[Claims] 1 In a vehicle that is driven by power from an engine via an automatic transmission equipped with a torque converter and a power transmission gear train, an input that detects the input rotational speed from the torque converter of the automatic transmission to the power transmission gear train. a speed change detection means, a speed change command detection means for detecting a speed change command of the automatic transmission, a speed change type determining means for determining the type of speed change command, and a speed change command detecting means for detecting a speed change command of the automatic transmission; a speed change type determining means for determining the type of speed change command; input rotation speed setting means for determining an input rotation speed for determining the start of a shift and an input rotation speed for determining the end of a shift by multiplying the coefficients for determining the start of a shift and for determining the end of a shift, respectively; A shift start timing determining means detects that the input rotation speed reaches the input rotation speed for determining the start of the shift and determines that the shift has started; and an engine output reducing means for reducing the output of the engine to a value required to prevent a shift shock from the start of the shift until the end of the shift. Characteristic transmission shock reduction device for vehicles equipped with automatic transmissions.