JPH05126236A - Speed change shock reducing device for automobile - Google Patents

Abstract

PURPOSE:To improve a follow-up characteristic to target torque, in the case of reducing a speed change shock by ignition timing control and fuel cut cylinder quantity control. CONSTITUTION:At the time of starting a speed change, a target torque waveform of a transmission output shaft during a speed change period is set by a means (a) and also setting a fuel cut cylinder quantity initial by a means (b). During the speed change period, actual torque of the transmission output shaft is detected by a means (c) while performing a fuel cut of the fuel cut cylinder quantity by a means (f), and a delay amount of ignition timing is set based on a torque deviation, so that this actual torque approaches target torque, to feedback control the ignition timing by a means (d). During feedback control, when the delay amount of the ignition timing reaches in the vicinity of a predetermined limit value, the fuel cut cylinder quantity is increased by 1 and reset by a means (e), thus to perform the fuel cut by the means (f).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift shock reducing device for an automobile having an automatic transmission.

[0002]

2. Description of the Related Art Conventionally, in order to reduce a shift shock at the time of shifting of an automatic transmission for an automobile, the ignition timing of the engine is retarded at the time of shifting to reduce the torque generated by the engine. It is known to suppress a sudden change in torque.

[0003]

However, the torque reduction due to the ignition timing retard control is limited due to exhaust performance and the like, and there are cases in which a sufficient shift shock reducing effect cannot be obtained. Therefore, the applicant of the present invention uses the retard control of the ignition timing and the control for stopping the fuel supply to some cylinders of the engine (fuel cut cylinder number control) to perform the torque down control during shifting. Proposed device (Japanese Patent Application No. 3-
27357).

Specifically, during the gear shift period, fuel is cut off for some cylinders of the engine, the actual torque of the transmission output shaft is detected, and the ignition timing is feedback-controlled so as to bring it closer to the target torque. The number of fuel cut cylinders is increased when the deviation between the actual torque and the target torque exceeds a predetermined value. However, in this device, the number of fuel cut cylinders initially set at the start of gear shifting is increased when the deviation between the actual torque and the target torque becomes greater than a predetermined value thereafter. When (quantity) reaches the limit value,
Until the torque deviation exceeds a predetermined value, effective control is not performed, the actual torque deviates from the target torque, and the followability to the target torque deteriorates, which causes a shift shock. There was still room for improvement.

It should be noted that, in FIG. 5, immediately after the start of gear shifting, the torque reduction amount T due to the initially set number of fuel cut cylinders T
The actual torque can be made to follow the target torque by D1 and the torque reduction amount TD2 by the ignition timing control. However, when the ignition timing control reaches the limit amount L on the way, the torque deviation becomes the predetermined value S or more. It shows that the actual torque is far from the target torque until the torque reduction TD3 due to the increase in the number of fuel cut cylinders is added.

In view of such circumstances, it is an object of the present invention to further improve the followability to the target torque when reducing the shift shock by the ignition timing control and the fuel cut cylinder number control.

[0007]

Therefore, according to the present invention, as shown in FIG. 1, a gear shift shock reducing device for an automobile is constructed by providing the following means a to f. a) Shift target torque setting means for setting the target torque of the transmission output shaft during the shift period at the start of shift b) Fuel cut cylinder number initial setting means for initially setting the number of fuel cut cylinders at the start of shift c) Shift Actual torque detection means for detecting the actual torque of the transmission output shaft during the period d) Ignition timing feedback control means for feedback controlling the ignition timing of the engine so that the actual torque approaches the target torque during the shift period e) Feedback controlled Fuel cut cylinder number increase / decrease setting means for increasing / decreasing and resetting the fuel cut cylinder number when the ignition timing near a predetermined limit value f) During the gear shift period, the fuel cut cylinder number initial setting means or the fuel Fuel cut control for stopping the supply of fuel to some cylinders of the engine corresponding to the number of fuel cut cylinders set by the cut cylinder number increase / decrease setting means Means

[0008]

In the above structure, the target torque (waveform) of the transmission output shaft during the shift period is set and the number of fuel cut cylinders is initialized at the start of the shift. Then, during the shift period, the actual torque of the transmission output shaft is detected while performing fuel cut for the number of fuel cut cylinders, and the ignition timing is feedback-controlled so that the actual torque approaches the target torque.

When the ignition timing reaches the vicinity of a predetermined limit value during the feedback control, the number of fuel cut cylinders is immediately increased or decreased and reset. As a result, the transmission output shaft torque can be linearly controlled by the ignition timing control while using the fuel cut to some cylinders at the same time, and the quick fuel cut can be performed when the torque deviation cannot be eliminated only by the ignition timing control. By increasing or decreasing the number of cylinders, the ability to follow the target torque can be improved.

[0010]

EXAMPLE An example of the present invention will be described below. A system diagram is shown in FIG. An automatic transmission 2 is connected to the output side of the engine 1. The automatic transmission 2 includes a torque converter 3 interposed on the output side of the engine 1, a gear type transmission 4 connected through the torque converter 3, and a combination of various transmission elements in the gear type transmission 4. And a hydraulic actuator 5 for performing a releasing operation. The hydraulic pressure for the hydraulic actuator 5 is ON / OFF controlled via various electromagnetic valves (not shown).

Signals from various sensors are input to the control unit 6. Examples of the various sensors include, for example, the opening T of the throttle valve 7 of the intake system of the engine 1.
A throttle sensor 8 for detecting VO is provided.
A crank angle sensor 9 is provided on the crankshaft of the engine 1 or a shaft that rotates in synchronization with the crankshaft. The signal from the crank angle sensor 9 is, for example, a pulse signal for each reference crank angle position, and the engine rotation speed N is calculated from the period.

A vehicle speed sensor 11 for detecting a vehicle speed VSP by obtaining a rotation signal from the output shaft 10 of the automatic transmission 2 is provided. Further, a magnetostrictive torque sensor 12 is provided which is attached to the output shaft 10 of the automatic transmission 2 and serves as an actual torque detecting means for detecting the output shaft torque T. The control unit 6 is, for example, an integrated type that incorporates an engine control CPU and an automatic transmission control CPU.
A dual port RAM accessible from the PU is used, and with such a configuration, the data calculated by both CPUs can be shared.

The engine control CPU controls the fuel injection amount and the like by controlling the fuel injection pulse signal to the fuel injection valve 13 provided for each cylinder in the intake system of the engine 1 based on the engine operating state, Further, the ignition timing is controlled by controlling an ignition signal to an ignition coil (not shown) connected to the spark plug 14 of each cylinder based on the engine operating state.

The automatic transmission control CPU, based on the operation position signal of the select lever operated by the driver, when the select lever is in the D range, the 1st to 4th speed change positions according to the throttle valve opening TVO and the vehicle speed VSP. Is automatically set, and shift control is performed to control the gear type transmission 4 to the shift position via the hydraulic actuator 5. In addition, the automatic transmission control CPU performs torque-down control during shifting in order to reduce shift shock according to the flowcharts shown in FIGS. 3 and 4, and sends the result to the engine control CPU,
Ignition timing retard control and fuel cut cylinder number control are performed.

The transmission torque down control will be described with reference to the flowcharts shown in FIGS. It should be noted that this routine is executed every predetermined time. First step 1
(Indicated as S1 in the figure. The same applies hereinafter), flag F
Is determined, and if F = 0 (before the start of control), the process proceeds to step 2. In step 2, shift starts (inertia phase)
Or not. For example, the output shaft torque T sharply decreases when the clutch is disengaged at the start of the gear shift, and then rapidly increases when the clutch is engaged. Therefore, the torque change can be detected and determined.

If it is determined that the shift is not started, F =
Since this is 0 and gear shifting is not in progress, this routine is ended. When it is determined that the shift is started, steps 3 to 7 are executed and then steps 8 to 15 are executed. In step 3, F = 1 (during control) is set.

In step 4, a timer TIM for counting the elapsed time after the start of gear shifting is started to 0. Step 5
Then, the target torque waveform during shift including the target shift time TIM ₀ (see FIG. 5) is set. It should be noted that the target torque waveform at the time of shifting is the output shaft torque T, the engine speed N,
Throttle valve opening TVO, gear ratio Gb before gear shift and gear ratio G after gear shift depending on the type of gear shift (first speed → second speed, second speed → third speed, etc.)
It is set based on the gear ratio GR (= Ga / Gb) and the like obtained from a.

In step 6, the number x of fuel cut cylinders is initialized. This is also set based on the throttle valve opening TVO, the gear ratio GR, and the like. However, the initial setting value includes x = 0. In step 7, a fuel cut command including information such as the number x of fuel cut cylinders initially set in step 6 is sent to the CPU for engine control to cut fuel for the set number x of fuel cut cylinders (corresponding fuel injection valve). (Prohibit output of fuel injection pulse signal to 13) is started.

In step 8, the current target torque T ₀ is read from the target torque waveform during shifting set in step 5. In step 9, the actual torque T of the transmission output shaft 10 is detected based on the signal from the torque sensor 12. In step 10, the deviation ΔT between the actual torque T and the target torque T ₀
= To calculate the T-T _0.

In step 11, the retard amount R = f (ΔT) of the ignition timing is set based on the torque deviation ΔT so that the actual torque T approaches the target torque T ₀ . Step 12
Then, an ignition timing retard command including information such as the retard amount R set in step 11 is sent to the engine control CPU to perform ignition timing retard control. In the engine control CPU, the retard amount R is calculated from the basic ignition timing (ignition advance) MADV set based on the engine operating condition (basically, the engine rotation speed N and the fuel injection amount Tp). The final ignition timing ADV is set by subtraction, and when the ignition timing ADV is reached, an ignition signal is output.

In step 13, the retard amount R set in step 11 is compared with a predetermined limit value R _MAX, and R <R
_In the case of _MAX , this routine ends. However, the limit value R _MAX here is a value slightly smaller than the actual limit value. When R ≧ R _MAX (that is, when the retard amount reaches near the limit value), the routine proceeds to step 14, where the fuel cut cylinder number x is incremented by 1. Then, in the next step 15, a fuel cut command including information such as the reset fuel cut cylinder number x is sent to the engine control CPU to cause the fuel cut for the reset fuel cut cylinder number x to be performed. , This routine ends.

After the start of gear shifting, that is, during gear shifting, when this routine is executed, the value of the flag F is determined in step 1, and since F = 1, the routine proceeds to step 16. Step 16
Then, the value of the timer TIM is compared with the target shift time TIM _0, and if TIM <TIM ₀ (during the shift period), steps 8 to 15 are executed to continue the control.

If TIM ≧ TIM ₀ , it is considered that the shift is completed, the above-mentioned fuel cut command and retard command are canceled in step 17, and the flag F = 0 is set in step 18.
This routine ends. The steps 5 and 8 correspond to the gear shift target torque setting means, the step 6 corresponds to the fuel cut cylinder number initial setting means, and the step 9
Together with the torque sensor 12 corresponds to the actual torque detecting means, the steps 10 to 12 correspond to the ignition timing feedback control means, the steps 13 and 14 correspond to the fuel cut cylinder number increasing / decreasing means, and the step 7 , 15 correspond to the fuel cut control means.

[0024]

As described above, according to the present invention, the output shaft torque of the transmission is linearly changed by the ignition timing control while the fuel cut to some of the cylinders is used together during the shift period, thereby achieving a high accuracy. When the torque deviation cannot be eliminated only by controlling the ignition timing, it is possible to quickly increase or decrease the number of fuel cut cylinders to reach the target torque when the ignition timing reaches the limit value. The following effect can be obtained, and the effect of reducing the shift shock can be further enhanced.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention.

FIG. 2 is a system diagram of an embodiment of the present invention.

FIG. 3 is a flowchart (part 1) of torque down control during shifting.

FIG. 4 is a flowchart (No. 2) of torque down control during shifting.

FIG. 5 is a torque waveform diagram at the time of shifting showing the problems of the prior art.

[Explanation of symbols]

 1 engine 2 automatic transmission 3 torque converter 4 gear type transmission 6 control unit 8 throttle sensor 9 crank angle sensor 10 transmission output shaft 11 vehicle speed sensor 12 torque sensor 13 fuel injection valve 14 spark plug

Claims (1)

[Claims] 1. A vehicle equipped with an automatic transmission on the output side of an engine, wherein a gear shift target torque setting means sets a target torque of a transmission output shaft during a gear shift period at the start of gear shift, and a fuel cut at the start of gear shift. Fuel cut cylinder number initial setting means for initializing the number of cylinders, actual torque detection means for detecting the actual torque of the transmission output shaft during the gear shift period, and the actual torque of the engine so that the actual torque approaches the target torque during the gear shift period. Ignition timing feedback control means for feedback controlling the ignition timing, and fuel cut cylinder number increase / decrease setting means for increasing / decreasing the number of fuel cut cylinders and resetting them when the ignition timing under feedback control reaches near a predetermined limit value. During the shift period, the number of fuel cut cylinders corresponds to the number of fuel cut cylinders set by the fuel cut cylinder number initial setting means or the fuel cut cylinder number increase / decrease setting means. Automotive gear shift shock reduction apparatus comprising: the fuel cut control means for stopping the supply of fuel, to be configured to include a to some cylinders of the engine.