JP2871019B2 - Hydraulic control device for automatic transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a control oil pressure for engaging or disengaging a friction engagement means in an automatic transmission, and in particular, for controlling a control oil pressure according to a driving state of an engine. It concerns the device.

2. Description of the Related Art As is well known, an automatic transmission for a vehicle is configured to set a predetermined gear position by changing a transmission path of power in a gear train by frictional engagement means such as a clutch or a brake. Since the load capacity (torque capacity) of these friction engagement means varies not only with the friction coefficient and the diameter of the friction material but also with the engagement pressure (that is, line oil pressure), the hydraulic pressure is changed according to the load applied to the friction engagement means. Controlling. In addition, when performing a shift, the rotational speed of various rotating members such as gears changes in addition to the engine speed, so that when performing a shift, the hydraulic pressure applied to the friction engagement means is slowly reduced for a certain period of time. , The frictional engagement means is slid, thereby absorbing the inertial energy accompanying the change in the number of revolutions to prevent a sudden change in the output shaft torque, that is, a shift shock.

The control of the engagement pressure is performed by applying a signal pressure corresponding to an engine load to a regulator valve for adjusting a hydraulic pressure generated by a hydraulic pump to change a pressure adjustment level. Specifically, a throttle pressure sent from a throttle valve whose pressure adjustment level is changed by a throttle cam or a throttle pressure sent from an electromagnetic proportional valve controlled in accordance with a throttle opening is applied as a control pressure to a regulator valve. The pressure regulation level is changing. The control during the shifting of the hydraulic pressure for engaging the friction engagement means is performed by applying the hydraulic pressure (line pressure) adjusted by the regulator valve to the back pressure chamber of the accumulator or by applying the hydraulic pressure from the accumulator control valve. In some cases. An example of changing the pressure regulation level using an electromagnetic proportional valve is described in Japanese Patent Application Laid-Open No. 62-215157.

Therefore, in the conventional general control method described above, the line pressure increases with an increase in the throttle opening, so that the torque capacity of the friction engagement means increases, and the hydraulic pressure during shifting changes at a relatively high pressure. As a result, even if the engine torque increases with an increase in the throttle opening, excessive slippage of the friction engagement means and deterioration of the shift shock can be prevented.
Conversely, if the throttle opening decreases and the engine torque decreases, the line pressure also decreases, so that the timing of engagement or disengagement of the friction engagement means during gear shifting is as expected and shift shock does not worsen. .

The conventional general control method described above is based on the premise that the throttle opening and the engine torque always correspond, and changes the pressure regulation level at the regulator valve according to the throttle opening. However, depending on the structure of the engine,
The torque may change discontinuously irrespective of the throttle opening, and the above-described conventional general control method cannot be adopted in an automatic transmission connected to this type of engine.

As an example, a case in which an automatic transmission is connected to an engine adopting a lean burn system (lean burn engine) will be described. The lean burn engine has an air-fuel ratio under a predetermined throttle opening (at a light load). The engine is designed to maintain both high fuel efficiency at light load and high output at high load by maintaining a high value, but when the air-fuel ratio is high (lean range), the cylinder It is necessary to stabilize the combustion inside and improve the combustion efficiency. Therefore, one of the intake ports divided into two is a spiral helical swirl port, and the other port is an on-off valve (swirl control valve: S
CV). At light load, the swirl control valve is closed to generate a spiral flow in the cylinder, which enables lean combustion.However, if the swirl control valve is closed, intake is restricted, so the throttle opening is When the load is higher than a predetermined value (high load), the swirl control valve is opened, and at the same time, the air-fuel ratio is reduced to the stoichiometric air-fuel ratio (stoichiometric) or the output air-fuel ratio so as to obtain sufficient power performance.

FIG. 6 is a diagram showing the relationship between the output torque and the throttle opening in the above-described lean burn engine. The thick solid line in FIG. 6 shows the actual engine torque. In addition,
The curve in FIG. 6 shows the torque characteristic at the time of lean burn (air burn ratio) of about "21". In this state, the swirl control valve is closed. The other curve shows the torque characteristics when the air-fuel ratio is a slightly lean air-fuel ratio of about "17" or "16". Further curves show torque characteristics when the air-fuel ratio is set to "14.5" (stoichiometric burn), and the swirl control valve is opened to perform intake. And the curve shows the air-fuel ratio as “12.5”
4 shows the torque characteristics when the output air-fuel ratio is of the order.

As shown in FIG. 6, the above-described lean bar engine performs lean burn with the air-fuel ratio set to about "21" when the throttle opening TA is equal to or less than the value indicated by TA1 in FIG. In a state where the opening degree TA is between the values indicated by TA1 and TA2 in FIG. 6 (TA1 ≦ TA <TA2), the air-fuel ratio is gradually changed to about “17 to 16” to continuously increase the engine torque. Let it. When the throttle opening TA exceeds TA2, the swirl control valve is opened, and at the same time, the air-fuel ratio is reduced to the output air-fuel ratio to secure torque in a high opening range. However, in the combustion state in which the swirl control valve is opened, the engine torque changes discontinuously as shown by T1 and T2 in FIG. 6 in conjunction with the change in the air-fuel ratio. In other words, even if a plurality of output characteristics can be set for one throttle opening, the output torque changes discontinuously due to a change in the output characteristics.

Such a discontinuous change in torque is caused by operating the swirl control valve,
The conventional method of controlling the line pressure and the accumulator back pressure in the automatic transmission based on the throttle opening is not caused by the change in the throttle opening, and thus the line pressure or the accumulator back pressure is controlled by the engine torque (or the automatic torque). (Input torque to the transmission).

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an improved control device capable of changing a control oil pressure in response to a step change in engine torque.

Means for Solving the Problems In order to achieve the above object, as shown in FIG. 7, the present invention relates to an engine 120 in which an output torque is discontinuously changed by changing an output characteristic, and An automatic transmission 121 capable of changing a ratio, wherein the control hydraulic pressure of the automatic transmission 121 capable of arbitrarily adjusting a control oil pressure acting on a gear ratio control mechanism for controlling a gear ratio is provided. Elapsed time detecting means 123 for detecting the elapsed time from the output of the change command signal for changing the value in accordance with the increase or decrease direction of the engine output, and after the elapse of a predetermined time is detected by the elapsed time detecting means An output characteristic control means 124 for executing control for changing the output characteristic is provided.

According to the present invention, after outputting the instruction signal for changing the value of the control oil pressure in accordance with the direction in which the output characteristic increases or decreases, the output characteristic of engine 120 is changed after a predetermined time has elapsed. Therefore, even if the control oil pressure changes with some response delay due to the viscosity of oil, etc., the change in engine torque substantially coincides with the change in control oil pressure. In addition, it is possible to prevent the engine torque and the control oil pressure from being in a mismatch state.

Embodiment Next, an apparatus of the present invention will be described based on an embodiment.

First, an engine E and an automatic transmission A connected to the engine E according to the present invention will be described. The engine E is configured such that the output torque is changed discontinuously by an on-off valve provided in an intake system. An example is the swirl control valve 1 shown in FIG. That is, as shown in FIG. 2, two intake ports 3, 4 and intake valves 5, 6 are provided for one cylinder 2, and one of the intake ports 3 has a swirl control valve 1 for opening and closing the same. Is provided. Therefore, when the swirl control valve 1 is closed, the intake air flows as shown by the arrow in FIG. 2 and flows into the cylinder 2 while turning around the valve stem of one intake valve 6, so that a strong swirl is generated. Let it. When the swirl control valve 1 is opened, air is taken in from both the intake ports 3 and 4. In the engine E, the air-fuel ratio is controlled together with the intake air control by the swirl control valve 1. At a light load, the value of the air-fuel ratio is increased, and the swirl control valve 1 is closed to perform lean burn. At the time of load, the air-fuel ratio is set to stoichiometric and the swirl control valve 1 is opened to perform stoichiometric burn. Therefore, the torque characteristic of the engine E is the torque characteristic indicated by the thick solid line in FIG. That is, in the engine E of this embodiment, similarly to the above-described conventional engine, the switching of the open / close state of the swirl control valve 1 and the change of the air-fuel ratio are simultaneously performed. Change.

In FIG. 1, reference numeral 7 denotes an electronic control unit (E-ECU) for controlling the engine E. The electronic control unit 7 includes an engine speed NE, an intake pipe negative pressure.
PM, the signal from the neutral switch NSW, throttle opening degree TA, the engine coolant temperature THW and the other signal is input and switching signal S _S and the fuel injection INJ of the swirl control valve 1, such as a signal for the igniter IGT is output .

On the other hand, the automatic transmission A has a well-known configuration in which the gear position is set by frictional engagement means such as a clutch or a brake, and controls a control oil pressure such as a line pressure or an accumulator back pressure by using an electromagnetic proportional valve or the like. It can be electrically controlled arbitrarily by use. An electronic control unit (T-ECU) 8 for controlling the automatic transmission A includes:
Signals such as vehicle speed SP2, engine speed NE, turbine speed NT, throttle opening TA, and brake signal BK are input.
Also, it outputs signals to a solenoid valve SPL for line pressure control, a solenoid valve SLU for lock-up, a solenoid valve SLN for accumulator back pressure, and solenoid valves S1, S2 for speed change. The friction engagement means such as the clutch and the brake corresponds to a speed ratio control mechanism of the present invention. The electronic control units 7 and 8 are electrically connected to each other, and a signal indicating the open / closed state of the swirl control valve 1 is sent from the electronic control unit 7 for the engine.
S _S is output, and the electronic control unit 8 for the automatic transmission outputs a signal Pok indicating that the setting of the line pressure and the back pressure of the accumulator is completed.

The control oil pressure such as the line pressure and the accumulator back pressure in the automatic transmission A is performed based on two types of maps. That is, when the swirl control valve 1 is in the closed state and in the open state, the engine torque changes discontinuously, and in each state, the torque changes substantially corresponding to the throttle opening. The electronic control unit 8 includes either a two-dimensional map M1 of the throttle opening and the engine speed when the swirl control valve 1 is closed or a one-dimensional map M1 of the intake pipe negative pressure, and a swirl control valve. Two types of maps M1 and M2 are provided, one of which is a two-dimensional map M2 of the throttle opening and the engine speed in a state where 1 is open, and the other is a one-dimensional map M2 of the intake pipe negative pressure. These maps are switched and used to control the control oil pressure.

More specifically, as shown in the flowcharts of FIGS. 3A to 3D, the electronic control unit 7 for the engine determines that the swirl control valve 1 should be switched from the closed state to the open state by determining that the throttle has been opened. Degree T
When the determination is made based on A (step 1), a signal of "SCV: 0 → 1" indicating that the determination is made is transmitted to the electronic control unit 8 for the automatic transmission (step 2). As described above, the target engine E here is:
The open / closed state of the swirl control valve 1 and the air-fuel ratio are controlled so as to increase the air-fuel ratio when the swirl control valve 1 is closed and decrease the air-fuel ratio when the swirl control valve 1 is open. Therefore, the air-fuel ratio is reduced with the switching of the swirl control valve 1 from the closed state to the open state, and the output increases.
On the other hand, the electronic control unit 8 for the automatic transmission is
When the signal of "SCV: 0 → 1" is received (step 10), the map for controlling the line pressure and the accumulator back pressure is switched from the map M1 of the former to the map M2 of the latter (step 11). ), Outputs a command signal for controlling the control oil pressure based on the map M2, that is, changing the pressure adjustment level of the control oil pressure, and instructs the engine electronic control unit 7 to start the change of the pressure adjustment level. : 0 → 1 signal is transmitted (step 1
2). In the engine electronic control unit 7,
After receiving the signal "Pok: 0 → 1" (step 20), the timer Tm is set (step 21), and the flag F1 is set to "1" (step 22). This flag F1 indicates that the predetermined delay time is being measured, and it is determined whether or not the flag F1 is "1" in the opening / closing control routine of the swirl control valve 1 (step 30). If the determination result is “no”, the process returns. If “yes”, the process proceeds to step 31 to determine whether or not the time α has elapsed. If the determination result is “No”, the process returns and waits for the lapse of time α, and “Yes”
If so, the switching of the swirl control valve 1 from the closed state to the open state is executed (step 32), and the flag F1
Is reset to zero (step 33). Therefore, the above-mentioned step 31 corresponds to the elapsed time detecting means in claim 3, and step 32 corresponds to the output characteristic controlling means.

The time α counted by the timer Tm is a length of time in consideration of a delay in hydraulic response, and is a constant or a variable according to the oil temperature.Therefore, the line pressure or the accumulator back pressure is the pressure according to the map M2. Coincides with the timing of the increase in engine torque caused by opening the swirl control valve 1.

According to the above-described control, at the time of a light load in which the swirl control valve 1 is closed and the air-fuel ratio is increased, the control hydraulic pressure is controlled based on the map M1, the swirl control valve 1 is opened, and the air-fuel ratio is reduced. When the load is high, the control oil pressure is controlled based on the map M2 with a high pressure adjustment level, so that the control oil pressure also changes in step with the step change in engine torque, and thus the control oil pressure corresponds to the engine torque. Therefore, deterioration of the shift shock and excessive wear of the friction material are prevented beforehand.

Further, since the switching of the swirl control valve 1 is performed after a predetermined time has elapsed from the switching of the map, that is, the output of the command signal for changing the pressure adjustment level, there is almost no effect due to the response delay of the hydraulic pressure. Excessive wear of the material or power loss is prevented.

In other words, taking the accumulator back pressure as an example, the accumulator back pressure will be reduced to the original pressure (indicated by a broken line) as shown by a solid line in FIG. 4 due to a delay in hydraulic response despite the increase in engine torque. If lower,
Izu ends shifting at time t1 which is the end of the accumulator region, wherein the end per accumulator (that moves the piston up to a limit position abut against the end face of the cylinder) is generated, the output shaft torque T ₀ As shown by the solid line, it temporarily changes suddenly, which is a shift shock.

When the accumulator back pressure increases prior to the increase in engine torque, the output shaft torque rapidly changes in a short time as shown by the solid line in FIG.

However, in the above-described device, since the engine torque and the control oil pressure are set in a state where they are compatible, it is possible to prevent deterioration of the shift shock, decrease in durability of the friction material, or loss of power.

The above description is about the control when the swirl control valve 1 changes from the closed state to the open state. On the contrary, the device of the present invention changes the swirl control valve 1 from the open state to the closed state. The same applies to the case of switching.

The above-described embodiment is directed to a so-called lean burn engine. The lean burn engine is designed to increase the intake air amount to increase the air-fuel ratio, or to increase the amount of exhaust gas recirculated. Any engine that increases the air-fuel ratio may be used.

Furthermore, in the engine that connects the automatic transmission according to the present invention, the essential point is that the intake path is divided in a complicated manner, an open / close valve is provided in any of the intake passages, and the output torque is discontinuous by switching the open / close of the open / close valve. It has a variable structure, and its on-off valve is not limited to a swirl control valve.

Effect of the Invention As described above, according to the present invention, the output characteristic of the engine is changed after the output signal of the control hydraulic pressure adjustment level is changed, thereby avoiding the influence of the response delay of the hydraulic pressure, The timing of the change of the hydraulic pressure and the timing of the change of the engine torque substantially coincide with each other, and as a result, there is substantially no period in which the control hydraulic pressure shifts to a higher or lower level with respect to the engine torque. Can be prevented.

[Brief description of the drawings]

1 is a block diagram showing an example of an object to be controlled by the apparatus of the present invention, FIG. 2 is a schematic cross-sectional view showing a swirl control valve thereof, and FIGS. 3 (A) to 3 (D) show an engine side and an automatic transmission side. FIG. 4 is a diagram showing changes in the accumulator back pressure and output shaft torque when the control oil pressure is low, and FIG. 5 is a diagram showing the accumulator back pressure and output shaft torque when the control oil pressure is high. , FIG. 6 is a diagram showing the torque characteristics of the lean burn engine, and FIG. 7 is a diagram corresponding to the claims of the present invention. 1 ... Swirl control valve, 2 ... Cylinder, 3,4
… Intake port, 7,8… Electronic control unit, A…
Automatic transmission, E ... engine.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification code FI F16H 59:76 (58) Investigated field (Int.Cl. ⁶ , DB name) F16H 39/00-61/12 F16H 61/16 -61/24 F16H 63/40-63/48 F02B 31/00 F02B 29/00-29/06 B60K 41/00-41/28

Claims (1)

(57) [Claims] An automatic transmission which is connected to an engine whose output torque changes discontinuously by changing output characteristics and is capable of changing a speed ratio, wherein the speed change ratio control mechanism for controlling the speed ratio is provided. An automatic transmission hydraulic control device capable of arbitrarily adjusting a control oil pressure applied thereto, wherein an elapsed time from an output of a change command signal for changing a value of the control oil pressure in accordance with an increase or decrease direction of an engine output is detected. An automatic transmission, comprising: elapsed time detecting means; and output characteristic control means for executing control for changing the output characteristic after the elapse of a predetermined time is detected by the elapsed time detecting means. Hydraulic control device.