JPH03262734A - Control device for power unit - Google Patents

Abstract

PURPOSE:To suppress a shock at the time of a fuel cut by starting the fuel cut while the rotating speeds of an engine and the turbine of a torque converter coincide when the fastening force of a lock-up clutch is controlled to cut fuel at the time of deceleration of a vehicle. CONSTITUTION:When the lock-up clutch 8 of a torque converter 1 is fastened to a case 4, the output shaft 3 of an engine 2 is directly connected to a turbine shaft 9. The oil pressure of the operating oil fed from an oil path 11 is controlled by a solenoid 12, thereby the fastening state between the lock-up clutch 8 and the case 4 is controlled. The fastening force of the lock-up clutch 8 is controlled by a control unit 13 to cut fuel at the time of deceleration of a vehicle. The fuel cut of the fuel injection valve 16 of the engine 2 is started while the engine rotating speed and the turbine rotating speed detected by sensors 14, 15 respectively coincide at the time of deceleration of the vehicle.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a control device for a power unit, and in particular to a control device for controlling the engagement force of a lock-up clutch of a torque converter in which a vapor-based material is used as a facing material for a friction plate. The present invention relates to a control device for a power unit, which includes a fastening force control means and a fuel cut means, and cuts fuel while controlling the fastening force of a lock-up clutch during deceleration.

(Prior Art) Torque converters used in automatic transmissions have a predetermined operating range that does not require torque increasing action or shift shock absorption action, etc., in order to prevent deterioration of engine fuel efficiency due to so-called slippage of the torque converter. A lock-up clutch that directly connects input and output members is generally provided.

However, when the lock-up clutch is engaged and the input/output components of the torque converter are directly connected, engine vibrations are directly transmitted to the transmission, especially in the low engine speed range, resulting in a problem in which the comfort of the vehicle deteriorates. Occur.

To solve this problem, for example, Japanese Patent Application Laid-Open No. 57-3
As disclosed in Japanese Patent No. 3253, a lock-up clutch is provided with a fastening force control means for controlling the fastening force of the lock-up clutch,
The lock-up clutch is partially engaged in a predetermined low rotation range and controlled into a slip state, thereby preventing the deterioration of fuel efficiency that would occur when the lock-up clutch is completely released, while also reducing the transmission of engine vibrations to the transmission. There is a controller configured to prevent this.

Furthermore, in addition to the engagement force control means that controls the engagement force of the lock-up clutch, it is equipped with a fuel cut means, which performs slip control of the lock-up clutch during deceleration and also cuts fuel to further improve fuel efficiency. There is also equipment. Conventionally, in such a control device, the accelerator O
With FF, slip control of the lock-up clutch during deceleration was started, and a timer that started at the same time as the accelerator was turned off started fuel cut after a predetermined time from when the accelerator was turned off.

(Problems to be Solved by the Invention) Paper-based materials are sometimes used as facing materials for friction plates of lock-up clutches. As shown in Fig. 3, the friction coefficient of this paper-based facing material has a correlation with the rotational speed difference △N between the clutch cover and the clutch disk, that is, the rotational speed difference △N between the engine and the turbine of the torque converter. In the small region of △N
increases as ΔN increases, and becomes a substantially constant value when ΔN exceeds a predetermined value. Therefore, the transmission torque capacity of a lock-up clutch in which a paper-based material is used as the facing material of the friction plate increases as ΔN increases in a region where the rotation speed difference ΔN between the engine and the turbine of the torque converter is small. When ΔN exceeds a predetermined value, it becomes a substantially constant value.

On the other hand, if you turn off the accelerator to decelerate while driving with the accelerator ON, the engine speed will drop rapidly over time, but the torque converter's turbine rotation speed will be reduced by the speed change gear device connected to the turbine. Because the moment of inertia of the axle connected to the axle, the wheels connected to the axle, etc. is large, the moment of inertia does not decrease rapidly. Therefore, as shown in FIG. 4, the rotational speed difference ΔN between the engine rotational speed ESP and the turbine rotational speed TSP of the torque converter decreases, becomes zero, and then increases as time passes after the accelerator is turned off. This change in ΔN over time changes depending on the value of ΔN at the time when the accelerator is turned off, the combination state of the transmission gears, and the like.

Incidentally, the shock generated in the engine during fuel cut is transmitted to the automatic transmission via the lock-up clutch of the torque converter, impairing the comfort of the vehicle. In order to reduce this shock during fuel cut, it is desirable that the transmission torque capacity of the lock-up clutch be as small as possible during fuel cut. In order to achieve this in the clutch, it is desirable that the rotational speed difference ΔN between the engine and the turbine of the torque converter be as small as possible during fuel cut.

However, in a power plant control device that is equipped with a fastening force control means for controlling the fastening force of the lock-up clutch and a fuel cut means, the lock-up clutch is controlled to slip during deceleration and the fuel is cut. , conventionally, slip control of the lock-up clutch during deceleration was started when the accelerator was turned off;
Since the fuel cut was started a predetermined time after the accelerator was turned off by a timer that started at the same time, the rotational speed difference △N between the engine and the torque converter turbine did not necessarily reach the minimum value, that is, zero, at the time of the fuel cut. For this reason, when paper-based materials are used as facing materials for the friction plates of lock-up clutches, the shock caused by fuel cut may not be sufficiently reduced, and the comfort of the vehicle may be impaired. There was a problem.

Therefore, an object of the present invention is to provide a torque converter in which a paper-based material is used as a facing material of a friction plate, and which is equipped with a fastening force control means for controlling the fastening force of a lock-up clutch, and a fuel cut means. An object of the present invention is to provide a control device for a power unit that can reliably reduce the shock at the time of fuel cut, in a power unit control device that sometimes cuts fuel while controlling the engagement force of a lock-up clutch.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes a fastening force control means for controlling the fastening force of the lock-up clutch of the torque converter, and a fuel cut means, and the lock-up clutch is fixed at the time of deceleration. In the power unit control device, which now cuts fuel while controlling the clutch engagement force, it is necessary to start fuel cut when the engine speed and torque converter turbine speed match during deceleration. A control device for a power unit is provided, characterized in that a fuel cut timing control means is provided.

(Function) According to the above configuration of the present invention, the fuel power/isolation timing control means controls the transmission torque at the time when the engine rotational speed and the turbine rotational speed of the torque converter match during deceleration, that is, the transmission torque of the lock-up clutch is applied. Since fuel power/soto starts when the capacity reaches its minimum, the shock when fuel is cut is reliably reduced.

(Example) Hereinafter, the present invention will be described in detail based on the accompanying drawings.

In FIG. 1, reference numeral 1 indicates a torque converter of a power unit provided with a control device according to an embodiment of the present invention.

The torque converter l is fixedly installed on one side of the case 4 connected to the output shaft 3 of the engine 2, and includes a pump 5 that rotates integrally with the engine output shaft 3, and a pump 5 located inside the case 4 opposite to the pump 5. A turbine 6 is disposed on the other side so as to be rotatable with respect to the case 4 and is rotationally driven via hydraulic oil by the rotation of the pump 5, and a turbine 6 is interposed between the pump 5 and the turbine 6. , a stator 7 that increases torque when the ratio of the turbine rotation speed to the pump rotation speed is below a predetermined value;
and a lock-up clutch 8 which is interposed between the turbine 6 and the case 4 and whose friction plates are made of a paper-based material as a facing material. The rotation of the turbine 6 is outputted by a turbine shaft 9 and inputted to a gear transmission mechanism 10, and the lock-up clutch 8 is connected to the turbine shaft 9, and the lock-up clutch 8 is connected to the case. 4, the engine output shaft 3 and the turbine shaft 9 are directly connected via the case 4.

Hydraulic oil supplied from a pump (not shown) is introduced into the lock-up clutch 8 through an oil path 11, and the oil pressure of the hydraulic oil is controlled by a solenoid 12 installed in the middle of the oil path 11. Lockup clutch 8
The fastening state between the case 4 and the case 4 is controlled.

Basically, the CPU, ROM, and R
A control unit 13 consisting of an AM is provided, and the control unit 13 receives an engine rotation signal and a turbine rotation signal from an engine rotation sensor 14 and a turbine rotation sensor 15, respectively, and receives an accelerator depression state from an accelerator sensor (not shown). An accelerator signal indicating this is input, and a manual valve signal from a manual valve (not shown) provided in the hydraulic circuit of the gear transmission mechanism 10 is also input. Furthermore, from the control unit 13,
Control signals are output to the solenoid 12 and the fuel injection valve 16 of the engine 2, respectively.

The operation of the control device according to the present embodiment configured as described above will be explained below based on the flowchart shown in FIG. Note that in the following description, S represents a control step.

Control starts when the engine starts. First, the control unit 13 determines whether the gear transmission mechanism 10 is in the D range based on the manual valve signal, that is, whether the vehicle is running (Sl), and then turns off the accelerator based on the accelerator signal. It is determined whether or not (S2).

The gear transmission mechanism 10 is in the D range and the accelerator is in the O position.
In the case of FF, the control unit 13 determines that the vehicle is running and is in a deceleration state, and sends a control signal to the solenoid 12 to place the lock-up clutch 8 in a half-engaged state, that is, in a slip state (S3).

Next, the control unit 13 determines, based on the engine rotation signal and the turbine rotation signal, whether the engine rotation speed ESP and the turbine rotation speed TSP are equal, that is, the rotation of the engine output shaft 3 and the turbine shaft 9 of the torque converter. To determine whether the number difference △N is zero or not, S4), Δ
This determination is repeated until N becomes zero. Then, when ΔN becomes zero, a control signal is sent to the fuel injection valve 16 of the engine to start fuel cut (S5). As a result, engine shock due to fuel cut occurs when the transmission torque capacity of lock-up clutch 8 is at its minimum, and the shock is reliably reduced.

Next, the control unit 13 determines whether or not the accelerator is off based on the accelerator signal again (S6). If the accelerator continues to be off, that is, if the deceleration state continues, the control unit 13 further determines whether the accelerator is off or not. , based on the engine rotation signal, it is determined whether the engine rotation speed ESP has become 11000 rpm or less (S7). The deceleration state continues and the engine speed ESP is 1100Orp.
If it is higher, the control unit) 13 continues the fuel cut. If the accelerator is not OFF, the vehicle is no longer in a deceleration state, so the control unit 13 sends a control signal to the fuel injection valve 16 of the engine 1 and ends the fuel cut (S8). In addition, even if the accelerator is OFF and the engine speed ESP is below 11,000 rpm, the fuel cut is terminated to avoid engine stalling (S8
).

Although the present invention has been described in detail above, it goes without saying that the present invention is not limited to the above embodiments, and that various modifications can be made within the scope of the invention as set forth in the claims.

(Effects) As can be seen from the above description, in the present invention, the fuel cut timing control means controls the transmission torque capacity of the lock-up clutch at the time when the engine rotation speed and the turbine rotation speed of the torque converter match during deceleration. Since the fuel cut is started at the point when the minimum value is reached, the shock at the time of the fuel cut is reliably reduced.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a power unit provided with a control device according to an embodiment of the present invention. FIG. 2 is a flow chart of the operation of the control device of FIG. FIG. 3 is a correlation diagram between the friction coefficient of the paper-based facing material and the rotational speed difference ΔN between the engine and the turbine of the torque converter. Figure 4 shows the engine speed ESP after the accelerator is turned off.
FIG. 3 is a diagram showing changes over time in the turbine rotational speed TSP of the torque converter. 1... Torque converter, 2 3 - Turbine, - Lock-up clutch, - Engine, - Control unit. Diagram No. 1

Claims (1)

[Claims] A control device for a power unit, which includes an engagement force control means for controlling the engagement force of a lockup clutch of a torque converter and a fuel cut means, and cuts fuel while controlling the engagement force of the lockup clutch during deceleration. A control device for a power unit, characterized in that a fuel cut timing control means is provided for starting fuel cut in a state where the engine rotational speed and the turbine rotational speed of the torque converter match during deceleration.