JP2000009158A - Vehicle with electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress power consumption of an electromagnetic clutch and save fuel consumption of a vehicle with the electromagnetic clutch by controlling a clutch current to the optimum value in accordance with clutch input torque after the electromagnetic clutch is completely locked. SOLUTION: When clutch input shaft rotating speed Ncin and clutch output shaft rotating speed Ncout coincide with each other at time t=t2 to completely lock an electromagnetic clutch 2, a clutch current Ic is thereafter controlled to the optimum value corresponding to clutch input torque Tcin. Accordingly, if the clutch input torque Tcin increases, the clutch current Ic also increases in accordance, and on the other hand, if the clutch input torque Tcin decreases, the clutch current Ic decreases in accordance. Compared to a vehicle maximizing the clutch current Ic regardless of operating conditions, power consumption of the electromagnetic clutch 2 can be considerably suppressed without lowering transmission efficiency of input torque, and fuel consumption can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle equipped with an electromagnetic clutch having an adjustable transmission torque.

[0002]

2. Description of the Related Art An electromagnetic clutch capable of adjusting a coupling force (transmission torque) according to the intensity of an exciting current (hereinafter, clutch current) flowing through an electromagnetic coil is interposed between an engine and a transmission. There is known a vehicle in which the power of an engine is transmitted to or cut off from a driving system by engaging and releasing the connection.

[0003]

In the conventional vehicle with an electromagnetic clutch, the engine speed and the transmission input shaft speed are monitored when the clutch is engaged, and the engine speed and the transmission input shaft speed are equal. When it was determined that the clutch was completely engaged, the clutch current was maximized regardless of the operating conditions.

FIG. 4 shows how the clutch current changes when the conventional clutch is engaged. As shown in FIG.
When a clutch engagement command is issued at t1, the clutch current increases, and the coupling force of the electromagnetic clutch increases. When the electromagnetic clutch is completely engaged at time t = t2, the clutch current increases to a maximum, and thereafter, the maximum current is maintained until a clutch release command is issued.

However, in such control, the clutch input torque during low-speed running, low load, and the like is small, and the maximum current is obtained even under operating conditions that can maintain the fully engaged state even if the current is not the maximum current. Power consumption increased, causing fuel efficiency to deteriorate.

The present invention has been made in view of such problems of the prior art, and has as its object to provide a vehicle with an electromagnetic clutch in which the power consumption of the electromagnetic clutch in a completely engaged state is suppressed.

[0007]

SUMMARY OF THE INVENTION A first aspect of the present invention is a means for detecting a clutch input torque in a vehicle equipped with an electromagnetic clutch in which a coupling force can be adjusted in a power transmission path of the vehicle. Means for controlling the clutch current in the engaged state to a value corresponding to the clutch input torque.

According to a second aspect of the present invention, in the first aspect, the means for detecting the clutch input torque obtains the engine torque from the engine speed and the throttle valve opening, and uses this as the clutch input torque. Is what you do.

[0009]

According to the first aspect, after the electromagnetic clutch is completely engaged, the clutch current is controlled to an optimum value according to the clutch input torque. Thus, the power consumption of the electromagnetic clutch can be suppressed while maintaining the fully engaged state, that is, without lowering the transmission efficiency of the input torque, and the fuel efficiency of the vehicle with the electromagnetic clutch can be improved.

According to the second aspect, the clutch input torque can be accurately detected from the engine speed and the throttle valve opening. Thereby, the control accuracy of the clutch current can be improved.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example in which the present invention is applied to a hybrid vehicle. As shown in FIG. 1, the power train of the hybrid vehicle includes a power transmission mechanism including an engine 1, an electromagnetic clutch 2, a motor 3, a transmission 4, a final reduction device (not shown), and the like.

The output shaft of the engine 1 is connected to the input shaft of the electromagnetic clutch 2, and the common output shaft of the electromagnetic clutch 2 and the motor 3 is connected to the input shaft of the transmission 4. Here, the motor 3 is interposed between the electromagnetic clutch 2 and the transmission 4 to make the power train compact. However, the motor 3 is connected to the opposite side of the transmission 4 from the electromagnetic clutch 2. You may.

The electromagnetic clutch 2 is a powder clutch capable of adjusting the torque transmitted from the input shaft to the output shaft according to the intensity of the exciting current (hereinafter, clutch current Ic) flowing through the electromagnetic coil. The clutch current Ic is controlled by a clutch ECU (controller, hereinafter the same) 12 which will be described later.
The vehicle can be driven by switching between the engine 1 and the motor 3 or both.

On the other hand, a generator 5 is connected to the output shaft of the engine 1 on the side opposite to the clutch 2 so that the power generated by the engine 1 can be regenerated as electric power.
The generator 5 also functions as a starter motor at the time of starting the engine 1 by receiving power supply from a battery (not shown).

The transmission 4 is a belt-type CVT (stepless transmission) in which the transmission ratio can be adjusted steplessly. However, other continuously-variable transmissions such as a toroidal type CVT and conventional gear-type transmissions are available. A step transmission may be used.

Engine 1, electromagnetic clutch 2, motor 3,
The transmission 4 and the generator 5 each have an engine EC
U11, clutch ECU12, motor ECU13, transmission ECU14, and generator ECU15 are controlled. The power train ECU 10 receives various signals from an accelerator pedal opening sensor (not shown), a vehicle speed sensor, and the like, and also operates the engine 1, the electromagnetic clutch 2, the motor 3, the transmission 4, and the generator 5 (rotation speed,
Torque, gear ratio, etc.) are input, and based on these, each EC
U11 to U15 are collectively controlled.

Here, the content of the clutch engagement control performed in the clutch ECU 12 will be described with reference to the flowchart shown in FIG. This flowchart is executed when a clutch engagement command is issued from the power train ECU 10 to the clutch ECU 12.

First, in step S1, the clutch current Ic is increased by a predetermined amount as in the conventional case, and the transmission torque Tc of the electromagnetic clutch 2 is increased. At this time, the input shaft rotation speed Ncin (engine rotation speed Ne) and the output shaft rotation speed Nco
If the start of engagement of the electromagnetic clutch 2 is started after the difference ut is adjusted to fall within a certain range, the shock at the time of engagement can be suppressed. Alternatively, the clutch current Ic may be gradually increased and the electromagnetic clutch 2 may be engaged while slipping.

Then, in step S2, the electromagnetic clutch 2
It is determined whether has been completed. Whether the electromagnetic clutch 2 is completely engaged is determined by the clutch input shaft rotation speed Nc.
The determination is made based on information such as whether in and the output shaft rotation speed Ncout match. Input shaft speed Ncin and output shaft speed N
Cout can be obtained by detecting the engine speed Ne and the transmission input shaft speed Npri, respectively. Step S until the electromagnetic clutch 2 is completely engaged.
Step S2 is repeated from 1 to gradually increase the clutch current Ic.

When the electromagnetic clutch 2 is completely engaged, the process proceeds to step S3, where the input torque Tcin of the electromagnetic clutch 2 is read. Since the clutch input torque Tcin is equal to the engine torque Te, the engine speed Ne and the throttle valve opening TVO (or the accelerator pedal opening AP
The engine torque Te is obtained by referring to a predetermined map based on O), and this is set as the clutch input torque Tcin.

In step S4, the clutch input torque Tc
The optimum clutch current Ic is set in accordance with “in”, and is output to the drive circuit of the electromagnetic clutch 2. Specifically, a limit current value at which the electromagnetic clutch 2 does not slip with respect to the clutch input torque Tcin is obtained from a predetermined map or function, and a value obtained by giving a predetermined margin to the limit current value is set as the clutch current Ic. I do.

Thereafter, steps S3 to S5 are repeated until a clutch release command is input in step S5, and the clutch current Ic is controlled to a value corresponding to the input torque Tcin. The clutch release command is issued when the engine 1 is disconnected from the transmission 4 or when the temperature of the electromagnetic clutch 2 rises excessively.
Is output to the clutch ECU 12.

Therefore, by processing this flowchart, the same control as that of the related art is performed until the electromagnetic clutch 2 is completely engaged. However, after the electromagnetic clutch 2 is completely engaged, the clutch current Ic is adjusted according to the clutch input torque Tcin. Controlled by value.

FIG. 3 is a timing chart showing how the clutch current Ic changes when the clutch is engaged.

When a clutch engagement command is issued at time t = t1, the clutch current Ic increases as in the conventional example shown in FIG. 4, and the engagement force of the electromagnetic clutch 2 gradually increases.

However, in this embodiment, the time t =
At t2, when the clutch input shaft rotation speed Ncin and the clutch output shaft rotation speed Ncout match and the electromagnetic clutch 2 is completely engaged, the clutch current Ic is thereafter controlled to an optimum value according to the clutch input torque Tcin. Therefore, when the clutch input torque Tcin increases, the clutch current Ic increases accordingly, and conversely, when the clutch input torque Tcin decreases, the clutch current Ic decreases accordingly.

As a result, the power consumption of the electromagnetic clutch 2 can be greatly reduced without lowering the transmission efficiency of the input torque, as compared with the conventional one in which the clutch current Ic is maximized irrespective of the operating conditions. Can be improved.

At this time, since the clutch current Ic is set to a value having a predetermined margin with respect to the clutch input torque Tc, the detected clutch input torque Tc
, It is possible to prevent the electromagnetic clutch 2 from slipping out.

Although the present invention has been described with reference to an example in which the present invention is applied to a hybrid vehicle, the present invention is not limited to the hybrid vehicle shown in FIG. The present invention can be applied to a vehicle that uses a vehicle.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a hybrid vehicle to which the present invention is applied.

FIG. 2 is a flowchart showing a process performed in a clutch ECU.

FIG. 3 is a timing chart showing how the clutch current changes when the clutch is engaged.

FIG. 4 is a timing chart showing how a clutch current changes when a conventional clutch is engaged.

[Description of Signs] 1 Engine 2 Electromagnetic clutch 4 Transmission 10 Powertrain ECU 12 Clutch ECU

Claims (2)

[Claims] 1. A vehicle equipped with an electromagnetic clutch in which a coupling force is adjustable in a power transmission path of the vehicle, means for detecting a clutch input torque, and a clutch current in a clutch engaged state according to the clutch input torque. A vehicle with an electromagnetic clutch. 2. An electromagnetic clutch according to claim 1, wherein said means for detecting the clutch input torque obtains an engine torque from an engine speed and a throttle valve opening, and uses this as a clutch input torque. vehicle.