JPS58124037A - Control of power system of vehicle - Google Patents

Abstract

PURPOSE:To save fuel consumption by a method wherein the output of the engine of the vehicle is controlled by the differential signal between an engine output command signal and an engine output measuring signal and the variable speed ratio of the engine is controlled by the differential signal between a signal obtained by adding to an engine r.p.m. command signal the differential signal between a drive shaft r.p.m. command signal and its measuring signal, and the engine r.p.m. measuring signal. CONSTITUTION:When the acceleration pedal 6 is stepped on to accelerate the engine, each of command signals from a detector 7 goes to H-level but the output and the number of revolutions of the engine 1 and the number of revolutions of the drive shaft 4 do not increase rapidly so that the signal from an engine control device 11 to a throttle valve adjusting device 13 goes to H-level to increase the opening degree of a throttle valve 12 and the output of the engine takes a command value to thereby stabilize the operation of the engine. At the same time, as the output of a drive shaft r.p.m. sensor 10 does not increase rapidly, the output of a comparator 14 increases and the output of an adder 15 increases further so that a high level signal is applied on a variable speed ratio adjusting device 9 from a variable speed control device 16 with the result that the variable speed ratio of the engine becomes high and the torque on the drive shaft 4 increases to thereby increase the speed of the vehicle. In this case, the output of a comparator 14 comes close to zero since the output of the drive shaft r.p.m. sensor 10 increases, and the variable speed ratio of the engine is stabilized at the command value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle power system control device that comprehensively controls a vehicle engine and transmission.

Generally, in an engine, the relationship between its rotational speed and output torque is as shown in Figure 1 (the negative pressure of the intake manifold is used as a parameter). The output torque changes depending on the number of rotations, and the output torque is small at low and high speed rotations, and reaches its maximum at an appropriate rotation speed between them. or,
The higher the intake pressure of the air-fuel mixture, the higher the output torque. A in FIG. 1 shows the case where the sloshitl valve is fully open and the suction pressure of the air-fuel mixture is at its highest.

□Furthermore, the output torque of the engine also changes depending on the mixture ratio of air and fuel, that is, the air-fuel ratio, and the ignition timing.

For this reason, the engine is controlled primarily by controlling the air-fuel ratio and ignition timing so as to obtain the intended operating performance.

However, in conventional vehicle power system control, engine control and transmission control are performed separately, and engine control is performed only by the engine. Therefore, if the transmission gear ratio is not appropriate, the power system will There was a problem that the performance could not be fully demonstrated.

For example, when you want to rapidly accelerate a vehicle, even if you increase the output torque of the engine, if the gear ratio of the transmission is small, sufficient torque will not be obtained and fuel consumption will increase. If you want to drive at high speed, increasing the main speed ratio will increase the engine speed, which will also result in more fuel consumption.On the other hand, since the transmission is individually controlled, A similar problem occurred.

The present invention was developed in an attempt to eliminate the above-mentioned interlocking points, and it is an object of the present invention to operate the vehicle efficiently with minimum fuel consumption by comprehensively controlling the engine and gearbox in the vehicle. The object of the present invention is to provide a vehicle power system control device that can perform the following functions.

Figure 2 shows an example of fuel consumption per engine output power.The solid line is the equal fuel consumption curve, and the dotted line is the line that vertically cuts the equal fuel consumption curve as the engine speed increases. is the lowest fuel consumption curve.The further you go to the center of the equal fuel consumption curve, the lower the fuel consumption becomes.

When trying to set the output torque and rotation speed on the output side of the transmission to a certain value, various combinations of the engine condition and the gear ratio of the transmission can be considered, but the control device according to the present invention can minimize fuel consumption. It controls the engine condition and gear ratio so that the

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

In FIG. 3, reference numeral 1 denotes an engine, and the engine 1 is connected to a continuously variable transmission 3 that can continuously change the gear ratio via its output shaft 2, and the continuously variable transmission 3 is connected to a drive shaft 4. The drive wheels 5 are connected via, for example. 6 is the actuator 1 (□) operated by the driver of the vehicle.

Serpeda 7 is a detector that detects the amount of operation of the accelerator pedal 6 and outputs an engine output command signal, an engine rotation speed command signal, and a drive shaft rotation speed command signal based on this. form. 8
is an air flow sensor that measures the intake air flow rate of the engine 1, and the air flow lid sensor 8 forms engine output measuring means. Reference numeral 9 denotes a gear ratio adjusting device that adjusts the gear ratio of the continuously variable transmission 3, and the gear ratio adjusting device 9 also serves as an engine rotation speed measuring means. 10 is a drive shaft rotation speed sensor provided on the drive shaft 4 and measures its rotation speed; 11 receives the engine output command signal from the detector 7 and the output signal of the air flow sensor 8 and outputs a difference signal between the two; engine control device, 12
is a throttle valve of the carburetor or mixer of the engine 1, and the throttle valve 12 adjusts the air cover and the amount of fuel taken into the engine 1 to adjust the engine output. The throttle valve 12 is not interlocked with the accelerator pedal 6. 13 is a throttle valve adjustment device that adjusts the opening degree of the throttle valve 12 in accordance with the output of the engine control device 11; 14 is a detector 7;
Drive shaft rotation speed command signal and drive shaft rotation speed sensor 10
15 is an adder that receives the engine rotational speed command signal of the detector 7 and the output signal of the comparator 14 and outputs a sum signal thereof; Reference numeral 16 denotes a transmission control device which receives the output signal of the adder 15 and the output signal of the speed ratio adjustment device 9 and outputs a difference signal.

In the above device, when the driver depresses the accelerator pedal 6, the detector 2 detects the depressing state of the accelerator pedal 6, and thereby detects the driver's intention, such as whether or not to accelerate or what the vehicle speed is. Correspondingly, an engine output command signal, an engine rotation speed command signal, and a drive shaft rotation speed command signal are issued. Therefore, the gear ratio of the continuously variable transmission 3 is automatically determined from the engine rotation speed command signal and the drive shaft rotation speed command signal. The above three command signals are respectively given to devices that control the engine 1 and the continuously variable transmission 3 via feedback control circuits.

First, an engine output command signal is sent to the engine 1 via the engine control device 11 to the throttle valve adjustment device 1.
3 to open the throttle valve 12.

In the case of sudden acceleration, a command is also given to increase the amount of fuel. On the other hand, since the engine output corresponds to the mass of the air-fuel mixture taken into the engine 1, the engine output can be measured, for example, by measuring the air flow rate or fuel flow rate to the engine 1. Therefore, the engine output can be detected by the output of the air flow sensor 8, and this output signal is fed back to the engine control device 11, and the throttle valve 12 receives the engine output command signal and the air flow lid sensor 8.
is controlled so that the output signal of

Next, a continuously variable transmission 3 is used to obtain an arbitrary gear ratio that matches the engine 1. The output signal of the drive @ [91 rotation speed sensor 10 is compared with the drive shaft rotation speed command signal in a comparator 14, and the difference signal is added to an adder 15 as a gear ratio deviation signal. Further, an engine rotation speed command signal is added to the adder 15 as a gear ratio command signal,
This signal and the output signal of the comparator 14 are added in an adder 15 and provided to a transmission control device 16 as a gear ratio signal. The transmission control device 16 compares this speed ratio signal and the output signal of the speed ratio adjustment device 9, and the difference signal is applied to the speed ratio adjustment device 9.
The gear ratio is feedback controlled.

If you now press the accelerator pedal 6 to accelerate, the command signals of the detector 7 will rise, but the output and rotational speed of the engine 1 and the rotational speed of the drive shaft 4 will not suddenly rise. . Therefore, the signal from the engine control device [11] to the throttle valve adjustment device 13 increases, thereby increasing the opening degree of the throttle valve 12, increasing the engine output, and stabilizing it to the command value. On the other hand, since the output of the drive shaft rotation speed sensor 10 does not suddenly increase, the comparator 14
As the output of the adder 15 increases, the output of the adder 15 further increases, a large signal is applied from the transmission control device 16 to the gear ratio adjusting device 9, and the gear ratio increases. In order to increase the vehicle speed, it is necessary to increase the torque of the drive shaft 4, but as the gear ratio increases as described above, the drive 111
4 torque increases and vehicle speed increases. by this,
As the rotational speeds of the output shaft 2 and the drive shaft 4 increase, and the drive shaft rotation ← the output of the sensor 10 increases, the output of the comparator 14 gradually approaches zero, and the output of the transmission control device 16 also gradually approaches zero. The gear ratio becomes smaller and stabilizes at the target value. Of course, during this time, the control of the engine 1 and the control of the continuously variable transmission 3 are not independent, and since the rotation speed of the engine 1 also changes as the gear ratio changes, the output of the engine 1 also changes.

Therefore, the signal from the engine control device 11 to the throttle valve adjustment device ft13 changes, and the throttle valve 12 operates so that the engine output becomes the command value.

By feedback-controlling the engine 1 and the continuously variable transmission 3 in this way, the output and rotation speed of the engine 1 and the rotation speed of the drive shaft 40 are controlled to correspond to the depression of the accelerator pedal 6, and the gear ratio is It is controlled to be large during sudden acceleration and small during constant speed driving.

In addition, in the process of control, each command signal from the detector 7 is a constant number of 4Ps depending on the state of the accelerator pedal 6,
It is possible to wait until the appropriate value is reached, depending on the inertia response of the vehicle, but in that case, the drivability and fuel consumption may not necessarily be as intended. Therefore, the detector 7 is programmed in advance to output an engine output command signal, an engine rotation speed command signal, and a drive shaft rotation speed command signal in response to the depression of the accelerator pedal 6 so that the fuel consumption of the engine 1 is minimized. It can also be made to change over time. In particular, it is preferable that the engine output command signal and the engine rotational speed command signal have a relationship that follows the minimum fuel consumption curve of the engine 1. Further, in the above embodiment, the air flow rate sensor 8 is used as the engine output measuring means, but a fuel flow rate sensor for measuring the intake fuel flow rate of the engine 1 may also be used. Further, although the gear ratio adjusting device 9 is also used as an engine rotation speed measuring means, an engine rotation speed sensor may be provided on the output shaft 2.

As described above, the present invention includes a command means for commanding engine output, engine rotation speed, and drive shaft rotation speed, measurement means for measuring the engine output, engine rotation speed, and drive shaft rotation speed, engine output adjustment means, and A gear ratio adjustment means is provided, and the engine output adjustment means is controlled by the difference signal between the engine output command signal and the engine output measurement signal, and the engine rotation speed command signal includes each drive shaft rotation speed command and the drive shaft rotation speed measurement signal. The gear ratio adjusting means is controlled by the difference signal between the signal obtained by adding the difference signal between the engine rotation speed measurement signal and the engine rotation speed measurement signal. For this reason, for example, during sudden acceleration, the gear ratio is automatically increased to obtain large torque and smooth acceleration, and as the vehicle speed increases, the gear ratio is automatically decreased to maintain the engine speed. You don't have to make it as big as necessary. As a result, the vehicle can be driven efficiently as intended by the driver and with minimum fuel consumption.

[Brief explanation of drawings]

FIG. 1 is an engine output characteristic diagram, FIG. 2 is an engine fuel consumption characteristic diagram, and FIG. 3 is a configuration of a heavy vehicle power system control device according to the present invention. ...Engine output shaft, 3...
・Continuously variable transmission, 4... Drive shaft, 5... Drive wheel, 6...
...Accelerator pedal, 7..Detector, ..Air flow rate sensor, 9..Transmission ratio adjustment device, 10..Drive shaft rotation speed sensor, 11..Engine control device, 12..
Throttle valve, 13... Throttle valve adjustment device, 14
... Comparator, 15 ... Adder, 16 ... Transmission control device. Agent Shin Kuzuno - Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) In a vehicle in which the engine output is transmitted to the drive shaft via a power transmission device with a continuously variable gear ratio, a command means by which the vehicle driver commands the engine output, the engine rotation speed, and the rotation speed of the drive shaft. , an engine output measurement means for measuring engine output, an engine rotation speed measurement means for measuring the engine rotation speed, a drive shaft rotation speed measurement means for measuring the rotation speed of the drive shaft, and an engine output command signal of the command means. An engine output adjusting means for adjusting the engine output according to a difference signal between the output signal and the output signal of the engine output measuring means; A vehicle characterized in that it is equipped with a gear ratio adjusting means for adjusting the gear ratio of the power transmission device in accordance with the difference signal between the output signal of the engine rotation speed measuring means and the output signal of the engine rotation speed measuring means. power system control device. (2) The first aspect of the present invention is characterized in that the command means is configured such that the engine output command signal and the engine rotation speed command signal have a relationship along a minimum fuel consumption curve.
A power system control device for a vehicle as described in 2.