JPS6233092B2 - - Google Patents

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 speed rotation and high speed rotation, and the output torque is maximum at an appropriate rotation speed between them. Furthermore, as the suction pressure of the air-fuel mixture increases, the output torque also increases. A in FIG. 1 shows the case where the sloshitl valve is fully open and the air-fuel mixture suction pressure 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, so if the transmission gear ratio is not appropriate, the power system will not function properly. There was a problem that the performance could not be 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 only fuel consumption will increase. Furthermore, if the gear ratio is increased when the vehicle wants to run at a constant high speed, the engine rotational speed will increase, which will also increase the amount of fuel consumed. on the other hand,
A similar problem arose in the transmission because it was individually controlled.

The present invention has been made in an attempt to eliminate the above-mentioned problems, and it is possible to drive the vehicle efficiently with minimum fuel consumption by comprehensively controlling the engine and transmission of the vehicle. The purpose of the present invention is to provide a vehicle power system control device that can perform the following tasks.

Figure 2 shows an example of fuel consumption per unit of output power of the engine.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, and the lowest This is the fuel consumption curve. The further you move toward the center of the isofuel consumption curve, the lower the fuel consumption will be. 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 an accelerator pedal operated by the driver of the vehicle; 7 is a detector that detects the amount of operation of the accelerator pedal 6 and outputs a corresponding engine output command signal, engine rotation speed command signal, and drive shaft rotation speed command signal; The accelerator pedal 6 and the detector 7 form a command means. 8 is an air flow sensor that measures the intake air flow rate of the engine 1;
forms an 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 to measure its rotation speed; 11 is a detector 7;
Engine output command signal from and air flow sensor 8
12 is a throttle valve of the carburetor or mixer of the engine 1, and the throttle valve 12 adjusts the amount of air and fuel taken into the engine 1. to adjust engine output. Throttle valve 1
2 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 comparator that receives the drive shaft rotation speed command signal from the detector 7 and the output signal of the drive shaft rotation speed sensor 10 and outputs a difference signal; 15 is the engine rotation speed command signal from the detector 7; An adder receives the output signal of the comparator 14 and outputs the sum signal, and 16 is a transmission that receives the output signal of the adder 15 and the output signal of the gear ratio adjustment device 9 and outputs the difference signal. It is a control device.

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 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 sent to the engine 1 through the feedback control circuit.
and a device for controlling the continuously variable transmission 3.

First, an engine output command signal is applied to the engine 1 via the engine control device 11 to the throttle valve adjusting device 13 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 air flow sensor 8
The engine output can be detected from the output of the engine, and this output signal is fed back to the engine control device 11, and the throttle valve 12 is controlled so that the engine output command signal and the output signal of the air flow sensor 8 are equal.

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 shaft 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 rotational speed command signal is added to the adder 15 as a gear ratio command signal, and this signal and the output signal of the comparator 14 are added in the adder 15 and provided to the transmission control device 16 as a gear ratio signal. It will be done. This gear ratio signal and the gear ratio adjustment device 9
The transmission control device 16 compares the output signal with the output signal of
The difference signal is applied to the gear ratio adjusting device 9, whereby the gear ratio of the continuously variable transmission 3 is feedback-controlled.

If you try to accelerate by depressing the accelerator pedal 6, each command signal from the detector 7 will increase, but the output and rotation speed of the engine 1 and the drive shaft 4 will increase.
The rotation speed does not suddenly increase. Therefore, from the engine control device 11 to the throttle valve adjustment device 1
The signal to the engine 3 increases, thereby increasing the opening degree of the throttle valve 12 and increasing the engine output, which becomes the command value and becomes stable. On the other hand, since the output of the drive shaft rotation speed sensor 10 does not suddenly increase, the output of the comparator 14 increases and the output of the adder 15 further increases, and a large signal is sent from the transmission control device 16 to the gear ratio adjustment device 9. is added, 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 torque of the drive shaft 4 increases, and the vehicle speed increases. As a result, the rotation speeds of the output shaft 2 and the drive shaft 4 increase, and the output of the drive shaft rotation speed sensor 10 increases, so the comparator 14
The output of the transmission controller 16 gradually approaches zero.
As the output gradually approaches zero, the gear ratio becomes smaller and stabilizes at the command 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 13 changes, and the throttle valve 12 operates so that the engine output becomes the command value. In this way, the engine 1 and the continuously variable transmission 3
engine 1 by controlling the feedback
The output and rotational speed of the drive shaft 4 and the rotational speed of the drive shaft 4 are controlled to correspond to the depression of the accelerator pedal 6, and the gear ratio is controlled so that it is large during rapid acceleration and small during constant speed operation.

In the process of control, each command signal from the detector 7 may be a constant signal depending on the state of the accelerator pedal 6, and may be left to the response due to the inertia of the vehicle and wait until it reaches an appropriate value. driveability and fuel consumption may not always 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 sensor 8 is used as the engine output measuring means, but a fuel flow sensor that measures 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, a throttle valve, and a gear ratio. The throttle valve is controlled by the difference signal between the engine output command signal and the engine output measurement signal, and the difference signal between the drive shaft rotation speed command signal and the drive shaft rotation speed measurement signal is used as the engine rotation speed command signal. The gear ratio adjusting means is controlled by the difference signal between the signal obtained by adding the above and the engine rotation speed measurement signal. Therefore, it is possible to control the engine output and the gear ratio at the same time. For example, when accelerating suddenly, the gear ratio automatically increases to obtain a large torque, making sudden acceleration smoother and increasing the vehicle speed. The gear ratio is automatically reduced and there is no need to increase the engine speed unnecessarily.
As a result, the vehicle can be driven efficiently as intended by the driver and with minimum fuel consumption.

[Brief explanation of the drawing]

FIG. 1 is an engine output characteristic diagram, FIG. 2 is an engine fuel consumption characteristic diagram, and FIG. 3 is a configuration diagram of a vehicle power system control device according to the present invention. 1...Engine, 2...Engine output shaft, 3
... Continuously variable transmission, 4... Drive shaft, 5... Drive wheel,
6... Accelerator pedal, 7... Detector, 8... Air flow rate sensor, 9... Gear 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.

Claims (1)

[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, the driver of the vehicle transmits the engine output, the engine rotation speed, and the rotation speed of the drive shaft. a command means for issuing a command; an engine output measuring means for measuring the engine output;
In response to the difference signal between the engine output command signal of the command means and the output signal of the engine output measurement means, the engine rotation speed measurement means measures the engine rotation speed, the drive shaft rotation speed measurement means measures the rotation speed of the drive shaft. a throttle valve that adjusts the engine output, and a signal obtained by adding the difference signal between the engine rotation speed command signal of the command means, the drive shaft rotation speed command signal of the command means and the output signal of the drive shaft rotation speed measurement means, and the engine rotation speed. 1. A power system control device for a vehicle, comprising: a gear ratio adjusting means for adjusting a gear ratio of a power transmission device in accordance with a difference signal between the measuring means and the output signal of the measuring means. 2. The vehicle power system control device according to claim 1, wherein 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 efficiency curve. .