JPS6233088B2 - - 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 throttle 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, 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 travel at a constant high speed, the engine rotational speed will increase, which will also increase fuel consumption. On the other hand, similar problems have arisen in transmissions because they are 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. Fuel consumption decreases as you move toward the center of the isofuel consumption curve. 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. The continuously variable transmission 3 is connected to a propulsion 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 and engine rotation speed command signal; This forms a command means. 8 is a shaft torque sensor provided on the output shaft 2 and measures its driving force, that is, shaft torque; 9 is an engine rotation speed sensor also provided on the output shaft 2 and measures its rotation speed; 10 is each sensor 8, 9 11 is an engine control device that receives the engine output command signal from the detector 7 and the output signal of the multiplier 10 and outputs a difference signal thereof; 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. 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 throttle valve adjustment device for the engine control device 11;
The adder 15 receives the engine rotational speed command signal from the detector 7 and the output signal of the converter 14, and outputs a sum signal thereof. 16 is a transmission control device which receives the output signal of the adder 15 and the output signal of the engine rotation speed sensor 9 and outputs a difference signal therebetween; 17 is a continuously variable transmission corresponding to the output signal of the transmission control device 16; This is a gear ratio adjustment device that adjusts the gear ratio of the machine 3.

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. Outputs an engine output command signal and an engine rotation speed command signal. On the other hand, shaft torque sensor 8
measures the shaft torque of the engine 1, and the engine rotation speed sensor 9 measures the rotation speed of the engine 1. Since the engine output corresponds to the product of the shaft torque and the engine rotation speed, the engine output signal is determined by the output signal of the multiplier 10. Output is measured. The throttle valve adjusting device 13 is connected to the detector 7 via the engine control device 11.
The opening degree of the throttle valve 12 is adjusted in accordance with the difference signal between the engine output command signal from the multiplier 10 and the engine output measurement signal from the multiplier 10, whereby the engine output is feedback-controlled. Further, the engine speed command signal from the detector 7 and the output signal of the engine control device 11 via the converter 14 are added to the adder 15, and the output signal of the adder 15 and the engine speed sensor 9 are added together. is applied to the transmission control device 16, and the gear ratio adjusting device 17 adjusts the gear ratio of the continuously variable transmission in response to the difference signal.

Now, if we consider the above operation in more detail, for example, if the accelerator pedal 6 is now depressed to accelerate, the engine output command signal and the engine rotation speed command signal from the detector 7 will first increase. In this case, since the vehicle speed does not suddenly increase, the output of the multiplier 10 also does not increase suddenly, and a difference occurs between the engine output command signal and the output signal of the multiplier 10, and the throttle valve is A signal is sent to the adjustment device 13 to increase the opening degree of the throttle valve 12. On the other hand, since both the engine speed command signal and the output signal of the engine control device 11 increase, the output signal of the adder 15 becomes even larger, and the output signal of the engine speed sensor 9 does not rise suddenly, so the transmission control device A large signal is applied from 16 to the gear ratio adjusting device 17 to increase the gear ratio of the continuously variable transmission 3. In order to increase the vehicle speed, it is necessary to increase the torque of the propulsion shaft 4, but now that the gear ratio has been increased, the torque of the propulsion shaft 4 increases, and the vehicle speed increases. As a result, the shaft torque and rotational speed of the engine 1 increase, and the output signal of the multiplier 10 increases, so that the output of the engine control device 11 gradually approaches zero.
Engine output is stable. Further, the output signal of the adder 15 approaches the engine speed command signal, and the output signal of the engine speed sensor 9 increases, so the output signal of the transmission control device 16 also approaches zero, and the gear ratio becomes smaller. Through such feedback control, the throttle valve 12 and the continuously variable transmission 3 are controlled so that the engine output and rotation speed correspond to the depression of the accelerator pedal 6,
Further, the gear ratio is controlled so that it increases during sudden acceleration and decreases during constant speed operation.

In the above embodiment, the shaft torque sensor 8 is used as the engine driving force measuring means, but an intake air pressure sensor that measures the intake air pressure of the engine 1 may also be used. Also, in the control process, for example, the second
The fuel consumption is controlled to be optimal by equipping the detector 7, converter 14, etc. with a program calculation function so that the engine output and engine speed change in accordance with the minimum fuel consumption curve shown by the dotted line in the figure. You can also.

As described above, the present invention includes command means for commanding engine output and rotation speed, engine driving force measurement means, engine rotation speed measurement means, speed ratio adjustment means for adjusting the speed ratio of the throttle valve and the power transmission device, etc. The engine output is controlled according to the difference signal between the engine output command signal and the product signal of the output signals of each measuring means, and the output of the engine revolution speed sensor is also controlled by a signal obtained by adding the difference signal to the engine revolution speed command signal. The gear ratio is controlled by the difference 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 and a large torque is obtained, allowing sudden acceleration to be performed smoothly, or at a constant speed at high speed. During operation, the gear ratio is automatically reduced so that the engine speed does not need to be increased unnecessarily. As a result, the vehicle can be operated efficiently 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... Propulsion shaft, 5... Drive wheel,
6...Accelerator pedal, 7...Detector, 8...Shaft torque sensor, 9...Engine speed sensor, 1
0... Multiplier, 11... Engine control device, 12
... Throttle valve, 13 ... Throttle valve adjustment device, 15 ... Adder, 16 ... Transmission control device,
17... Gear ratio adjustment device.

Claims (1)

[Scope of Claims] 1. In a vehicle in which engine output is transmitted to drive wheels via a continuously variable transmission ratio power transmission device, a command means for a vehicle driver to command engine output and engine rotation speed; An engine driving force measuring means for measuring the driving force of the engine, an engine rotational speed measuring means for measuring the engine rotational speed, an engine output command signal of the commanding means, and each output of the engine driving force measuring means and the engine rotational speed measuring means. A throttle valve that adjusts the engine output according to the difference signal between the signal and the product signal, and a difference signal between the signal obtained by adding the difference signal to the engine rotation speed command signal of the command means and the output signal of the engine rotation speed measurement means. 1. A power system control device for a vehicle, comprising: a speed ratio adjusting means for adjusting a speed ratio of a power transmission device accordingly. 2. The vehicle power system control device according to claim 1, wherein an engine shaft torque sensor for measuring the shaft torque of the engine is used as the engine driving force measuring means. 3. The vehicle power system control device according to claim 1, wherein an intake air pressure sensor for measuring intake air pressure of the engine is used as the engine driving force measuring means. 4. According to any one of claims 1 to 3, 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 consumption curve. A power system control device for the vehicle described above.