JPH03117631A - Load control method for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide smooth output characteristics responding to an operation condition by a method wherein the change gear ratio of a hydraulic type continuously variable transmission is decided by a region deciding means and varied according to a region, and the number of revolutions of a mechanical type supercharger is controlled according to a pedalling amount of an accel. CONSTITUTION:In a control unit 40, based on an accel opening from a second 22, the target number of revolutions of a secondary pulley is retrieved by means of a real change gear ratio (i) by a retrieving means 43 according to a region decided by a region deciding means 42. A target change gear ratio is calculated by a calculating means 44, and through control of a solenoid valve 62, the change gear ratio of a hydraulic type continuously variable transmission is varied. Based on an accel opening and the number Ne of revolutions of an engine, corresponding engine torque is determined by a retrieving means 47, a target line pressure is set by a set means 48, a line pressure is controlled through a duty ratio retrieving means 49, a drive part 50, and a solenoid valve 61, and the number of revolutions of a mechanical supercharger is controlled. This method simplifies the whole of a system, and provides smooth output characteristics responding to an operation condition.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for controlling the load of an internal combustion engine equipped with a mechanical supercharger. The load on the internal combustion engine is controlled by controlling the rotational speed of the engine (supercharger).

[Conventional technology]

Conventionally, in order to control the load on an internal combustion engine, it is common to adjust the amount of intake air by throttling a throttle valve installed in the intake passage. Due to the strong negative pressure, pump loss increases and the efficiency (output) of the internal combustion engine decreases.

Furthermore, in order to increase the output of an internal combustion engine, it is known that a supercharger is installed in the intake passage.

However, with this method, in order to control the supercharging pressure according to the load of the internal combustion engine, a clutch mechanism that turns on and off the drive of the supercharger and a bypass passage that bypasses the supercharger are installed. When starting supercharging, the clutch mechanism is turned on and a shock is generated, and when the internal combustion engine is running at high speeds, the intake capacity of the internal combustion engine decreases. Since the pressure rises too much, the supercharging pressure must be bypassed, and there are problems such as an increase in supply air temperature and loss of drive torque.

Therefore, as a countermeasure against these problems, for example, Japanese Patent Application Laid-Open No. 61-932
As shown in Publication No. 32, a prior art system in which a supercharger installed in the intake passage is driven via a continuously variable transmission, and the rotation of the continuously variable transmission is controlled in relation to accelerator operation. The technology is known.

[Problem to be solved by the invention]

However, in the above-mentioned prior art, in areas where the intake air amount is low, such as in the low and medium load areas of the engine, the low pressure air throttled by the throttle valve is supercharged by the supercharger, so the pump loss is reduced. However, there is a problem in that the amount of work required to drive the supercharger increases, resulting in a decrease in the efficiency of the engine.

The present invention has been made in view of the above-mentioned circumstances, and a positive displacement supercharger is disposed downstream of a throttle valve provided in the intake passage of an engine, and in regions other than extremely low load regions, the supercharger is The amount of intake air is controlled by controlling the rotational speed, and in the region between the extremely low load region and the high load region, there is no supercharging, and high efficiency is achieved in the entire engine operating region. The purpose is to provide a control method.

[Means to solve the problem]

In order to achieve this object, the present invention provides a system in which the rotation of the intake pipe downstream of the throttle valve, which supplies the air taken in from the air cleaner to the combustion chamber, is controlled by the engine crankshaft via a hydraulic continuously variable transmission. In an internal combustion engine that is provided with a mechanical supercharger and has a control unit that controls the gear ratio of the continuously variable transmission, the throttle valve is fully opened when the accelerator pedal is depressed by a predetermined amount or more; The unit has a region determining means for determining the load region of the engine, and when the region determining means determines the extremely low load region, the mechanical supercharger is driven at a predetermined constant low rotation speed. The gear ratio of the continuously variable transmission is controlled based on the signal from the control unit, and when the load exceeds an extremely low load range, the gear ratio of the continuously variable transmission is controlled based on the signal from the accelerator pedal. of the mechanical supercharger so that the pressure ratio of the mechanical supercharger is at least 1 or less in the region between the extremely low load region and the high load region. The gear ratio of the continuously variable transmission is controlled so that the rotation speed is controlled according to the amount of depression of the accelerator pedal, and in a high load region, the mechanical supercharging pressure is set to a boost pressure corresponding to the output of the engine. The present invention is characterized in that the gear ratio of the continuously variable transmission is controlled so as to obtain the rotational speed of the feeder.

[For production]

Based on the above configuration, in the load control method for an internal combustion engine according to the present invention, the throttle valve is fully opened in regions other than the extremely low load region, and intake air is controlled by the supercharger rotation speed.

The area between the extremely low load area and the high load area, that is, the low
In the medium load region, the gear ratio of the continuously variable transmission is changed according to the amount of depression of the accelerator pedal, and the rotation speed of the supercharger is variably controlled by this gear ratio. By setting the pressure ratio of the supercharger in this region to 1 or less, the supercharger enters a non-supercharging state, and the intake air amount is controlled by the supercharger rotation speed.

In a high load region, a supercharging state is established, and the supercharger is driven at a rotational speed that provides the supercharging pressure necessary for supercharging.

Therefore, in low and medium load regions, the turbocharger's shaft torque is transmitted to the engine crankshaft, reducing engine fuel consumption, and in high load regions, the turbocharger can achieve the required boost pressure. Since the supercharger is driven at a lower rotational speed, the supercharger drive torque is reduced.

〔Example〕

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

FIG. 1 is a schematic configuration diagram showing a load control method for an internal combustion engine according to the present invention. In the figure, l is an engine, 2 is a combustion chamber of the engine 1, 3 is an intake valve, 4 is an exhaust valve, and 5 is an injector. , 6 indicates a spark plug, 7 indicates an air cleaner, and 8 indicates an intake pipe.

A throttle body 9 having a throttle valve 10 is installed downstream of the air cleaner 7 of the engine 1, and a rotor 11 is installed downstream of the throttle valve IO.
A positive displacement supercharger 11 and an intercooler 12 are provided.

In addition, 13 is a hydraulic continuously variable transmission, and its human power shaft 1
The input pulley 14a attached to the belt 4 is a belt.

The rotational drive shaft 18 of the supercharger 11 is driven to rotate by a crank pulley 17 attached to the crankshaft 1a of the engine l via a chain transmission device 16, etc. Directly connected, supercharger 11
The rotation speed is variably controlled by the gear ratio of the continuously variable transmission 13.

Further, the throttle valve 10 includes a known throttle valve t<
-10a is provided, and the throttle lever 10a and the accelerator pedal 20 are interlocked and connected by an accelerator wire 21. As shown in FIG. 4, the throttle valve 10 is adjusted in accordance with the depression amount ψ of the accelerator pedal 20 so that the opening degree θ of the throttle valve 10 becomes fully open with the depression amount ψ1 of the accelerator pedal 20 in the A region at extremely low load. The opening degree θ of the IO is controlled to open or close. Further, an accelerator opening sensor 22 that detects the amount of depression of the accelerator pedal 20 is installed, and a crank angle sensor 22 for detecting the amount of depression of the accelerator pedal 20 is installed. An engine rotation speed sensor 23 that detects the engine rotation speed is installed in the mla.

The output signals from the accelerator opening sensor 22 and the engine rotation speed sensor 23 are input to the control unit 40, and the control unit 40 outputs a shift control signal and a line pressure control signal to the hydraulic control circuit 60, and the hydraulic control circuit 60 is configured to output a signal to the continuously variable transmission 13.

The continuously variable transmission 13 has an input shaft 14 and an output shaft 15 parallel to the human power shaft 14, as shown in FIG. A primary pulley 30 is provided on the output shaft 15, and a secondary pulley 31 similarly provided with a secondary cylinder 31a is provided on the output shaft 15. Also, the primary pulley 30. A drive belt 32 is wound around the secondary pulley 31, and the primary cylinder 30a and the secondary cylinder 31a are configured in a hydraulic control circuit 60. Line pressure corresponding to the transmission torque is supplied to the primary cylinder cylinder 30a and the secondary cylinder 31a to apply a pulley pressing force, and the primary pressure causes the primary pulley 30 of the drive belt 32 to be pressed. The winding around the secondary pulley 31 is configured to change the ratio of diameters to perform stepless speed change control.

Further, the primary pulley 30 of the continuously variable transmission 13 has a primary pulley rotation speed sensor 33 that detects the primary pulley rotation speed Np, and the secondary pulley 31 has a secondary pulley rotation speed sensor 34 that detects the secondary pulley rotation speed Ns. These brima rear rotation speed sensors 33. Secondary pulley rotation speed sensor 3
The signals Np and Ns from the accelerator opening sensor 22.
The signals ψ and N'e from the engine speed sensor 23 are input to the control unit 40 to calculate a shift control signal for the continuously variable transmission 13.

Next, referring to FIG. 3, the gear ratio control system of the continuously variable transmission 13 will be described.
3. The rotation speed Np of the secondary boolean rotation speed sensor 34,
Ns is input to the actual gear ratio calculating means 41 and the actual gear ratio is 1-
The actual gear ratio i is calculated from Np/Ns. Further, the accelerator pedal 20 detected by the accelerator opening sensor 22
The amount of depression ψ of the accelerator is input to the area determining means 42, and the load area of the engine 1 is determined by a map based on the amount of accelerator depression ψ as shown in FIG. The signal of the load region determined by the region determining means 42, the actual gear ratio l from the actual gear ratio calculating means 41, and the signal of the depression amount ψ of the accelerator pedal zO from the accelerator opening sensor 22 are used as the target secondary boolean. The target secondary pulley rotation speed NSD obtained by inputting to the rotation speed search means 43 and the primary pulley rotation speed Np from the primary pulley rotation speed sensor 23 are input to the target speed ratio calculation means 44, and the target speed ratio IS is inputted to the target speed ratio calculation means 44. Calculated. The target gear ratio is and the actual gear ratio 1 are then input to the duty ratio search means 45. Here, the duty ratio Di of the manipulated variable of the continuously variable transmission 13 is searched using a map (is-1) of the target gear ratio IS and the actual gear ratio l, and
The value of the duty ratio Di of the operation amount of the continuously variable transmission 13 is outputted to the shift control solenoid valve 62 of the hydraulic control circuit 60 via the drive unit 46.

Next, the line pressure control system will be described. It has an engine torque search means 47 which inputs the engine speed Ne of the engine speed sensor 23 and the depression amount ψ of the accelerator pedal 20 of the accelerator opening sensor 22, and calculates the engine torque T from the torque characteristic map of ψ-Ne. . The engine torque T and the actual gear ratio i of the actual gear ratio calculating means 41 are calculated by manually inputting the target line pressure setting means 48 to the product of the necessary line pressure corresponding to the actual gear ratio 1 and the engine torque T. P1 and d are determined, and this target line pressure PLd is manually inputted to the duty ratio search means 49 to determine the duty ratio D L corresponding to the target line pressure P1 and d. This duty ratio DL is outputted to the line pressure control solenoid valve 61 of the hydraulic control circuit 60 via the drive unit 50.

Next, the operation of the load control method for an internal combustion engine configured as described above will be explained.

First, in region A, which is an extremely low load region including an idling state when the vehicle is stopped and the accelerator pedal 20 is released, the target gear ratio IS of the continuously variable transmission 13 is set small, and the rotation speed of the secondary pulley 31, that is, the The rotation speed of the feeder 11 is controlled to a predetermined constant low rotation speed. On the other hand, the throttle valve 10 is controlled to open and close according to the depression amount ψ of the accelerator pedal 20, and controls the amount of air discharged from the supercharger (1).

When the accelerator pedal 20 is further depressed under extremely low load conditions, the throttle valve 10 is fully opened and the continuously variable transmission 13 is opened.
In this case, the speed of the output shaft 15 is increased at the target speed ratio IS according to the accelerator opening degree φ caused by depression of the accelerator pedal 20 shown in FIG. The power of the engine 1 in response to the depression of the accelerator pedal 20 is generated by the crankshaft 1a.

Crank pulley 17. Input side pulley 1 of continuously variable transmission 13
4a to the continuously variable transmission 13.

The power input to the primary pulley 30 of the continuously variable transmission 13 is transferred to the secondary pulley 3 via the drive belt 32.
1. It is transmitted to the output shaft l, and the drive shaft 18 of the supercharger 11
The supercharger 11 is driven to increase its speed, and the intake air is supplied to the engine 1.

In addition, outside the extremely low load region, the larger the engine torque T, the larger the target line pressure is set, and the duty signal DL corresponding to this is input to the line pressure control solenoid valve 42 to generate a control pressure. The line pressure PL is increased by controlling the line pressure using the averaged pressure.

Then, as the gear ratio l becomes smaller and the engine torque T also becomes smaller, the line pressure PL is controlled to decrease by acting in a similar manner. exert force.

The line pressure PL is always supplied to the secondary cylinder 31a (jF), and the gear shift is controlled by supplying and draining oil to the primary cylinder 30a' by a shift control valve (not shown) using the control pressure of the shift control solenoid valve 62. This will be explained below.

First, the primary pulley rotation speed sensor 33. Secondary pulley rotation speed sensor 34 and accelerator opening sensor 22
The signals Np, Ns, and ψ are read from the control unit 40, and the actual gear ratio calculation means 41 of the control unit 40 calculates the actual gear ratio l.

On the other hand, the signals Ne and ψ from the engine speed sensor 23 and the accelerator opening sensor 22 are read, and the region determining means 42 determines extreme load, low/medium load, and high load.
The target secondary pulley rotation speed search means 43 determines that the actual gear ratio is 1. The target secondary pulley rotation speed NSD is searched by the map based on the depression amount ψ of the accelerator pedal 20, and the target secondary pulley rotation speed NSD is determined by the target gear ratio calculation means 44.
A target gear ratio Is corresponding to SD is calculated.

The actual speed ratio l and the target speed ratio is are manually input to the duty ratio search means 45 to search for the duty ratio Di.

The duty signal Di is the solenoid valve 6 for speed change control.
2, a pulse-like control pressure is generated manually, thereby repeatedly operating a speed change control valve (not shown) in two positions: oil supply and oil drain. Here, when the duty ratio DI becomes smaller, the shift control valve operates for a longer time in the refueling position due to the off time, and the primary cylinder 30a is refueled.
This increases the gear ratio. On the other hand, when the duty ratio increases, the operation time at the oil draining position becomes longer due to the ON time, and the oil is drained from the primary cylinder 30a, thereby reducing the gear ratio. Since the change in the duty ratio is small and the flow rate change in the primary cylinder Boa is small, the shift speed becomes slow.

On the other hand, as the deviation between the target speed ratio IS and the actual speed ratio I increases, the change in the flow rate of the primary cylinder 30a increases due to a change in the duty ratio, and the speed change speed becomes faster.

In this way, the continuously variable transmission 13 changes the speed continuously while changing the speed change speed.

Therefore, in the A region in FIG. 4, that is, in the extremely low load region, the gear ratio of the continuously variable transmission 13 is set small so that the rotation speed of the supercharger 11 is a low constant predetermined rotation speed,
The supercharger 11 is driven at a predetermined rotation speed and discharges a constant amount of air, and the amount of discharged air is controlled by opening and closing the throttle valve 10 in accordance with the amount of depression of the accelerator pedal 20.

Next, in the low/medium load area of area B, the accelerator pedal 2
0 fully opens the throttle valve 10, and the gear ratio of the continuously variable transmission I3 changes according to the amount ψ of the accelerator pedal 20, thereby controlling the rotational speed of the supercharger 11 and preventing the intake air amount from becoming excessive. Controlled by the rotation speed of feeder ■1. At this time, the upstream pressure of the supercharger 11 is approximately atmospheric pressure, and the downstream pressure J is negative pressure due to the intake action of the engine 1.
The pressure ratio (discharge side pressure/suction side pressure) of the supercharger 11 is “1”
As shown in the characteristic diagram of pressure ratio and driving force in Figure 5, the work of the supercharger U is negative, so the rotational torque of the supercharger 11 is transferred to the engine 1. The transmission is recovered, reducing fuel consumption.

Furthermore, the high load region of region C is a supercharging region, in which the rotation speed of the supercharger 11 is high (and the engine output is increase

In addition, in the above embodiment, the opening and closing of the throttle valve IO is as follows:
It is also possible to configure the system to be electrically controlled instead of using a mechanical link device linked to the accelerator pedal 20.

〔Effect of the invention〕

As explained above, the load control method for an internal combustion engine according to the present invention installs a mechanical supercharger in the middle of the intake pipe whose rotation speed is controlled from the crankshaft via a hydraulic continuously variable transmission. The gear ratio of the continuously variable transmission is made variable in accordance with the region determined by the region determining means of the control unit, and the rotation speed of the mechanical supercharger is controlled in accordance with the amount of depression of the accelerator pedal. This eliminates the need for a clutch mechanism to turn on and off the turbocharger drive or a bypass passage to control boost pressure, making the structure simple and simplifying the entire system.
There is no shock when switching clutches, etc., and smooth output characteristics can be obtained depending on driving conditions.

Furthermore, in the low and medium load range of the engine, the supercharger is driven by the pressure difference before and after the supercharger, which means that driving force is supplied to the engine side, improving engine output and fuel consumption. amount is reduced.

Furthermore, when the engine is under high load, a supercharging pressure corresponding to the engine output is obtained, so the supercharger driving torque is reduced and knocking due to high supercharging is prevented.

[Brief explanation of drawings]

Fig. 1 is a schematic block diagram showing the load control method for an internal combustion engine according to the present invention, Fig. 2 is a block diagram of the control system, Fig. 3 is a block diagram of the control unit, and Fig. 4 shows the accelerator pedal depression amount and the throttle valve. A characteristic diagram showing the relationship between the opening degree and the gear ratio of the continuously variable transmission, and FIG. 5 is a characteristic diagram showing the relationship between the pressure ratio of the supercharger and the driving torque. ■...Engine, 1a...Crankshaft, 8...Intake pipe, 10...Throttle valve, 11...Mechanical supercharger, 13...Continuously variable transmission, 20... Accelerator pedal, 22... Accelerator opening sensor, 23... Engine rotation speed sensor, 40... Control unit, 42... Area determination means. Patent applicant Fuji Heavy Industries Co., Ltd.

Claims (1)

[Claims] A mechanical supercharger whose rotation is controlled by the engine crankshaft via a hydraulic continuously variable transmission, downstream of the throttle valve in the intake pipe that supplies air drawn from the air cleaner to the combustion chamber. and a control unit for controlling the gear ratio of the continuously variable transmission, and the throttle valve is fully opened when the accelerator pedal is depressed by a predetermined amount or more, and a region determining means for determining a load region of the engine, and when the region determining means determines an extremely low load region, the mechanical supercharger is driven at a predetermined constant low rotation speed. The gear ratio of the continuously variable transmission is controlled based on the signal from the control unit, and when the load exceeds an extremely low load range, the gear ratio of the continuously variable transmission is varied according to the amount of depression of the accelerator pedal. In the region between the extremely low load region and the high load region, the rotation speed of the mechanical supercharger is controlled by the accelerator so that the pressure ratio of the mechanical supercharger is at least 1 or less. The gear ratio of the continuously variable transmission is controlled according to the amount of pedal depression, and in a high load region, the rotation speed of the mechanical supercharger is such that the boost pressure corresponds to the output of the engine. A load control method for an internal combustion engine, characterized in that the gear ratio of the continuously variable transmission is controlled so as to obtain the following.