JPH03141826A - Boost pressure control method for internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain appropriate boost pressure in the whole operating region of an engine by controlling the speed change ratio of a continuously variable transmission by the deviation between the actual boost pressure and the target boost pressure set by the engine speed and load, thereby controlling the boost pressure of a mechanical supercharger. CONSTITUTION:Output signals from an accelerator opening sensor 22 installed at a throttle valve 10, an engine speed sensor 23 installed at the crankshaft 1a of an engine 1 and a boost pressure sensor 24, installed on the downstream side of an engine- driven supercharger 11, for detecting the actual boost pressure are inputted into a control unit 40. A speed change control signal and a line pressure control signal are outputted into a hydraulic control circuit 60, and signals from the hydraulic control circuit 60 are further outputted into a continuously variable transmission 13. The speed change ratio of the continuously variable transmission 13 is then controlled by the deviation between the actual boost pressure and the target boost pressure preset from the engine speed and the accelerator opening. The rotating speed of the supercharger 11 is increased when the actual boost pressure is lower than the target boost pressure and reduced when the actual boost pressure is higher than the target boost pressure.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for controlling boost pressure of an internal combustion engine, and more specifically, the present invention relates to a method for controlling boost pressure of an internal combustion engine, and more particularly, to It is possible to control the rotation speed of the engine and supply appropriate boost pressure.

[Conventional technology]

Hitherto, various proposals have been made as means for controlling the boost pressure of this type of internal combustion engine, for example, Japanese Patent Laid-Open No. 61-21
As shown in Japanese Patent No. 8732, a prior art is known in which the intake pressure is monitored by a pressure sensor and the opening/closing of a bypass passage is controlled so that the supercharging pressure is at a set value in any case.

[Problem to be solved by the invention]

However, in the above-mentioned prior art, the bypass passage is opened in order to adjust the boost pressure to a preset map value, so it is not possible to set the bypass amount to zero at the set boost pressure. This is impossible, and there is a problem in that driving power is wasted due to supercharging.

The present invention has been made in view of the above-mentioned circumstances, and includes a positive displacement supercharger that is driven via a continuously variable transmission downstream of a throttle valve provided in the intake passage of an engine. The supercharger rotation speed is controlled by controlling the gear ratio of the continuously variable transmission so that the boost pressure of the charger becomes the preset map data based on the engine rotation speed and load, and the entire engine operation is controlled. It is an object of the present invention to provide a method of controlling boost pressure for an internal combustion engine that can obtain an appropriate boost pressure in the above range.

[Means to solve the problem]

In order to achieve this object, the present invention disposes a mechanical supercharger whose rotation is controlled from the crankshaft of the engine via a continuously variable transmission downstream of the throttle valve of the intake pipe. In an internal combustion engine that has a control unit that controls the gear ratio, the deviation between the actual boost pressure of the mechanical supercharger and the target boost pressure that is preset based on the engine speed and load causes the above-mentioned failure to occur. The present invention is characterized in that the supercharging pressure of the mechanical supercharger is controlled by controlling the gear ratio of the gear transmission.

[For production]

In the boost pressure control method for an internal combustion engine according to the present invention, the gear ratio of the continuously variable transmission is determined by the deviation between the actual boost pressure and the target boost pressure that is preset based on the engine speed and the accelerator opening. When the actual boost pressure is lower than the target boost pressure, the supercharger rotation speed is increased by the continuously variable transmission, and when the actual boost pressure is high, the supercharger rotation speed is decreased. It will be done.

In this way, the gear ratio of the continuously variable transmission is controlled by the deviation between the target boost pressure and the actual boost pressure, thereby controlling the supercharger rotation speed. Boost pressure can be obtained.

〔Example〕

Hereinafter, embodiments of the present invention will be explained in detail based on the accompanying drawings.

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

A throttle body 9 having a throttle valve IO is installed downstream of the air cleaner 7 of the engine t, and a rotor IO is installed downstream of the throttle valve IO.
A positive displacement supercharger 11 and an intercooler I2 are provided.

In addition, the i3 is a hydraulic continuously variable transmission, and its human power shaft 1
The human pulley 14a attached to the belt 4 is a belt.

A crank pulley I7 attached to the crankshaft 1a of the engine 1 rotates simultaneously through a chain transmission device 16 such as a chain. It is directly connected to the supercharger 11.
The rotation speed is variably controlled by the gear ratio of the continuously variable transmission 13.

Further, the throttle valve IO is provided with a known throttle lever 10a, and the throttle lever 10a and an accelerator pedal 20 are interlocked and connected by an accelerator wire 21. Further, an accelerator opening sensor 22 that detects the amount of depression of the accelerator pedal 2o is installed, and an engine rotation speed sensor 23 that detects the engine rotation speed is installed on the crankshaft 1a of the engine i.

On the other hand, a boost pressure sensor 24 that detects the actual boost pressure is installed downstream of the supercharger 11, and a signal from this boost pressure sensor 24 is input to the control unit 4°. There is.

and accelerator opening sensor 22. Engine speed sensor 23. The output signal from the boost pressure sensor 24 is 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 outputs the continuously variable transmission 13. It is configured so that a signal is output to.

The continuously variable transmission 13, for example, as shown in FIG.
d114, and an output shaft 15 parallel to the input shaft 14,
The human power shaft 14 is provided with a primary pulley 30 having a variable interval between the bobbles and a primary cylinder 30a, and the output shaft 15 is provided with a secondary pulley 31 having a secondary cylinder 31a. Also, the primary pulley 30. Secondary pulley 3 (drive belt 32
The primary cylinder 3°a1 and the secondary cylinder 31a are connected to a hydraulic control circuit 60. and the primary cylinder 30a.

A line pressure corresponding to the transmitted torque is supplied to the secondary cylinder 31a to apply a boolean pressing force, and the primary pressure causes the drive belt 32 to wrap around the primary pulley 30 and secondary pulley 31 steplessly by changing the diameter ratio. It is configured to control the speed change.

Further, the primary pulley 30 of the continuously variable transmission 18 includes a primary pulley rotation speed sensor 33 that detects the primary pulley rotation speed Np, and the secondary pulley 31 includes a secondary pulley rotation speed sensor 34 that detects the secondary pulley rotation speed Ns. are respectively arranged, and these primary pulley rotation speed sensors 33. Secondary boolean rotation speed sensor 3
The signals Np and Ns from the accelerator opening sensor 22.
Engine speed sensor 23. The signals ψ, Ne, and P from the supercharging pressure sensor 24 are manually input to a 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. Signals Np, N of secondary pulley rotation speed sensor 34
s is input to the actual gear ratio calculating means 41 and the actual gear ratio is 1-N.
The actual gear ratio 1 is calculated from p/Ns. The gear ratio 1 and the depression amount ψ of the accelerator pedal 20 detected by the accelerator opening sensor 22 are based on the accelerator opening ψ inputted into the target secondary pulley rotation speed search means 42.
Search for the target secondary pulley rotation speed NSD using the map. Then, the target secondary pulley rotation speed NSD and the primary pulley rotation speed Np detected by the primary pulley rotation speed sensor 33 are input to the target speed ratio calculation means 43, and the target speed change ratio is is calculated. Here, the target gear ratio 1s is corrected by the target gear ratio correction means 4B.

Then, the corrected target gear ratio 1s1 and the actual gear ratio I are input to the duty ratio search means 47. Here, continuously variable transmission 1
The duty ratio DI of the manipulated variable 3 is the corrected target gear ratio is
1 and the actual speed ratio l (ls-1), and the value of the duty ratio DI of the operation amount of the continuously variable transmission 13 is determined by the speed change of the hydraulic control circuit BO via the drive unit 48. It is output to the control solenoid valve 62.

On the other hand, the engine rotational speed Ne and the depression amount φ of the accelerator pedal 20 are input manually to the target supercharging pressure setting means 44, and the target supercharging pressure setting means 44 sets the supercharging pressure Ps to the engine rotational speed Ne.
, the supercharging pressure P actually detected by the supercharging pressure sensor 24 and the target supercharging pressure Ps are searched using a map of the supercharging pressure with respect to the depression amount ψ (load) of the accelerator pedal 20, and the comparison and determination means 45 compares the supercharging pressure P and the target supercharging pressure Ps actually detected by the supercharging pressure sensor 24. are compared, and the deviation ΔP-(Ps-P) is determined.

Then, in the target gear ratio correction means 4B, when ΔP>0, the corrected target gear ratio 1s1 is set to Isl<Is, when ΔP-0, it is set to 181-Is, and when ΔP<0, Isl>Is.
The target gear ratio is is corrected so that the corrected target gear ratio 1s1 is manually inputted to the duty ratio search means 47.

Next, the line pressure control system will be described. The engine rotation speed Ne of the engine rotation speed sensor 23 and the depression amount ψ of the accelerator pedal 20 of the accelerator opening sensor 22 are manually input to the engine torque search means 49, and the result is ψ-N.

Find the engine torque T from the torque characteristic map. The engine torque T and the actual gear ratio l of the actual gear ratio calculation means 41 are calculated manually by the target line pressure setting means 50, and the target line pressure is determined by the product of the required line pressure corresponding to the actual gear ratio l and the engine torque T. PLd is determined, and this target line pressure PLd is manually input to the duty ratio search means 51 and set as the target line pressure PLd.
The duty ratio DL is determined according to the following. This duty ratio DL is then outputted to the line pressure control solenoid valve 61 of the hydraulic control circuit 60 via the drive unit 52.

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

First, in a low load region including an idling state when the vehicle is stopped and the accelerator pedal 20 is released, the continuously variable transmission 13
The target speed ratio IS is set small, and the rotation speed of the secondary pulley 31, that is, the rotation speed of the supercharger 11, is controlled to a predetermined low rotation speed.

In the state of low load, the accelerator pedal 20 is further depressed, the throttle valve lO opens and closes according to the amount of depression of the accelerator pedal 20, and the continuously variable transmission 13
Target gear ratio Is according to accelerator opening degree ψ due to depression of
The speed of the output shaft 15 is increased. The power of the engine I in response to the depression of the accelerator pedal 20 is transmitted to the crankshaft 1a, the crank pulley 17. Input end pulley 14 of continuously variable transmission 13
It is transmitted to the continuously variable transmission 13 via a.

The power manually applied to the primary pulley 30 of the continuously variable transmission i3 is transferred to the secondary pulley 3 via the drive belt 32.
1. is transmitted to the output shaft 15, and the drive shaft I8 of the supercharger 11
The supercharger 1t is driven to increase its speed, and the intake air is supercharged to the engine 1.

When the engine torque T increases, the higher the target line pressure is set, except when the engine torque T increases, and the duty signal DL corresponding to this is manually applied to the line pressure control solenoid valve 6 to generate a control pressure, and the average The line pressure PL is increased by controlling the line pressure using the reduced 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, and the gear shift is controlled by supplying and draining oil to the primary cylinder 3oa 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 boot rotation speed sensor 34 and accelerator opening sensor 22
The numbers Np, Ns, and ψ are read, and the actual gear ratio calculation means 41 of the control unit 40 calculates the actual gear ratio l.

Then, in the target secondary boot rotation speed search means 42,
The target secondary boost rotation speed NSD is searched from the map based on the actual gear ratio I and the depression amount ψ of the accelerator pedal 20, and the target gear ratio ls corresponding to this target secondary boost rotation speed NSD is set by the target gear ratio correction means 46. be done.

On the other hand, the target boost pressure setting means 44 sets the engine speed N
e, target supercharging pressure P based on the amount of depression of the accelerator pedal 20 ψ
s is searched by the map, and the comparison/judgment means 45 compares the actual supercharging pressure P detected by the supercharging pressure sensor 24 with the target supercharging pressure Ps. The deviation ΔP-Ps-P is calculated. Then, in the target gear ratio correction means 46, the target gear ratio I is determined by the deviation ΔP.
s is corrected to the corrected target gear ratio 1s1.

That is, when the deviation ΔP is ΔP>0 (Ps > p),
The corrected target gear ratio 1s1 is corrected so that Isl<Is, and when the deviation ΔP is ΔP-0 (Ps - P), the corrected target gear ratio 1s1 is corrected so that Isl - Is, and the deviation ΔP When ΔP<0 (Ps<P), the corrected target speed ratio 1s1 is corrected so that Isl>Is.

The actual speed ratio 1 and the corrected target speed ratio fs1 are then input to the duty ratio search means 45 to retrieve the duty ratio D1.

The duty signal D1 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 operating time at the oil draining position becomes longer due to the ON time, and the oil is drained from the primary cylinder 3Qa, thereby reducing the gear ratio. Since the change in the duty ratio is small and the flow rate change in the primary cylinder 30a is small, the shift speed becomes slow.

On the other hand, as the deviation between the corrected target gear ratio 1s1 and the actual gear ratio 1 becomes larger, the change in the flow rate of the primary cylinder 30a increases due to a change in the duty ratio, and the shift speed becomes faster. In this way, the continuously variable transmission 13 changes the speed continuously while changing the speed change speed.

Therefore, when the actual supercharging pressure P is smaller than the target supercharging pressure Ps, the rotation speed of the output shaft 15 of the continuously variable transmission 13 is increased, and the rotation speed of the supercharger 11 is increased.

Furthermore, when the actual supercharging pressure P is larger than the target supercharging pressure Ps, the rotational speed of the output shaft 15 of the continuously variable transmission 13 is decelerated and the rotational speed of the supercharger H is reduced. In the entire operating range of 1, an appropriate boost pressure corresponding to the engine speed and load can be obtained.

Therefore, a predetermined supercharging pressure is always obtained without providing a bypass passage between the upstream and downstream of the supercharger 11 to bypass the supercharging pressure, and the engine l drives the supercharger 11. The driving loss is reduced, and the rise in intake air temperature is suppressed.

Further, the supercharging pressure can be set in accordance with the rotational speed of the engine 1, and high output can be obtained while avoiding knocking.

In this embodiment, a hydraulic continuously variable transmission is used, but the present invention is not limited to this.

〔Effect of the invention〕

As explained above, the internal combustion engine supercharging pressure control method according to the present invention allows the actual supercharging pressure of the mechanical supercharger to be adjusted to the target supercharging pressure preset based on the engine speed and load. The supercharging pressure of the supercharger is controlled by controlling the gear ratio of the continuously variable transmission using the deviation, so the proper supercharging pressure corresponding to the engine speed and load can be obtained in all engine operating ranges. It will be done.

Furthermore, since a predetermined supercharging pressure is always obtained without escaping supercharging pressure, supercharger drive loss is reduced and an increase in intake air temperature is suppressed.

Furthermore, since the supercharging pressure can be set in accordance with the engine speed and load, high output can be obtained while avoiding knocking.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a boost pressure control method for an internal combustion engine according to the present invention, FIG. 2 is a configuration diagram of a control system, and FIG. 3 is a block diagram of a control unit. l...engine, la...crankshaft, 8...intake pipe, lO...throttle valve, 11...mechanical supercharger, 13...continuously variable transmission, 20... Accelerator pedal, 22... Accelerator opening sensor, 23... Engine speed sensor, 24... Boost pressure sensor, 40... Control unit, 44... Target boost pressure setting means, 4B.・
・Target gear ratio correction means.

Claims (1)

[Claims] An internal combustion engine comprising a mechanical supercharger whose rotation is controlled from the engine crankshaft via a continuously variable transmission downstream of a throttle valve in an intake pipe, and a control unit for controlling the gear ratio of the continuously variable transmission. By controlling the gear ratio of the continuously variable transmission according to the deviation between the actual boost pressure of the mechanical supercharger and a target boost pressure preset according to the rotation speed and load of the engine. , A method for controlling boost pressure of an internal combustion engine, characterized in that the boost pressure of the mechanical supercharger is controlled.