JPS6321321A - Mechanical control device for supercharger of internal combustion engine with auto-drive-device for vehicle - Google Patents

Abstract

PURPOSE:To obtain acceleration, suppressing the shock caused when the car operation is switched to the supercharging condition during the auto-drive-mode, by keeping a by-pass control valve open, regardless of the signal from the by-pass-operating-signal-forming-means, while the auto-drive-device is on operation. CONSTITUTION:When the ratio of the intake-air flow Q to the engine revolving speed NE is smaller than 0.5, or Q/NE<0.5(l/rev), a solenoid clutch is released. A by-pass-operating-signal-forming-means 6 keeps a by-pass valve 5 open, while the intake-air is supplied to an internal combustion engine via a by-pass passage 4. When Q/NE>0.5, the solenoid clutch is engaged with, thereby turning a supercharger 3 and closing the by-pass valve 5. Under the auto-drive-mode, a gate-means 7 keeps the by-pass control valve 5 open, regardless of the signal from the by-pass-operating-signal-forming-means 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a boost pressure control device for a vehicle internal combustion engine having an autodrive device and a mechanical supercharger.

[Conventional technology]

In order to improve the output of internal combustion engines, it has been proposed to install a mechanical supercharger in the intake pipe. A mechanical supercharger is usually connected to the engine crankshaft via a clutch, and the clutch is engaged or released depending on the load.

That is, when the load is high, the clutch is engaged and the supercharger is operated to perform supercharging, and when the load is light, the clutch is released and the supercharger is stopped and no supercharging is performed.

An autodrive device may be installed in a vehicle, and in this case, in autodrive mode, the throttle valve is automatically opened and closed so that the vehicle speed reaches a set value. Accordingly, the clutch is engaged when the load crosses the load value at which the supercharger is to be activated due to operation of the autodrive device. this is,
There is a risk that the engine torque will increase rapidly and the steering stability will be impaired.

Therefore, Japanese Utility Model Application No. 61-17427 proposes a system in which the supercharger operating clutch is always released and held when the autodrive device is operated.

[Problem that the invention seeks to solve]

In the prior art, the clutch was released in the operating mode of the autodrive device. Therefore, the supercharger is not activated in this mode regardless of load demands. Therefore, the engine output is significantly reduced, and there is a possibility that the intended acceleration may not be obtained when a relatively high engine torque is required, such as when operating on a gentle slope in auto drive mode.

This invention makes it possible to obtain necessary acceleration while suppressing shock when switching to supercharging conditions in autodrive mode.

[Means for solving problems]

In FIG. 1, an internal combustion engine has an autodrive device 1, a mechanical supercharger 3 in an intake pipe 2, and a bypass control valve 5 in a bypass passage 4 that bypasses the supercharger.

The supercharger control device of the present invention includes a means 6 for forming an actuation signal for the bypass control valve 5 according to engine load conditions, and a bypass actuation signal forming means 6 for forming an actuation signal for the bypass control valve 5 during operation of the autodrive device 1.
means 7 for holding the bypass control valve 4 open regardless of signals from the bypass control valve 4;

[For production]

When not in the auto drive mode, the bypass operation signal forming means 6 operates the bypass control valve 5 according to the engine load.
generates an activation signal.

In the auto drive mode, the gate means 7 keeps the bypass control valve 5 open regardless of the signal from the bypass operation signal forming means.

〔Example〕

FIG. 2 shows the overall configuration of the embodiment. 10 is a cylinder block, 11 is a piston, 12 is a connecting rod,
13 is a crankshaft, 14 is a combustion chamber, 15 is a cylinder head, 16 is an intake valve, 17 is an intake boat, 18 is an exhaust valve,
19 is an exhaust port. The intake boat 17 is the intake pipe 20
．． It is connected to a throttle body 23 via a mechanical supercharger 22 .

A throttle valve 24 is arranged within the throttle body 23, and an air flow meter 25 and an air cleaner 26 are arranged upstream thereof.
is located.

The mechanical supercharger 22 is a Roots pump in this embodiment, and includes a pair of rotors 31 and 32.
The compression operation is performed by rotating the housing 29 while maintaining a small gap with respect to the housing 29. A pulley 33 is provided on the rotating shaft 32A of one rotor 32 of the pair of rotors via a clutch mechanism 34, and this boot IJ33
is the boot IJ36 on the crankshaft 16 via the belt 35.
connected to.

A bypass passage 41 is arranged to bypass the supercharger 22, and one end of the bypass passage 41 is connected to the throttle valve 24.
The other end of the bypass passage 41 is connected to the intake pipe 20 upstream of the supercharger 22 downstream of the supercharger 22 .
connected to. Bypass control valve 42 in bypass passage 41
is placed.

The bypass control valve 42 is of a diaphragm-driven type, is connected to a diaphragm 43, and is opened and closed according to the pressure applied to the diaphragm 43. The diaphragm 43 is switched by an electromagnetic three-way valve 44 between an intake pipe negative pressure port 45 downstream of the throttle valve 24 and an atmospheric pressure boat 46 upstream. The diaphragm 43 is communicated with the negative pressure port 45 when the solenoid valve 44 is turned off (OFF), and with the atmospheric pressure boat 46 when it is energized (ON). Solenoid valve 44 and negative pressure port 4
A delay element 47 is arranged between 5 and 5. This delay element 4
7 is composed of an orifice 47a and a check valve 47b arranged in parallel.

This vehicle is equipped with an auto-drive device, and in auto-drive mode, engine output can be controlled to maintain the vehicle speed at a set value. 48 is an autodrive actuator, which is connected to the throttle valve 24. The operation of the actuator 48 is well known and will not be explained in detail, but in the auto drive mode, the actuator 4
8 opens and closes the throttle valve 24 so that the vehicle speed matches the set value.

Reference numeral 50 denotes a control circuit that controls the operation of the clutch 34, the solenoid valve 44, the autodrive actuator 48, and other engine control devices not shown because they are not related to this invention, and is configured as a microcomputer system. The control circuit 50 includes a microprocessing unit (MPU) 51, a memory 52, an input port 53,
It consists of an output port 54 and a bus 55 that interconnects these ports. Signals from each sensor are input to the input port 53. A signal related to the intake air amount Q is obtained from the air flow meter 25. Further, a signal regarding the rotation speed NE of the crankshaft 13 is obtained from the rotation speed sensor 61. A drive signal is sent from the output port 54 to the clutch 34 and the solenoid valve 44 according to a control program stored in the memory 52.

The operation of the control circuit 50 will be explained below. Incidentally, the operation of the autodrive actuator 48 itself is well known;
Further, since it is not directly related to this invention, the explanation will be omitted. Third
The figure shows a flowchart of a routine for controlling the actuation of clutch 34 and solenoid valve 44 in accordance with the present invention.

Needless to say, a program for implementing this flowchart is stored in the nonvolatile area of the memory 52.

The routine shown in FIG. 3 is a time interrupt routine that is executed every fixed period of time, for example, 100 msec. In step 99, the intake air amount to revolution speed ratio Q/NE is input as a representative load value. At step 100, the ratio of the intake air amount Q to the engine speed NB is a predetermined value (for example, 0.57!
/rev ). Q/NE<
If it is 0.5, proceed to step 101, and electromagnetic clutch 3
4 will be released. Therefore, the rotation of the engine is controlled by the supercharger 2.
Not transmitted to 2. Next, in step 102, the solenoid valve 44
is demagnetized (turned off). Therefore, the diaphragm 43
The negative pressure of the negative pressure port 45 acts on the bypass control valve 42.
When the valve is opened, intake air is supplied to the engine via the bypass passage 41.

When Q/NE>0.5, the process advances from step 100 to step 104, where a command to excite the clutch 34 is issued from the output port 54, the clutch 34 is engaged, and the rotation of the crankshaft 13 is controlled by the pulley 36, Belt 35, Boo I
It is transmitted to the rotating shaft of the supercharger 22 via J33, and the rotors 31 and 32 are rotated. In step 105, it is determined whether the autodrive switch 63 is OFF. If it is not the auto drive mode, the process advances from step 105 to step 106, and the intake air amount to revolution speed ratio Q/NE>0
．． It is determined whether the number is 6 or not. When Q/NE≦0.6, the process proceeds from step 106 to step 107, where the solenoid valve 44 is demagnetized and the bypass control valve 42 is maintained open. Therefore, weak supercharging is performed. Q/NE in step 106>
When it is 0.6, the process proceeds to step 110, where the solenoid valve 44 is excited and the diaphragm 43 is communicated with the atmospheric pressure port 46.

Therefore, the spring 49 closes the bypass control valve 42 via the diaphragm 43. Thus, bypass passage 4
1 is closed and air from the supercharger 22 is introduced into the engine without being bypassed. Therefore, full supercharging will be performed. In step 114, the flag FVSV
= 1.

Next, I will explain the operation in auto drive mode.
The process advances from step 105 to step 102, where the bypass control valve 42 is kept open. Therefore, during auto drive mode. Even if Q/NE>0.6, the bypass control valve remains open, the bypass is not opened or closed during autodrive, and there is no sudden change in engine output or occurrence of shock.

〔effect〕

In this invention, the clutch is controlled even during auto-drive, but bypass control is not performed.

By controlling the clutch, the necessary engine output can be obtained even during autodrive, and acceleration performance will not be lost. That is, in FIG. 4, the straight line l indicates the engagement of the clutch 34,
m indicates the torque characteristic when the bypass control valve 42 is closed, that is, at full supercharging, m indicates the torque characteristic when the clutch is engaged and the bypass control valve is open, and n indicates the torque characteristic when the clutch is disengaged and the bypass control valve is open. During autodrive, the characteristic is m, and the torque obtained is smaller than when fully supercharged, but it is sufficient to obtain acceleration performance during autodrive.

In addition, by prohibiting the opening and closing of the bypass during autodrive, even if the clutch switches from disengagement to engagement during autodrive, the change in engine output at that time is appropriately suppressed, so there is no switching shock. It never occurs. In other words, compared to the torque in the non-supercharged state n, the torque in the bypass open state m with the clutch engaged is not that far from the torque in the fully supercharged state l, so when the bypass is opened and closed with the clutch engaged. The change in torque is not enough to cause a shock.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of this invention. FIG. 2 is a schematic diagram of the entire configuration of this invention. FIG. 3 is a flowchart explaining the control operation of the first embodiment of the present invention. Figure 4 is a graph showing the relationship between throttle valve opening and torque for various types of full supercharging, partial supercharging (m), and non-supercharging (n). 13...Crank, 22...・Supercharger, 24... Throttle valve, 25... Air flow meter, 34... Clutch, 41... Bypass passage, 42... Bypass control valve, 44... Solenoid valve, 48...・Auto drive actuator, 50...
Control sum circuit, 63...Auto drive switch.

Claims (1)

[Claims] In a vehicle internal combustion engine equipped with an autodrive device, a mechanical supercharger in the intake pipe, and a bypass control valve installed in the bypass passage that bypasses the supercharger, the bypass control valve is operated according to engine load conditions. A mechanical supercharger control device for an internal combustion engine, comprising means for forming a signal and means for holding a bypass control valve open during operation of an autodrive device, regardless of the signal from the bypass activation signal forming means.