JPH0421053B2 - - Google Patents

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 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. Mechanical superchargers are typically connected to the engine crankshaft via a clutch, which is engaged or disengaged 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.

In a device that suppresses a supercharger by a clutch, by delaying the switching from engagement to disengagement of the clutch, unnecessary operation of the clutch due to the temporary return of the throttle valve is prevented, There are some devices that reduce the number of clutch operations and improve the durability of the clutch (for example, Japanese Patent Application Laid-open No. 1324/1983).

The delay time from the transition from the clutch engagement condition to the disengagement condition until the clutch is actually released is determined by a trade-off between clutch durability and fuel consumption. In other words, the longer the delay time, the more the clutch is turned on and off in order to maintain engagement when the clutch is shifted to the clutch release condition and then immediately returned to the clutch engagement condition.
Since the frequency of this decreases, the durability of the clutch is improved. However, since the engagement time of the clutch is extended, the supercharger is driven in vain, and the fuel consumption rate worsens by the amount of power loss.
Conventionally, delay times have been set so that these contradictory demands are reconciled.

[Problem that the invention seeks to solve]

Since the load condition changes during a shift change, the clutch engagement condition often crosses the clutch release condition. Therefore, it is necessary to extend the delay time to reduce the frequency of clutch engagement and release during shift changes. However, if the delay time is extended, the engagement of the clutch will be maintained even during idling when the shift change is directly transferred to idling conditions. In this case, the idle rotation will drop due to the drive torque of the supercharger, and there is a risk that the engine will stall.

This invention turns on the supercharger during shift change.
- The purpose is to provide a supercharger control method that reduces OFF frequency.

[Means for solving problems]

According to this invention, as shown in FIG. 1, a mechanical supercharger 2 is provided in the intake pipe, and the mechanical supercharger 2 is connected to a rotating shaft 4 of an internal combustion engine via a clutch 3. In a vehicle where the clutch is engaged and released by the clutch control means 5 depending on whether the load is large or small, there is a clutch release condition detection means 6 for detecting the operating condition under which the clutch 3 should be switched from the engaged state to the released state, and the clutch engagement state. a delay means 7 for setting a delay time for switching from an engaged state to a released state; and a clutch release delay prohibited region detection means for detecting an engine idling operating region and a similar region in which a delay in clutch release is not allowed. 8, in operating ranges other than the idle operating range of the engine and operating ranges close to this, the clutch is controlled after the delay time set by the delay means 7 has elapsed after detecting the conditions for switching the clutch from the engaged state to the disengaged state. driving means 5 to release clutch 3;
A switching means 9 is provided for driving the clutch control means 5 so that the clutch 3 is released without waiting for the elapse of the delay time when the engine is in an idle operating range or an operating range close to this. A mechanical supercharger control device for an internal combustion engine is provided.

[Effect]

The clutch control means 5 engages and disengages the clutch 3 depending on the magnitude of the engine load.

Clutch release condition detection means 6 detects operating conditions under which the clutch 3 should be switched from an engaged state to a released state. The delay means 7 sets a delay time for switching the clutch 3 from the engaged state to the released state. The clutch release delay prohibited area detecting means 8 detects the clutch 3 in the engine idling operating area and close to this.
Detects a clutch release delay prohibition area that does not cause a delay in release of the clutch.

The switching means 9 detects a condition for switching the clutch from an engaged state to a disengaged state in an engine operating range other than the idle operating range and an operating range close to this, and after a delay time set by the delay means 7 has elapsed. Using the clutch control means 5, the clutch 3
If the engine is in the idling operating range or in an operating range close to this, the clutch is driven to be released, and immediately upon detecting the conditions for switching the clutch from the engaged state to the disengaged state, without waiting for the elapse of the delay time. Then, the clutch control means 5 is activated so that the clutch 3 is released.

〔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 port, 18 is an exhaust valve, and 19 is an exhaust port. The intake port 17 is connected to a throttle body 23 via an intake pipe 20, an intercooler 21, and a mechanical supercharger 22. Throttle body 2
A throttle valve 24 is disposed within the throttle valve 3, and an air flow meter 25 and an air cleaner 26 are located upstream thereof. The intercooler 21 is arranged to lower the temperature of air that has been heated by being compressed by the mechanical supercharger 22 and to increase charging efficiency.

Mechanical supercharger 22 is located downstream of throttle valve 24 and upstream of intercooler 21 . The mechanical supercharger 22 is a roots pump in this embodiment,
A pair of rotors 31 and 32 are provided, and the rotor 31,
32 rotates while maintaining a minute gap with respect to the housing 33, thereby performing a compression operation. Rotating shaft 3 of one rotor 32 of a pair of rotors
A pulley 34' is connected to the clutch mechanism 34 on 2A.
A pulley 34' is connected to a pulley 36 on the crankshaft 13 via a belt 35. As schematically shown in Fig. 2, this clutch mechanism is an electromagnetic clutch, and has a pair of friction plates 3.
7, 38 and a solenoid 39, and by controlling the energization of the solenoid 39, the friction plates 37, 3
This controls the engagement of 8. One friction plate 3
7 is connected to the rotating shaft 32A, and the other friction plate 38
is adapted to rotate freely about the rotating shaft 32A, and its outer periphery forms the aforementioned pulley 34'.

A bypass passage 41 is arranged to bypass the supercharger 22, one end of the bypass passage 41 is connected to the intake pipe 23 downstream of the throttle valve 24 and upstream of the supercharger 22, and the other end of the bypass passage 41 is connected to the intake pipe 23 downstream of the throttle valve 24 and upstream of the supercharger 22. It is connected to the intake pipe 20 downstream of the intercooler 21 . A bypass control valve 42 is arranged in the bypass passage 41 . The bypass control valve 42 is electromagnetically driven, and is controlled to open and close by an electric signal from a control circuit, thereby controlling the bypass air flowing through the bypass passage 41.

A control circuit 50 controls the operation of the clutch 34 and the bypass control valve 42, and is configured as a microcomputer system. The control circuit 50 includes a microprocessing unit (MPU) 51,
Memory 52, input port 53, and output port 5
4 and a bus 55 that interconnects these. 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 N of the crankshaft 13 is obtained from the rotation speed sensor 61. The solenoid 39 of the clutch 34 and the bypass control valve 4 are activated from the output port 54 according to the control program stored in the memory 52.
A drive signal is sent to 2.

FIG. 3 shows a flowchart of a routine for controlling actuation of clutch 34 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, every 50 milliseconds. In step 100, the ratio of the intake air amount Q measured by the air flow meter 25 to the engine rotational speed N measured by the crankshaft sensor 61 is input. This intake air amount-rotational speed ratio Q/N is a factor representing the engine load. In 102, Q/N is a predetermined value a (for example,
0.5/rev). Q/
If N is greater than the predetermined value a, the process proceeds to 104, where the counter SCDC is cleared. This counter
As will be described later, SCDC is a software counter that measures the time elapsed after the clutch is switched from the engagement condition to the release condition. In the next step 106, a command to energize the solenoid 39 of the clutch 34 is issued from the output port 54, and the friction plates 37 and 38 of the clutch come into engagement, and the rotation of the crankshaft 13 is controlled by the pulley 36, belt 35, Pulley 3
4' to the rotating shaft of the supercharger 22, and the rotors 31 and 32 are rotated. In step 108, a closing command is issued from the output port 54 to the bypass control valve 42, and the bypass passage 41 is closed. Therefore, air from the supercharger is introduced into the engine without being bypassed. Therefore, supercharging will be performed.

102 when Q/N is not greater than the predetermined value a.
Then, the process proceeds to 110, and Q/N is set to a predetermined value b [for example, 0.2
/rev). When Q/N is smaller than b (N ₀ at 110), the engine speed signal N is input at step 112, and the engine speed signal N is input at step 113.
In step , it is determined whether N is larger than a predetermined value c (for example, 1500 rpm). When the engine is at or near idle conditions, the Q/N
Since <b and N<c, 1 from 110
12, the program branches to _N0 at 113, the program flows to 114, and the output port 54 connects the clutch 3.
A command is issued to demagnetize the solenoid 39 of the clutch 4, so that the friction plates 37 and 38 of the clutch are separated and the rotation of the crankshaft 13 is no longer transmitted to the rotor of the supercharger 22. Therefore, supercharging is not performed. At 116, a command is issued to the bypass control valve 42 to open the control valve 42, so that the bypass passage 41 is opened and a portion of the intake air is introduced into the engine via the bypass passage 41.

When the idle condition is not met, Q/N>b, or even if Q/N<b, N>c. Therefore, from 110 to 118 or from 110 to 1
It flows to 118 via 12 and 113. At 118 the counter SCDC is incremented and then at 12
0, the counter SCDC is a predetermined value d (for example, 20)
It is determined whether or not it has been reached. This predetermined value b sets the delay time T until the clutch actually starts releasing after the clutch transitions from the engagement condition to the release condition, but if d is set to 20,
This routine runs every 50ms, so T=20×50=
It will be 1 second.

If the predetermined delay time T set at 120 has not elapsed, the determination is _No , and the process proceeds to step 106, where the clutch 34 is engaged. In other words, the clutch 34 will remain engaged despite the operating clutch release condition of the supercharger 22.

If the counter SCDC has reached the predetermined value d at 120, it indicates that the set delay time T has elapsed. 54 issues a command to demagnetize the solenoid 39 of the clutch 34, so that supercharging is not performed. Further, at 116, a command is issued to the bypass control valve 42 to open the control valve 42, so that the bypass passage 41 is opened and a portion of the intake air is introduced into the engine via the bypass passage 41.

FIG. 4 is a timing diagram illustrating the operation of the invention described above. When Q/N exceeds a predetermined value a at time _t1 , the clutch is engaged. If Q/N falls below the predetermined value a at time t ₂ after starting deceleration, if Q/N is smaller than the predetermined value b and the rotation speed N
If c is smaller than the predetermined value c, the clutch 34 is immediately released. Counter SCDC maintains zero.
Next, when acceleration is performed again at time _t3 , the clutch is similarly engaged and the supercharger 22 is activated. When the deceleration starts and time t ₄ is reached, Q/N reaches the predetermined value b.
or the rotation axis N is larger than c, so the counter SCDC starts incrementing c. Therefore, the clutch 34 is released after the time T elapses after the counter SCDC measures d.

FIG. 5 is a map showing the clutch operation pattern. The hatched area is the clutch engagement area, the dotted area is the clutch release area with delay, and the pure white area is the clutch release area without delay.

〔Effect of the invention〕

According to this invention, by releasing the delay control when the clutch is switched from engagement to disengagement when the engine is at or near idle, the clutch is delayed when the clutch shifts to the disengagement condition in this range. be released without any trouble. Therefore,
When the engine is idling, the load of the supercharger is not applied to the engine, and the idling speed is maintained at a high level, thereby preventing the engine from stalling during a shift change.

[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 illustrating the control operation of the present invention. FIG. 4 is an operation timing diagram of this invention. Figure 5 shows the operation map of the supercharger. DESCRIPTION OF SYMBOLS 13... Crankshaft, 22... Supercharger, 24... Throttle valve, 25... Air flow meter, 34... Clutch, 41... Bypass passage, 42... Bypass control valve, 50... Control circuit, 61... Rotational speed sensor.

Claims (1)

[Claims] 1. A mechanical supercharger is provided in the intake pipe, and the mechanical supercharger is connected to the rotating shaft of the internal combustion engine via a clutch, and the clutch is engaged by a clutch control means depending on whether the engine load is large or small. In a vehicle to be released, a clutch release condition detection means detects a driving condition under which the clutch should be switched from an engaged state to a released state, and a delay means sets a delay time for switching the clutch from an engaged state to a released state; Clutch release delay prohibition area detection means for detecting an engine idling operating area and an area close to this in which a delay in clutch release is not allowed; After detecting the conditions for switching from the engaged state to the disengaged state, the clutch control means is driven so that the clutch is released after a delay time set by the delay means has elapsed, and the clutch is driven to be released in the idle operating range of the engine. A mechanical supercharger for an internal combustion engine, characterized in that the mechanical supercharger for an internal combustion engine is equipped with a switching means for driving the clutch control means so that the clutch is released without waiting for the elapse of a delay time in an operating region close to Control device.