JPH0562223B2 - - Google Patents

Description

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

[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 usually 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 terms of the original function of the supercharger, it is sufficient to control the clutch based on the load alone, but engaging the clutch at high engine speeds is unfavorable for the durability of the friction surfaces of the clutch, so the engine The opening/closing control of the clutch is performed by taking into account the factor of rotational speed (for example, Utility Model Application No. 110330/1983).

[Problem that the invention seeks to solve]

If the engagement of the clutch is controlled by the load and rotational speed, the clutch will be engaged under rotational conditions even during light load operation that does not require supercharging, so the number of engagements of the clutch will increase. Although the rotational speed at which switching occurs is set low in consideration of the durability of the friction surface of the clutch, the frequency of switching is unfavorable for the durability of the friction surface.
In addition, it is susceptible to torque fluctuations during connection,
Even in a light load range with low torque, there is a point at which the clutch switches from disengaged to engaged depending on the rotational conditions, and a shock may occur due to a sudden change in torque at the time of switching. Furthermore, since the rotation speed at the time of switching must be set low, the time the clutch is engaged is relatively long, meaning that the supercharger is being driven unnecessarily, which increases fuel consumption. cause deterioration of

SUMMARY OF THE INVENTION The object of the present invention is to solve these problems and provide a structure that can reduce the frequency of clutch engagement and that does not impair driveability or fuel consumption.

[Means for solving problems]

As shown in FIG. 1, a mechanical supercharger control device for an internal combustion engine according to the present invention includes an intake pipe 1a of an internal combustion engine 1
Mechanical supercharger 2 located in and mechanical supercharger 2
a clutch means 3 for selectively connecting the clutch to the engine rotating shaft 1b, a clutch control means 3a for selectively driving the clutch 3, a load detecting means 4a for detecting the load factor of the engine, and a rotation speed factor of the engine. a rotation speed detection means 4b for detecting the rotation speed, and a first setting means 5 for determining the operating state of the supercharger according to the load and the rotation speed.
a, second setting means 5b for determining the operating state of the supercharger according to the load, and means 6 for detecting a change in the operating state of the supercharger between supercharging conditions and non-supercharging conditions.
When switching from supercharging conditions to non-supercharging conditions, the first setting means 5a is connected to the clutch control means 3a, and when switching from non-supercharging conditions to supercharging conditions, the second setting means 5b is connected to the clutch control means 3a. and a switching means 7 connected to.

〔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
Ha 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. A throttle valve 24 is arranged within the throttle body 23, and an air flow meter 25 and an air cleaner 26 are located upstream thereof. Intercooler 21 is mechanical supercharger 2
It is arranged to lower the temperature of the air, which has been heated up by being compressed by the pump 2, and to increase the filling 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.
A pulley 34 is connected to a rotating shaft 32A of one of the pair of rotors 32 via a clutch mechanism 34.
¹ is provided, and this pulley 34 ¹ is connected via a belt 35 to a pulley 36 on the crankshaft 16 . 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 relative to the housing, and its outer periphery forms the aforementioned pulley ³⁴¹ .

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 amount of 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. A drive signal is sent from the output port 54 to the solenoid 39 of the clutch 34 and the bypass control valve 42 according to a control program stored in the memory 52. The contents of the control program will be explained below with reference to the flowcharts of FIGS. 3 and 4 and the diagram of FIG. 6.

FIG. 3 shows a calculation routine for the intake air amount-rotational speed ratio Q/N, which is a representative load value, and this routine is executed within the main routine. At 80, the program is started, and at 82, a signal representing the amount of intake air Q from the air flow meter 25 is input. Therefore, the input port 53 is equipped with an A/D converter (not shown). In step 84, the rotation speed sensor 6
The rotational speed N is calculated by processing the pulse signals from 1. In 86, Q/N is calculated and stored in a predetermined area of the memory 52. 88 generally represents other processing executed in the main routine.

FIG. 4 shows the clutch 34 and bypass control valve 42.
This is a flowchart of a driving routine, which is a time interrupt routine that is executed every fixed period of time, for example, every 4 milliseconds. In step 100, it is determined whether the supercharger 22 is in operation. If the supercharger 22 is not in operation, it branches to No and proceeds to 102 to calculate the intake air amount -
The rotation speed ratio Q/N is a predetermined value a (for example, 0.5/rev)
It is determined whether or not the value is greater than or equal to the value. If the Q/N has not reached the predetermined value a, it is determined as No, and the process proceeds to 104, where a command is issued from the output port 54 to demagnetize the solenoid 39 of the clutch 34, so that the friction plates 37 and 38 of the clutch are separated, and the crank The rotation of shaft 13 is not transmitted to the rotor of supercharger 22. Therefore, supercharging is not performed. At step 106, output port 5
4, 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 part of the intake air flows into the bypass passage 41.
is introduced into the engine via the

If it is determined in 102 that the Q/N exceeds the predetermined value a, the process proceeds to 108 and a command is issued to energize the solenoid 39 of the clutch 34 from the output port 54.
The friction plates 37 and 38 of the clutch come into engagement, and the rotation of the crankshaft 13 is transmitted to the rotating shaft of the supercharger 22 via the pulley 36, belt 35, and pulley ³⁴¹ , and the rotors 31 and 32 are rotated. be done.
110, a closing command is issued to the bypass control valve 42 from the output port 54, and the bypass passage 41
is closed so that air from the supercharger is introduced into the engine without being bypassed. As described above, when switching from a non-supercharging condition to a supercharging condition, the operation of the supercharger is controlled depending on whether Q/N, which is a representative engine load value, is equal to or greater than a predetermined value.

If the supercharger is in operation, a determination of Yes is made at 100, and the process proceeds to 112, where it is determined whether the engine speed N is equal to or higher than a predetermined value b (for example, 4000 rev/min). If the rotation speed has not reached the predetermined value b, proceed to 102,
The above-mentioned processing is performed, and clutch control and bypass control are executed according to the load. When the rotational speed is greater than b, the process proceeds to step 108, where the clutch is engaged and the bypass is closed. In this way, the supercharger is controlled not only by Q/N, which is the representative load value, but also by the rotational speed when the supercharger switches from the operating range to the stop range.

Figure 5A shows a map for switching the clutch 34 from disengagement to engagement, that is, switching the turbocharger from stop to operation. The feeder is starting to operate from stop. On the other hand, Ro is clutch 34
The map shows the case when switching from engagement to disengagement, that is, when moving the turbocharger from operation to stop. In this case, not only the load Q/N but also the rotation speed N is the criterion for switching judgment, and Q/ The clutch is switched from engagement to disengagement when N is below the limit ^l1 or when the rotational speed N crosses m.

〔Effect of the invention〕

According to this invention, the switching from stop to start of the supercharger is controlled only by the load, and the switch from start to stop of the supercharger is controlled by the load and rotation speed, so that under high load conditions that require supercharging, The clutch 34 is engaged and the transition to supercharging occurs only when the transition is made to
Compared to the conventional method in which the clutch is switched by detecting the rotational speed, the frequency of clutch engagement can be reduced. In the case shown by arrow g, the clutch switches to engagement b even at high speeds, but there are very few operations where the clutch shifts to acceleration at high speeds, so there is no problem of damage to the friction surface of the clutch. . Since the clutch is connected by detecting only high-load situations where torque is present, the clutch does not switch during low-load situations where shocks are likely to occur due to large torque fluctuations, and shocks can be prevented. Furthermore, since there is no unnecessary clutch engagement at low loads, the supercharger is not engaged unnecessarily, and the fuel consumption rate is improved accordingly. Since the clutch release condition in the high rotation range is controlled by the rotation speed, the frequency of engagement in the high rotation range hardly increases.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of this invention. FIG. 2 is a schematic diagram of the entire configuration of this invention. FIGS. 3 and 4 are flowcharts illustrating the control operation of the present invention. FIG. 5 is an operational diagram of this invention. 13...Crankshaft, 22...Supercharger, 24...
... Throttle valve, 25 ... Air flow meter, 3
4...Clutch, 41...Bypass passage, 42...
...Bypass control valve, 50...control circuit.

Claims (1)

[Claims] 1. A mechanical supercharger control device for an internal combustion engine comprising the following elements: A mechanical supercharger disposed in the intake pipe of the internal combustion engine; a clutch means for connecting to the clutch, a clutch control means for selectively driving the clutch, a load detection means for detecting a load factor of the engine, a rotation speed detection means for detecting a rotation speed factor of the engine, and a clutch control means for selectively driving the clutch; A first setting means for determining the operating state of the supercharger; a second setting means for determining the operating state of the supercharger according to the load; operation of the supercharger between supercharging conditions and non-supercharging conditions. A means for detecting a change in state, and a means for detecting a change in the state, and a first
Switching means for connecting the setting means to the clutch control means and for connecting the second setting means to the clutch control means when switching from non-supercharging conditions to supercharging conditions.