JPS62298621A - Control device for engine with supercharger - Google Patents

Abstract

PURPOSE:To prevent the lowering of an idling engine speed on a high land by connecting an air introducing passage to an annular space formed on the periphery of the rotor shaft of a super-charger consisting of a Roots pump and providing a control valve which is opened on a high load in said passage. CONSTITUTION:In a mechanical supercharger 20 which consists of a Roots pump having a pair of rotors 22 and which is provided in the intake passage 12 of an engine 10, holes for inserting rotor shafts 26 are formed on the end plate 24a of its housing 24. Due to this hole, an annular space 36 is formed on the periphery of the rotor shaft 26 in between the end face of the rotor 22 and the inside seal 30 of a bearing 28. And, ports 38 which extend in the radial direction are formed on the end plates 24a so as to introduce the air into the spaces 36, and an air introducing passage 40 in which a control valve 42 is provided in connected to the ports 38. The control valve 42 is controlled so as to be opened when a vehicle is traveling on a high land, by means of an ECU 50.

Description

[Detailed description of the invention] 3. Detailed description of the invention [Industrial application field] The present invention relates to a control device for a supercharged engine.

[Conventional technology]

An engine equipped with a mechanical supercharger constituted by a Roots pump is described, for example, in Japanese Patent Laid-Open No. 16232/1983. Roots pumps include a pair of synchronously rotated rotors, each supported by a rotor shaft. The rotor shaft is attached to the housing by bearings. However, since the leakage pressure of the pump acts on this bearing, there is a problem in that its ability to retain oil and grease is reduced.
Japanese Patent No. 16232 introduces the atmosphere inside the bearing to equalize the pressure on both sides of the bearing. Air is introduced by a control valve depending on the operating state of the engine.

[Problem that the invention seeks to solve]

In a mechanical supercharger such as the one mentioned above, the control valve (opening the auricle and introducing atmospheric air into the inside of the bearing means that air is also drawn into the engine from the control valve). If the control valve is opened when the engine is idling with a small amount of intake air, the idle rotational speed will fluctuate due to the air introduced from the control valve, so the control valve is closed when the engine is idling.

Conventionally, at high altitudes, the amount of intake air decreases due to a decrease in atmospheric density, and valve means to compensate for this decrease has sometimes been used. The present invention provides means that can eliminate the drop in idle speed even at high altitudes without using such valve means.

[Means for solving problems]

In order to solve the above problems, a control device for a supercharged engine according to the present invention provides a system in which a Roots pump constituting a mechanical supercharger includes a housing, a rotor disposed in the housing, and a rotor that supports the rotor. The rotor shaft is attached to the housing by a bearing in order to A control valve is provided, and the control valve is configured to be closed at high altitudes.

〔Example〕

1 and 2, 10 indicates an engine, and an air cleaner 14, an air flow meter 16, a throttle valve 18, and a mechanical supercharger 20 are installed in the intake passage 12 connected to the engine 10 in this order from the upstream side. Placed. The mechanical supercharger 20 is constituted by a roots pump having a pair of rotors 22.

As shown in FIG. 1, the rotor 22 of the mechanical supercharging lR2O has a bilobal cross-sectional shape, and it is known that the pumping action is performed by rotating in opposite directions in synchronization with each other. be. These rotors 22 engage with each other with a minute clearance, and each rotor 22 contacts the housing 24 with a minute clearance (FIG. 2). The housing 24 is the end plate 2
4a, and the end of each rotor 22 also comes into contact with the end plate 24a of the housing 24 with a minute clearance. Therefore, the clearance space between the end surface of the rotor 22 and the end plate 24a communicates with the suction side and the discharge side of the pump, and leakage pressure of the pump is generated there.

Each rotor 22 is supported by a rotor shaft 26, respectively. The rotor shaft 26 extends within a hole formed in the end plate 24a, and has a bearing 2 at each end.
8 is attached to the end plate 24a. In order to alleviate the aforementioned leakage pressure applied to the bearing 28, a labyrinth seal is formed at a relatively inner diameter portion between the end surface of the rotor 22 and the opposing end surface of the end plate 24a. Furthermore, a seal 3 is provided inside each bearing 28.
0 is placed. The right end of each rotor shaft 26 in FIG. 2 protrudes from the bearing 28, and a gear 32 meshing with the protruding end is attached to the rotor shaft 26 so that the pair of rotors 22 can rotate in opposite directions. An electromagnetic clutch 34 is housed at the left end of the lower rotor shaft 26, so that the mechanical supercharger 20 can be driven from the crankshaft of the engine 10.

An oil chamber 32a is formed to lubricate the gear 32, and the right bearing 28 is lubricated by this oil.

On the other hand, the left bearing 28 is filled with grease.

As is clear in FIG. 2, the end plate 24a of the housing 24 has a hole for passing the rotor shaft 26, and this hole is located between the end face of the rotor 22 and the seal 30 inside the bearing 28. An annular space 36 is formed around 26. In order to introduce the atmosphere into this annular space 36, a boat 38 is formed on the end plate 24a of the housing 24 and extends in the radial direction. A control valve (ACV) 42 is disposed in the middle of the connecting conduit 40.

As shown in FIG. 1, the control valve 42 is configured as a solenoid valve, in which a valve member 46 biased by a spring 44 is actuated by a solenoid 48, thereby opening and closing the atmospheric inlet conduit 40. This control valve 42 is controlled by a control device (ECU>50).

The control device 50 is composed of a microcomputer,
Central processing unit (CPU) 52 with calculation and control functions
Read-only memory (ROM) that stores programs
54, and a random access memory (RAM>56) for storing data etc. These are interconnected by a bus 58, and the bus 58 is used for input/output (I/O).
lo) Also connected to the boat 60. Detection signals from sensors such as a throttle sensor 62 and a rotation speed sensor 64 are input to detect the operating state of the engine, and a detection signal from an atmospheric pressure sensor 66 is input to determine whether the vehicle is at a high altitude. High altitude can also be determined using other sensors.

Next, the operation will be explained.

The mechanical supercharger 20 is driven by the engine and supplies a large amount of air to the engine. At this time, mechanical supercharging 1f
There is leakage pressure generated by the suction pressure and discharge pressure of the pump in the clearance space between the end surface of the rotor 22 of the i20 and the end plate 24a. This leakage pressure acts on the inside of the bearing 28 and tries to push out the oil and grease, so by introducing the atmosphere from the atmosphere introduction passage 40 and the control valve 42, the oil and grease are prevented from being pushed out. . However, as mentioned above,
Introducing atmospheric air means supplying the engine with an amount of air greater than that controlled by the throttle valve 18. For example, since it is undesirable to supply uncontrolled air during idle, it is controlled by a command from the electronic control unit 50. valve·
42), and the introduction of atmospheric air into the annular space 36 next to the bearing 28 of the mechanical supercharger is interrupted. This eliminates the supply of excess air during idle, making it possible to obtain the set idle speed. In addition, since the rotation of the engine and the supercharger 20 is not high at idle, and the pressure applied to the bearing 28 is not very high, the annular space 3 next to the bearing 28
Even if the introduction of atmospheric air at 6'\ is interrupted, the durability of the bearing 28 is not significantly affected.

In operating conditions other than idle, the control valve 42 is opened and atmospheric air is introduced into the annular space 36 next to the supercharger bearing 28. This reduces leakage of air from the supercharger to the bearing 28, and improves the durability of the bearing 28.

In the present invention, while maintaining the above-mentioned advantages, it is further possible to prevent the idle speed from decreasing at high altitudes where the air density is low. FIG. 4 shows a flowchart of control for implementing the present invention, in which it is determined whether the atmospheric pressure detected in step 70 is higher than a predetermined value A, thereby determining whether the system is located at a high altitude. If it is determined that the area is at a high altitude, the process proceeds to step 71 to open the control valve 42, thereby allowing air to flow through the control valve 42 to the internal combustion engine to prevent the idle speed from decreasing. If the altitude is not high, the process proceeds to step 72, and if the vehicle is idling, the control valve 42 is closed (step 73), and if the vehicle is not idling, the control valve 42 is opened to supply atmospheric air to the bearing 28.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to increase the durability of a supercharger and to prevent a decrease in the idle speed at high altitudes.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of a supercharged engine according to the present invention;
1 is a cross-sectional view of the supercharger of FIG. 1, FIG. 3 is a diagram showing the configuration of the control device of FIG. 1, and FIG. 11 is a diagram of the control device of the present invention without showing a flowchart. 20...Supercharger, 22...Rotor, 26
...rotor shirt), 28 mountain bearing, 38...atmosphere introduction passage, 42...control valve, 66...atmospheric pressure sensor. Fig. 2 20...Supercharger 40...Atmospheric introduction passage 22...
・Rotor 42...Sub-side valve 28...Bearing 6
6... Atmospheric Pressure Senna Figure 3 Figure 4 Procedural Amendment (Voluntary) July 3, 1985 Commissioner of the Patent Office Black 1) Akira Who 1, Incident Indication Patent Application No. 140383 of 1985 2, Name of the invention: Supercharged engine control '4B device 3. Relationship with the case of the person making the amendment. Name of patent applicant (320) l-Yota Jidosha Co., Ltd. 4. Address of agent: 105 Toranomon-chome, Minato-ku, Tokyo. No. 8, No. 10, No. 5,
Target of amendment (1) "Claims" column of the specification (2) "Detailed description of the invention" column 6 of the specification, contents of amendment (1) Claims are amended as shown in the attached sheet I will 9 (2)
) On page 4 of the specification, in the first line, "I made it so that it could be closed by pressing..." was corrected to "I made it so that it could be opened by pressing...". 7. List of Attached Documents Amendment Claims 1 2. Claims In an engine equipped with a mechanical supercharger constituted by a Roots pump, the Roots pump has a housing,
a rotor disposed within the housing; a rotor shaft attached to the housing by a bearing to support the rotor; and an annular ring formed around the rotor shaft between an end surface of the rotor and the bearing. A supercharger comprising an air introduction passageway for introducing air into a space, and a control valve disposed in the air introduction passageway, the control valve being arranged so that a common plate is formed at a high altitude. Control device for the attached engine.

Claims (1)

[Claims] In an engine equipped with a mechanical supercharger configured with a Roots pump, the Roots pump includes a housing;
a rotor disposed within the housing; a rotor shaft attached to the housing by a bearing to support the rotor; and an annular ring formed around the rotor shaft between an end surface of the rotor and the bearing. A control device for a supercharged engine, comprising an air introduction passage for introducing air into a space, and a control valve disposed in the air introduction passage, the control valve being closed at high altitudes. .