JPS62142824A - Combined supercharger - Google Patents

Abstract

PURPOSE:To control superchargers to be smoothly switched, by actuating an exhaust supercharger, when its speed reaches a predetermined value, after a mechanical supercharger is actuated when an engine is accelerated, in case of the engine which set in series the exhaust supercharger and the mechanical supercharger in an intake pipe. CONSTITUTION:The captioned device sets a mechanical supercharger 3, driven by an engine through a belt 5 or the like, and an exhaust supercharger 2, comprising a compressor part 2a and a turbine part 2b, successively from the upstream side in an intake system of an internal combustion engine. When action of the above superchargers 2, 3 is controlled by a control circuit 20, the device, first driving the mechanical supercharger 3 by turning on a clutch 4 and closing a control valve 9 when the engine is accelerated by depressing a throttle pedal, operates the engine to be supercharged, immediately after it is accelerated, by the mechanical supercharger 3. Next the device, when a speed of the exhaust supercharger 2, detected by a speed sensor 25, reaches a predetermined value, controls a supercharge so as to be transferred to the supercharge by the exhaust supercharger 2 by turning off the clutch 4 and opening the control valve 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a composite supercharging device in which an exhaust type supercharger and a mechanical supercharger are arranged in series in an intake pipe.

[Conventional technology]

There are two types of superchargers: exhaust type superchargers and mechanical type superchargers, and both have advantages and disadvantages. That is, an exhaust type supercharger uses exhaust energy for its drive, so it can be driven economically, but there is a delay in response called turbo lag. On the other hand, although a mechanical supercharger has the advantage of not having such a response delay, it is disadvantageous in terms of fuel consumption because a part of the engine power is used to drive the supercharger.

Therefore, it is known to use both an exhaust type supercharger and a mechanical type supercharger in order to compensate for the drawbacks of both and take advantage of their strengths. (Refer to Japanese Utility Model Application Publication No. 59-67537.) That is, the mechanical supercharger is activated initially during acceleration, and when the exhaust type supercharger becomes operational, the mechanical supercharger is stopped.

[Problem that the invention seeks to solve]

In conventional composite supercharging devices, supercharging operation is switched from a mechanical supercharger to an exhaust supercharger by detecting whether or not the engine speed is above a predetermined value. However, the engine speed does not necessarily represent the supercharging state. Therefore, the mechanical supercharger may be stopped even though the exhaust supercharger has not reached its full capacity, and in this case, a shock may occur due to a sudden change in torque.

The present invention aims to solve this problem and enable smooth transition of supercharging operation between a mechanical supercharger and an exhaust supercharger.

[Means for solving problems]

According to this invention, an exhaust supercharger and a mechanical supercharger are installed in series in the intake pipe of an internal combustion engine, and supercharging is performed between the mechanical supercharger and the exhaust supercharger in a transient state. In a composite supercharging device having a control means for controlling the transition of operation, the control means includes a speed detection means for detecting the rotation speed of the exhaust type supercharger, and a speed detection means for detecting the rotation speed of the exhaust type supercharger from the speed detection means. Provided is a composite supercharger internal combustion engine characterized by comprising means for controlling the operation of a mechanical supercharger.

〔Example〕

FIG. 1 shows the entire configuration of an embodiment of the present invention, in which 1 is an internal combustion engine, 2 is an exhaust type supercharger, and 3 is a mechanical supercharger. With respect to the flow direction of intake air, the exhaust type supercharger 2 is on the downstream side, and the exhaust pipe is on the upstream side, and they are arranged in series. As is well known, the exhaust type supercharger 2 includes a compressor section 2a and a turbine section 2b. The mechanical supercharger is, for example, a Roots pump, and its rotating shaft is a clutch with a pulley 4,
It is connected to the crankshaft of the internal combustion engine via a belt 5 and a boot IJ 6. The throttle valve 7 is arranged downstream of the exhaust type supercharger 2. A bypass passage 8 is provided to bypass the mechanical supercharger 3. The control valve 9 is installed at a connection point between the bypass passage 8 and the intake pipe IO. The intake pipe 10 is connected to an air flow meter 12 and then to an air cleaner 13 on the upstream side. 14 is a catalytic converter.

According to the present invention, the control circuit 20 is for controlling the clutch 4 that controls the mechanical supercharger 3 and the step motor 15 for driving the control valve 9, and is configured as a microcomputer system. The control circuit 20 includes a microprocessing unit (MPU) 20a and a memory 2.
0b, an input port 20c, an output port 20d, and a bus 20e connecting these elements. The input port 20c is connected to each sensor, and various engine operating status signals are applied thereto. The air flow meter 12 is installed in the intake pipe 10 immediately downstream of the air cleaner 13, and a signal corresponding to the intake air fQ is sent to the input port 20C. The engine rotation speed sensor 18 supplies a signal corresponding to the rotation speed NH of the crankshaft of the engine 1 to the human-powered boat 20c. According to this invention, a sensor 25 for detecting the rotation of the exhaust type supercharger 2 is provided, and a rotation speed signal Na is applied to the input port 20c.

FIGS. 2 and 3 show details of the compressor section 2a of the exhaust type supercharger at the mounting portion of the rotation speed sensor 25. FIG. The compressor section 2a includes a housing 30 and a housing 30.
It consists of a compressor wheel 31 arranged inside. As is well known, an inlet pipe 32 is connected to the center of the housing 30, and an outlet pipe (not shown) is connected tangentially thereto. The compressor wheel 31 is connected to a turbine wheel (not shown) of the turbine section 2b by a rotating shaft 36. The compressor wheel 31 is fixed to the end of the rotating shaft 36 by a NAND 38.

A magnet piece 39 is buried inside the nut 38 (see Figure 3).
The direction of magnetization is perpendicular to the rotation axis 36. A rotation speed sensor 25 composed of a Hall element or the like is arranged facing the outer wall of the inlet pipe 32, and is fixed to the sensor 30 by a fixture 42 such as an angle. A rotation speed sensor 25, which is a magnetic sensor, detects an alternating magnetic field based on the rotation of the permanent magnet 39 accompanying the rotation of the rotation shaft 36, and a pulse signal corresponding to the rotation speed is obtained. The rotation of the exhaust type supercharger 2 can be known by processing this pulse signal. Incidentally, this type of sensor is the same type as that disclosed in Japanese Patent Application Laid-Open No. 56-8552.

The MPU 20a performs calculations according to a program stored in the memory 20b based on the driving state factors detected by the above-mentioned sensors. As a result, the clutch 4 of the mechanical supercharger
A drive signal for the step motor 5 for driving the control valve 9 is obtained and set to the output boat 20d. The output boat 20d is connected to the clutch 4 and the step motor 15, and is driven by the calculated drive signal.

The operation of the control circuit 20 will be explained below with reference to the flowchart shown in FIG. The routine shown in FIG. 5 is a time interrupt routine that is executed at predetermined time intervals. Step 5
At 0, the intake air amount to revolution speed ratio Q/NE is input. Q
/NE is a value representative of the engine load. Q is detected by the air flow meter 12, NE is detected by the engine speed sensor 18, and their ratio Q/N
It is assumed that E is calculated in a separate routine. In step 51, it is determined whether the intake air amount to revolution speed ratio Q/NE is larger than a predetermined value a. If the judgment is negative, it is recognized that supercharging is unnecessary because the load condition is low, and the process proceeds to step 52.
Then, a release signal is output to the clutch 4 from the output boat 20d. Therefore, the rotation of the engine 1 is not transmitted to the mechanical supercharger 3. In the next step 53, bypass opening processing is executed. That is, a command to move the bypass control valve 9 in the opening direction is sent to the step motor 15 from the output boat 20d. Therefore, the bypass control valve 9 is driven in the direction of opening the bypass passage 8.

When the determination in step 51 is Yes, it is a high load condition. Next, the process proceeds to step 54, in which the rotation speed NA of the exhaust type supercharger detected by the rotation speed control valve 25 is set to a predetermined value b (for example, 50. It is determined whether or not it is smaller than (OOOrpm). At the beginning of acceleration, the exhaust type supercharger 2 due to so-called turbo lag.
Since the number of rotations is low, the determination is Yes, and step 56
Then, the engagement signal for the clutch 4 is output. Therefore,
The clutch 4 is engaged, and the rotation of the internal combustion engine 1 is caused by the pulley 6,
The signal is transmitted to the mechanical supercharger 3 via the belt 5, and the operation of the mechanical supercharger 3 is started. In the next step 57, a rotation command is sent to the step motor 15 to close the bypass control valve 9. Therefore, the step motor 15 is driven to rotate so as to gradually close the bypass passage 8.

When the exhaust type supercharger eliminates the turbo lag and reaches its full capacity, the rotational speed N7 becomes larger than the predetermined illb value, so the determination in step 54 is NO and the process proceeds to the aforementioned steps 52 and 53. , the clutch is released and the bypass is released, and the operation of the mechanical supercharger is stopped.

FIG. 5 is a timing diagram illustrating the invention in detail. At time tA, the throttle valve 7 is depressed, the intake air amount-to-rotation speed ratio Q/NE rises, and when it exceeds a predetermined value a at time t8, the clutch 4 is engaged (d) and the bypass 8 is closed. The control valve 9 is driven (e), and air is supplied to the mechanical supercharger 3. The rotation of the mechanical supercharger increases immediately as shown in (c) l, but the exhaust type supercharger 3
The rise of is delayed as m. Therefore, immediately after acceleration, supercharging is performed by the mechanical supercharger 3.

When the rotation speed NT of the exhaust type supercharger 2 reaches a predetermined value at time tc, the clutch 4 is released, the control valve 9 is driven in the direction of opening the bypass 8, and finally the air is transferred to the mechanical supercharger. It is directly supplied to the exhaust type supercharger 2 from the bypass passage 8 without passing through the charger 3. Therefore, the mechanical supercharger 3 is stopped, and the exhaust supercharger 2 takes over the supercharging operation.

〔Effect of the invention〕

In this invention, the operation of the mechanical supercharger 3 is controlled by detecting the actual rotation of the exhaust supercharger, so that the mechanical supercharger 3 is connected to the exhaust supercharger 2 during acceleration. The transition of the supercharging operation can be performed after the exhaust type supercharger 2 reliably enters the operating state. Therefore, smooth switching without shock can be realized, and drivability can be improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the compressor section at the aff point of the rotation speed sensor of the exhaust type supercharger. FIG. 3 is a cross-sectional view taken along line mm in FIG. 2. FIG. 4 is a flowchart showing the operation of the control circuit. FIG. 5 is a timing diagram illustrating the operation of the bypass control valve of the present invention. 2... Exhaust type supercharger 3... Mechanical supercharger 4.
...Clutch 7...Throttle valve 8...
Bypass passage 9...Control valve 15...Step motor 20...Control circuit 25...Exhaust type supercharger rotation speed sensor 38...Permanent magnet

Claims (1)

[Claims] An exhaust supercharger and a mechanical supercharger are installed in series in the intake pipe of an internal combustion engine, and the transition of supercharging operation between the mechanical supercharger and the exhaust supercharger is controlled in a transient state. In a composite supercharging device having a control means, the control means includes a speed detection means for detecting the rotational speed of the exhaust type supercharger, and a mechanical supercharger based on the rotation of the exhaust type supercharger from the speed detection means. A composite supercharging device comprising means for controlling the operation of the supercharging device.