JPH02119629A - Supercharger - Google Patents

Abstract

PURPOSE:To obtain sufficient supercharging pressure over entire engine speed range by a turbocharger by starting a motor to drive the turbocharger, when the number of revolutions of an engine or turbocharger is below a specified limit. CONSTITUTION:An exhaust gas turbine 21 is formed by providing a turbine rotor 15 in a turbine housing 1 rotatably by means of a shaft 19. Also, a compressor rotor 45 is provided at the top end of the shaft 19 passing through a back plate rotatably in a compressor housing 33. Thus an centrifugal compressor 51 and a turbocharger 53 are formed. In addition, the ends of a one-way clutch 55 are connected to the shaft 19 and the rotor 61 of a D.C. motor, respectively. When the number of rotations of the turbocharger 53 is below a specified limit, the D.C. motor is started by a controller 63 to drive the centrifugal compressor 51.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) This invention relates to a supercharger that supplies air to the cylinders of an engine to increase output.

(Prior art) As is well known, a turbocharger that uses an exhaust turbine to drive a centrifugal compressor does not increase the rotation speed in the low speed range where the exhaust pressure of the engine is low. I can't do it. Also, the boost pressure increases through the process of increasing engine speed → increasing turbine speed → increasing compressor pressure, so from the time the operation starts until the boost pressure increases and the engine output increases. Accompanied by response delay (turbo lag). Therefore, there is a method in which a mechanically driven supercharger that drives a compressor using engine power is combined with a turbocharger (combined type) to compensate for the lack of torque in the low range and the turbo lag as described above. (Refer to Japanese Unexamined Patent Publication No. 63-105231.) However, since the compressor of a mechanically driven supercharger has a normal rotation speed close to the engine rotation speed and does not require a special speed increase mechanism, it is similar to a Roots blower (compressor). A constant volume compressor is used. Therefore, the above-mentioned composite supercharger is constructed by simply combining a turbocharger and a supercharger without sharing any mutual components, and is large, has a complex structure, and is heavy. , is expensive.

(Problems to be Solved by the Invention) Therefore, the purpose of the present invention is to provide a supercharger that can obtain sufficient boost pressure from the low engine speed range to the high engine speed range, and that is simple in structure, compact, lightweight, and inexpensive. shall be.

[Configuration of the Invention (Means for Solving the Problems) The supercharger of the present invention includes an exhaust turbine that rotates using the exhaust energy of an engine, and a centrifugal turbine that is driven by the exhaust turbine and supplies compressed air to the intake side of the engine. The present invention is characterized in that it includes a turbocharger equipped with a type compressor, an electric motor that drives the turbocharger, and a controller that operates the electric motor within a range where the rotational speed of the engine or the turbocharger is below a certain value.

(Operation) The exhaust turbine is rotated by the exhaust energy of the engine and drives the compressor. The compressor supplies compressed air to the intake side of the engine and feeds the cylinders. Sufficient supercharging pressure can be obtained in a range where the engine or turbocharger rotational speed is sufficiently high. In addition, if the controller sets the rotation speed (constant value) at which the electric motor operates to the rotation speed at which boost pressure starts to become insufficient, the electric motor will drive the turbocharger 11 below this rotation speed, so it will change from the low rotation range to the high rotation range. Sufficient boost pressure can be obtained over the entire range. In addition, turbo lag is normally so short that it is not a problem in the high rotation range, and a certain driving force is applied to the electric motor until the rotation reaches a certain level, and in the low rotation range, the turbo lag is driven by the electric motor without waiting for the engine rotation speed to rise, so the turbo lag is completely reduced. Turbo lag is extremely short across the rev range.

In addition, this turbocharger uses only one set of centrifugal compressors, which are small and simple in structure, and does not use two sets of compressors of different types as in conventional composite superchargers, so the structure is simple. It's a small $I Ll.

(Example) One embodiment will be explained with reference to FIG. 1 and FIG. 2.

First, the configuration will be explained with reference to FIG. Note that the left and right directions hereinafter refer to the left and right directions in the same figure.

The turbine housing 1 has a discharge port 3 that opens at its left end, an annular chamber 5 communicating with the discharge port 3, and an inlet (not shown) that opens into the annular chamber 5. A back plate 7 is arranged in the through hole on the right end side of the turbine housing 1, and the turbine housing 1 is attached to a bolt 9.
It is fixed to the center housing 13 together with the back plate 7 by a fixing plate 11. Turbine rotor 15
has a large number of radial spiral blades 17, and is disposed inside the turbine housing 1 coaxially with the central axis of the discharge port 3. The turbine rotor 15 is fixed to the left end of @19, and the shaft 19 passes through the back plate 7 and is rotatably arranged. The intake port is connected to the exhaust manifold side of the engine, and the high-temperature, high-pressure exhaust gas rotates the turbine rotor 15 at a high speed of tens of thousands of revolutions and is exhausted from the discharge port 3.

In this way, the exhaust turbine 21 is configured.

The shaft 19 passes through the center housing 13 and is rotatably supported by ball bearings 23,25. Lubricating oil is injected into the center housing 13 from a lubricating boat 27 and circulates through an oil chamber 29 provided around the shaft 19 to form an oil film around the shaft 19. The oil is lubricated, cooled, and then discharged from the oil drain port 31.

A compressor housing 33 is attached to the right side of the center housing 13 with bolts 35 and a fixing plate 37. The right side wall of the center housing 13 serves as a differential user 37 of the compressor housing 33. A back plate 39 is attached to the diffuser 37 with bolts 41.

The shaft 19 rotatably passes through the back plate 39, and a compressor rotor 45 having a large number of radial spiral blades 43 is fixed to the tip thereof. The compressor housing 33 has an annular chamber 47, an inlet port 49 that communicates with the annular chamber 47, and a discharge port (not shown) that opens into the annular chamber v47. When the compressor rotor 45 rotates, air is sucked in from the suction port 49 via an air filter (not shown), is accelerated by the compressor rotor 45, and is pressurized by the differential user 37, while the air is drawn into the annular chamber 49.
7 from the discharge port to the intercooler (not shown)
It becomes high-pressure, high-density through the gas, and is supercharged to the engine cylinder. In this way, the centrifugal compressor → No. 51
is opened and a turbocharger V53 is configured.

A one-way clutch 55 is disposed on the compressor housing 33 , and a shaft 57 on the negative side thereof passes through the compressor housing 33 and is rotatably supported by a ball bearing 59 . connected.

The other side of the one-way clutch 55 is connected to a rotor 61 of a DC motor (electric motor) supported on the compressor housing 33.

The controller 63 is the engine or turbocharger 53
When the number of revolutions falls below a set value (set to the lower limit of the number of revolutions required to obtain the necessary supercharging pressure), the DC motor is started and the centrifugal compressor 51 is driven.

The one-way clutch 55 operates when the rotation of the turbocharger 53 rises above a certain value and exceeds the rotational speed of the DC motor to disconnect the DC motor from the turbocharger 53 and protect it.

Next, the functions of this embodiment will be explained.

When the exhaust turbine 21 is rotated by the engine exhaust,
A coaxial centrifugal compressor 51 is driven to supply air to the cylinder. At this time, if the rotational speed of the engine or turbocharger 53 is equal to or higher than the set value, sufficient supercharging pressure can be obtained. Further, in a range where the rotational speed is below the set value, the DC motor drives the centrifugal compressor 51 to provide the necessary rotational speed, so that sufficient supercharging pressure can be obtained. Therefore, sufficient supercharging pressure is obtained from a low rotation range to a high rotation range, and the output of the engine is increased. In addition, when starting the turbocharger, in the low rotation range, the supercharging pressure is increased by being driven by the DC motor without waiting for the engine rotation speed to rise, and even in the high rotation range, the supercharging pressure of the exhaust turbine 21 is increased. In addition to the driving force,
Since the motor is driven by the DC motor until the rotation speed reaches the set value, the turbo lag is so short that it does not pose a problem in practice.
Acceleration performance is improved.

In the graph of Fig. 2, the thick curve a is the output characteristic of the engine with the supercharger of the embodiment, the curve A is the output characteristic of a normal turbocharger, and the curve C is the output characteristic of a mechanically driven supercharger. . As shown in this graph, in the range below a certain rotational speed (n) where the output decreases in a turbocharger that drives a centrifugal compressor only with the exhaust turbine, the turbocharger of the example outputs the shaded part by driving the DC motor. is backed up, and output equal to or greater than that of a supercharger can be obtained within this range.

The centrifugal compressor 51 is much smaller and has a simpler structure than the Roots blower used in superchargers. Therefore, the supercharging method of this embodiment has performance equivalent to or better than a composite supercharger of a turbocharger and a mechanically driven supercharger, and is also simple in structure, small in size, lightweight, and inexpensive.

[Effects of the Invention] As described above, according to the supercharger of the present invention, the engine output increases from a low rotation range to a high rotation range, and the turbo lag is short, so that rapid acceleration is possible. Moreover, this supercharger has a simple structure, is small, lightweight, and inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of one embodiment, and FIG. 2 is a graph comparing the output characteristics of engines according to this embodiment and a conventional example. 21...Exhaust turbine 51...Centrifugal compressor 53...Turbocharger 61...Rotor (electric motor) 63...Controller representative Patent attorney Yasuo Miyoshi 21...Exhaust turbine 51...Centrifugal Formula compressor 53 - turbo charge? 61...Rotor (electric)
)63・-Controller Figure 1 Rotation speed: N Figure 2

Claims (1)

[Claims] A turbocharger includes an exhaust turbine rotated by the exhaust energy of the engine, a centrifugal compressor driven by the exhaust turbine and supplying compressed air to the intake side of the engine, an electric motor that drives the turbocharger, and the engine or the turbocharger. A supercharger comprising: a controller that operates the electric motor within a range where the rotational speed of the charger is below a certain value.