JP2003293785A - Turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbocharger capable of efficiently cooling an electric motor in the turbocharger having the motor rotatively driving a compressor and/or a turbine. <P>SOLUTION: This turbocharger comprises the electric motor 6 capable of rotatively driving the compressor 4 (turbine 3), a turbo housing 2 incorporating the electric motor 6, a coolant flow passage 8 for coolant circulation formed in the turbo housing 2, and a fuel feed means 10 feeding the fuel of the internal combustion engine as coolant into the coolant flow passage. The electric motor 6 can be efficiently cooled by the fuel at all times. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbocharger with a motor capable of driving a compressor and / or a turbine of the turbocharger with a motor. 2. Description of the Related Art Attempts to obtain a high output (or low fuel consumption) by supercharging an intake air amount of an engine (internal combustion engine) with a turbocharger have been conventionally used. One of the demands for the improvement of the turbocharger is that the boosting of the supercharging pressure in the low rotation speed range is poor, and the engine output characteristics in the low rotation speed range are not good. This is a phenomenon that occurs in a low rotation speed region where the exhaust energy is small due to the principle of the turbocharger in which the intake air is supercharged using the exhaust energy. In order to improve this, twin turbos are generally used. However, an attempt has been made to obtain a desired supercharging pressure by incorporating a motor into a turbine / compressor and forcibly driving the turbine. Has been done. As such a turbocharger with a motor, there is one as described in JP-T-2001-527613. [0003] In a turbocharger with an electric motor, it is rotated at a high speed even in a low-to-medium rotation range, so that its cooling is important. If the cooling is insufficient, seizure of the rotating shaft (shaft) of the turbine / compressor occurs. Further, when the temperature of the electric motor itself becomes high, there is a problem that the permanent magnet inside the electric motor is demagnetized (or demagnetized) or the efficiency of the electric motor is reduced due to the temperature rise. In addition, when an electric motor is an induction motor (induction motor) or the like, there is a concern that a laminated material having low heat resistance that solidifies a laminated steel sheet used as a rotor may be melted. Therefore, in the turbocharger with an electric motor described in the above-mentioned publication, the turbocharger (particularly, the shaft) is cooled using engine oil. [0004] However, the engine oil also has a role of cooling the engine body, and absorbs the heat of the engine during high-speed, high-load operation when the engine itself becomes hot. Temperature rises. For this reason, in a situation where the temperature of the engine itself becomes high, such as during high-speed / high-load operation, there is a possibility that the cooling efficiency of the electric motor of the turbocharger is reduced. Accordingly, an object of the present invention is to provide a turbocharger having a motor for rotationally driving a compressor and / or a turbine, which can efficiently cool the motor. [0006] A turbocharger according to the present invention comprises: an electric motor capable of driving a compressor and / or a turbine in rotation; a turbo housing containing the electric motor;
It is characterized by comprising a coolant passage for cooling fluid circulation formed in the turbo housing, and fuel supply means for supplying fuel of the internal combustion engine as a coolant into the coolant passage. It is characterized by: An embodiment of the turbocharger according to the present invention will be described below. First, a cross-sectional view of the turbocharger of the present embodiment is shown in FIG. As shown in FIG. 1, a turbine wheel 3 is disposed on the exhaust passage side and a compressor wheel 4 is disposed on the intake passage side inside the housing 2 of the turbo unit 1, and both wheels are connected by a shaft 5. . The shaft 5 is held by a bearing in the housing 2 so as to smoothly rotate at high speed. A plurality of rotors 6a, which are components of the electric motor 6, are fixed to the center of the shaft 5. The rotor 6a is a permanent magnet. A stator 6b, which is a component of the electric motor 6, is provided around the rotor 6a. The stator 6 b is formed by winding a plurality of laminated steel sheets with windings, and is fixed to the housing 2. An electric motor 6 having the shaft 5 as an output shaft is constructed inside the housing 2 using the rotor 6a and the stator 6b as main components. The electric motor 6 is a three-phase AC motor. The electric motor 6 is controlled by controlling the electric power flowing through the winding of the stator 6b. An oil passage 7 for supplying engine oil is formed in the housing 2 to lubricate the shaft 5. The oil flow path 7 exists in a normal turbo unit that does not include a motor. Engine oil is introduced into the oil flow passage 7 from a pair of inflow portions formed on one side of the housing 2 and supplied to a pair of bearings holding the shaft 5. The engine oil after lubricating the bearing and the sliding surface between the shaft 5 and the housing 2 is discharged to the outside of the housing 2 through a pair of discharge portions. Note that the pair of discharge portions merge into one inside the housing 2. Further, in the present embodiment, the electric motor 6
Is formed so as to surround the outer periphery of.
The coolant flow path 8 may be formed so as to completely go around the outer circumference of the electric motor 6 or may be formed in a C-shape when viewed from the axial direction of the shaft 5. However, since it is for cooling the electric motor 6, it is preferable that the electric motor 6 is formed so as to surround substantially the entire circumference of the electric motor 6. In the coolant passage 8,
Fuel (the engine of the present embodiment is a gasoline engine, gasoline here) is introduced from an inlet formed on one side of the housing 2. In this embodiment, the fuel is used as the cooling liquid. The fuel introduced from the inflow portion absorbs heat around the electric motor 6 and then flows into the housing 2.
From the discharge section formed on the opposite side of the Here, the coolant passage 8 is provided with a fuel tank 9.
Is located on the fuel flow path from the engine to an injector (not shown) of the engine. That is, the fuel combusted by the engine is after passing through the turbo unit 1.
A fuel pipe, a fuel tank 9, a fuel pump 10 for generating a fuel flow in the coolant flow path 8, and the like function as a fuel supply unit that supplies the fuel as a coolant into the coolant flow path 8. The fuel pump 10 is driven by the output of the engine, and is originally for supplying fuel to the engine (injector). Here, the fuel pump 10 is used. Thus, using fuel as a coolant,
By cooling the turbo unit 1 with the built-in electric motor 6 using this fuel, it is possible to suppress the demagnetization of the permanent magnets in the electric motor 6 and the decrease in the efficiency of the electric motor 6 due to the high temperature, and to drive the electric motor 6 efficiently. it can. The cooling by the coolant flow path 8 contributes not only to the cooling of the electric motor 6 but also to the cooling of the entire housing 2. Importantly, the temperature of the fuel is relatively low regardless of the operating condition of the engine, and the housing can be cooled to a lower temperature. For example, when the housing 2 is to be cooled using engine oil, the temperature of the engine oil reaches about 100 ° C. under a high load or high-speed running. 2) cannot be cooled. However, since the temperature of the fuel is low even at a high load or at a high speed, the electric motor 6 (housing 2) can be cooled to 50 ° C. or less by using the fuel as a coolant. Further, such a configuration has an advantage that it can be dealt with only by changing an existing fuel pipe so as to pass through the turbo unit 1, and there is no need to add a special part. Further, the fuel can be warmed by using this mechanism, and it can be used as a mechanism for improving the startability of the engine. When the engine is started, the fuel is passed through the turbo unit 1 (if necessary, the electric motor 6 is actively driven to generate heat) to raise the temperature of the fuel, thereby promoting the vaporization of the fuel. As a result, the ignitability of the air-fuel mixture after the fuel and the intake air are mixed is improved, and the startability is improved. The present invention is not limited to the above-described embodiment. For example, the configuration of the fuel supply means may be different from that of the above-described embodiment. In the above-described embodiment, the fuel pump 10 driven by the engine output is located on the downstream side of the coolant flow path 8, but may be configured on the upstream side. Further, in the above-described embodiment, the fuel that has passed through the coolant flow path 8 is directly sent to the injector for combustion. Although such a configuration is preferable,
This need not be the case. For example, the cooling system of the turbo unit 1 using fuel and the fuel supply system to the engine may be completely independent. According to the turbocharger of the present invention, an electric motor capable of rotationally driving a compressor and / or a turbine, a turbo housing incorporating the electric motor, and a cooling liquid circulation formed in the turbo housing. And the fuel supply means for supplying the fuel as the cooling liquid into the cooling liquid flow path, the motor can always be efficiently cooled by the fuel.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of an embodiment of a turbocharger of the present invention. [Description of Signs] 1 ... Turbo unit, 2 ... Housing, 3 ... Turbine wheel, 4 ... Compressor wheel, 5 ... Shaft, 6
... Electric motor, 7 ... oil flow path, 8 ... coolant flow path, 9 ... fuel tank, 10 ... fuel pump (fuel supply means).

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Hironari Hashimoto             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Inside the car company (72) Inventor Katsura Masuda             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Inside the car company (72) Inventor Chiba Kanba             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Inside the car company F-term (reference) 3G005 EA04 EA16 EA20 FA28 GB86                       GB93                 5H609 BB01 BB15 BB19 PP02 PP05                       PP06 QQ05 QQ13 RR26 RR30

Claims (1)

Claims: 1. A turbocharger for supercharging an internal combustion engine, an electric motor capable of rotating a compressor and / or a turbine, a turbo housing incorporating the electric motor, and an inside of the turbo housing. 1. A turbocharger comprising: a coolant flow passage formed in the coolant passage; and a fuel supply unit that supplies fuel of the internal combustion engine as a coolant into the coolant flow passage.