JP2012097608A - Cooling system of electric power-assisted turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling system of an electric power-assisted turbocharger capable of cooling a motor of the electric power-assisted turbocharger.SOLUTION: In this electric power-assisted turbocharger 10, a rotor 13 of the motor 12 is connected to a turbo-shaft 23 of the turbocharger, and a bearing housing 28 for journaling the turbo-shaft 23 and a compressor housing 27 of the turbocharger are connected by a motor case 11, the motor 12 constituted of the rotor 13 and a stator 14 is stored in the motor case 11, and a water-cooled chamber 15 is formed in the motor case 11 on the outer periphery of the stator 14.

Description

  The present invention relates to an electric assist turbocharger in which an electric motor (motor) is combined with a turbocharger, and more particularly to an electric assist turbocharger cooling device for cooling a motor of the electric assist turbocharger.

  As shown in FIG. 2, the turbocharger 20 is configured by connecting a turbine 21 and a compressor 22 with a turbo shaft 23. The turbine 21 includes a turbine wheel 24 and a turbine housing 25 that surrounds the turbine wheel 24 and into which exhaust gas is introduced. The compressor 22 includes a compressor wheel 26 and a compressor housing 27 that surrounds the compressor wheel 26 and into which intake air is introduced. A turbo shaft 23 connecting the turbine wheel 24 and the compressor wheel 26 is accommodated in a bearing housing 28 and supported by a bearing portion 29 provided in the bearing housing 28. A lubricating oil inlet 30 for supplying lubricating oil to the bearing portion 29 is provided in the upper part of the bearing housing 28, and a lubricating oil discharge path 31 is formed in the lower part.

  FIG. 3 shows an intake / exhaust system and a cooling system using lubricating oil when the turbocharger 20 is added to the engine 40.

  In the turbocharger 20, the turbine 21 is connected to the exhaust pipe 41 of the engine 40, the compressor 22 is connected to the intake pipe 42, and exhaust gas exhausted from the combustion chamber 43 of the engine 40 is supplied to the turbine 21 through the exhaust pipe 41. The turbine 21 is driven, and the intake air is introduced into the compressor 22 from the air cleaner 44 and compressed, cooled by the intercooler 46, and introduced into the combustion chamber 43 of the engine 40 through the intake throttle 45.

  The turbocharger 20 uses lubricating oil from the engine 40 through the oil supply pipe 47 to lubricate the bearing portion 29 in the bearing housing 28 and cool the bearing portion 29 by receiving heat from exhaust gas. The lubricating oil supplied to the bearing housing 28 is returned to the oil pan from the lubricating oil discharge path 31 through the oil return pipe 48, and is again cooled. It is circulated in the bearing housing 28.

  In the system in which the turbocharger 20 is added to the engine 40, there is a problem that the boost pressure rises in a low rotation range of the engine and the output characteristics of the engine are not good even when high torque is required at low rotation.

  Therefore, recently, the motor rotor is directly connected to the turbo shaft of the turbocharger, and when high torque is required, the turbo shaft is rotated by the motor to increase the supercharging pressure, and conversely, the motor is generated by rotating the turbine. An electrically assisted turbocharger used as the above has been developed (Patent Documents 1 and 2).

JP 2004-169629 A JP 2006-320143 A

  In this electrically assisted turbocharger, a motor is installed between the bearing housing and the compressor housing. However, when the motor is driven, the temperature of the motor rises to 200 ° C. or more due to self-heating of the stator and heat received from the turbine. There is a problem that the driving force is reduced.

  FIG. 4 shows motor speed characteristics and motor current characteristics with respect to torque when the motor temperature is −20 ° C., + 25 ° C., and + 75 ° C. When the motor temperature is high, the motor current characteristics and speed characteristics are poor. Become.

  Therefore, when the motor temperature rises to 100 ° C. or more, the boost rise time is delayed, the exhaust gas performance and the driving response are deteriorated, and the heat resistance of the motor is also problematic.

  Accordingly, an object of the present invention is to solve the above-described problems and to provide a cooling device for an electric assist turbocharger that can cool the motor of the electric assist turbocharger.

  In order to achieve the above object, an invention according to claim 1 is an electric assist turbocharger in which a rotor of a motor is connected to a turboshaft of a turbocharger. A motor housing includes a bearing housing that supports the turboshaft and a compressor housing of the turbocharger. The motor-assisted turbocharger cooling apparatus is characterized in that a motor including a rotor and a stator is accommodated in a motor case and a water cooling chamber is formed in the motor case on the outer periphery of the stator.

  According to a second aspect of the present invention, there is provided a stator cooling line including a cooling water inlet of the water cooling chamber at a lower portion of the motor case, a cooling water outlet at an upper portion, and a radiator between the cooling water inlet and the cooling water outlet. It is a cooling device of the electrically assisted turbocharger of Claim 1 connected.

  According to a third aspect of the present invention, the water cooling chamber includes a cooling water passage that cools the outer periphery of the stator, and an end surface cooling passage that is continuous with the cooling water passage and insulates heat from the bearing housing side of the stator. A cooling device for an electrically assisted turbocharger according to claim 1 or 2.

  The invention of claim 4 is the cooling device for the electric assist turbocharger according to claim 3, wherein the bearing housing and the motor case are connected via a heat insulating gasket.

  INDUSTRIAL APPLICABILITY The present invention has an excellent effect that the cooling performance of the stator of the motor is improved, the reduction in motor driving force can be prevented, and the power generation efficiency can be improved when the motor is used as a generator.

It is a figure which shows one embodiment of this invention. It is sectional drawing which shows the conventional turbocharger. It is the figure which incorporated the conventional turbocharger in the engine intake-exhaust system. It is a figure which shows the speed characteristic and electric current characteristic with respect to the torque in each temperature of a motor.

  A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 denotes an electrically assisted turbocharger. Except for the configuration of the motor 12, the turbine and the compressor are basically the same as the structures of the turbine 21 and the compressor 22 of the turbocharger 20 described in FIG. The same reference numerals are given and the description thereof is omitted.

  The bearing housing 28 and the compressor housing 27 are connected by a motor case 11, and the motor 12 is provided in the motor case 11 to constitute the electrically assisted turbocharger 10.

  The motor 12 includes a rotor 13 connected to a turbo shaft 23 and a stator 14 disposed on the outer periphery of the rotor 13 via an air gap. A motor case 11 is provided so as to surround the stator 14. A water cooling chamber 15 is formed in the motor case 11.

  The motor case 11 forming the water cooling chamber 15 is formed by an outer peripheral wall 11o, a side wall 11s in contact with the bearing housing 28, a side wall 11r in contact with the compressor housing 27, and an inner peripheral wall 11i that connects both side walls 11s and 11r. The inner peripheral wall 11i has a stator outer peripheral wall portion 16a in contact with the stator 14, a stator end surface wall portion 16b extending along the compressor housing 27 side end surface center of the stator 14, an inner peripheral end of the stator end surface wall portion 16b, and a bearing housing. The inner peripheral wall portion 16c is connected to the side wall 11s on the 28th side.

  The water cooling chamber 15 includes a hollow ring-shaped cooling water flow path 15a formed by a side wall 11r in contact with the compressor housing 27, a stator outer peripheral wall portion 16a of the inner peripheral wall 11i, and an outer peripheral wall 11o, and a stator end face wall portion 16b of the inner peripheral wall 11i. And an end surface cooling flow path 15b formed by the inner peripheral wall portion 16c and the side wall 11s on the bearing housing 28 side.

  A heat insulating gasket 18 is provided between the side wall 11 s of the motor case 11 and the bearing housing 28 to prevent heat input from the bearing housing 28 to the end face of the stator 14. An oil seal 17 is provided on the inner periphery of the side wall 11 s of the motor case 11.

  A thrust bearing 32 that receives the thrust load of the turbo shaft 23 is provided on the heat insulating gasket 18 side of the bearing housing 28.

  In the present embodiment, an example in which the turbo shaft 23 is directly supported by the bearing portion 29 as in FIG. 2 is shown. However, the turbo shaft 23 may be configured to be supported by a ball bearing.

  A cooling water inlet 33 is provided in the lower part of the motor case 11, a cooling water outlet 34 is provided in the upper part, and a stator cooling line 36 including a radiator 35 is connected between the cooling water inlet 33 and the cooling water outlet 34. The

  The stator cooling line 36 is branched from the engine cooling line 50.

  The engine cooling line 50 has a cooling water pump 37, passes through the oil cooler 38 from the cooling water pump 37, passes through the cylinder block 40 s and the cylinder head 40 h of the engine 40, returns to the cooling water pump 37 through the radiator 35. The stator cooling line 36 is configured to be branched from the cylinder block 40 s of the engine cooling line 50. Cooling water from the cylinder block 40s flows to the cooling water inlet 33 through the inlet-side stator cooling line 36a, passes through the water cooling chamber 15, passes from the cooling water outlet 34 through the outlet-side stator cooling line 36b, and exits from the cylinder head 40h. The cooling line 50 is merged.

  Further, the lubricating oil is supplied to the bearing portion 29 and the thrust bearing 32 of the bearing housing 28 in the bearing housing 28 through the oil supply pipe 47 through the cylinder block 40s and the cylinder head 40h as described in FIG. The bearing portion 29 and the thrust bearing 32 are lubricated and cooled, and returned from the lubricating oil discharge passage 31 to the oil pan through the oil return pipe 48 and circulated.

  Next, the operation of this embodiment will be described.

  When a high torque is required at a low load and the supercharging pressure is increased, the rotor 13 is rotated by energizing the coil of the stator 14 of the motor 12, the compressor 22 is driven via the turbo shaft 23, and the turbine 21 When power is generated from driving, the battery is charged with a regenerative current generated in the coil of the stator 14.

  Since the stator 14 generates heat to 200 ° C. when the motor 12 is driven, the temperature of the motor 12 is cooled to 80 ° C. or less by flowing cooling water from the stator cooling line 36 into the water cooling chamber 15 in the motor case 11. can do. Further, in the water cooling chamber 15, in addition to the cooling water flow path 15a for cooling the outer peripheral portion of the stator 14, an end surface cooling flow path 15b for cooling the end face of the stator 14 is formed. Heat transfer from the housing 28 can be cut, and heat reception can be cut by the heat insulating gasket 18 provided between the bearing housing 28 and the motor case 11. The heat insulating gasket 18 is provided adjacent to the thrust bearing 32 of the bearing housing 28, and cuts heat transmitted from the turbine 21 side to the motor 12 together with a cooling effect by the lubricating oil supplied to the thrust bearing 32. can do.

DESCRIPTION OF SYMBOLS 10 Electric assist turbocharger 11 Motor case 12 Motor 13 Rotor 14 Stator 15 Water cooling chamber 21 Turbine 22 Compressor 23 Turbo shaft 27 Compressor housing 28 Bearing housing

Claims (4)

  In an electrically assisted turbocharger in which a rotor of a motor is connected to a turboshaft of a turbocharger, a bearing housing that supports the turboshaft and a compressor housing of the turbocharger are connected by a motor case, and a motor including a rotor and a stator is installed in the motor case. A cooling device for an electrically assisted turbocharger, characterized in that a water cooling chamber is formed in a motor case on the outer periphery of the stator.   The cooling water inlet of the said water cooling chamber is provided in the lower part of the said motor case, the cooling water outlet is provided in the upper part, The stator cooling line containing a radiator is connected between the cooling water inlet and a cooling water outlet. Cooling device for electric assist turbocharger.   The said water cooling chamber consists of the cooling water flow path which cools the outer periphery of the said stator, and the end surface cooling flow path which continues the cooling water flow path and insulates the heat from the bearing housing side of a stator. Cooling device for electric assist turbocharger.   The cooling device for an electrically assisted turbocharger according to claim 3, wherein the bearing housing and the motor case are connected via a heat insulating gasket.