JP5699541B2 - Electric assist turbocharger cooling system - Google Patents

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 housing 27 that surrounds the compressor wheel 26 and into which intake air is introduced. A turbo shaft 23 for connecting the compressor wheel 26 is accommodated in a bearing housing 28 and supported by a bearing cylinder 29 provided in the bearing housing 28. A lubricating oil inlet passage 33 for supplying lubricating oil to the bearing cylinder 29 is provided in the upper portion of the bearing housing 28, and a lubricating oil discharge passage 34 is formed in the lower portion.

  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 cylinder 29 in the bearing housing 28 and cool the bearing cylinder 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 passage 34 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. A motor composed of a rotor and a stator is accommodated in the motor case, and a cooling oil passage is formed in the motor case to supply the lubricating oil in the bearing housing to the air gap between the stator and the rotor and return it to the bearing housing. This is a cooling device for an electrically assisted turbocharger.

  According to a second aspect of the present invention, the cooling oil passage includes a lubricant introduction passage and a discharge passage provided between the bearing housing and the motor case, an air gap between the rotor and the stator, and between the compressor housing and the motor case. The cooling device for an electrically assisted turbocharger according to claim 1, comprising a lubricating oil circulation path formed in an inner peripheral portion.

  According to a third aspect of the present invention, the bearing housing is provided with a shaft tube portion, and a turbo shaft is supported on the shaft tube portion via a ball bearing, and the ball bearing and the cooling oil passage are disposed in an upper portion of the bearing housing. 2. A lubricating oil inlet flow path for flowing lubricating oil is formed in the bearing housing, and a lubricating oil outlet flow path for lubricating oil from a ball bearing and lubricating oil from the cooling oil path is formed in a lower portion in the bearing housing. Or it is a cooling device of the electric assist turbocharger of 2.

  The invention of claim 4 is the cooling device for the electrically assisted turbocharger according to any one of claims 1 to 3, wherein the motor case is formed with a water cooling chamber for cooling the outer periphery of the stator.

  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 turbo shaft 23 supported by the bearing cylinder 29 in the bearing housing 28 is supported by ball bearings 30, 30 provided at both ends in the bearing cylinder 29, and a thrust collar 31 is provided between the ball bearings 30, 30. A ball bearing 30 on the motor case 11 side is supported by an end plate 32.

  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.

  A lubricating oil inlet channel 33 for supplying lubricating oil to the ball bearings 30 and 30 is formed in the upper portion of the bearing housing 28, and a lubricating oil discharge channel 34 is formed in the lower portion.

A cooling oil passage 35 is formed in the motor case 11 to supply the lubricating oil from the lubricating oil inlet passage 33 to the air gap g between the stator 14 and the rotor 13 and to return to the lubricating oil discharge passage 34 of the bearing housing 28. Is done.

  The cooling oil passage 35 includes a lubricating oil introduction passage 35 i provided in the end plate 32, a discharge passage 35 o formed in the lower portion of the end plate 32, an air gap g between the rotor 13 and the stator 14, a compressor It is composed of a lubricating oil circulation path 35n formed in the inner periphery between the housing 27 and the motor case 11.

  A cooling water inlet 36 is provided in the lower part of the motor case 11, a cooling water outlet 37 is provided in the upper part, and a stator cooling line 39 including a radiator 38 is connected between the cooling water inlet 36 and the cooling water outlet 37. The

  The stator cooling line 39 is branched from the engine cooling line 50.

  The engine cooling line 50 includes a cooling water pump 51, passes through the oil cooler 52 from the cooling water pump 51, passes through the cylinder block 40 s and the cylinder head 40 h of the engine 40, and returns to the cooling water pump 51 through the radiator 38. The stator cooling line 39 is provided to be branched from the cylinder block 40s of the engine cooling line 50. Cooling water from the cylinder block 40s flows to the cooling water inlet 36 through the inlet-side stator cooling line 39a, passes through the water cooling chamber 15, passes from the cooling water outlet 37 through the outlet-side stator cooling line 39b, and exits from the cylinder head 40h. The cooling line 50 is merged.

  Further, the lubricating oil is supplied to the bearing cylinder 29 of the bearing housing 28 by the lubricating oil passing through the cylinder block 40s and the cylinder head 40h through the oil supply pipe 47 as described in FIG. It is introduced into the flow path 33, supplied from the lubricating oil inlet flow path 33 to the ball bearings 30, 30 of the bearing cylinder 29, lubricates and cools the ball bearings 30, 30 and flows into the lubricating oil discharge path 34. The lubricating oil supplied to the lubricating oil inlet channel 33 flows into the cooling oil passage 35 formed in the motor case 11 to cool the motor 12 and then returns to the lubricating oil discharge passage 34. That is, the lubricating oil from the lubricating oil inlet passage 33 passes through the lubricating oil introduction passage 35i provided in the end plate 32 and flows into the air gap g, where the rotor 13 and the stator 14 are cooled, and the compressor housing It flows in the lubricating oil circulation path 35n formed in the inner peripheral part between 27 and the motor case 11, flows again through the air gap g between the rotor 13 and the stator 14, and flows from the discharge path 35o to the lubricating oil discharge path 34.

  The lubricating oil that has flowed into the lubricating oil discharge passage 34 is returned to the oil pan by the oil return pipe 48 and circulated again.

  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 at 200 ° C. when the motor 12 is driven, the lubricating oil in the bearing housing 28 flows from the lubricating oil inlet passage 33 to the cooling oil passage 35 to cool the motor 12 and at the same time. By flowing the cooling water from the cooling line 39 into the water cooling chamber 15 in the motor case 11, the temperature of the motor 12 can be cooled to 80 ° C. or less. 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.

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 33 Lubricating oil inlet flow path 35 Cooling oil path

Claims (3)

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. accommodated in the motor case, Ri Na form a cooling oil passage for returning the bearing housing supplies lubricating oil in the bearing housing to the air gap between the stator and the rotor,
The cooling oil passage includes a lubricating oil introduction passage formed at an upper portion of an end plate provided between the bearing housing and the motor case, a discharge passage formed at a lower portion of the end plate, and between the rotor and the stator. A cooling device for an electrically assisted turbocharger comprising an air gap and a lubricating oil circulation path formed in an inner peripheral portion between a compressor housing and a motor case . A shaft housing is provided in the bearing housing, and a turbo shaft is supported on the shaft tube through a ball bearing. A lubricating oil that flows through the ball bearing and the cooling oil passage is provided in an upper portion of the bearing housing. The electrically assisted turbocharger according to claim 1, wherein an inlet flow path is formed, and a lubricating oil outlet flow path for lubricating oil from a ball bearing and lubricating oil from the cooling oil path is formed in a lower portion in the bearing housing. Cooling system. The cooling device for an electrically assisted turbocharger according to claim 1 or 2 , wherein a water cooling chamber for cooling the outer periphery of the stator is formed in the motor case.

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