JP5903760B2 - Electric assist turbocharger cooling device - 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 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 from the air cleaner 44 into the compressor 22 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. A motor consisting of a rotor and a stator is accommodated in the motor case, a main water cooling chamber is formed in the motor case on the outer periphery of the stator, and a sub water cooling chamber communicating with the main water cooling chamber is formed in the bearing housing. It is a cooling device of the electric assist turbocharger characterized.

  In the invention of claim 2, the cooling water inlet of the main water cooling chamber is provided at the lower part of the motor case, the cooling water outlet of the auxiliary water cooling chamber is provided at the upper part of the bearing housing, and between the cooling water inlet and the cooling water outlet. The cooling device for an electrically assisted turbocharger according to claim 1, wherein a stator cooling line including a radiator is connected to the radiator.

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

  The invention according to claim 4 is the cooling device for the electrically assisted turbocharger according to any one of claims 1 to 3, wherein the auxiliary water cooling chamber has an annular cooling flow path located on the turbine casing side.

  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 main water cooling chamber 15 is formed in the motor case 11.

  The bearing housing 28 is formed with a sub water cooling chamber 19 communicating with the main water cooling chamber 15.

  The motor case 11 forming the main 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. The inner peripheral wall portion 16c is connected to the side wall 11s on the housing 28 side.

  The main water cooling chamber 15 includes a hollow ring-shaped cooling water passage 15a formed by the side wall 11r contacting the compressor housing 27, the stator outer peripheral wall portion 16a of the inner peripheral wall 11i, and the outer peripheral wall 11o, and the stator end face wall portion of the inner peripheral wall 11i. 16b, and the 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.

  The auxiliary water cooling chamber 19 formed in the bearing housing 28 is connected to the upper portion of the main water cooling chamber 15, and includes an introduction flow path 19 a extending to the turbine 21 and an annular cooling flow path 19 b formed on the turbine housing 25 side. Composed.

  A cooling water inlet 33 for introducing cooling water into the main water cooling chamber 15 is provided at the lower part of the motor case 11, and the cooling water is discharged from the annular cooling channel 19 b of the auxiliary water cooling chamber 19 at the upper part of the bearing housing 28. A cooling water outlet 34 is provided, 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 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 main water cooling chamber 15, passes from the cooling water outlet 34 through the outlet side stator cooling line 36b, and is disposed on the outlet side of the cylinder head 40h. The engine 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.

  When the motor 12 is driven, the stator 14 generates heat to 200 ° C., so that the cooling water from the stator cooling line 36 flows into the main water cooling chamber 15 in the motor case 11 and also flows into the sub water cooling chamber 19 of the bearing housing 28. Thus, the temperature of the motor 12 can be cooled to 80 ° C. or lower. Further, in the auxiliary water cooling chamber 19, heat transmitted from the turbine 21 side to the bearing housing 28 is cut. Further, the main water cooling chamber 15 is formed with an end surface cooling flow path 15b for cooling the end surface of the stator 14, whereby heat transfer from the turbine 21 through the bearing housing 28 can be cut, and the bearing housing 28 and the motor The heat reception can be cut by the heat insulating gasket 18 provided between the cases 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 Main water cooling chamber 19 Sub water cooling chamber 21 Turbine 22 Compressor 23 Turbo shaft 27 Compressor housing 28 Bearing housing

Claims (4)

In the electrically assisted turbocharger in which the motor is connected to the turboshaft's turboshaft,
A bearing housing for bearing the turbo shaft;
A compressor housing of the turbocharger;
A motor case connecting the bearing housing and the compressor housing;
The motor housed in the motor case and connected to the turboshaft and a stator; and
A main water cooling chamber formed in the motor case around the stator;
A secondary water cooling chamber formed in the bearing housing;
A heat insulating gasket provided between the main water cooling chamber and the sub water cooling chamber;
A communication passage communicating the main water cooling chamber and the auxiliary water cooling chamber via the heat insulating gasket;
An electrically assisted turbocharger cooling device comprising:   A cooling water inlet of the main water cooling chamber is provided at a lower portion of the motor case, a cooling water outlet of the auxiliary water cooling chamber is provided at an upper portion of the bearing housing, and a radiator is included between the cooling water inlet and the cooling water outlet. The cooling device for an electrically assisted turbocharger according to claim 1, wherein a stator cooling line is connected.   The bearing housing and the motor case are connected via the heat insulating gasket, and the main water cooling chamber is continuous with the cooling water passage for cooling the outer periphery of the stator, the cooling water passage, and the bearing housing of the stator. The cooling device for an electrically assisted turbocharger according to claim 1 or 2, comprising an end face cooling channel that insulates heat from the side.   The cooling apparatus for an electrically assisted turbocharger according to any one of claims 1 to 3, wherein the auxiliary water cooling chamber has an annular cooling channel located on the turbine casing side.