U.S. patent application number 11/915350 was filed with the patent office on 2011-03-31 for turbo charger ii.
Invention is credited to Thomas Bischof, Holger Godeke, Ralf Heber, Oliver Kampfer, Rudolf Loffler, Sandra Stehmer.
Application Number | 20110076166 11/915350 |
Document ID | / |
Family ID | 38421585 |
Filed Date | 2011-03-31 |
United States Patent
Application |
20110076166 |
Kind Code |
A1 |
Godeke; Holger ; et
al. |
March 31, 2011 |
Turbo Charger II
Abstract
A turbocharger includes a compressor arrangement for compressing
fresh air for internal combustion engines, containing a compressor
wheel as well as an electric motor with a rotor and stator. A rotor
magnet of the rotor is designed such that it is partially or
completely integrated into the compressor wheel, and the smallest
diameter of the stator is 1.5- to 8-times the size of the largest
outer diameter of the rotor. The turbocharger has a very
spontaneous response behaviour in the transient range, as well as
the possibility of an exact real-time regulation of the mass flow.
It furthermore renders possible the energy recovery and this
contributes to increasing the total efficiency.
Inventors: |
Godeke; Holger; (Achstetten,
DE) ; Loffler; Rudolf; (Unteressendorf, DE) ;
Heber; Ralf; (Erbach-Ersingn, DE) ; Bischof;
Thomas; (Illerbeuren, DE) ; Stehmer; Sandra;
(Wurzach, DE) ; Kampfer; Oliver; (Mainz,
DE) |
Family ID: |
38421585 |
Appl. No.: |
11/915350 |
Filed: |
October 25, 2007 |
PCT Filed: |
October 25, 2007 |
PCT NO: |
PCT/EP2007/009446 |
371 Date: |
March 24, 2010 |
Current U.S.
Class: |
417/410.1 |
Current CPC
Class: |
F05D 2270/304 20130101;
F05B 2270/304 20130101; F05B 2220/7068 20130101; H02K 9/06
20130101; F01N 13/107 20130101; F05B 2220/70642 20130101; H02K
5/128 20130101; H02K 7/14 20130101; F04D 13/0646 20130101; Y02T
10/12 20130101; F05D 2220/768 20130101; F01D 5/025 20130101; F02B
37/10 20130101; F05D 2220/40 20130101; Y02E 10/30 20130101; F04D
25/024 20130101; Y02E 20/14 20130101; F05B 2220/40 20130101; F05B
2220/706 20130101; F05D 2220/76 20130101; H02K 7/1823 20130101;
F02B 37/025 20130101; F04D 25/0606 20130101; F02B 39/10 20130101;
F05D 2220/7642 20130101; Y02E 10/20 20130101; F03B 17/061 20130101;
F01D 25/16 20130101 |
Class at
Publication: |
417/410.1 |
International
Class: |
F04B 35/04 20060101
F04B035/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 24, 2007 |
EP |
07090100.4 |
Jun 20, 2007 |
EP |
07075496.5 |
Aug 1, 2007 |
EP |
07075661.4 |
Claims
1-44. (canceled)
45. A turbocharger, comprising: a compressor arrangement
compressing fresh air for an internal combustion engine, the
compressor arrangement including a compressor wheel and an electric
motor, the motor including a rotor and a stator, wherein a rotor
magnet of the rotor is one of partially integrated and completely
integrated into the compressor wheel, and wherein a smallest inner
diameter of the stator is between 1.5- and 8-times as large as a
largest outer diameter of the rotor.
46. A turbocharger according to claim 45, wherein the rotating
compressor wheel leads through a rotor gap at least 50% of an air
mass flow to be compressed.
47. A turbocharger according to claim 45, wherein the rotating
compressor wheel leds through a rotor gap at least 90% of an air
mass flow to be compressed.
48. A turbocharger according to claim 45, further comprising: a
turbine wheel connected to the compressor wheel, the motor being
arranged on a side of the compressor wheel which is distant to the
turbine wheel.
49. A turbocharger according to claim 45, wherein the rotor is
connected to the compressor wheel in a rotationally fixed manner,
and is designed in a freely projecting manner.
50. A turbocharger according to claim 45, further comprising: a
turbine wheel permanently connected to the compressor wheel in a
rotationally fixed manner.
51. A turbocharger according to claims 45, further comprising: a
turbine wheel; a housing including a turbine housing situating the
turbine wheel; and a compressor housing situating the compressor
wheel.
52. A turbocharger according to claim 51, wherein the mounting of
at least one of the turbine wheel and the compressor wheel is given
exclusively in a region between the turbine wheel and the
compressor wheel.
53. A turbocharger according to claim 52, further comprising: a
bearing housing receiving bearing elements for the turbine wheel
and the compressor wheel, the bearing housing being situated
between the turbine housing and the compressor housing.
54. A turbocharger according to claim 45, wherein the rotor magnet
is surrounded by a sheathing.
55. A turbocharger according to claim 51, wherein the stator has a
substantially hollow-cylindrical shape.
56. A turbocharger according to claim 55, wherein the stator is
part of an inner wall of the compressor housing.
57. A turbocharger according to claim 55, wherein the stator is
applied, as an insert, into a corresponding opening of the
compressor housing.
58. A turbocharger according to claim 45, wherein a rotor gap is
located between the rotor and the stator, the rotor gap being an
inlet air opening for the compressor wheel.
59. A turbocharger according to claim 58, wherein the inlet air
opening is free of struts between the rotor and the stator.
60. A turbocharger according to claim 54, wherein the sheathing has
a substantially cylindrical shape.
61. A turbocharger according to claim 54, wherein the rotor magnet,
on an inside and in regions, is hollow for sticking onto a common
shaft with the compressor wheel.
62. A turbocharger according to claim 45, wherein the compressor
wheel is composed of a non-metallic material
63. A turbocharger according to claim 45, wherein the compressor
wheel is composed of one of a reinforced plastic and a
non-reinforced plastic.
64. A turbocharger according to claim 51, wherein the turbine
housing is connected to an exhaust gas conduit of the internal
combustion engine to drive of the turbine wheel using the exhaust
gas flowing out of the internal combustion engine.
65. A turbocharger according to claim 45, wherein the motor is
switched over from a motor operation into a generator
operation.
66. A turbocharger according to claim 45, wherein a nominal voltage
of the motor is one of 12, 24 and 48 V.
67. A turbocharger according to claim 45, wherein a mass of the
rotor magnet is between 50 and 1000 g,
68. A turbocharger according to claim 45, wherein when the
turbochager is a motor vehicle turbocharger, a mass of the rotor
magnet is between 10 and 100 g.
69. A turbocharger according to claim 45, wherein a mass moment of
inertia of the rotor magnet with respect to an axis of the rotor is
between 0.1 kgmm2 and 10 kgmm2.
70. A turbocharger according to claim 45, wherein a mass moment of
inertia of the rotor magnet with respect to an axis of the rotor
for a motor vehicle application is a between 0.3 kgmm2 and 1.0
kgmm2.
71. A turbocharger according to claim 45, wherein the compressor
wheel has a conveyor structure in a form of one of worms, blades
and wings, and wherein front edges of the conveyor structure, in an
air inlet flow direction, lie one of downstream and upstream with
regard to one of a magnetically effective front edge of the rotor
magnet and a magnetically effective front edge of the stator.
72. A turbocharger according to claim 45, wherein the compressor
wheel has a conveyor structure in a form of one of blades, worms
and wings, and wherein rear edges of the conveyor structure in an
air inflow direction, lie one of downstream and upstream with
respect to at least one of a rear edge of the rotor magnet and a
rear edge of the stator.
73. A turbocharger according to claim 45, wherein at least one of
the stator and the rotor is inclined with respect to an axis of the
compressor wheel.
74. A turbocharger according to claim 45, wherein the rotor magnet
with respect to an axis of the compressor wheel is arranged
radially outside a hub of the compressor wheel.
75. A turbocharger according to claim 74, wherein the compressor
wheel leads air radially within and radially outside the rotor
magnet.
76. A turbocharger according to claim 75, wherein the compressor
wheel leads at least 50% of the air mass flow radially outside the
rotor magnet.
77. A turbocharger according to claim 75, wherein the compressor
wheel leads at least 70% of the air mass flow radially outside the
rotor magnet.
78. A turbocharger according to claim 75, wherein the compressor
wheel leads at least 90% of the air mass flow radially outside the
rotor magnet.
79. A turbocharger according to claim 45, wherein in at least one
cross section, a ratio of a cross-sectional area of an inlet
opening to a cross-sectional area of the rotor magnet is between
0.5 and 100.
80. A turbocharger according to claim 45, wherein in at least one
cross section, a ratio of a cross-sectional area of an inlet
opening to a cross-sectional area of the rotor magnet is between
0.8 and 50.
81. A turbocharger according to claim 45, wherein in at least one
cross section, a ratio of a cross-sectional area of an inlet
opening to a cross-sectional area of the rotor magnet is between 2
and 20.
82. A turbocharger according to claim 79, wherein the cross section
runs through one of magnetically effective sections and
electrically effective sections of the stator.
83. A turbocharger according to claim 45, wherein, in at least one
cross section, a ratio of a cross-sectional area of the stator to a
cross-sectional area of the rotor magnet is between 2 and 100.
84. A turbocharger according to claim 45, wherein, in at least one
cross section, a ratio of a cross-sectional area of the stator to a
cross-sectional area of the rotor magnet is between 10 and 50.
85. A turbocharger according to claim 79, wherein the cross section
is perpendicular to an axis.
86. A turbocharger according to claim 45, wherein the rotor is
connected to the compressor wheel, the compressor wheel being
axially mounted on both sides.
87. A turbocharger according to claim 45, wherein the turbocharger
is a compressor system having at least one compressor wheel, the at
least one compressor wheel being axially mounted on one of one side
and both sides.
88. A turbocharger according to claim 45, further comprising: a
turbine wheel, wherein the motor is arranged on one of a first side
of the compressor wheel which faces the turbine wheel and between
the first side and a second side of the compressor wheel which is
distant to the turbine wheel.
89. A turbocharger according to claim 45, wherein the smallest
inner diameter of the stator is between 1.1- and 1.49-times larger
than the largest outer diameter of the rotor.
90. A turbocharger according to claim 45, wherein the smallest
inner diameter of the stator is between 1.25- and 1.49-times larger
than the largest outer diameter of the rotor.
91. A turbocharger according to claim 45, wherein the smallest
inner diameter of the stator is 8.01- to 15-times larger than the
largest outer diameter of the rotor.
92. A turbocharger according to claim 45, wherein the smallest
inner diameter of the stator is between 8.01- and 12-times larger
than the largest outer diameter of the rotor.
93. A drive system for a motor vehicle, comprising: an internal
combustion engine; a storage device storing an electrical energy;
and a turbocharger including a compressor arrangement compressing
fresh air for an internal combustion engine, the compressor
arrangement including a compressor wheel and an electric motor, the
motor including a rotor and a stator, the rotor magnet of the rotor
being one of partially integrated and completely integrated into
the compressor wheel, and wherein a smallest inner diameter of the
stator is between 1.5- and 8-times as large as a largest outer
diameter of the rotor, wherein the motor is connected to the
storage device to receive the electrical energy during in a motor
operation of the turbocharger and to feeding-in the electrical
energy in a generator operation of the turbocharger.
94. A drive system according to claim 91, wherein the storage
device is connected to an electromotoric drive of the motor
vehicle.
95. A drive system according to claim 93, wherein the turbocharger
includes a turbine wheel, a turbine housing and a compressor
housing, the drive system further comprising: control electronics
determining a rotational speed of one of the turbine wheel and the
compressor wheel, actual values of pressure conditions on a side of
the turbine housing and a side of the compressor housing, and
further values of the internal combustion engine of relevance to a
torque.
96. A drive system according to claim 95, wherein the control
electronics include a sensor.
97. A method for an operation of a turbocharger, the turbocharger
including a compressor arrangement and at least one compressor
wheel, the compressor arrangement compressing fresh air for an
internal combustion engine, the compressor arrangement including a
compressor wheel and an electric motor, the motor including a rotor
and a stator, wherein a rotor magnet of the rotor is one of
partially integrated and completely integrated into the compressor
wheel, wherein a smallest inner diameter of the stator is between
1.5- and 8-times as large as a largest outer diameter of the rotor,
and wherein the least one compressor wheel is driven by the motor
to compress air, a rotor gap being arranged between the rotor and
the stator, at least 50% of an air mass flow led to the compressor
wheel being led through the rotor gap in at least one operating
condition of the turbocharger.
98. A method according to claim 97, wherein at least 90% of the air
mass flow is led through the rotor gap in at least one operating
condition of the turbocharger.
99. A method according to claim 97, wherein the operating condition
is given at a rotational speed between 5000 and 300000 r.p.m of the
compressor wheel.
100. A method according to claim 97, wherein the operating
condition is given at a rotational speed between 40000 and 200000
r.p.m of the compressor wheel.
101. A method according to claim 97, wherein the operating
condition is given at a rotational speed between 40000 and 60000
r.p.m of the compressor wheel.
102. A method according to claim 97, wherein the operating
condition is given at a rotational speed between 50 and 20000 r.p.m
of the internal combustion engine supplied by the turbocharger with
fresh air.
103. A method according to claim 97, wherein the operating
condition is given at a rotational speed between 100 and 1500 r.p.m
of the internal combustion engine supplied by the turbocharger with
fresh air.
104. A method according to claim 97, wherein the operating
condition is given at a rotational speed between 2000 and 4000
r.p.m of the internal combustion engine supplied by the
turbocharger with fresh air.
105. The use of a turbocharger as a basic module of a micro-turbine
for a power/heat generation, the turbocharger including a
compressor arrangement compressing fresh air for an internal
combustion engine, the compressor arrangement including a
compressor wheel and an electric motor, the motor including a rotor
and a stator, wherein a rotor magnet of the rotor is one of
partially integrated and completely integrated into the compressor
wheel, and wherein a smallest inner diameter of the stator is
between 1.5- and 8-times as large as a largest outer diameter of
the rotor.
Description
[0001] The invention relates to a turbocharger.
[0002] Internal combustion engines with turbochargers are basically
known in the motor vehicle sector. Typically, an exhaust gas flow
out of the combustion engine is used to drive a turbine wheel. This
turbine wheel for example is coupled via a shaft to a compressor
wheel which ensures a compression of supplied fresh air in the
combustion space. Such a precompression or "charging" leads to an
increased engine power or increased torque compared to conventional
internal combustion engines. However, with internal combustion
engines charged in such a manner, there exists the problem of the
so-called "turbolag", which in particular occurs on running up and
accelerating from low rotational speeds of the vehicle, thus when
the internal combustion engine is to be rapidly accelerated into
regions of increased power. This is due to the fact that the
increased air quantity requirement on the air feed side may only be
provided with some delay (amongst other things caused by the
inertia of the system of the turbine wheel and compressor
wheel).
[0003] It is therefore the object of the present invention, to
provide a turbocharger which supplies precisely the correct
quantity of fresh air with the smallest possible delay, and which
furthermore is simple in its construction and is susceptible to
trouble as little as possible.
[0004] This object is achieved by the subject-matters of the
independent patent claims.
[0005] The invention relates to a turbocharger with a compressor
arrangement for compressing fresh air for internal combustion
engines, containing a compressor wheel as well as an electric motor
with rotor and stator, wherein a rotor magnet of the rotor is
designed such that it is partially or completely integrated into
the compressor wheel (thus the rotor magnet or rotor on the one
hand, and the compressor wheel on the other hand are connected to
one another) and the smallest inner diameter of the stator is 1.5-
to 8-times as large as the largest outer diameter of the rotor. The
specified lengths here, in each case relate to the largest
extensions or smallest extensions of the participating elements,
however only in the region of the electrically or magnetically
effective elements, i.e. for example only over a length of the
rotor magnet.
[0006] "Turbochargers" in the context of the present invention are
to be understood as all means which may lead precompressed air to
an internal combustion engine, by which means a larger air mass
gets into the combustion space. (A classic compressor wheel-turbine
wheel coupling is therefore not absolutely necessary).
[0007] The invention further relates to a turbocharger containing
at least one compressor wheel, wherein the compressor wheel may be
driven via at least one electric motor, and the electric motor
comprises a rotor, a stator, as well as a rotor gap between the
rotor and the stator, and the rotor gap is designed such that with
a rotating compressor wheel, at least 50%, preferably at least 90%
of the air mass flow to be compressed is led through the rotor
gap.
[0008] The mentioned percentage numbers in each case specify
minimum ranges. The percentage numbers here apply basically to the
whole rotational speed range of the turbocharger or an internal
combustion engine connected thereto.
[0009] In a particularly advantageous further formation, the
complete airflow which is led to the respective compressor wheel,
is led through this rotor gap.
[0010] The limitation with regard to the numerical values, amongst
other things, has the purpose of accordingly ruling out undesired
or "coincidental" leakage flows, as could occur in the state of the
art. A "recirculation flow" between the rotor and the stator with
subject-matter according to the state of the art, with which the
rotor is attached to the outer side of the compressor wheel, very
close to the stator, should however not be seen as an "air mass
flow to be compressed", since such "recirculation air" strictly
speaking has already passed the compressor wheel.
[0011] What is advantageous is an "integral" construction form,
with which a large part of the air mass flow to be compressed or
even the complete air mass flow to be compressed, is led to the at
least one compressor wheel through the rotor gap.
[0012] In contrast to the attachment of rotors on the radial outer
sides of the compressor wheel, it is advantageous to arrange the
rotor or its magnetically effective parts as close as possible to
the rotation axis of the compressor wheel. This on the one hand is
very favourable from a mechanical point of view with quickly
running turbochargers, since here, under certain circumstances,
mechanical damage could occur due to the very high and rapidly
changing centrifugal forces. What is also advantageous is the fact
that the rotation moments of inertia may be kept relatively small
in this manner, since magnets lying radially at the outside usually
have a high specific weight and thus a very high rotation moment of
inertia. The instationary behaviour of the compressor may be
considerably improved by way of this. Added to this is the fact
that with magnets lying at the outside on the compressor wheel,
these are also thermally loaded to a greater extent, since larger
temperature increases arise at these outer sides due to the
compression work, which in turn may have a negative effect on the
life duration of the magnets or the rotor.
[0013] Turbochargers are known from the literature, which are used
for the production of electricity. These turbochargers are designed
as small gas turbines and likewise have a turbine as well as a
rigidly coupled compressor. A conventional generator for the
production of electricity is flanged on the rotor shaft of the
turbine. The generator represents a very high flow resistance since
it is arranged within the intake tract, and this flow resistance
reduces the efficiency, and very high loads on the bearing
components simultaneously occur.
[0014] One advantageous further design of the turbocharger
according to the invention envisages this being used as a
microturbine for the power/heat cogeneration or the power/cooling
cogeneration. Thereby, the combustion air flows between the rotor
and stator of the electric motor/generator into the compressor, and
is compressed there and thus preheated to approx. 200.degree. C.
The preheated, compressed air is brought to a higher temperature
level by the hot exhaust gas in a heat exchanger. The compressed,
warm air together with a fuel e.g. regenerative gas, is combusted
in a combustion chamber which is arranged downstream. The hot gases
which thus arise, are expanded in the turbine and drive the turbine
wheel and thus the compressor as well as the generator. The thermal
energy of the exhaust gas, in the heat exchanger, is partly
directly dispensed to the compressed combustion air. Furthermore,
this turbocharger according to the invention may be coupled to a
second heat exchanger, in order to utilise the total residual heat
for the production of warm water, or to lead it to a heating
circuit e.g. for the heating and cooling a building. The generator
may be used as an electric motor for starting the process. Thus for
example, the inexpensive small block-type thermal power stations
may be produced with the turbocharger according to the invention,
whose essential components consist of components manufactured on a
large scale.
[0015] One advantageous further design envisages the mass of the
rotor magnets being between 5 g and 1000 g, preferably between 10 g
and 100 g for motor vehicle turbochargers. The mass moment of
inertia of the magnetically (actively) effective mass of the
electric motor with respect to the rotation axis of the rotor here
is between 0.1 kgmm.sup.2 and 10 kgmm.sup.2, preferably between 0.3
kgmm.sup.2 and 1.0 kgmm.sup.2, for motor vehicle applications.
[0016] Thus masses as well as mass moments of inertia of the
electrically or magnetically effective motor components are small
on account of the fact that relatively large air gaps are possible
with the rotor gap according to the invention, and a very
homogonous field arises despite this.
[0017] A further advantageous design envisages the compressor wheel
being mounted on a shaft and containing blades, wherein the front
edges of the blades (thus the section of the compressor wheel on
which the air first impinges), in the air inlet flow direction, lie
upstream with respect to a magnetically effective front section of
the rotor and/or a magnetically effective front section of the
stator.
[0018] This thus means that the active components of the electric
motor (rotor or stator) are arranged axially even more towards the
air inlet, and the actual compressor wheel is arranged downstream.
Amongst other things, by way of this, it is possible to lead the
entire inlet air to be led to the compressor wheel, through the
rotor gap.
[0019] However with regard to design, it is possible to apply the
rotor into the compressor wheel or even on the side of the
compressor wheel which faces the turbine wheel, in order to reduce
the bending moment on the compressor wheel, but despite this, to
primarily lead the air mass flow to be compressed, through the
rotor.
[0020] A mixed construction of several different rotor magnets at
different locations of the compressor wheel (in front of, within
and/or behind) permits an optimisation of the necessary
construction space with a simultaneous optimization of the motor
torque, and a reduction of the bending load of the impeller shaft.
Thereby, the shape of the rotor/stator does not necessarily have to
be circularly cylindrical, but is may also be adapted to the shape
of the compressor wheel.
[0021] The invention furthermore envisages a method for operation
of the turbocharger according to the invention. The turbocharger,
as mentioned above, comprises at least one compressor wheel for
compressing air, and the compressor wheel may be driven by an
electric motor, wherein a rotor gap is arranged between the rotor
and the stator of the electric motor, and at least 50%,
particularly preferably at least 90% of the air mass flow led to
the compressor wheel, is led through the rotor gap in at least one
operating condition of the turbocharger.
[0022] This "operating method" is already mentioned in the device
claims, and that which is mentioned there accordingly applies to
the operating method claimed here. What is important is that the
proportionate air mass flows of at least 50% or at least 90% or
even 100% mentioned above may be achieved in normal operation of
the turbocharger, for example in an operating condition, with which
the rotational speed of the compressor wheel is between 5000 and
300000 r.p.m, preferably between 40000 and 200000 r.p.m, or also
the rotational speed of a connected combustion engine is between 50
and 200000 r.p.m, preferably between 100 and 15000 r.p.m with
reciprocating engines.
[0023] It should be mentioned once again that a "turbocharger" in
the context of the present invention does not necessarily have to
contain a turbine wheel driven by an exhaust gas flow. What is
important is merely that at least one compressor wheel (driven by
whatever means) is contained for leading precompressed combustion
air to a combustion engine in the "turbocharger".
[0024] In a further design, the turbocharger according to the
invention contains a turbine wheel as well as a compressor wheel
connected thereto, wherein an electric motor is provided on the
side of the compressor wheel which is distant to the turbine wheel,
and a rotor of the electric motor which is connected to the
compressor wheel in a rotationally fixed manner, is designed in a
freely projecting manner.
[0025] Given an increased fresh air demand (e.g. ascertained by
control electronics), the electric motor serves for an additional
acceleration of the compressor wheel by the electric motor.
Electric motors are favourable for this, since these may be
accelerated with a large torque without a noticeable run-up
delay.
[0026] It is further advantageous that the electric motor in the
present case is not arranged between the turbine wheel and the
compressor wheel. Such an arrangement would lead to thermal
problems and represents a large design modification from
conventional (purely mechanical) turbochargers. Apart from the
increased design effort, the repair effort with such constructions
is considerable.
[0027] It is advantageous (but also not necessary within the
framework of the invention) that a sequence "turbine wheel, shaft
(mounting), compressor wheel, electric motor" seen in the axial
direction, is given in the present case. The electric motor is then
subjected only to the temperature of the surroundings, so that a
thermal decomposition of the stator winding etc. may not occur.
[0028] One advantage lies in the freely projecting end on the other
side of the compressor wheel. The rotor of the electric motor is
attached here. It is possible, but not absolutely necessary, to
attach a further bearing location here, in order to thus mount the
rotor on both sides. Such a bearing location on the one hand, under
certain circumstances, may upset the electrical characteristics of
the electric motor and under certain conditions would represent a
static redundancy. Furthermore, the friction work in the system is
increased. Moreover, under certain circumstances, the supply of
fresh air is also hindered by such a bearing, since suitable
struts/members reduce the inlet air opening in size towards the
compressor wheel. Such a bearing location, i.e. a mounting of the
compressor wheel axial on both sides, is however also easily
possible.
[0029] Furthermore, the design difference to purely mechanical
turbochargers is conceivably small with the "projecting" rotor, so
that an electric motor may be supplemented on conventional
turbochargers in this way, and in a very inexpensive, modular and
easily repairable manner.
[0030] The drive system according to the invention, apart from the
inventive turbocharger, comprises an internal combustion engine. An
"internal combustion engine" in the context of the present
invention is to be understood as any motor which requires fresh
air/fresh gas as well as produces exhaust gas, so that a suitable
turbocharger may be applied here. Furthermore, the drive system
also comprises a storage device for electrical energy. Here,
preferably the electric motor of the turbocharger is connected to
the storage device for electrical energy, for the removal of
electrical energy in a motor operation of the turbocharger, and for
feeding electrical energy in a generator operation of the
turbocharger.
[0031] The exhaust gas is blown away unused by up to 30% in many
operating conditions of a turbocharger (e.g. full load, thrust
operation etc.). The energy of this excess exhaust gas may be
energetically additionally utilised with the described embodiment
of the turbocharger, by way of using the electric motor as a
generator. In this manner, on the one hand excess "thermal/kinetic
energy" may be recovered as electrical energy, and the energy
balance of the drive system is considerably improved by way of
this. Ideally, the turbocharger may even be designed such that the
combustion engine located in the vehicle no longer requires any
additional dynamo.
[0032] It is also particularly advantageous with this drive system,
if the electric motor of the turbocharger or the electrical storage
device connected to it, may be additionally connected to an
electromotoric drive of a motor vehicle. This electromotoric drive
may for example be a hub electric motor (or another electric motor
provided in the drive train), which is fastened on a drive wheel of
the motor vehicle. In this manner, an additional provision of
torque or motor power is achieved on accelerating, in modern
so-called "hybrid vehicles", since apart form the internal
combustion engine motor, it is also the electrical hub motors which
are responsible for the acceleration. A braking effect and thus a
recovery of kinetic energy into electrical energy may be achieved
with braking procedures by way of the switch-over of the electrical
hub motors into generator operation, and this electrical energy is
intermediately stored in a suitable storage device. If the electric
motor of the turbocharger is now connected to this storage device,
then the complete electrical energy may be "managed" in a central
manner, in order to be able to fall back on this at any time, in a
useful manner.
[0033] Apart from this, it is of course also possible for the
turbocharger system and the electrical hub motors (or other motors
in the drive train), to have electrical storage devices which are
independent of one another.
[0034] The turbocharger according to the invention is furthermore
also suitable for the application in electricity production
installations which may be modulated and which may be operated with
fuels such as natural gas, liquid gas, heating oil as well as
regenerative gases such as bio-gas, sewage gas and waste gas, or
solid fuels such a chopped word, pieced wood material, straw, etc.
One may realise inexpensive installations for energy production
with a high efficiency by way of this type of power/heat
cogeneration. The turbocharger according to the invention may thus
also be used as a basic module of a microturbine for the power/heat
cogeneration.
[0035] Control electronics are preferably provided in the drive
system for the control of the electrical energy, the charging and
discharging procedure, or for providing an optimal torque, with a
low consumption. The rotational speed of the turbine wheel or
compressor wheel, actual values of the pressure conditions on the
turbine housing side and the compressor housing side, as well as
further characteristic variables for the internal combustion engine
of relevance to the torque, serve as control parameters.
[0036] One advantageous further design envisages the turbine wheel
and the compressor wheel being permanently connected to one another
in a rotationally fixed manner. This means that no coupling between
the turbine wheel and the compressor wheel is given, by which means
the mechanical construction and the susceptibility to failure of
the system would be increased. Instead of this, one strives to
limit the moved rotational masses by way of a light rotor, a light
compressor wheel, a light shaft and a suitably low-mass turbine
wheel.
[0037] The housing of the turbocharger is preferably constructed in
a modular manner, i.e. apart from a turbine housing for the turbine
wheel, there is also a compressor housing for the compressor wheel.
The turbine housing is preferably connected to an exhaust manifold
which leads exhaust gas from the individual cylinders of the
internal combustion engine, to the turbine wheel. The design
demands are somewhat different than with the compressor housing
which surrounds the compressor wheel, on account of the thermal
loading of the turbine housing. The actual mounting of the turbine
wheel and the compressor wheel preferably takes place exclusively
between the turbine wheel and the compressor wheel. This means that
no additional mounting is given on the side of the compressor wheel
which is distant to the turbine wheel, since it is indeed here that
the stator of the electric motor projects freely. Preferably, a
bearing housing is provided between the turbine housing and the
compressor housing, which serves for receiving bearing elements for
the turbine wheel and the compressor wheel.
[0038] The electric motor preferably contains a stator which has an
essentially hollow-cylindrical shape and which surrounds the rotor
in a concentric manner. Here, it is advantageous that the stator
may be designed as part of the inner wall of the compressor
housing. The stator may for example also be applied as an insert
into a corresponding opening of the compressor housing. The
advantage with these embodiments is the fact that only an as small
as possible design change of conventional mechanical turbochargers
is necessary, so that cost- and competitive advantages may be
realised by way of this, in particular with large-scale
production.
[0039] The rotor of the electric motor preferably has a rotor
magnet which is surrounded by a sheathing. The rotor magnet is
mechanically protected by way of this. One may also have an
influence on the type of magnetic field in this manner. The rotor
magnet may be designed such that it is partly or completely
integrated into the compressor wheel. If the compressor wheel
consists of fibre-reinforced or non-reinforced plastic, then on
production, the rotor magnet may be directly peripherally injected
with the plastic mass, by which means an inexpensive large-scale
manufacture is possible.
[0040] The sheathing of the rotor is preferably designed in the
manner of a "hollow cylinder".
[0041] It is advantageous with regard to manufacturing technology,
for the rotor magnet to be hollow in the inside in regions, for
placing on a common shaft with the compressor wheel. An inexpensive
manufacture is possible in this manner.
[0042] The compressor wheel consists preferably of a
non-magnetisable material which does not negatively compromise the
electromagnetic field. The compressor wheel may also be of a
non-metallic material, preferably of a reinforced or non-reinforced
plastic.
[0043] One further advantageous design envisages the rotor gap
between the rotor and the stator representing an (and specifically
the only intended) inlet air opening for the compressor wheel. This
in turn means that the electric motor hardly gets in the way of the
air feed flow, and that no additional air feed openings need to be
provided, which would unnecessarily increase the flow resistance.
It is therefore even possible for the inlet opening to be free of
struts between the rotor and stator. Here, such a provision of
struts is not necessary due to the omission of the "counter
bearing". Notwithstanding, such a "counter bearing" may be applied
with "classical turbochargers" with turbines, as well as with
turbochargers which are designed merely as one compressor stage
(for example with particularly high rotational speeds, critic
natural frequencies etc.).
[0044] The inlet opening may be provided with a large
cross-sectional area, depending on the dimensioning of the rotor or
stator. Preferably, the smallest inner diameter of the stator is
1.2- to 10-times, preferably 1.5- to 8-times, particularly
preferably 2- to 4-times the size of the largest outer diameter of
the rotor. The specified lengths here in each case relate to the
greatest extensions or smallest extensions of the participating
elements, but only in the region of the electrically or
magnetically effective elements (thus only over the length of the
rotor magnet for example) and a subsequent thickening (for example
in the region of the compressor wheel) is not important here. It is
sufficient for the values to be fulfilled in a single cross-section
(of a cross-sectional area).
[0045] A further advantageous further design envisages the
compressor wheel containing a conveyor structure in the form of
worms, blades or wings, wherein the front edges of the conveyor
structure, in the air inlet flow direction, lie upstream or
downstream with regard to a magnetically effective front edge of
the rotor magnet or a magnetically effective front edge of the
stator. In this context, "magnetically effective front edges" are
meant as the actual electrical and magnetic components, but without
insulating casings, etc. With this, one has the freedom to arrange
the stator or the rotor in a practically infinite manner with
respect to the compressor wheel, depending on the application case.
For example, the arrangement of the front edge of the rotor magnet
upstream with regard to the air inlet flow direction make sense, if
a compressor wheel of a metallic material is used. The electrical
or magnetic characteristics of the respective motor are
particularly favourable by way of the fact that the rotor magnet
projects out of the compressor wheel. If however, one demands a
minimisation of constructional space, then the rotor magnet may not
begin not until within a conveyor structure of the compressor
wheel. This for example lends itself if the conveyor structure
consists of a plastic material. The front edge of the stator may
likewise be arranged downstream or upstream with respect to a front
edge of the conveyor structure. Here, it is also considerations
with regard to construction space as well material which are at the
forefront.
[0046] A further (alternatively or cumulatively to that which is
mentioned here) construction envisages the compressor wheel
containing a conveyor structure in the form of blades, worms or
wings, wherein the rear edges of the conveyor structure in the air
inflow direction lie downstream or upstream with respect to a rear
edge of the rotor magnet and/or a rear edge of the stator. Thus the
elements "to be driven" may also be arranged partly downstream of
the conveyor structure, depending on the dielectric or magnetic
characteristics of the surrounding material, dimensions of the
rotor magnet or of the stator or of the compressor wheel/conveyor
structure. Particularly large or powerful stator arrangements or
rotor magnets here may also be designed so long, that they axially
project beyond the conveyor structure or the compressor wheel on
both sides (thus downstream and upstream).
[0047] A further advantageous design envisages the stator and/or
rotor being inclined with respect to an axis of the compressor
wheel.
[0048] This therefore means that the outer contour or the inner
contour of the rotor magnet or stator do not need to be cylindrical
or hollow-cylindrical, but that also other shapes may be given
here, for example truncated cone shapes or hollow truncated cone
shapes. With these inclined structures, the inventive diameter or
area relationships also only need to be realised in a single step,
in order to realise the inventive teaching of the patent.
[0049] A further advantageous design envisages the rotor magnet
being arranged radially outside the hub of the compressor wheel
with respect to the axis of the compressor wheel. This arrangement,
although not always desirable on account of the increased
mechanical and also thermal loading of the rotor magnet, however
provides for an even greater flexibility, for example the
possibility of a compact hub (for example the omission of the hub
in the ideal case) and of an additional airflow in the centre of
the compressor. For this, the compressor wheel may also be designed
such that air may be led radially within as well as radially
outside the rotor magnet. Here for example, one may imagine the
rotor magnet being designed in an essentially circularly annular
manner, but this however may also be realised by way of an
arrangement of several rotor magnets.
[0050] With regard to this, the compressor wheel may be designed
such that at least 50%, preferably at least 70%, particularly
preferably at least 90% of the air mass flow is led radially
outside the rotor magnet.
[0051] A particularly advantageous further formation envisages the
ratio of the cross-sectional area of the inlet opening to the
cross-sectional area of the rotor magnet (expressed with regard to
a formula: V.sub.QE=A.sub.inlet opening/A.sub.rotor magnet) being
between 0.5 and 100, preferably between 0.8 and 50, particularly
preferably between 0.8 and 50, particularly preferably between 2
and 20.
[0052] The primary work power of the media gap motor is the
delivery of media through the gap between the rotor and stator, or
as a generator, the drive by the delivery medium in the media
gap.
[0053] "Cross-sectional area of the inlet opening" is to be
understood as the actual open cross section in which air or a fluid
may be led. This is therefore the actual "net cross-sectional area
of the inlet opening" in this region. For example, with a
circularly round inlet opening, it is firstly assumed to be the
total circular area, but however the respective cross-sectional
area of the blades or the hub (including sheathing, rotor magnet
etc.) is subtracted for determining the net cross-sectional area.
The measure found here is thus a ratio of the actual rotor magnet
(with regard to area) to the actual cross section through which air
may flow.
[0054] The cross section applied for evaluating V.sub.QE preferably
runs through a region in which not only is the rotor magnet
present, but also a magnetically or electrically effective section
of the stator.
[0055] A further advantageous design envisages the ratio of the
cross-sectional area of the stator to the cross-sectional area of
the rotor magnet (expressed with regard to a formula:
V.sub.QS=A.sub.stator/A.sub.rotor magnet) being between 2 and 100,
preferably between 10 and 50. Here, it is in each case the "net
cross-sectional areas" of the electrically effective components of
the stator or rotor magnet which are to be specified. Insulating
components or components which are not electrically/magnetically
effective are not taken into account. Thus with a stator, a metal
base body (including copper windings for example) is taken into
account in the cross-section, but not a surrounding insulating
plastic. Accordingly, with regard to the rotor magnet, it is also
only the actually magnetically effective areas which are taken into
account, even if the rotor consists of different parts (the
individual areas are then to be added accordingly, so that one may
evaluate a total area of the rotor magnet).
[0056] The cross sections mentioned above preferably lie
perpendicular to the axis of the compressor wheel.
[0057] A further advantageous formation envisages the rotor being
connected to the compressor wheel, and the compressor wheel being
axially mounted on both sides. Here, the compressor wheel may or
may not be connected to a turbine wheel, what is merely important
is that the compressor wheel is axially mounted on both sides, thus
does not protrude.
[0058] A further advantageous design envisages the turbocharger
being designed merely as a compressor system with at least one
compressor wheel, and the at least one compressor wheel being
axially mounted on one or both sides. In this case, the compressor
wheel would therefore not be connected to the turbine wheel.
[0059] A further advantageous design envisages the turbocharger
comprising a turbine wheel and the compressor wheel, wherein the
electric motor is arranged on the side of the compressor wheel
which faces the turbine wheel or between the side of the compressor
wheel which faces the turbine wheel and the side which is distant
to the turbine wheel.
[0060] A further advantageous design envisages the smallest inner
diameter of the stator being 1.1 to 1.49-times, preferably 1.25 to
1.49 times larger than the largest outer diameter of the rotor.
[0061] A further advantageous design envisages the smallest inner
diameter of the stator being 8.01 to 15 times, preferably 8.01 to
12 times larger than the largest outer diameter of the rotor.
[0062] The specified lengths here in each case relate to the larges
extensions or smallest extensions of the participating elements,
however only in the region of the electrically or magnetically
effective elements (thus only for example of the rotor magnet) and
a subsequent thickening, for example in the region of the
compressor wheel, is not important here.
[0063] For reducing the current intensity and for increasing the
energetic efficiency, here the nominal voltage of the electric
motor may be more than 12 V, for example 24 or 48 V.
[0064] It is particularly advantageous for the electric motor to be
able to be switched over from motor operation into generator
operation. If the charging pressure (in the turbine housing)
reaches a certain nominal value, then additional energy is produced
whilst applying a converter capable of regeneration. Furthermore,
ideally by way of the energetic conversion of braking energy, one
may do away with a waste gate/pressure dose for blowing off excess
exhaust gas pressure.
[0065] The control of the motor/generator operation for the first
time permits the almost real-time, targeted closed-loop control of
the charging procedure. The rotational speed of the compressor as
well as the turbine wheel and thus the air mass flow may be
evaluated in an exact manner since the electric motor is preferably
controlled with a closed-loop via a frequency converter. The
control of the charging procedure of the internal combustion engine
is preferably integrated into the central motor control. With this,
it is possible to realise a charging which is controlled in the
input-output map. Thus, an exact adjustment and optimisation of the
combustion parameters (fuel quantity, air quantity, charging
pressure, exhaust gas return rate, ignition time etc) is possible,
by which means one may achieve a significant reduction in the fuel
consumption. This therefore represents an active extension of the
input-output map, by which means the energy balance of the
combustion engine may be considerably improved. This control loop
permits the closed-loop control and optimisation of the complete
combustion process within the combustion space of an internal
combustion engine.
[0066] Further advantageous designs are specified in the remaining
dependent claims.
[0067] The present invention is now explained by way of several
figures. There are shown in:
[0068] FIG. 1a a first embodiment of a turbocharger according to
the invention, in a part section;
[0069] FIG. 1b a section of the turbocharger from FIG. 1a,
according to A;
[0070] FIG. 1c a section of the turbocharger of FIG. 1a, according
to B;
[0071] FIG. 1d a part exploded drawing of the turbocharger of FIG.
1a;
[0072] FIG. 2a a second embodiment of a turbocharger according to
the invention, in a part section;
[0073] FIG. 2b a part-exploded view of the turbocharger shown in
FIG. 2a;
[0074] FIG. 3a an explanation of the proportions and arrangement of
the rotor magnet, stator and compressor wheel;
[0075] FIG. 3b an embodiment of a compressor wheel with an inclined
rotor and inclined stator;
[0076] FIGS. 4a to 4c an explanation of geometric relations with
regard to the turbochargers according to the invention.
[0077] FIGS. 5 and 6 a further embodiment of a turbocharger
according to the invention, as a microturbine for power
generation.
[0078] The basics of the invention are to be shown hereinafter by
way of the first embodiment according to FIGS. 1a to 1d.
[0079] FIGS. 1a to 1d show an electrically modified mechanical
turbocharger 1 which may be coupled to a turbine housing 5 on an
internal combustion engine. After the combustion, the exhaust gas
is collected by way of the exhaust gas fans shown in FIG. 1a and is
used for driving a turbine wheel 2. The turbine wheel 2 is
surrounded by the turbine housing 5 and is essentially deduced from
a conventional mechanical turbocharger. A bearing housing 7
connects to the turbine housing 5, and then a compressor housing 6.
A compressor wheel 6 is attached in this compressor housing 6, and
compresses the air fed through an inlet opening (this inlet opening
is in particular easily seen in FIG. 1c) and leads it to the
combustion space of the internal combustion engine in a manner
which is not shown here. The compressor wheel 3 on the left side in
FIG. 1a shows a continuation, to which a rotor 4a of an electric
motor is given. The rotor 4a is attached centrally in the inlet air
opening 4e. The air inlet flow direction 4e is indicated at LES in
FIG. 1a (here coaxially to the axis of the compressor wheel).
[0080] A stator 4b which has an essentially hollow-cylindrical
shape and is represented as part of the inner wall of the
compressor housing in the region of the inlet air opening, is
provided around the rotor 4a. Here, the stator 4b is even provided
as an insert into a suitable opening, so that this may be assembled
very easily. Here therefore, in FIG. 1a, the rotor gap between the
rotor 4a and the stator 4b is the inlet air opening 4e for the
compressor wheel. With this, the inlet air opening 4e is free of
struts between the rotor and the stator also according to FIG. 1a.
In the shown section, the smallest inner diameter of the stator
(see "d.sub.s" in FIG. 1d) is for example 1.5 times larger than the
largest outer diameter d.sub.R of the rotor (the drawing is
schematic and only for clarifying the size relations).
[0081] The rotor 4a of the electric motor 4 comprises a rotor
magnet 4c which here is surrounded by a sheathing (see e.g. FIG.
1d). With this, the sheathing is designed in an essentially
"beaker-shaped" manner, wherein the base of the beaker is almost
completely closed towards the compressor wheel (disregarding a
centric assembly bore).
[0082] The compressor wheel may (but need not) be of a non-metallic
material, here with one embodiment, for example of a non-reinforced
plastic, and the influence on the electromagnetic field of the
electric motor is minimised. The rotor magnet 4c in turn is hollow
in regions for placing on a common shaft with the compressor wheel.
Here, a bore 4c of the rotor magnet is to be accordingly seen in
FIG. 1d. Furthermore, it may be seen that a sequence of elements is
shown in the sequence of the rotor (consisting of the rotor magnet
4c and sheathing 4d), the compressor wheel 3, shaft 8, turbine
wheel 2, which minimises a thermal loading of the electric motor.
The shaft 8 here, in the present embodiment, is designed such that
the turbine wheel 2, compressor wheel 3 as well as rotor 4a are
firmly (rotationally fixedly) connected to one another, thus may
not be separated by a rotation clutch or free-wheel. However, it is
basically possible to provide such a clutch within the framework of
the present invention, if it is the case for example that the
turbine wheel 2 is very high, but however the design effort would
in turn also be increased by way of this.
[0083] The nominal voltage of the electric motor 4 in FIG. 1a here
is 12V, but other voltages (for example 48V for hybrid vehicles)
are also possible.
[0084] A turbocharger with a compressor arrangement for compressing
fresh air for internal combustion engines is shown in FIG. 1d,
containing a compressor wheel 3 as well as an electric motor 4 with
a rotor 4a and stator 4b, wherein a rotor magnet 4c of the rotor is
designed such that it is partially or also completely integrated
into the compressor wheel or is connected to this, and the smallest
inner diameter of the stator is 1.5- to 8-times larger than the
largest outer diameter of the rotor. The arrangement of the rotor
magnet, the stator or the compressor wheel is variable here in the
axial direction, and the later FIG. 3a is particularly referred to
with regard to this. The mass of the rotor magnet 3c (the total
mass, even if this is to consist of several parts) here is 50 g.
The mass moment of inertia of the rotor magnet with respect to the
axis of the rotor is 0.6 kgmm.sup.2.
[0085] The ratio of the cross-sectional area of the inlet opening
to the cross-sectional area of the rotor magnet (V.sub.QE) is 7:1.
The ratio of the cross-sectional area of the stator to the
cross-sectional area of the rotor magnet is for example
V.sub.Qs=16:1.
[0086] The electric motor may be operated in motor operation (for
accelerating and avoiding a "turbolag"), as well as in generator
operation (for recovering energy). If the charging pressure (in the
turbine housing) reaches a certain nominal value, then additional
energy is produced by way of using a converter capable of return
feed. Ideally, one may do away with a waste gate/pressure dose for
blowing out excess exhaust gas pressure, as is represented in FIG.
1b, numeral 9, by way of this energetic conversion of the braking
energy in generator operation.
[0087] The turbocharger according to the invention is used in a
drive system according to the invention for motor vehicles which
contains an internal combustion engine connected to the
turbocharger, as well as a storage device for electrical energy.
The electric motor of the turbocharger 1 here is connected to the
storage device for electric energy for taking electrical energy in
a motor operation of the turbocharger 1, and for feeding in
electrical energy in a generator operation of the turbocharger. In
a particularly preferred embodiment, the electric motor of the
turbocharger is connected to an electrical storage device, wherein
this electrical storage device is additionally connectable to an
electromotoric drive of a motor vehicle. This may be a "hub motor"
of a motor vehicle or another electric motor, which is provided in
the drive train of a motor vehicle (for example in the region of
the gear). This connection of the electrical turbocharger to a
hybrid vehicle is particularly energy efficient.
[0088] Control electronics for determining the rotational speed of
the turbine wheel 2 or the compressor wheel 3, actual values of
pressure conditions on the turbine housing side and compressor
housing side, as well as further values relevant to the torque for
the internal combustion engine are provided for the efficient
control of the drive system or the turbocharger.
[0089] The most important components of the first embodiment
according to FIGS. 1a to 1d are shown in FIG. 1d, at the top right
as a part exploded drawing. Here, it is to be seen that it is the
case of a turbocharger 1 which comprises a turbine wheel 2 as well
as a compressor wheel 3 connected thereto, wherein an electric
motor 4 is provided on the side of the compressor wheel which is
distant to the turbine wheel consisting of rotor 4a and stator 4b,
and a rotor 4a of the electric motor 4 which is connected to the
compressor wheel 3 in a rotationally fixed manner, is designed in a
freely projecting manner.
[0090] This "freely projecting" manner is advantageous, since the
design effort is reduced by way of this and for example a static
overdimensioning of the total mounting is avoided. "Freely
projecting" is to be understood as those arrangements with which
the rotor is not mounted in a separate and permanent manner.
Possibly provided "support cages" etc., which are to prevent a
bending of the freely projecting rotor which may be too large, for
example on account of bending resonance, are not to be seen in the
context of "bearings".
[0091] A second embodiment is shown in the FIGS. 2a and 2b. Here,
the rotor magnet 4c has been partially integrated into the
compressor wheel 3 on manufacture. The stator forms the inner
contour of the compressor housing.
[0092] The electric motor may be operated in motor operation (for
accelerating and avoiding a "turbolag") as well as in generator
operation (for recovering energy). If the charging pressure (in the
turbine housing) reaches a certain nominal value, then additional
energy is produced by way of using a converter capable of return
feed. One may do away with a wastegate/pressure dose for blowing
out excess exhaust gas pressure, as is represented in FIG. 1b,
numeral 9, by way of this energetic conversion of the braking
energy in generator operation.
[0093] FIG. 3a shows a schematic representation of the compressor
wheel 3, the stator 4b as well as the rotor 4c for illustrating the
geometric conditions. What is shown is the compressor wheel which
is mounted on a shaft 10 on one or on both sides, and is subjected
to flow in an air inlet flow direction LES. The air flow which
flows in, is accelerated by the compressor wheel 3 which comprises
a conveyor structure F. The front edge of the conveyor structure is
indicated at VF, and the rear edge of the delivery structure is
indicated at HF. The front edge of the rotor magnet 4c is indicated
at VR and the rear edge of the rotor magnet 4c is indicated at HR.
The front edge of the stator is indicated at VS, and the rear edge
of the stator is indicated at HS (the stator here is rotationally
symmetrical, but here the upper stator section has been shown for
reasons of a better overview). The compressor wheel 3 thus has a
conveyor structure F in the form of blades, wherein the front edges
VF of the conveyor structure, in the air inlet flow direction, lie
downstream with respect to a magnetically effective front edge of
the rotor magnet 4c and a magnetically effective front edge VS of
the stator. The compressor wheel with its rear edge HF in contrast,
in the air inlet flow direction, lie upstream with respect to the
rear edge HR of the rotor magnet 4c as well as the rear edge of the
stator 4b.
[0094] However, other arrangements are also possible here, with
which the rotor magnet or stator only project beyond one edge of
the compressor wheel, and it is also possible for the rotor magnet
to lie completely within the compressor wheel, and thus to be
laterally enclosed by the edges of the conveyor structure.
[0095] FIG. 3b shows a further embodiment, with which the stator 4b
(this is rotationally symmetrical with respect to the axis 10), is
inclined with respect to the axis 10. The stator thus here has
essentially the shape of a hollow truncated cone. The same also
applies to the rotor 4a or the respective rotor magnets, and this
too with its sections is inclined with respect to the axis 10 (thus
these are not parallel/co-linear, but would intersect in their
extensions).
[0096] The compressor wheel shown in FIG. 3b is mounted on both
sides (see indicated bearing locations L1 and L2). However, the
embodiment forms of the further figures may basically also be
mounted on both sides (even if this, under certain circumstances,
means more constructional effort).
[0097] With regard to FIG. 3b, it is the case that the rotor magnet
4c is arranged radially outside the hub of the compressor wheel
with respect to the axis 10 of the compressor wheel 3. The
compressor wheel here is designed such that air may be led radially
within, as well as radially outside the rotor magnet. Here, the
compressor wheel is also designed such that at least 70% of the
supplied air mass (or of the supplied air mass flow), is led
radially outside the rotor magnet.
[0098] FIGS. 4a and 4b serve for illustrating the evaluation of the
diameter dimensions with geometries which are not the same
throughout.
[0099] FIG. 4a makes it clear that the largest diameter d.sub.R of
the rotor is measured at the location at which this rotor (but only
in the region of the extension of the rotor magnet) has its
greatest extension. A later widening of the rotor in the region of
the compressor wheel 3 is not included, since the rotor magnet is
not led further there.
[0100] Accordingly, the stator is also measured at the narrowest
location (see d.sub.s) over which the respective electrically or
magnetically effective component of the stator extends (indicated
by the black bar which shows a laminated core with copper
wire).
[0101] FIG. 4b shows a closer illustration for cross sections which
are not circular. The "largest outer diameter" of the rotor magnet
is to be understood as the diameter which indicates the smallest
circumscribing circle around the whole rotor (see above description
with respect to 4a with regard to the axial positioning). The wavy
outer line shown in FIG. 4b is not circular, and the circumscribed
circle is essentially tangent to the projecting locations of the
outer rotor.
[0102] The same applies to the stator 4b, which likewise does not
have a circular shape. Here the largest inscribed circle, is
assumed with a diameter d.sub.5.
[0103] FIG. 4c once again shows a cross section through a stator 4b
and rotor 4a, according to the invention. Here one may see a rotor
magnet 4c which consists of individual segments (three distributed
over the periphery). Alternatively to this, one may also imagine
e.g. a cylindrical single magnet for example. A sheathing 4d is
attached around this rotor magnet 4c. In turn, a conveyor structure
F (here in section, therefore hatched) is shown on this sheathing.
An air passage or media passage opening 4e is given around the
conveyor structure and is surrounded radially to the outside by a
shielding 11 (this is of plastic and is magnetically/electrically
insulating). The electrically effective part of the stator 4b is
given around the shielding 11.
[0104] In the cross section shown in FIG. 4c, the cross-sectional
area of the media passage opening or the air passage or the inlet
opening 4e, to the cross-sectional area of the four segments of the
rotor magnet (defined as V.sub.QE=A.sub.inlet opening/A.sub.rotor
magnet)=4:1.
[0105] Here, the inlet opening 4e is defined as the opening which
may indeed be subjected to through-flow, thus the area content
within the sheathing 11, but minus the areas of the hatched
conveyor structure, as well as the hub of the rotor (the hub
includes the sheathing 4d as well as everything located therein).
What is meant here is the "net cross-sectional area" of the inlet
opening. The cross section in FIG. 5c visibly runs through the
electrically and magnetically effective section of the stator 4b.
In this cross section, the ratio of the cross-sectional area of the
stator to the cross-sectional area of the rotor magnet (defined as
V.sub.Qs=A.sub.stator/A.sub.rotor magnet)=13:1.
[0106] Here, only the electrically or magnetically effective part
(thus core metal+copper wire, however minus copper wire coating as
well as possible "hollow areas") is to be understood as the
cross-sectional area of the stator. Accordingly, it behaves as with
the rotor magnet, and here only the cross sections of the pure
rotor magnet segments in this cross section are applied.
[0107] The above-mentioned ratios for the relation of the smallest
inner diameter of the stator to the largest outer diameter of the
rotor, supplementarily to 1.5 to 8-fold, may also lie in other
intervals, specifically 1.1- to 1.49-fold, preferably 1.25- to
1.49-fold. Accordingly however, at the other end of the scale, the
smallest inner diameter of the stator may also be 8.01- to 15-fold,
preferably 8.01- to 12-fold the size of the largest outer diameter
of the rotor.
[0108] All turbochargers shown in the figures contain at least one
compressor wheel 3 for compressing air, and may be driven by the
electric motor 4, wherein a rotor gap is arranged between the rotor
4a and the stator 4b of the electric motor, and at least 50%,
preferably at least 90% of the air mass flow led to the compressor
wheel is led through the rotor gap in at least one operating
condition of the turbocharger. With the representations in the
Figures, this operating condition is given at a rotational speed
between 5000 and 300000 r.p.m, preferably between 40000 and 200000
r.p.m, mainly at 100000 r.p.m. The rotational speed of the crank
shaft of a connected reciprocating motor here is between 100 and
15000 r.p.m, preferably between 1500 and 8000 r.p.m., mainly for
example 25000r.p.m
[0109] FIGS. 5 and 6 show the turbocharger according to the
invention as a base module of a microturbine for the power/heat
cogeneration. FIG. 5 shows the basic construction, FIG. 6 an
explaining exploded view. An electric motor/generator is
characterised with the reference numeral 11, a recuperator with the
reference numeral 12, a heat exchanger with the reference numeral
13 and a heat storage device with the reference numeral 14. For
this reason, the important parts (rotor, stator, compressor wheel,
turbine wheel) are indicated with the same reference numerals in
the figures, as with the previous embodiment examples. The manner
of functioning, put in different words, is as follows (what is
important here is not primarily the function of the power/heat
cogeneration, but the fact that the turbocharger according to the
invention which here shows a compressor wheel and a turbine wheel,
may also be applied outside the car).
[0110] The combustion air flows completely between the rotor and
the stator of the electric motor/generator 11, into the compressor.
By way of the compression effected there to approx. 4 bar, the
combustion air already heats to approx. 200.degree. C. The heated
combustion air is led out of the compressor into a first heat
exchanger and is lifted to a temperature level of approx.
500.degree. c. by the hot exhaust gases flowing past. In a
combustion chamber arranged downstream, the combustion air is burnt
together with a fuel e.g. a regenerative gas. The hot gases which
arise in this manner, are expanded in the turbine and drive the
turbine wheel and thus the compressor and the generator. The
thermal energy of the exhaust gas is partly dispensed in the heat
exchanger directly to the compressed combustion air again.
Furthermore, this turbocharger according to the invention may be
coupled to a second heat exchanger, in order to utilise the total
residual heat for the supply of warm water, or may lead it to a
heating circuit, e.g. for heating and cooling a building. The
generator may be used as an electric motor for starting the
process. Thus for example with the turbocharger according to the
invention, one may for example produce inexpensive block power
plants whose essential components consist of components
manufactured in a large scale from the motor car industry. The
noise emission as well as the body sound transmission are avoided
in adjacent buildings on account of the low-oscillation running.
The module is also suitable as an auxiliary drive for producing
electricity in aircraft due to the compact construction and low
weight.
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