U.S. patent number RE38,671 [Application Number 09/962,992] was granted by the patent office on 2004-12-21 for method and apparatus for starting an engine having a turbocharger.
This patent grant is currently assigned to Visteon Global Technologies, Inc.. Invention is credited to Gurinder Singh Kahlon, Ning Liu, Robert Joseph Mohan.
United States Patent |
RE38,671 |
Kahlon , et al. |
December 21, 2004 |
Method and apparatus for starting an engine having a
turbocharger
Abstract
A system (40) for starting an internal combustion engine (12) of
an automotive vehicle (10) has a controller (54) coupled to a
starter/alternator (42). The engine (12) has a crankshaft (50) and
a turbocharger (24). The controller (54) initiates the starting of
the engine (12) by rotating the crankshaft (50). The rotating
crankshaft (50) displaces an amount of air from the cylinders (14)
of the engine (12) to rotate the rotor shaft of the turbocharger
(21). The turbocharger (25) thus draws in air, compresses the air
and provides the compressed air to the cylinders (14). When the
engine is started the initial power is increased due to the
compressed air.
Inventors: |
Kahlon; Gurinder Singh (Canton,
MI), Liu; Ning (Novi, MI), Mohan; Robert Joseph
(Canton, MI) |
Assignee: |
Visteon Global Technologies,
Inc. (Dearborn, MI)
|
Family
ID: |
23809856 |
Appl.
No.: |
09/962,992 |
Filed: |
September 25, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
455686 |
Dec 7, 1999 |
06233935 |
May 22, 2001 |
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Current U.S.
Class: |
60/605.1;
123/179.5 |
Current CPC
Class: |
F02B
37/18 (20130101); F02N 9/04 (20130101); F02N
11/04 (20130101); F02N 11/00 (20130101); Y02T
10/144 (20130101); Y02T 10/12 (20130101) |
Current International
Class: |
F02B
37/00 (20060101); F02N 11/00 (20060101); F02B
037/00 (); F02N 011/00 () |
Field of
Search: |
;60/605.1,607,608
;123/179.12,179.16,179.17,179.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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195 29 740 |
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Feb 1997 |
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DE |
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3-202632 |
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Sep 1991 |
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JP |
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4-342828 |
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Nov 1992 |
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JP |
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5-231163 |
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Sep 1993 |
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JP |
|
Primary Examiner: Koczo; Michael
Attorney, Agent or Firm: Kajander; John
Claims
What is claimed is:
1. A method of controlling the starting of an internal combustion
engine having a .[.starter.]. .Iadd.starter/alternator
.Iaddend.coupled to the crankshaft of the engine and a turbocharger
having a rotor, said method comprising the steps of: .Iadd.rotating
the crankshaft of the engine with the starter/alternator;.Iaddend.
rotating the rotor of the turbocharger to a predetermined speed;
and starting the engine when the turbocharger reaches the
predetermined speed.
2. A method as recited in claim 1 wherein the step of rotating the
rotor shaft comprises the step of generating a mass airflow from
the engine and coupling the mass airflow to said rotor shaft of the
turbocharger.
3. A method as recited in claim 2 wherein the step of rotating the
rotor shaft comprises rotating the crankshaft of the vehicle with a
.[.starter.]. .Iadd.starter/alternator .Iaddend.and wherein the
step of generating a mass airflow comprises the step of displacing
air by moving pistons coupled to the crankshaft.
4. A method as recited in claim 1 wherein the step of starting the
engine comprises the step of operating the fuel pump; and providing
fuel to cylinders of the engine.
5. A method as recited in claim 1 further comprising the step of
determining the approximate speed of the rotor shaft of the
turbocharger from the length of time that the crankshaft has been
rotated.
6. A method as recited in claim 1 further comprising the step of
generating power from the .[.starter.]. .Iadd.starter/alternator
.Iaddend.after the step of starting the engine.
7. A method of starting a vehicle with a starter, and a
turbocharger and an internal combustion engine comprising the steps
of: rotating the crankshaft of the engine with the starter; moving
pistons in a respective cylinder; displacing air into the exhaust
system with the piston; rotating a shaft of the turbocharger with
the displaced air to a predetermined speed; and starting the engine
when the turbocharger reaches the predetermined speed.
8. A method as recited in claim 7 wherein the step of rotating the
rotor shaft comprises the step of generating a mass airflow from
the engine and coupling the mass airflow to said rotor shaft of the
turbocharger.
9. A method as recited in claim 7 wherein the step of starting the
engine comprises the step of operating the fuel pump; and providing
fuel to cylinders of the engine.
10. A method as recited in claim 7 further comprising the step of
determining the approximate speed of the rotor shaft of the
turbocharger from the length of time that the crankshaft has been
rotated.
11. A method as recited in claim 7 further comprising the step of
generating power from the starter after the step of starting the
engine.
12. A system for an automotive vehicle comprising: an internal
combustion engine having a crankshaft coupled to pistons; a
turbocharger having a rotor shaft; a starter/alternator coupled to
the crankshaft; a controller coupled to the starter/alternator
initiating the rotation of said crankshaft to displace air from the
pistons and rotate the rotor shaft of said turbocharger, said
controller starting said engine upon the rotor shaft reaching a
predetermined speed.
13. A system as recited in claim 12 further comprising a fuel
pump.
14. A system as recited in claim 13 wherein said controller
operating said fuel pump during starting the engine.
15. A system as recited in claim 12 wherein said starter is a
starter/alternator.
16. A system as recited in claim 12 further comprising a speed
sensor coupled to the shaft of the turbocharger.
17. A system as recited in claim 12 further comprising a power
inverter coupled to said starter.
18. A system as recited in claim 12 further comprising an energy
storage device coupled to said power inverter.
Description
TECHNICAL FIELD
The present invention relates generally to internal combustion
engines for automotive vehicles, and more specifically, to an
automotive vehicle having a starter/alternator and a turbocharger
coupled to the engine.
BACKGROUND
Automotive vehicles with internal combustion engines are typically
provided with both a starter motor and alternator. In recent years,
a combined alternator and starter motor has been proposed. Such
systems have a rotor mounted directly to the crankshaft of the
engine and a stator sandwiched between the engine block and the
bell housing of the transmission. During initial startup of the
vehicle, the starter/alternator functions as a starter. While
functioning as a starter, the starter/alternator rotates the
crankshaft of the engine while the cylinders are fired.
After the engine is started, the starter/alternator is used as a
generator to charge the electrical system of the vehicle.
Many vehicles have turbochargers incorporated with the engine.
These turbochargers are commonly referred to as exhaust-gas
turbochargers. A turbocharger consists of two machines: a turbine
and a compressor mounted on a common shaft. The turbine is coupled
to the exhaust system and uses the energy obtained in the flow of
the exhaust system to drive the compressor. The compressor in turn,
draws in outside air, compresses it and supplies it to the
cylinders. The compressed air increases the power output of the
engine.
Exhaust gas turbochargers operate using the mass flow of the
exhaust gas. Thus, some time is associated with providing enough
exhaust gas to rotate the turbocharger at a sufficient speed to
provide compression at the output of the turbocharger. Such time is
typically referred to as turbo lag. During turbo lag the engine
output power is less than that when the turbocharger is
operating.
In foreseeable automotive applications, the engine may be shut down
during stops (e.g., red lights). When the accelerator is depressed,
the starter/alternator starts the motor and the engine will resume
firing. Thus, many startups may occur over the course of a
trip.
It would therefore be desirable to reduce the amount of turbo lag
and thus increase the amount of power of the engine during
startup.
SUMMARY OF THE INVENTION
It is therefore one object of the invention to increase the power
output of the engine during startup.
In one aspect of the invention, a method of controlling the
starting of an internal combustion engine having a starter coupled
to the crankshaft of the engine and a turbocharger comprises the
steps of: rotating the shaft of the turbocharger to a predetermined
speed and starting the engine when the turbocharger reaches the
predetermined speed.
In a further aspect of the invention, a system for an automotive
vehicle comprises an internal combustion engine having a crankshaft
coupled to pistons. A turbocharger has a rotor that is fluidically
coupled to the pistons. A starter/alternator is coupled to the
crankshaft of the engine. A controller is coupled to the
starter/alternator to initiate the rotation of the crankshaft to
displace air from the pistons and rotate the rotor of the
turbocharger. The controller starts the engine upon the rotor
reaching a predetermined speed.
One advantage is that power from the engine may be increased at
startup.
Other objects and features of the present invention will become
apparent when viewed in light of the detailed description of the
preferred embodiment when taken in conjunction with the attached
drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of an automotive vehicle having a
starter/alternator system according to the present invention.
FIG. 2 is a schematic view of a piston of the engine with a
turbocharger fluidically coupled thereto.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is described with respect to a particular
configuration of a starter/alternator. However, the teachings of
the present invention may be applied to various starters for
internal combustion engines.
Referring now to FIG. 1, an automotive vehicle 10 is illustrated
having an internal combustion engine 12 having cylinders 14 with
pistons 16 located therein. Each cylinder 14 is coupled to a fuel
pump 18 through a fuel injector (not shown) or other fuel delivery
system. Each cylinder 14 also has a spark plug 20 or other ignition
source coupled to a powertrain control unit. A powertrain control
unit 22 controls the ignition timing and fuel pump operation 18 in
a conventional manner subject to the improvements of the present
invention.
Engine 12 has a turbocharger 24 coupled to the exhaust system
(shown below in FIG. 2) of engine 12. Thus, turbocharger 24 is
commonly referred to as an exhaust gas turbocharger. Also, the
present invention applies to superchargers as well. Turbocharger as
used herein refers to both.
Engine 12 is coupled to a transmission 26. Transmission 26 may be
automatic, manual or continuously variable. Transmission 26 is
coupled to a differential 28 to drive an axle 30 to provide power
to wheels 32. Of course, the present invention is also applicable
to four wheel drive systems in which all of the wheels 32 are
driven. A starter/alternator system 40 that includes a
starter/alternator 42 and its associated control electronics is
coupled to engine 12. In the present invention, starter/alternator
42 is positioned between a housing 44 of transmission 26 and the
engine 12. Starter/alternator 42 has a stator fixedly attached to
bell housing 44 and a rotor 48 coupled to a crankshaft 50 of engine
12. A clutch 52 is used to engage and disengage engine 12 from
transmission 26. As will be further described below,
starter/alternator 42 is used as a starter during engine startup
and as an alternator to supply power to recharge the batteries of
the vehicle and to supply electrical loads. Clutch 52 allows
starter/alternator 42 to start the engine prior to engagement of
the transmission.
Starter/alternator system 40 has a system controller 54 that is
coupled to powertrain control unit 22 and to a power inverter 56.
In practice, the power inverter 56 and system controller 54 may be
contained in a single package. The inverter 56 is used to convert
DC power to AC power in the startup mode and AC power to DC power
in power generation mode as will be further described below.
Power inverter 56 is coupled to an energy storage device 58 such as
an ultra capacitor, a first DC to DC converter 60, and a second DC
to DC converter 62. DC to DC converter 60 is coupled to a 36 volt
battery 64. DC to DC converter 62 is coupled to a 12 volt battery
66. Of course, the actual battery voltage is dependent on the
particular system to which it is attached.
Referring now to FIG. 2, a turbocharger 24 is shown coupled to an
exhaust system 70 of engine 12 with cylinders 14 and a piston 16.
Only one cylinder 14 and piston 16 is shown for simplicity. Piston
16 is coupled to crankshaft 50. Gasses are input and exhausted from
cylinders 14 by valves 71, 72, respectively. Although two valves
are illustrated, the present invention applies to multi-valve
engines. Turbocharger 24 is also coupled to an air intake system
74. A waste gate 76 having a piston 78 may be used to control the
pressure into turbocharger 24 by diverting an amount of exhaust gas
as is commonly known in the art. Waste gate 76 is a bypass around
turbocharger 24.
Turbocharger 24 has a common rotor shaft 80 that couples the
turbine portion 82 to compressor portion 84 of turbocharger 24. As
gasses move from within cylinder 14 through exhaust system 70, the
turbine portion 82 is caused to rotate which in turn through rotor
shaft 80 causes compressor portion 84 to rotate. Compressor portion
84 draws in external air through a filter element 86 of an air
induction system and compresses the air to force the air into
cylinder 14. This compression causes the power output of engine to
increase. However, the power is not increased until a sufficient
amount of airflow through exhaust system 70 is established. In
prior systems, the airflow was exhaust gasses.
In certain operating conditions of a motor vehicle, it may be
desirable to provide a greater amount of power from engine upon
startup. The present invention is particularly applicable to
systems in which the engine is completely shut down when the
vehicle is at rest, such as at a stop light. In such a system, upon
immediate depression of the acceleration pedal a great amount of
power is required. The starter/alternator provides the required
power in a substantially shorter time then the engine firing.
In operation, the rotor shaft 80 of the turbocharger 24 is spun to
provide power upon startup of the vehicle. The rotor shaft 80 of
turbocharger 24 is rotated to a predetermined speed that allows the
compressor portion 84 to increase the power of the engine. The
starting process of engine 12 is initiated by a key placed in the
ignition position or the depression of the accelerator pedal (not
shown). Thirty-six volt battery 64 provides electrical power for
starter/alternator 42 which is stepped up to 300 volts by DC to DC
converter 60. The 300 volts is used to charge energy storage 58.
Inverter 56 converts the DC power to three-phase AC power. The AC
power is supplied to the stator 46 of starter/alternator 42. The
starter/alternator 42 rotates rotor 48 which in turn rotates
crankshaft 50 of engine 12. During the startup process, the valves
71, 72 are alternately placed in the open position and closed
position depending on the position of the crankshaft which in turn
is coupled to the camshaft (not shown) driving the valves. The
rotation of crankshaft 50 and thus the movement of the pistons 16
causes an amount of air to be displaced into exhaust system 70.
The starter/alternator 42 is used to displace a sufficient amount
of air (i.e., mass airflow) to turn rotor shaft 80 by rotation of
the turbine portion 82 of turbocharger 24. The compressor portion
84 in turn compresses intake air and provides it to cylinder 14. As
rotor shaft 80 turns, the power input to engine 12 will be
increased upon startup of the engine. When the rotor shaft 80 of
turbocharger 24 reaches a predetermined speed, the engine 12 is
started by supplying fuel through fuel pump 16 and controlling the
spark timing through spark plugs 20 through powertrain control unit
22. Thus, as the engine is started, the turbocharger is increasing
the power to engine 12. The speed of rotor shaft 80 may be measured
directly by using a sensor 90 coupled to rotor shaft 80. Thus, upon
rotor shaft 80 reaching a sufficient speed, the controller 54 may
trigger the starting of the combustion process in the engine.
Another method for determining the approximate speed of rotor shaft
80 is by inferring the speed by the amount of time that the engine
and thus the pistons 16 have been displacing air into the exhaust
system 70. Because the cylinders 14 contain a predetermined volume,
the volume and thus the mass airflow of air into the turbine
portion 82 of turbocharger 24 may be inferred. The time may be
measured by system controller 54.
Once the turbo rotor is turning at a sufficient speed and the
engine combustion process is initiated, the starter/alternator 42
is used in a generating mode. In the generating mode, the energy
storage system 58, and batteries 64, 66 are monitored to determine
whether they are fully charged. If any of the energy storage
sources drop below a predetermined range, three-phase power from
starter/alternator 42 is converted to 300 volts DC by power
inverter 56. DC to DC converters 60, 62 are used to convert the 300
volts DC to 42 volts and 14 volts respectively. It should be noted
that the ultra capacitors of energy storage 58 are charged directly
by power converter 56.
While particular embodiments of the invention have been shown and
described, numerous variations and alternate embodiments will occur
to those skilled in the art. Accordingly, it is intended that the
invention be limited only in terms of the appended claims.
* * * * *