Hybrid powertrain

Details Hybrid powertrain Hybrid powertrain

2000-04-21

2004-05-25

Ho, Ha (Department: 3681)

Interrelated power delivery controls, including engine control

Electric engine

With clutch control

C477S003000, C477S005000, C475S005000

Reexamination Certificate

active

06740002

ABSTRACT:

TECHNICAL FIELD
The present invention is concerned with hybrid powertrains for vehicles, i.e. the combined devices needed for propelling vehicles including engines, motors, mechanical transmission means such as shafts, gears, axles, etc., and finally the exterior driving devices such as wheels and tires acting by friction on a surface of the ground such as that of a road.
BACKGROUND
A powertrain or drive train for a vehicle generally comprises some kind of motor or thermal or heat engine producing a mechanical force or torque and some transmission means converting the force or torque to a movement of the vehicle. The transmission means thus normally comprise a gear box or generally some mechanical conversion means, the wheels of the vehicle and various shafts from the motor and between the components of the transmission means. Such powertrains for vehicles can use a one or two electric motors which are capable of driving the vehicle at least at moderate power levels using energy stored in an electric energy storage unit such as an electrochemical accumulator and at the same time such a powertrain can use a thermal engine to charge the electrical storage system and to possibly supply extra power during time periods when high power levels are required. Alternatively the thermal engine can ordinarily drive the vehicle and simultaneously charge the energy storage, from which power is supplied to an electric motor when extra driving power is required. This kind of powertrains using two different motors of quite different types is called hybrid powertrains.
Classical hybrid powertrains comprise two basic types, the serial type, the construction of which is schematically illustrated in
FIG. 1
, and the parallel type, the construction of which is schematically illustrated in FIG.
2
.
In the SEV (“Serial Hybrid Vehicle”) system illustrated in
FIG. 1
, an electric motor
101
directly drives the wheels
108
of a vehicle and thus provides all of the power required by the wheels for propelling the vehicle. The electric motor receives electric power from an accumulator
104
. At high power levels, the thermal engine
103
is activated to drive a generator
102
and thus adds through the generator additional power to the accumulator, this additional power being the difference between the power required by the electric motor and the power which can be directly taken from the accumulator. At least for longer trips, the thermal engine
103
and the generator
102
will when required charge the accumulator
104
and thereby supply most of the power required by the electric motor
101
for driving the wheels.
In most applications, a mechanical reduction
105
is used to allow the use of electric motors
101
having a lower torque and a higher speed than what is normally required for driving the wheels
108
. The mechanical reduction
105
is thus connected between the electric motor
101
and the wheels
108
. However, the electric motor
101
must be dimensioned to provide all the power required by the wheels at all times, and a torque which varies linearly with the torque of the wheels.
Serial hybrid vehicle systems of the kind described above are often designed to use small thermal engines which are dimensioned to be capable of providing little more than the average power required for driving the vehicle on a horizontal highway at high speeds, such as in typical designs about some 10 kW. This permits the thermal engine to work either at an optimum load point or not at all, thereby keeping its average efficiency close to an optimum point. During accelerations and short inclinations a much higher power is taken from the accumulator, which can be an electro-chemical battery, a flywheel, a supercapacitor, etc. Long heavy inclinations require a high power over a long time period for driving the vehicle, what in turn either requires a thermal engine having a high output power or an accumulator having a high energy content.
In the PHV (“Parallel Hybrid Vehicle”) system as schematically illustrated by the block diagram of
FIG. 2
a thermal engine
203
is connected to convey a torque to the differential gearing and wheels
208
through a disengageable clutch
207
and a gearbox
206
. The gearbox
206
can also receive input torque from an electric generator/motor
201
through an optional mechanical reduction
205
. The electric generator/motor receives its input power from an energy storage unit or accumulator
204
. The torques provided by the thermal engine
203
and the electric generator/motor
201
are thus both input to the gearbox, this implying that also torque can be provided from e.g. the thermal engine
203
to the electric generator/motor
201
, when there is sufficient power available in the thermal engine. In such cases the accumulator can be charged by the electric generator/motor which then operates as a generator.
Generally, the accumulator
204
and the electric generator/motor
201
and its electronic drive circuits, not shown, have to provide a power being the difference between the power required for driving the wheels and the power which is provided by the thermal engine
203
. In many applications, a mechanical reduction
205
is used to allow the use of electric motors having a lower torque and a higher speed than those provided by the thermal engine.
When the thermal engine
203
is switched off it is also disconnected from the wheels by operating the clutch
207
. All of the traction power is in this case supplied from the energy storage
204
through the electric motor
201
which can also work as an electric generator. The energy storage
204
can, as has already been mentioned, be charged by the thermal engine
203
while the vehicle is running. The parallel hybrid vehicle system as described above has the disadvantage that the speed of the thermal engine
203
is dependent on the speed of the tires of the wheels and the setting of the gearbox
206
and therefore the thermal engine has a non-constant speed during running and then also during charging the energy storage or accumulator
204
. The torque of the thermal engine
203
can however be maintained at a suitable value by selecting a suitable torque (positive or negative) for the electric generator/motor
201
. As the engine will loose its load as soon as the clutch is disengaged, the torque of the thermal engine
203
must change quickly as soon as a gearshift is performed. For many thermal engine designs, this operation in addition causes high peaks of environmentally unwanted emissions.
Parallel hybrid vehicle systems are disclosed in U.S. Pat. Nos. 4,533,011, 5,337,848, 5,492,189 and 5,586,613.
In
FIGS. 3
a
and
3
b
block diagrams of two hybrid systems are shown which can be described to be mixtures or combinations of the serial hybrid vehicle systems and the parallel hybrid vehicle systems as described above. Employing the terms used in the published European patent application EP 0 744 314 A1 they can be called PSHV (“Parallel Serial Hybrid Vehicle”) systems.
The parallel serial hybrid vehicle system illustrated by the block diagram of
FIG. 3
a
is described in the cited EP 0 744 314 A1, see the description of
FIG. 9
in this document. The system according to
FIG. 3
a
has the advantage that it to some extent can use both the advantages of a serial hybrid vehicle system and a parallel hybrid vehicle system. Here the thermal engine
303
has an electric generator/motor
309
directly mechanically coupled to its output shaft, not shown. To the output shaft is also an electric motor
301
connected but through a clutch
307
. The output shaft thus drives through the clutch
307
, when it is engaged, the differential gearing and the wheels
308
. The electric generator/motor
309
and the electric motor
301
can when required be powered by the electric energy storage
304
and the electric generator/motor
309
can also charge the energy storage.
When the clutch
307
is disengaged and freely running, the vehicle system of
FIG. 3
a
acts as an SHV system and gives a constant or slowly varying load o

Affiliated with

Also associated with

Rating

Hybrid powertrain does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Hybrid powertrain, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hybrid powertrain will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3195514