Patent Application
20140031158
The present invention relates to automatic transmissions for motor vehicles, specifically for automatic transmissions for electric-gasoline hybrid engines (“hybrids” or “hybrid engines”) and more specifically for automatic transmissions adapted for hybrid engines.
Electric-gasoline hybrid vehicles usually need unique drivetrains and transmissions to obtain maximum efficiency from that type of engine. Typical hybrid drivetrains are either “starter/alternator” drivetrains or unique drivetrains manufactured for a one or a few specific vehicle models. The disadvantage of a starter/alternator drivetrain is that it cannot be operated in an “electric only” mode in which the electric motor alone drives the car. Thus the gasoline engine is always engaged with the drivetrain during braking and energy recovery mode.
The primary drawback of unique hybrid drivetrains, such as found in the Toyota Prius is its expense. These drivetrains require unique transmissions and two distinct electric motors.
Thus, there is a need in the field for a transmission that is inexpensive, that is operable with a single electric motor, possesses an operation mode in which the electric motor is engaged with the drivetrain during braking and energy recovery mode and can be operated only with the electric motor.
The present invention broadly comprises an automatic transmission for a hybrid motor vehicle having at least one planetary gear set and comprising a single electric motor/generator having a motor output shaft; a combustion (hydrocarbon fueled) engine; a first one transmission input shaft; a lockup (engine) clutch wherein the engine clutch operatively attaches the combustion engine to the first engine transmission input shaft; a motor/generator clutch; a plurality of transmission clutches; and, a plurality of transmission clutch brakes.
In at least one embodiment, the motor clutch is a dog clutch.
In an alternate embodiment, the motor clutch is a friction clutch.
In a second alternate embodiment, the engine clutch is replaced by a torque converter.
In various embodiments, the combustion engine may be fueled by gasoline, diesel fuel, and/or natural gas.
One object of the invention is to modify existing automatic transmissions to include a hybrid transmission capability with a single electric motor.
A second object of the invention is to supply a less expensive hybrid transmission.
A third object of the invention is to provide hybrid transmissions that possess different modes of operation.
The nature and mode of the operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing Figures, in which:
At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical structural elements of the invention. It also should be appreciated that figure proportions and angles are not always to scale in order to clearly portray the attributes of the present invention.
While the present invention is described with respect to what is presently considered to be the preferred embodiments, it is understood that the invention is not limited to the disclosed embodiments. The present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Furthermore, it is understood that this invention is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. It should be appreciated that the term “substantially” is synonymous with terms such as “nearly”, “very nearly”, “about”, “approximately”, “around”, “bordering on”, “close to”, “essentially”, “in the neighborhood of”, “in the vicinity of”, etc., and such terms may be used interchangeably as appearing in the specification and claims. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described. It should be appreciated that the term “proximate” is synonymous with terms such as “nearby”, “close”, “adjacent”, “neighboring”, “immediate”, “adjoining”, etc., and such terms may be used interchangeably as appearing in the specification and claims.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described.
The present invention is directed to modifications of an automatic transmission for a motor vehicle in is equipped with at least one planetary gear system. The modifications add a hybrid functionality to the transmission by adding an electric motor or preferably a motor/generator and accompanying inputs to the transmission.
Adverting to the drawings,
The gear sets 30, 32, and 34 are connected to transmission clutches (Cxxx) and transmission clutch brakes (CBxxx) to connect and brake the various planetary gear elements to transmit torque from input shaft 24 to output gear 36. The clutches and brakes engage and disengage as different drive gears are operated as explained below.
In mode b, motor/generator mode, motor clutch 42 is arranged to engage motor shaft 44 with engine transmission input shaft 24a and also engage a second transmission input shaft, motor transmission input shaft 24b which is functionally attached to sun gear 32a. When engine clutch 16 is disengaged only motor 40 provides torque to transmission 10 for an electric drive mode. When motor clutch 42 is in the same position and engine clutch 16 is engaged (i.e., when battery power is low), the main driving power is provided by engine 12 and motor/generator 40 can boost the gasoline engine, recover braking and coasting energy and charge the battery (not shown). By functional attachment is meant that the attachment between motor transmission input shaft 24b and sun gear 32a allows drive power to be supplied to sun gear 32a enabling sun gear 32a to function. Engine clutch 16 may be selectively disengaged to increase efficiency of energy recovery from braking and coasting.
In engine drive mode c, motor clutch 42 connects the two transmission input shafts 24a and 24b with motor shaft 44 disengaged. In this mode, only engine 12 provides driving power to transmission 10 and no energy recovery is made from braking or coasting. The transmission operates as a conventional transmission in this mode, which may be useful as a towing mode or as a ‘limp home’ mode after a failure of the motor, batteries, or electric controls, for example.
Mode d is the hybrid drive mode in the modification shown in
In start engine mode c′, motor clutch 42 connects engine 12 and torque converter 18 with motor/generator 40 through torque converter output shaft 12a and motor shaft 44. In mode c′, lockup clutch 16a is engaged. In hybrid mode d′, motor clutch 42 connects transmission input shaft 24 with torque converter output shaft 12a while motor shaft 44 is connected with input gear set 32. In the hybrid mode d′, motor 40 inputs power to gear set 32, preferably sun gear 32a to power transmission 10 in the lower gears with engine 12 powering transmission 10 through torque converter 18 and torque converter output shaft 12a to gear set 30 preferably using an infinite variable transmission system.
In all the modifications described above, transmission 10 includes clutches (Cxxx) and clutch brakes (CBxxx) in line with the output from gear sets 30, 32, and 34. Also seen in is one way clutch OWC.
The motor clutches can be controlled and moved into the various mode positions discussed above using hydraulic systems as in automatic transmissions or by using electronic actuators. These systems can be controlled by the on board vehicle computer.
Thus it is seen that the objects of the invention are efficiently obtained, although changes and modifications to the invention should be readily apparent to those having ordinary skill in the art, which changes would not depart from the spirit and scope of the invention as claimed.
This applications claims the benefit under 35 U.S.C.§119(e) of U.S. Provisional Application No. 61/677,145, filed Jul. 30, 2012, which application is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61677145 | Jul 2012 | US |
