Planetary gear transmission systems or components – Input from independent power sources – Including electric motor input
Reexamination Certificate
2000-08-22
2002-04-16
Estremsky, Sherry (Department: 3681)
Planetary gear transmission systems or components
Input from independent power sources
Including electric motor input
C180S065700
Reexamination Certificate
active
06371878
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to transmissions and more particularly to an electric continuously variable transmission for improving hybrid vehicle efficiency.
BACKGROUND OF THE INVENTION
The powertrains of conventional vehicles are designed to provide more power than required for the vehicle at cruising speeds. Specifically, the engine of conventional vehicles is larger than required to provide power for acceleration and hill climbs. This extra power is not required once the vehicle is at cruising speed. As a result, conventional vehicle powertrains are inefficient.
Therefore, it is desirable to have an improved vehicle powertrain for implementation in a vehicle, such as a hybrid vehicle, which overcomes inefficiencies inherent in a conventional powertrain.
Additionally, various types of continuously variable transmissions (CVTs) have been developed throughout the years. The object of a CVT is to provide a continuously variable drive ratio from a transmission enabling an engine to run at an optimum point on a brake specific fuel consumption curve. Essentially, CVTs aim at improving engine efficiency by enabling the engine to continuously run at its most efficient point. Due to the significant complexity, traditional CVTs have posed problems in both implementation and application. Traditional belt drive-type CVTs are also inefficient in that significant parasitic losses occur in achieving continuously variable transmission ratios. Moreover, such devices are power limited.
Therefore, it is desirable in the industry to provide an improved CVT for implementation in a vehicle, such as a hybrid vehicle, which overcomes the deficiencies of traditional CVTs.
SUMMARY OF THE INVENTION
In achieving the above identified objectives, the present invention provides an electric continuously variable transmission comprising an input shaft and an output shaft in mechanical communication with first and second planetary splitters. A first electric motor/generator selectively drives the first planetary splitter or generates electrical energy from the first planetary splitter. A second electric motor/generator selectively drives the second planetary splitter or generates electrical energy from the second planetary splitter. A lock-up clutch or brake is in mechanical communication with the first planetary splitter for selectively locking a sun gear of the first planetary splitter. A low range is achieved by feeding electrical energy from the second electric motor/generator to the first electric motor/generator for driving the first planetary splitter. A mid range is achieved by feeding electrical energy from the first electric motor/generator to the second electric motor/generator for driving the second planetary splitter. A high range, or overdrive, is achieved by engaging the brake. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.
REFERENCES:
patent: 5558589 (1996-09-01), Schmidt
patent: 6041877 (2000-03-01), Yamada et al.
patent: 6053833 (2000-04-01), Masaki
patent: 6083138 (2000-07-01), Aoyama et al.
patent: 6083139 (2000-07-01), Deguchi et al.
patent: 6090005 (2000-07-01), Schmidt et al.
patent: 6098733 (2000-08-01), Ibarak et al.
patent: 6110066 (2000-08-01), Nedungadi et al.
Estremsky Sherry
Harness & Dickey & Pierce P.L.C.
New Venture Gear Inc.
LandOfFree
Electric continuously variable transmission does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electric continuously variable transmission, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electric continuously variable transmission will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2892943