METHOD AND APPARATUS FOR POWER FLOW MANAGEMENT IN ELECTRO-MECHANICAL TRANSMISSIONS
First Claim
1. A power transmission system for regulating the delivery of power to a drive shaft, said power transmission system comprising:
- an engine having an output shaft;
a pair of planetary trains operatively coupled between said output shaft and said drive shaft for transmitting power output from said engine to said drive shaft, each of said planetary trains including a sun member, a ring member, a set of planet members, and a planet carrier;
a first electric machine linked with at least said one member of a first planetary train in said pair of planetary trains for receiving and transmitting power to and from said drive shaft;
a second electric machine linked with said one member of a second planetary train in said pair of planetary trains for receiving and transmitting power to and from said drive shaft;
a set of torque transfer components operatively coupled to said pair of planetary trains, said set of torque transfer components including a clutch for selectively coupling a member of said first planetary train to a member of said second planetary train, and a brake for selectively coupling said a member of said second planetary train to a fixed member of the power transmission system;
an engine control unit configured to provide an engine torque responsive to a target torque level established based on a performance objective;
a power control unit operatively coupled to said first and second electric machines, said power control unit configured to control a flow of electric power to and from each of said electric machines to regulate a magnitude of delivered power to the drive shaft, and said power control unit further configured to control of said at least one set of torque transfer components.
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Accused Products
Abstract
A method for power management in an electro-mechanical power-split infinitely variable transmission (eVT) designed to operated within a designated speed ratio range for vehicular applications. The eVT is comprised of an input shaft coupled to the output shaft of a drive engine to receive power, a drive shaft, two electric machines, and a pair of planetary trains each having a sun member, a ring member, a set of planetary members, and a planet carrier. The eVT further contains one or more torque transfer devices to connect or disconnect members of the planetary trains for transferring torque. The drive shaft is coupled with a final drive of a vehicle for delivering or recapturing power to or from the vehicle drive wheels. The two electric machines are interconnected electronically via a power control unit and are coupled respectively with members of the planetary train. The method of power management in the eVT is selected based on the current speed and torque of the input and drive shafts, and upon the desired operating parameters.
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Citations
32 Claims
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1. A power transmission system for regulating the delivery of power to a drive shaft, said power transmission system comprising:
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an engine having an output shaft;
a pair of planetary trains operatively coupled between said output shaft and said drive shaft for transmitting power output from said engine to said drive shaft, each of said planetary trains including a sun member, a ring member, a set of planet members, and a planet carrier;
a first electric machine linked with at least said one member of a first planetary train in said pair of planetary trains for receiving and transmitting power to and from said drive shaft;
a second electric machine linked with said one member of a second planetary train in said pair of planetary trains for receiving and transmitting power to and from said drive shaft;
a set of torque transfer components operatively coupled to said pair of planetary trains, said set of torque transfer components including a clutch for selectively coupling a member of said first planetary train to a member of said second planetary train, and a brake for selectively coupling said a member of said second planetary train to a fixed member of the power transmission system;
an engine control unit configured to provide an engine torque responsive to a target torque level established based on a performance objective;
a power control unit operatively coupled to said first and second electric machines, said power control unit configured to control a flow of electric power to and from each of said electric machines to regulate a magnitude of delivered power to the drive shaft, and said power control unit further configured to control of said at least one set of torque transfer components. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for series hybrid operation in a power transmission system including an engine having an output shaft, a pair of planetary units between the engine output shaft and an output drive shaft, each planetary unit having ring member located around a sun member, planet members located between the sun and ring members, and a carrier member coupled with the planets and providing axes about which the planet members rotate, one of the members of the first planetary unit engageable with one of the members of the second planetary unit to form a first compound member branch, another of the members of the first unit engageable with another of the members of the second planetary unit to form a second compound branch, a first electric machine coupled to the sun member of the first planetary unit, and a second electric machine coupled to the sun member of the second planetary unit, a power control unit coupled to the first and second electric machines, the method comprising:
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decoupling said first and second planetary trains from each other;
configuring said first planetary train as a speed increaser;
driving said first electric machine from said engine output shaft through said first planetary train to generate electrical power;
configuring said second planetary train as a speed reducer;
delivering said electrical power from said first electric machine to said second electric machine;
driving said output drive shaft from said second electric machine through said secondary planetary train; and
regulating said generation and delivery of electrical power from said first electric machine to said second electric machine to control said output drive shaft rotational speed.
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26. A method for power regulation in a power transmission system including an engine having an output shaft, a pair of planetary units between the engine output shaft and an output drive shaft, each planetary unit having ring member located around a sun member, planet members located between the sun and ring members, and a carrier member coupled with the planets and providing axes about which the planet members rotate, at least one of the members of the first planetary unit engagable with one of the members of the second planetary unit to form a compound member branch, a first electric machine coupled to one member of the first planetary unit, and a second electric machine coupled to one member of the second planetary unit, a power control unit coupled to the first and second electric machines, the method comprising:
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identifying the output drive shaft rotational speed and driver inputs;
calculating engine output utilizing said output drive shaft rotational speed and at least one driver input;
determining a engine operating point based on a selected performance objective;
calculating a speed ratio between said output drive shaft and said engine output shaft;
selecting an operating regime for said power transmission system based upon said calculated speed ratio;
selecting a control routine for each of said first and second electric machines based upon said calculated speed ratio;
controlling one of said electric machines to provide torque to regulate said engine rotational speed based upon said operating regime and control routines;
controlling a second of said electric machines to provide torque to balance power in said first and second planetary units based upon said operating regime and control routines; and
regulating the engine to achieve a desired engine output torque based on a selected performance objective. - View Dependent Claims (27, 28, 29, 30, 31, 32)
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Specification