Drive system for a vehicle and method for operating a drive system
First Claim
1. For use with a vehicle having wheels and a drive train, a drive system comprising:
- an internal combustion engine;
a transmission located between the internal combustion engine and the wheels of the vehicle, the transmission having one of a continuous and finely graded variable transmission ratio;
an electric generator; and
at least one control device in communication with the transmission for selecting the transmission ratio within a range of possible transmission ratios to optimize the total efficiency of the internal combustion engine and the electric generator, wherein the control device optimizes the total efficiency by considering an efficiency of each of;
(a) a combination of the internal combustion engine and the drive train, and (b) a combination of the internal combustion engine and the electric generator, at least as a function of speed, and wherein the efficiencies of;
(a) the combination of the internal combustion engine and the drive train and (b) the combination of the internal combustion engine and the electric generator are weighted for purposes of the optimization based upon power fractions associated with driving the vehicle and driving the electric generator, the power fractions being referenced to a total power released by the internal combustion engine.
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Accused Products
Abstract
The invention concerns a drive system, especially for a vehicle, with a drive unit, especially an internal combustion engine, a transmission with variable transmission ratio between drive unit and drive, and especially with a continuously variable transmission ratio or one variable in fine gradations, at least one additional unit driven by the drive unit, especially an electric generator, a control, which selects the transmission ratio within a range of possible transmission ratios, so that the highest possible efficiency is achieved with joint consideration of the individual efficiency functions of the vehicle drive and the additional unit(s) and their drive, in which the individual efficiency functions are incorporated in the total efficiency with a weight corresponding to the power fraction of the vehicle drive and additional unit(s). The invention is also geared toward a corresponding method.
24 Citations
17 Claims
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1. For use with a vehicle having wheels and a drive train, a drive system comprising:
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an internal combustion engine; a transmission located between the internal combustion engine and the wheels of the vehicle, the transmission having one of a continuous and finely graded variable transmission ratio; an electric generator; and at least one control device in communication with the transmission for selecting the transmission ratio within a range of possible transmission ratios to optimize the total efficiency of the internal combustion engine and the electric generator, wherein the control device optimizes the total efficiency by considering an efficiency of each of;
(a) a combination of the internal combustion engine and the drive train, and (b) a combination of the internal combustion engine and the electric generator, at least as a function of speed, and wherein the efficiencies of;
(a) the combination of the internal combustion engine and the drive train and (b) the combination of the internal combustion engine and the electric generator are weighted for purposes of the optimization based upon power fractions associated with driving the vehicle and driving the electric generator, the power fractions being referenced to a total power released by the internal combustion engine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. For use with a vehicle having and internal combustion engine, an electric generator and a transmission, the transmission having one of a continuous and finely graded variable transmission ratio, a method comprising the steps of:
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determining an instantaneous speed of the internal combustion engine; determining power generated by the internal combustion engine; determining power generated by the electric generator; determining an efficiency of the internal combustion engine by reference to the instantaneous speed and the power of the internal combustion engine; determining an efficiency of the electric generator by reference to the instantaneous speed of the internal combustion engine and the power of the electric generator; determining a first power weight associated with the power of the internal combustion engine and a second power weight associated with the power of the electric generator; determining a total efficiency function based upon the first power weight, the second power weight, the efficiency of the internal combustion engine and the efficiency of the electric generator; based on the total efficiency function, identifying a target speed at which the total efficiency is maximized; and if the target speed is different from the instantaneous speed of the internal combustion engine, adjusting the transmission ratio of the transmission to at least substantially eliminate the difference.
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12. For use with a vehicle having wheels and a drive train, a drive system comprising:
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an internal combustion engine; a transmission located between the internal combustion engine and the wheels of the vehicle, the transmission having one of a continuous and finely graded variable transmission ratio; an electric generator; and at least one control device in communication with the transmission for selecting the transmission ratio within a range of possible transmission ratios to optimize the total efficiency of the internal combustion engine and the electric generator, wherein the control device optimizes the total efficiency by considering an efficiency of each of;
(a) the internal combustion engine, and (b) the electric generator at least as a function of speed, and wherein the efficiencies of the internal combustion engine and the electric generator are weighted for purposes of the optimization based upon power fractions associated with the internal combustion engine and the electric generator, the power fractions being referenced to a total power released by the internal combustion engine. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification