Opinion ID: 210274
Heading Depth: 2
Heading Rank: 1

Heading: Patents in Suit

Text: The three patents at issue in this case relate to drive trains for hybrid electric vehicles. In a conventional automobile, the wheels are driven using torque (rotational force) supplied only by an internal combustion engine (ICE or engine). In hybrid electric vehicles, on the other hand, the wheels are driven using torque supplied by an ICE, an electric motor, or a combination of the two. This adds an additional layer of complexity because the relative torque contributions of the ICE and the electric motor must be combined and controlled. To that end, the drive train disclosed in the '970 patent employs a microprocessor and a controllable torque transfer unit (CTTU) that accepts torque input from both the ICE and the electric motor: As shown in figure 11 of the '970 patent, illustrated above, the ICE output shaft 86 and the electric motor output shaft 26 extend into the CTTU housing 92 and terminate at bevel gears 94 and 96, respectively, each of which mesh with two other bevel gears, 98 and 100. In this embodiment, bevel gears 98 and 100 are equipped with microprocessor-controlled locking devices 106 for setting the gears' rotational freedom, if any, relative to the housing. '970 patent, col. 15, II. 50-53. In one mode of operation the microprocessor locks the bevel gears, causing the housing and the drive shaft 30 to rotate about their horizontal axes in response to any torque provided by the output shafts of the ICE or electric motor (or both). Id. at col. 15, l. 64  col. 16, l. 3. In this locked mode of operation, the two shafts rotate at the same speed, although the amount of torque provided by the individual shafts may differ. See id. The CTTU's microprocessor, by virtue of its ability to control the amount of torque provided at each shaft, is able to control the relative amounts of torque transferred from the ICE and the electric motor to the drive shaft. See id. at col. 10, II. 4-43. The microprocessor is able to do so by holding the inputs constant and merely sending control signals to the locking devices. For example, if the ICE is disengaged (and not providing any torque) while the bevel gears are locked, there is a one-to-one transfer of torque from the electric motor output shaft, through the CTTU, to the drive shaft. J.A. 1494. In another mode of operation (differential mode), however, the microprocessor releases the bevel gears such that they are free to rotate. '970 patent, col. 16, II. 11-27. If the ICE is disengaged in this mode, there is a one-to-two transfer of torque from the motor output shaft, through the CTTU, to the drive shaft. J.A. 1494. Claims 11 and 39 of the '970 patent are relevant to this appeal. Because claim 39 depends from claim 32, and because the issues we must decide do not implicate the additional limitation of claim 39, only claims 11 and 32 are reproduced below: 11. A hybrid electric vehicle, comprising: two or more drive wheels receiving torque for propelling said vehicle from an output shaft, and a power unit supplying drive torque to said output shaft, said power unit comprising: a controllable torque transfer unit adapted to receive torque from two sources and transfer said torque to said output shaft; an engine adapted to consume combustible fuel and supply torque to said torque transfer unit; an AC electric motor adapted to receive electric energy from a battery and supply torque to said torque transfer unit, said motor being further adapted to be operable as a generator; a battery for supply of stored electric energy to said motor, and for receiving and storing electric energy from said motor when operated as a generator; solid state switching means for converting DC supplied by said battery to AC for supply to said electric motor, and for rectifying AC generated by said motor when operated in a regenerative mode to provide DC to charge said battery; and a controller for controlling the operation of said engine, said electric motor, said solid state switching means, and said torque transfer unit, such that said torque transfer unit receives torque from either or both of said internal combustion engine and said electric motor and transmits torque therefrom to said drive wheels by way of said output shaft, and for controlling the relative contributions of the internal combustion engine and electric motor to the torque driving the wheels. '970 patent, col. 23, II. 36-68 (emphasis added). 32. A hybrid electric vehicle, comprising: a controllable torque transfer unit, operable to transfer torque in three modes: (a) from either or both of two input shafts to an output member, said output member transmitting torque to drive wheels of said vehicle; (b) between said input shafts; and (c) from said output member to one or both of said input shafts; an electric motor adapted to apply torque to a first of said input shafts responsive to supplied electrical energy, said motor further being operable in a generator mode, to provide electrical energy when driven by torque transferred thereto via said first input shaft; a combustible-fuel-burning internal combustion engine adapted to apply torque to a second of said input shafts; a battery adapted to supply electrical energy to and store energy received from said electric motor; and a controller adapted to receive input commands from a driver of said vehicle to monitor operation of said vehicle and to control operation of said controllable torque transfer unit, said motor, and said internal combustion engine, wherein said controller comprises means for performing the following functions responsive to input commands and monitored operation of said vehicle: selecting an appropriate mode of operation of said vehicle from at least the following possible modes of operation: low speed running; steady state running; acceleration or hill climbing; battery charging; braking; and engine starting; selecting the appropriate flow paths of electrical energy and/or combustible fuel and of torque to effectuate the selected mode of operation; and controlling operation of said controllable torque transfer unit, said electric motor and said internal combustion engine in accordance with said selected appropriate flow paths and selected mode of operation. Id. at col. 26, l. 39-col. 27, l. 15 (emphasis added). The drive train of the '672 and '088 patents differs from the drive train of the '970 patent in that it employs a clutch  rather than a CTTU  to combine the torque contributions from the ICE and the electric motor. As illustrated in figure 3 of the '672 patent (illustrated below), torque from electric motor 25 is directly transferred to differential 32 (and therefore to the wheels 34). Torque from ICE 40, on the other hand, is only indirectly transferred to the wheels because output shaft 41 of the ICE is routed through clutch 51. Consequently, when the clutch is disengaged, the electric motor is the sole source of torque transferred to the wheels. When the clutch is engaged, however, torque provided by both the ICE and the electric motor is transferred to the wheels. Another difference from the drive train of the '970 patent is that the drive train of the '672 and '088 patents use road load to determine the proper combination of torque from the ICE and the electric motor. [2]