HYBRID VEHICLES
`
`'Inventors: Alex J. Severinsky
`Theodore N. Louckes‘_
`
`
`This application is a continuation-in—part of Ser. No.
`09/264,817, filed March 9, 1999, now U. s. patent 6, 209, 672,
`issued
`April 3, 2001, which in turn claims priority from provisional
`applicatiOn Ser. No.
`60/100, 095, filed September 14,1998, and is
`also a continuation—in-part of Ser. No. 09/392, 743, filed September
`9, 1999, which in turn claims priority from provisional application
`Ser. No. 60/122,296, filed March 1, 1999.
`
`Eield-oof the xnventign
`This application relates to improvements in hybrid vehicles,
`that is, vehicles in which both an internal combustion engine and
`
`_driving wheels of the vehicle. More particularly, this invention
`relates to a hybrid electric vehicle that is fully competitive with
`presently conventional vehicles as regards performance, operating
`convenience, and cost, while achieving substantially improved fuel
`economy and reduced pollutant emissions.
`
`D SC 55 'on
`e
`'o
`t
`For many years great attention has been given to the problem
`of reduction of fuel consumption of automobiles and other highway
`vehicles. Concomitantly very substantial attention has been paid
`to reduction of pollutants emitted by automobiles
`and other
`vehicles. To a degree, efforts to solve these problems conflict
`with one another. For example,
`increased thermodynamic efficiency
`and thus reduced fuel consumption can be realized if an engine is
`operated at higher temperatures. Thus there has been substantial
`interest in engines built of ceramic materials withstanding higher
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`Page 1 of 161
`Page 1 Of161
`
`-
`
`FMC 1034
`FMC1034
`
`

`

`combustion temperatures than those now in use. However, higher
`combustion temperatures in gasoline-fueled engines lead to increase
`in certain undesirable pollutants, typically NOX.
`~
`Another possibility for reducing emissions is to burn mixtures
`of gasoline and ethanol ("gasohol"), or straight ethanol. However,
`to date ethanol has not become economically competitive with
`gasoline,
`and consumers have not accepted ethanol
`to any great
`degree. Moreover,
`to make an alternate fuel
`such as ethanol'
`available
`to the
`extent necessary‘ to achieve
`appreciable
`improvements in nationwide air quality and fuel conservation would
`require immense costs for infrastructure improvements; not only the
`entire nation's motor fuel production and delivery system, but also
`the vehicle manufacture, distribution, and repair system, would
`have to be extensively revised or substantially duplicated.
`One proposal for reducing pollution in cities is to limit the
`use of vehicles powered by internal combustion engines and instead
`employ electric vehicles powered by rechargeable batteries. To
`~date, all such "straight electric" cars have had very limited
`range,
`typically no more than 150 miles, have insufficient power
`for acceleration and hill climbing exCept when the batteries are
`substantially fully" charged,
`and.
`require substantial
`time for
`battery recharging. Thus, while there are many circumstances in.
`which the limited range and extended recharging time of
`the
`batteries would not be an inconvenience, such cars are not suitable
`for all the travel requirements of most individuals. Accordingly,
`an electric car would have to be an additional vehicle for most
`users, posing a substantial economic deterrent. Moreover, it will '
`be appreciated that
`in the United States most electricity is
`generated in coal——fired. power' plants,
`so that using electric
`vehicles merely moves the source of the pollution, but does not
`eliminate it. Furthermore, comparing the respective net costs per
`mile of driving,. electric vehicles are not competitive with
`ethanol-fueled vehicles, much less with conventional gasoline-
`fueled vehicles. See, generally, Simanaitis, "Electric Vehicles",
`
`10
`
`15
`
`20
`
`25’
`
`3O
`
`Page 2 of 161
`Page 2 of 161
`
`i
`
`' FMC 1034
`FMC 1034
`
`

`

`"AC Propulsion
`
`Road & Track, May 1992, pp. 126-136; Reynolds,
`p. 126-129.
`, CRX", Road & Track, October 1992, p
`Brooks et a1 U.S. patent 5,492,192 shows such an electric
`pears to be directed to incorporation of
`vehicle; the invention ap
`control
`technologies
`into an
`antilock braking and
`traction
`_
`otherwise conventional electric vehicle.-
`to
`the _years
`Much attention has also been paid over
`internal combustion
`thus eliminating the defect of limited
`0 vehicles. The simplest such
`range exhibited by simple electri
`—electric
`general principle as diesel
`vehicles operate on the same
`In such systems, an internal
`locomotives used by most railroads.
`combustion engine drives a generator provi
`heels of the vehicle.
`traction motors connected directly to the w
`le gear
`ratio
`This
`system has
`the ;advantage that
`no variab
`transmission is required between the engine and the wheels of the
`
`vehicle.
`
`centrifugal
`
`More particularly, an internal combustion engine produces zero
`torque at zero engine speed (RPM)
`and reaches its torque peak
`,somewhere in the middle of its operating range. Accordingly, all
`bustion engine (other
`vehicles driven directly by an internal com
`single-speed vehicles using friction or
`than certain
`ing) require a variable-
`and not useful for normal driv
`clutches,
`nd the wheels, so that the
`ratio transmission between the engine a
`‘s torque can .be matched to 'th
`engine
`lutch must be provided so that
`encountered. Further,
`some sort of c
`decoupled from the wheels, allowing
`the engine can be mechanically
`and to allow
`the vehicle to stop while the engine is still running,
`the engine with respect to the drive train while
`some slippage of
`It would not be practical
`to provide a
`starting from a stop.
`with a multiple speed transmission,
`diesel locomotive, for example,
`the additional
`complexity of
`the
`a’ clutch. Accordingly,
`or
`erator
`and electric traction motors
`is accepted. Electric
`gen
`que at zero RPM and thus can be
`traction motors produce full tor
`
`e road speeds and loads
`
`10
`
`15
`
`20
`
`25
`
`30
`
`Page 3 of 161
`Page 3 of 161
`
`FMC 1034
`FMC1034
`
`

`

`connected directly to the wheels; when it is desired that the train
`should accelerate,
`the diesel engine is simply throttled to
`increase the generator output and the train begins to move.
`The same drive system may be employed in a smaller vehicle
`as
`an
`automobile or
`truck,
`but has
`several distinct
`such
`disadvantages in this application. In particular, and as discussed
`in detail below in connection with Figs.
`1 and 2, it is well known
`.that
`a gasoline or other
`internal combustion engine is most
`efficient‘ when
`producing
`near
`its maximum output
`torque.
`Typically, the number of diesel locomotives on a train is selected
`in accordance with the total tonnage to be moved and the grades to
`be overcome, so that all the locomotives can be-operated at nearly
`full torque production. Moreover, such locomotives tend to be run
`at steady speeds for long periods of time. Reasonably efficient
`fuel use is thus achieved. However,
`such a direct drive vehicle
`would not achieve good fuel efficiency in typical automotive use,
`involving many short trips,
`frequent stops in traffic, extended
`low-speed operation and the like.
`So—called "series hybrid" electric vehicles have been proposed
`for automotive use, wherein batteries are used as energy storage
`devices, so that an internal combustion engine provided to power a
`generator can be operated in its most fuel-efficient output power
`range while still allowing the electric traction motor(s) powering
`the vehicle to be operated as required. Thus the engine may be
`loaded by supplying torque to a generator charging the batteries
`vniile supplying electrical power
`to the traction motor(s)
`as
`required, so as to operate efficiently. This system overcomes the
`limitations of electric ‘vehicles noted above with respect
`to
`limited range and long recharge times.
`Thus, as compared to a
`conventional vehicle, wherein the internal‘ combustion engine
`delivers torque directly to the wheels,
`in a series hybrid electric
`vehicle,
`torque is delivered from the engine to the wheels via a
`serially connected generator used as
`a battery charger,
`the
`battery, and the traction motor. However, energy transfer between
`
`10
`
`15
`
`20
`
`25
`
`30
`
`Page 4 of 161
`Page 4 of 161
`
`FMC 1034
`FMC 1034
`
`

`

`least approximately 25% of engine
`those components consumes at
`power. Further, such components add substantially to the cost and ,
`weight of the vehicle;
`in particular, an electric motor capable of
`providing sufficient torque to meet all expected demand, e.g.,
`to
`allow reasonable performance under acceleration,
`-during hill-
`climbing and the like, is rather heavy and expensive. Thus, series
`hybrid vehicles have not-been immediately successful.
`A more promising "parallel hybrid" approach is shown in U.S.
`Patent Nos. 3,566,717 and 3,732,751 to Berman et al. In Berman et
`al an internal combustion engine and an electric motor are matched
`through a: complex gear
`train so that both can provide torque
`directly to the wheels,
`the vehicle being operated in several
`different modes. Where the output of the internal combustion engine
`is more
`than necessary to drive the vehicle
`("first mode
`operation") the engine is run at constant speed and excess power is
`converted by a: first motor/generator
`("Speeder“)
`to electrical
`energy for storage in a battery.
`In "second mode operation",
`the
`internal combustion engine drives the wheels directly,
`and is
`throttled. When more power is needed than the engine can provide,
`a second motor/generator or "torquer“ provides additional torque as
`
`needed.
`Berman et a1 thus show two separate electric motor/generators
`separately powered by the internal combustion engine; the "speeder"
`charges the batteries, while the “torquer" propels the vehicle
`forward in traffic. This arrangement
`is a source of additional
`complexity, cost and difficulty, as two separate modes of engine
`control are required. Moreover,
`the operator must control
`the
`transition between the seVeral modes of operation.
`Such a complex
`vehicle is unsuited for
`the automotive market.
`Automobiles
`intended for mass production can be no more complicated to operate
`than conventional vehicles, and must be essentially "foolproof",
`that
`is, resistant to damage-that might be caused by operator
`error. Further,
`the gear train shown by Berman et al appears to be
`quite complex and difficult to manufacture economically. Berman et
`
`10
`
`15
`
`20
`
`25
`
`30
`
`Page 5 of 161
`FMC 1034
`
` Page 5 of 161 FMC1034
`
`

`

`al also indicate that one or even two variable-speed transmissions
`may be required; see, e.g., col. 3,
`lines 19 — 22 and 36 - 38 of
`patent 3,566,717, and col. 2,
`lines 53 - 55 of patent-3,732,751.
`Lynch et a1 patent 4,165,795 also shows an early parallel
`hybrid drive.
`Lynch argues that maximum fuel efficiency can be
`realized when a relatively small
`internal combustion engine is
`provided,
`such that when the engine is operated at an efficient
`speed, it produces approximately the average power required over a
`typiCal mission.
`The example given is of an engine producing 25
`hp maximum and 17 hp at its most efficient speed, about 2500 rpm.
`This is to be combined with an electric motor—generator of about 30
`peak hp. This vehicle requires a variable—ratio transmission to
`achieve reasonable performance. It appears that the engine is to be
`run continuously, at
`a
`steady speed, with additional
`torque
`provided by the motor when needed and excess torque produced by the
`engine being used to charge the batteries.
`In a first embodiment,
`torque provided by the motor is transmitted to the drive wheels
`through the engine, while in a second embodiment their respective
`positions are reversed.
`Nishida U.S. patent 5,117,931 shows a parallel hybrid vehicle
`where torque from an electric motor may be combined with torquen
`from an internal combustion engine in a "torque transmission unit"
`comprising paired bevel gears
`and 'means
`for controlling the
`relative rates of rotation of the motor and engine, so that the
`motor can be used to start the engine, absorb excess torque from
`the engine
`(by
`charging a battery),
`or provide additional_
`propulsive torque.
`A 'variable—speed transmission is coupled
`between the torque transmission unit and the propelling wheels.
`Both
`the
`torque
`transmission unit
`and
`the
`variable—speed
`transmission are complex, heavy, and expensive components,
`the use
`of which would preferably be avoided.
`Helling U.S. patent 3,923,115 also shows a hybrid vehicle
`having a torque transmission unit for combining torque from an
`electric motor and an internal combustion engine.
`However,
`in
`
`10
`
`15
`
`20
`
`25
`
`30
`
`Page 6 of 161
`Page 6 of 161
`
`FMC 1034
`FMC’1034
`
`

`

`the motor and engine
`Helling the relative rates of rotation of
`input shafts are fixed,
`a flywheel is provided to store excess
`mechanical energy as well as a battery to store excess electrical
`energy. Albright, Jr. et a1 patent 4,588,040 shows another hybrid
`
`excess energy; various complicated mechanical connections are
`provided between the various components. Capacitors have also been
`proposed for energy storage; see Bates et a1 U. S patent 5,318,142.
`Fjallstrom U. S. patent 5,120,282 shows a parallel hybrid drive
`rtrain wherein torque from two electric motors is combined with
`torque produced by an internal combustion engine; the combination
`is performed by a complex arrangement of paired planetary gearsets,
`and unspecified control means are alleged to be able to allow
`variation of road speed without a variable—ratio transmission.
`Hunt U.S. Patent Nos. 4,405,029 and 4,470,476 also disclose
`parallel hybrids requiring complex gearing arrangements,
`including
`multiple speed transmissions. More specifically,
`the Hunt patents
`disclose several embodiments of parallel hybrid vehicles. Hunt
`indicates (see col. 4,
`lines 6 - 20 of the '476 patent) that an
`electric motor may drive the vehicle at low speeds up to 20 mph,
`and an internal combustion engine used for speeds above 20 mph,
`while "in certain speed ranges,
`such as from 15 — 30 mph, both
`power sources may be energized... Additionally, both-power sources
`could be utilized under heavy load conditions." Hunt also indicates
`that "the vehicle could be provided with an automatic changeover
`device which automatically shifts from the electrical power source
`to the internal combustion power source, depending on the speed of
`
`the vehicle" (col. 4,
`lines 12 — 16).
`'However,
`the Hunt vehicle does not meet the objects of the
`present invention, as discussed in detail below. Hunt's vehicle in
`each embodiment
`requires
`a conventional manual or automatic
`transmission. See col. 2,
`lines 6
`— 7. Moreover,
`the internal
`combustion engine is connected to the transfer case (wherein torque
`from the internal combustion engine and electric motor is combined)
`
`10
`
`15
`
`20
`
`25
`
`30
`
`Page 7 of 161
`Page 7 of 161
`
`FMC 1034
`FMC 1034
`
`

`

`conventional
`torque‘ converter of
`"fluid coupling. or
`a
`by
`construction". Col. 2,
`lines 16 - 17. Such transmissions and fluid
`couplings or torque converters are very inefficient, are heavy,
`bulky, and costly, and are to be eliminated according to one object
`of the present invention, again as discussed in detail below.
`Furthermore,
`the primary means of battery charging disclosed
`by Hunt involves a further undeSirable complexity, namely a turbine
`driving the electric motor in generator configuration. The turbine
`is fueled by waste heat from the internal combustion engine. See
`col. 3,
`lines 10 - 60; Hunt's internal combustion engine is also
`fitted- with an alternator,
`for additional battery charging
`capability, adding yet further compleXity' Thus it is clear that
`Hunt fails to teach a hybrid vehicle meeting the objects of the
`present
`invention - that
`is,
`a hybrid vehicle competitive with
`conventional vehicles with respect
`to performance,
`cost
`and
`complexity, while achieving substantially improved fuel efficiency.
`Kawakatsu U. S. Patents Nos. 4, 305, 254 and 4,407,132 show a
`parallel hybrid involving a single internal combustion engine‘
`coupled to the drive wheels through a conventional variable—ratio
`transmission,
`an electric 'motor,
`and. an alternator,
`to allow _
`efficient use of the internal combustion engine. As in the Hunt
`disclosure,
`the engine is intended to be operated in a relatively
`‘ efficient range of engine speeds; when it produces more torque than
`is needed to propel the vehicle,
`the excess is used to charge the
`batteries; where the engine provides insufficient torque,
`the motor
`
`is energized as well.
`shows a hybrid
`A further Kawakatsu patent, No. 4, 335, 429,
`vehicle,
`in this case comprising an internal combustion engine and
`'two motor/generator units.
`A first larger motor/generator, powered
`by ea battery,
`is used"
`to provide additional
`torque when that
`provided by the engine is insufficient,
`the larger motor—generator
`. also converts excess torque provided by the engine into electrical
`energy,
`to be stored by the battery,_and is used in a regenerative
`braking mode.
`The second smaller motor/generator is similarly used
`
`10
`
`15
`
`20
`
`25-
`
`30
`
`Page 8 of 161
`Page 8 of 161
`
`FMC 1034
`FMC 1034
`
`

`

`to provide additional torque and.additional regenerative braking as
`
`needed.
`the latter Kawakatsu patent asserts that
`More particularly,
`a single electric motor sized to provide Sufficient
`torque to
`propel the vehicle would not be capable of providing sufficient
`regenerative braking force; see col. 1,
`line 504- col.
`2 line 8.
`Accordingly, Kawakatsu provides two separate motor/generators, as
`noted; a separate engine starting motor is also provided." See col.
`6,
`lines» 22'
`-
`23.
`In the
`embodiment
`shown,
`ther larger
`motor/generator is connected to the wheel drive shaft, while the
`engine and the smaller motor/generator are connected to the wheels
`through ‘a
`complex ~mechanism comprising
`three: separately-
`controllable clutches. See col. 5,
`lines 50 — 62.
`Numerous patents disclose hybrid Vehicle drives tending to
`fall into one or more of the categories discussed above. A number
`of patents disclose systems wherein an operator is required to
`select between electric and internal combustion operation;
`for
`~ example,
`an electric motor
`is provided' for operation inside
`buildings where exhaust fumes would be dangerous, and an internal
`combustion engine provided for operation outdoors.
`It is also
`known to propose a hybrid vehicle comprising an electric motor for
`use at low speeds, and an internal combustion engine for use at
`higher speed. The art also suggests using both when maximum torque-
`is required.
`In several cases the electric motor drives one set of
`wheels and the internal combustion engine drives a different set.
`See generally Shea (4,180,138); Fields et a1 (4,351,405); Kenyon
`(4,438,342); Krohling (4,593,779); and Ellers (4,923,025).
`Many of these patents show hybrid vehicle drives wherein a
`variable speed transmission is required, as do numerous additional
`references. A transmission as noted above is typically required
`' where the internal combustion engine and/or the electric motor are
`not capable of supplying sufficient torque at low speeds. See Rosen
`(3,791,473); Rosen (4,269,280); Fiala (4,400,997); and Wu et a1
`.(4,697,660). Kinoshita (3,970,163)
`shows a vehicle of this general
`
`10
`
`15
`
`20
`
`.25
`
`30
`
`Page 9 of 161
`Page 9 of 161
`
`‘
`
`FMC 1034
`FMC1034
`
`

`

`type wherein a gas turbine engine is coupled to the road wheels
`- through a three-speed transmission; an electric motor is provided
`to supply additional torque at low speeds.
`._
`For further examples of series hybrid vehicles generally as
`discussed above, see Bray (4,095,664); Cummings (4,148,192); Monaco
`et‘
`a1
`(4,306,156);
`Park
`(4,313,080); McCarthy" (4,354,144);
`Heidemeyer
`(4,533,011); Kawamura
`(4,951,769);
`and Suzuki et al
`(5,053,632). Various of these address specific problems arising in
`the manufacture or use of hybrid vehicles, or specific alleged
`design improvements.
`For example, Park addresses certain specifics
`of battery charging and discharge characteristics, while McCarthy
`shows
`a: complex drive system involvingcan internal combustion
`engine driving two electric motors;
`the torque generated by the
`latter is combined in a complex differential providing continuously
`variable gear ratios.
`Heidemeyer
`shows connecting an internal
`combustion engine to an electric motor by a first friction Clutch,
`and connecting the motor to a transmission by a second friction
`clutch.
`.
`.
`Other patents of general relevance to this subject matter
`include Toy
`(3,525,874),
`showing a series hybrid using a gas
`turbine as internal combustion engine; Yardney (3,650,345), showing
`use of a cmmpressed-air or similar mechanical starter for the
`internal combustion engine of a series hybrid, such that batteries
`of
`limited current
`capacity could be used;
`and Nakamura
`(3,837,419), addressing improvements in thyristor battery—charging
`and motor drive circuitry.
`Somewhat further afield but of general
`interest are the disclosures of
`‘Deane
`(3,874,472); Horwinski'
`"(4,042,056); Yang
`(4,562,894); Keedy
`(4,611,466);
`and Lexen
`(4,815,334); Mori
`(3,623,568); Grady,
`Jr. 4(3,454,122); Papst
`(3,211,249); Nims et al
`(2,666,492); and Matsukata (3,502,165).
`Additional references showing parallel hybrid vehicle drive systems
`include Froelich (1,824,014) and Reinbeck (3,888,325).U.S. Patent
`No. 4,578,955 to Medina shows a hybrid system wherein a gas turbine
`is used to driveia generator as needed to charge batteries. Of
`
`10
`
`15
`
`20
`
`25
`
`30
`
`10
`
`Page 10 of 161
`
`FMC 1034
`
`

`

`particular interest to certain aspects of the present invention is
`that Medina discloses that the battery pack should have a voltage
`in the range of 144, 168 or 216 volts and the generator should
`deliver current in the range of 400 to 500 amperes. Those of skill
`in the art will
`recognize that
`these high currents
`involve
`substantial resistance heating losses,
`and additionally require
`that all electrical connections be made by positive mechanical
`means such as bolts and nuts, or by welding. More specifically, for
`reasons of safety and in accordance with industry practice,
`currents in excess of about 50 amperes cannot be carried by the
`conventional
`plug-in
`connectors
`preferred
`for
`reasOns
`of
`convenience and economy, but must be carried by much heavier, more
`expensive and
`less
`convenient
`fixed connectors
`(as used on
`conventional starter and battery cable connections) Accordingly,
`it would be desirable to operate the electric motor of a hybrid
`vehicle at’ lower currents.
`U. S. patent 5, 765, 656 to Weaver also shows a series hybrid
`wherein a gas turbine is used as the internal combustion engine;
`hydrogen is the preferred fuel.
`U.S. Patent No. 4, 439, 989 to Yamakawa shows a system wherein
`two different
`internal combustion engines are provided,
`so that
`only one need be run when the load is low. This arrangement would
`be complex and expensive to. manufacture.
`Detailed discussion of
`'various aspects of hybrid 'vehicle
`drives may be found in Kalberlah, "Electric Hybrid Drive Systems
`for Passenger Cars
`and Taxis",
`SAE Paper No.
`910247
`(1991).
`Kalberlah first compares "straight" electric, series'hybrid, and
`parallel hybrid drive trains, and concludes that parallel hybrids
`are preferable, at least when intended for general use (that is,
`straight electric vehicles may be useful under certain narrow
`conditions of low-speed,
`limited range urban driving). Kalberlah
`then compares various forms of parallel hybrids, with respect to
`his Fig. 4, and concludes that the most practical arrangement is
`one in which an internal combustion engine drives a first pair of
`
`11
`
`20
`
`25
`
`30
`
`Page 11 of 161
`Page 11 of 161
`
`FMC1034
`FMC 1034
`
`

`

`more particularly,
`the second;
`and EH1 electric motor
`wheels,
`Kalberlah indicates that mechanical combination of the torque from
`an internal combustion engine and an electric motor is impractical.
`Gardner U.S.
`patents
`5,301,764
`and
`5,346,031
`follow
`Kalberlah's teachings,
`in that Gardner shows separately driving at
`least two pairs of wheels; one pair is driven by a first electric
`motor, and the second by a second electric motor or alternatively
`by a small internal combustion engine. Three different clutches
`are provided to allow ‘various sources 'of drive torque to be.
`connected to the wheels,
`and to a generator, depending on the
`vehicle's operation mode.
`The internal combustion engine is run
`continuously, and provides the driving torque when the vehicle is
`in a cruise mode; at other times it is used to charge the batteries
`powering the electric motors.
`Bullock,
`“The Technological Constraints of Mass, Volume,
`Dynamic Power Range and Energy Capacity on the Viability of Hybrid
`and Electric Vehicles",
`SAE Paper No. 891659 (1989) provides a
`‘ detailed theoretical analysis of electric vehicles in terms of the
`loads thereon, and a careful analysis of the various battery types
`then available.
`Bullock concludes that
`ii vehicle having two
`electric motors of differing characteristics, driving the wheels
`through a variable-speed tranSmission, would be optimal
`for
`automotive use;
`see the discussion of Fig.
`8.
`Bullock also
`suggests the use of an internal combustion engine to drive battery
`charging, but does not addreSs combining the engine's torque with
`that from the motors; see pp. 24 - 25.
`Further related papers are collected in Electric and Hybrid
`ec
`o o
`, volume SP-915, published by SAE in February
`e 'c
`See also Wouk, "Hybrids: Then and Now"; Bates, "0n the road
`1992.
`with a Ford HEV", and King et a1, "Transit Bus takes the Hybrid
`Route", all in l§E§_§pggtrpm, Vol. 32, 7,
`(July 1995).
`Urban et al U.S. patent 5,667,029 shows two embodiments of
`parallel hybrids; a first embodiment is shown in Figs.
`1 - 9 and
`11, and a second in Figs. 12 - 17. Both embodiments have numerous
`
`10
`
`15
`
`2O
`
`25
`
`30
`
`12
`
`Page 12 of 161
`Page 12 of 161
`
`FMC 1034
`FMC1034
`
`

`

`-Referring to
`including similar operating modes.
`common features,
`the first embodiment, an internal combustion engine provides torque
`to the road wheels or to a generator;
`two electric motors can
`provide torque to the road wheels, or charge batteries during
`regenerative braking.v_ Torque from the; engine and motors
`is
`combined at
`the input shaft
`to a variable-ratio transmission.
`Overrunning clutches are provided, e.g.,
`to allow the engine's
`torque to be applied to-the road wheels without also rotating the
`
`motors.
`lines 25 — 54, certain transitions
`indicated at col. 6,
`As
`between various operating modes are made automatically, responsive
`to the position of
`the accelerator pedal;
`for example,
`if the
`operator does not depress the pedal beyond a given point, only the
`internal combustion engine is employed to propel the vehicle; if
`the operator depresses the pedal more fully,
`the electric motors
`are also energized.
`other changes in the operational mode must be
`made by the operator directly;
`for example,
`the vehicle may be
`operated as a "straight electric" vehicle, e.g. for short duration
`trips, by the operator's making an appropriate control action.
`See
`col° 7,
`lines 49 - 56.
`The Urban et al design appears to suffer from a number of
`‘significant defects.
`First,
`the internal combustion engine is
`stated to provide all torque needed to accelerate the vehicle to
`cruising speed under normal circumstances (see col. 5,
`lines 3 -
`10), and also to propel the vehicle during cruising (see col. 6,
`lines 48 - 54).
`The electric motors are to be used only during
`rapid acceleration and hill-climbing; col. 5,
`lines 10 - 13._A 20
`horsepower engine, operated through a continuously variable—ratio
`transmission and a torque converter,
`is stated to be adequate for
`this purpose.
`Such components are clearly complex and expensive;
`further,
`torque converters are notoriously inefficient. Moreover,
`using the internal combustion engine as the sole source of power
`for low-speed running would require it to be run at.1ow speeds,
`e.g., at traffic lights, which is very inefficient and highly
`
`10
`
`15
`
`20
`
`25
`
`30
`
`13
`
`Page 13 of 161
`
`FMC 1034
`
`

`

`that excess
`(Various additional references suggest
`polluting.
`torque can be used to charge batteries; if this were incorporated
`
`5
`
`10
`
`15
`
`-
`
`20
`
`25
`
`30
`
`efficient output level while the vehicle was stationary, but this
`would lead to high levels of noise and vibration.
`In any event
`Urban does not appear to consider this possibility.)
`;
`'
`On the other hand, Urban does Suggest that the vehicle can be
`operated as a "straight electric" under low-speed conditions, but
`this requires the operator to provide an explicit control
`input;
`this complexity is unacceptable in a vehicle intended to be sold in
`quantity, as Would be required in order to reach Urbanfs stated
`goals of reduction of atmospheric pollution and reduced energy
`consumption.
`As noted,
`hybrid vehicle operation must
`be
`essentially "foolproof", or "transparent" to the user,
`to have any
`chance of commercial success.
`Urban's.second embodiment is mechanically simpler, employing
`but a single "dynamotor",
`through which torque is transmitted from
`h the engine to the variable-ratio transmission, but suffers from the
`same operational deficiencies.
`A second Urban et al patent, 5,704,440,
`is directed to the
`method of operation of the vehicle of the '029 patent and suffers
`the same inadequacies.
`Various articles describe several generations of Toyota Motor
`‘ Company hybrid vehicles, believed to correspond to that available
`commercially as the "Prius"°
`See, for example, Yamaguchi, "Toyota
`readies gasoline/electric hybrid system", Automotiye Engineering,
`July 1997, pp. 55 - 58; Wilson, "Not Electric, Not Gasoline, But
`Both", Autgmeek, June 2, 1997, pp.
`17 - 18; Bulgin,
`"The Future
`Works, Quietly", Autoweeh February 23, 1998, pp.
`12 and 13; and
`"Toyota Electric and Hybrid Vehicles", a Toyota brochure.
`A more
`detailed discussion of the TOydta vehicle's powertrain is found in
`Nagasaka et a1,
`"Development of
`the Hybrid/Battery ECU for the
`Toyota Hybrid System",
`SAE paper 981122
`(1998), pp.
`19
`- 27.
`According to the Wilson article, Toyota describes this vehicle as
`
`14
`
`
`
`
`‘Page14of161 FMC1034 '
`Page 14 of 161
`FMC 1034
`
`
`
`

`

`a "series-parallel hybrid"; regardless of the label applied, its
`powertrain appears to be similar to that of the Berman patents
`described above, that is,
`torque from either or both of an internal
`combustion engine and an electric motor are controllably combined
`in a "power-split mechanism" and transmitted to the drive wheels
`through a planetary gearset providing the functionality of
`a
`variable-ratio transmission.
`See the Nagasaka article at pp. 19 -
`
`20.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`internal combustion engine driving a first set of wheels through a
`variable-ratio transmission and an electric motor driving a second
`set of wheels. The engine is apparently intended to be run
`continuously; at
`low speeds,
`it drives a generator
`to charge
`batteries providing energy to the motor, and at higher speeds the
`engine or both engine and motor propel
`the vehicle.
`In some
`circumstances the transmission may not be required; compare, for
`example, col. 3,
`lines 4 — 8 with col. 5,
`lines 59 — 64.
`U.S. patent 5,842,534 to Frank shows a "charge depletion"
`control method for hybrid vehicles;
`in this scheme,
`the internal
`combustion engine is essentially used only when the state of the
`batteries is such that
`the vehicle cannot otherwise reach' a
`recharging point.
`See col. 3,
`lines 50'- 55.
`In normal Operation,
`the batteries are recharged from an external power source.
`Frank
`also discusses
`two—mode brake pedal operation, wherein mechanical
`brakes are engaged in addition to regenerative braking when the
`pedal is depressed beyond a preSet point.
`U.S. patent 5,823,280 to Lateur et a1 shows a parallel hybrid
`wherein the shafts of an internal combustion engine and first and
`second electric motors are all coaxial;
`the engine is connected to
`the first motor by a clutch, and the first motor to the second by
`a planetary gearset,
`allowing the speeds of
`the motors to be
`varied so as to_operate them in their most efficient range.
`See
`col. 4,
`line 57 - col. 5,
`line 60.
`U.S. patent 5,826,671 to Nakae et a1 shows a parallel hybrid
`
`15
`
`Page 15 of 161
`Page150f161
`
`FMC 1034
`‘ FMC1034
`
`

`

`wherein torque from an internal combustion engine is combined with
`that
`from a motor
`in a planetary gearSet; a clutch is provided
`therebetween. The specific invention relates to sensing of engine
`warmup conditions, so as to limit emission of unburnt fuel and thus
`
`U.S. patent 5,846,155 to Taniguchi et a1 shows a parallel
`hybrid wherein torque from an internal combustion engine and a
`motor'
`is again combined in a planetary gearset;
`the specific
`
`'10
`
`15
`
`20
`
`25
`
`30
`
`transmission.
`
`It will be appreciated by those of skill in the art that there
`are significant
`limitations inherent
`:hi
`the- use of planetary
`gearsets as a means for connecting different sources, e.g.,
`an
`internal combustion engine and an electric motor,
`to the drive
`wheels of a vehicle, namely, that unl