A High-Expansion-Ratio Gasoline
`Engine for the TOYOTA Hybrid System
`
`Toshifumi Takaoka** Yasushi Nouno**
`Katsuhiko Hirose*
`Hiroshi Tada**
`Tatehito Ueda*
`Hiroshi Kanai*
`
`BEST AVAILABLE COPY
`
`Abstract
`A 50% reduction in CO2 and fuel consumption in comparison with a vehicle with the same engine displace(cid:173)
`ment has been achieved by the newly developed gasoline engine for the Toyota Hybrid System. This is
`achieved by a combination of an electric motor and an internal-combustion engine that is optimized in
`terms of its displacement and heat cycle. Delaying the closing of the intake valve effectively separates the
`compression ratio and expansion ratio, so that the expansion ratio, which is normally set to 9:1 to 10:1 to
`suppress knocking, can be set to 13.5:1. Motor-assisted quick start, improv.ed catalyst warm-up, and the
`elimination of light-load firing allow the system to achieve emissions levels that are only one-tenth of the
`current Japanese standard values.
`
`Keywords: hybrid, low fuel consumption, low emissions, low friction, variable valve timing
`
`1.
`
`Introduction
`
`The earth's remaining reserves of fossil fuels are said to total approx(cid:173)
`imately two-trillion barrels. or about a SO-year supply. The electri_s ve(cid:173)
`hicle, because of its zero emissions level and the diversity of sources to
`supply electrical energy, is regarded as a promising automobile for the
`future. On the other hand, the energy limitations of on-board batteries,
`which is to say, their inferior energy density in comparison with fossil
`fuels, has meant that the electric vehicle has remained no more than just
`one future technology. The internal-combustion/electric hybrid system
`is promoted as a technology that compensates for this shortcoming of
`the electric vehicle, but it is also the object of attention as a system that.
`eliminates the problems of the internal-combustion engine.
`Because the drive energy of the hybrid system comes either from
`electrical generation by the internal-combustion engine or from the en(cid:173)
`gine's direct drive of the axle, the efficiency of the engine, the primary
`power source, strnngly influences the efficie.ncy· of the entire system.
`In the development of the Toyota Hybrid System, a new gasoline en(cid:173)
`gine was developed with more emphasis on thermal efficiency than on
`specific output. Because priority was given to the total efficiency of
`the entire system, it was decided that a high-expansion-ratio cycle
`would be used, and the engine displacement and maximum output
`were chosen to reduce friction loss. This paper describes the inves(cid:173)
`tigative process and the results that were obtained.
`
`2. Hybrid System and Engine Specifications
`
`2.1 Hybrid System
`
`/
`
`...
`.
`~
`The configuration of THS is shown in Fig. 1. The system links the
`
`• Engine Engineering Div. II
`•• Power Train Engineering Div. II
`
`engine output and the motor output by means of a planetary gear sys(cid:173)
`tem to control the power split. One notable feature is that because the
`drive power is the combined power of the engine and the motor. the
`engine output can be set to a relatively low value without reducing ve(cid:173)
`hicle performance . .
`
`Power split device
`
`Generator
`
`Inverter
`
`Battery
`
`Motor
`
`~
`Electric
`
`path -Mechanical
`
`Hybrid transmission
`
`power path
`
`Fig. 1 Toyota Hybrid Sys~em Configuration
`
`Fig. 2 shows the relationship between output and efficiency. One
`issue for the engine was how to raise the net thermal efficiency from
`point A to point 8 .
`
`2.2 Engine Specifications
`
`In order to achieve the thermal efficiency objective. the engine for
`the hybrid vehicle was planned with the following three points in
`mind:
`(I) The only restriction to be pl.iced on the choice of engine displace(cid:173)
`ment would tie that it be within a range that satisfies the engine
`output and installability requirements. This makes it possible to
`use a high-expansion-ratio cycle with delayed iniake valve clos-
`
`TOYOTA Technical Review Vol. 47 No. 2 Apr. 1998
`
`53
`
`BMW1081
`Page 1 of 19
`
`

`

`> u
`C .,
`·u
`:i= .,
`.;
`
`E a; = .;
`
`z
`
`THS vehicle
`
`.
`~co
`onvent1onal
`improvement
`vehicle
`•T 1"1----..__-Average efficiency
`
`A: Optimized engine operating range
`
`B: Improved engine efficiency
`
`Engine output
`
`Fig. 2 Relationship of Engine Output and Efficiency
`
`ing, as well as to reduce friction loss by lowering the engine
`speed.
`(2) In order to achieve a major reduction in emissions, the engine
`would operate with A = I over its entire range, and the exhaust
`system would use a 3-way catalyst.
`(3) Active measures would be taken to reduce weight and increase ef(cid:173)
`ficiency .
`Fig. 3 shows the relationship between the S/V ratio (the ratio of
`combustion chamber surface area to combustion chamber volume) and
`the indicated mean effective pressure. The smaller the SN ratio, the
`less heat is dissipated into the coolant. raising the indicated mean ef(cid:173)
`fect ive pressure. Since the S/V ratio tends to decrease as the displace(cid:173)
`ment per cylinder increases. this also raises the indicated mean effec(cid:173)
`tive pressure.
`Fig. 4 shows the relationship between displacement and friction
`loss in two engines designed to have identical output. Because the
`maximum engine speed can be set lower as the displacement increas-
`
`Pe: Brake mean effective pressure
`Pi·=Pe+Pfm+Pfp Pfm: Friction mean effective pressure
`Pfp: Pumping mean effective p0ressure
`
`1.40
`
`1.35
`
`1.30
`
`1.25 .__ ___ ...... __ __ ...__ _ _ _ __, __ __ ....
`
`0.2
`
`0.22
`
`0.24
`
`0.26
`
`0 .28
`
`SN ratio ( 1/mml
`
`'·1
`
`J •
`
`es, it is possible to reduce friction loss by reducing both the load on
`the valve system springs and the tensile strength of the piston rings
`while maintaining the same output.
`Based on these considerations, the relationship between displace(cid:173)
`ment and fuel consumption was calculated. The results are shown in
`Fig . 5 and Fig. 6. From Fig. 5 it can be seen that in the high-output
`range, thermal efficiency rises as the displacement becomes larger, but
`in the low-output range, the1Tnal efficiency is higher with a small-dis(cid:173)
`placement engine. Both the indicated thermal efficiency and the me(cid:173)
`chanical efficiency (friction loss) improve as displacement becomes
`larger. but in the low-output range, because of the effect of the pump(cid:173)
`ing loss that results from the shift to a pariial load, thermal efficiency
`is better with a small-displacement engine.
`Fig. 6 shows the relationship between displacement and fuel con(cid:173)
`sumption. For the reasons cited above, 1500 cc was deemed the opti(cid:173)
`mum engine displacement, given the curb weight of the THS vehicle.
`
`~
`
`e
`.. .. .2
`-~ .t
`
`C
`.2
`
`5
`
`4
`
`3
`
`2
`
`0
`0
`
`5
`
`10
`
`20
`
`40
`
`Output (kW)
`.. .:
`Fig . 4 Relationship of Displacement and Friction
`
`~
`> u
`C
`a,
`·c:;
`:i: .,
`.;
`E
`
`40
`
`30
`
`~ = ., .,.
`"' co
`
`20
`
`u
`100 !
`> u
`C .,
`--------1 50 ~
`., -~ ;;;
`
`::,
`CT
`
`"5
`E
`::, u
`
`0
`
`10
`
`20
`
`30
`
`40
`
`Engine output tkW)
`
`Fig. 3 Relationship of S/V Ratio and Indicated Mean
`Effective Pressure
`
`Fig. 5 Displacement and Engine Efficiency
`
`54
`
`BMW1081
`Page 2 of 19
`
`

`

`A High-L<pansic,n-natio G2s,Jline C:ngi,,oo fo; th.J TO\'OTt-. Hyb, id S'j:;icn,
`
`3.2 Relationship of Mechanical Compression Ratio,
`Valve Timing, and Brake Thermal Efficiency
`
`Before a prototype of the high-expansion-ratio engine was built, the ef(cid:173)
`fects of the mechanical compression ratio and valve' timing on brake ther(cid:173)
`mal efficiency were studied. An in-line four-cylinder. 2164-cc Toyota 5S(cid:173)
`FE engine was used in the experiments.
`Fig. 9 shows the changes in thermal efficiency with differen1 combina(cid:173)
`tions of expansion ratio and valve timing. If the expansion ratio is in(cid:173)
`creased and intake valve closing is delayed, brake thermal efficiency rises.
`but it reaches a limit at an expansion ratio of 14.7: I. Also, the maximum
`value of the brake mean effective pressure drops as the delay in intake
`valve closing increases.
`
`2400rpm
`
`32 ------<."?./.-·------·-----·--------(cid:173)
`..___,,......,...,..... ..
`.... ·
`• 9.5
`• 13.7
`
`28
`
`Expansion
`ratio
`
`0
`
`12.1
`
`24
`
`0
`14.7
`16.8
`.A
`Effective compression ratio = 9.0
`20 ..._ _ _ __. ___ _._ ____ ....._ ____ .._--1
`
`0.2
`
`0.6
`0.4
`0.8
`Brake mean effective pressure Pme (MPa)
`
`Fig. 9 Expansion Ratio and Thermal Efficiency
`
`Fig. 10 shows the relationship between brake thermal efficiency
`and brake mean effective pressure under full load. As the expansion
`ratio increases, the timing advance becomcfs slower due to knocking.
`and the brake thermal efficiency drops, but if the intake valve closing
`
`35
`
`~ 34
`
`(';"
`C:
`"' ·.:;
`:i:
`"' io
`E
`.;
`£
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`ID
`
`33
`
`32
`
`31
`
`~~1
`~~-
`~
`__J I
`..
`' • 9.5
`• 13.7
`<>
`A
`
`Intake va
`closing d
`
`A
`
`A
`
`-
`
`Expansion
`ratio
`
`a
`
`12.1
`
`30
`0.8
`0.7
`0.9
`1. 1
`Brake mean effective pressure under full load (MPa)
`
`14.7
`16.8
`
`>-:: EC gE
`0"'
`u >
`Q) a.
`"'0
`.r .s
`
`~ 10 r---..---..----r----r----r----,
`Vehicle fuel economy
`
`~ 0
`>(cid:173)(.)
`C
`"' ·.:;
`~
`"' 7ii
`E .;
`f
`.:,,t; ..
`"'
`ID
`
`35
`
`1000
`
`1200
`
`1400
`
`1600
`
`1800
`
`Displacement (cc)
`
`Fig. 6 Displacement and Fuel Economy
`
`3. Improving Efficiency by Means of High Expansion Ratio
`
`3.1 Principle
`
`The theoretical thermal efficiency of an equivalent charge .cycle is
`improved by raising the compression ratio. But if the compression
`ratio is raised in a gasoline engine, the compression end temperature
`rises, and knocking occurs. To prevent knocking in the high-expa~(cid:173)
`sion-ratio engine, the timing of intake valve closing was delayed con(cid:173)
`siderably, thus lowering the effective compression ratio and raising the
`expansion ratio, which essentially controls the thermal efficiency.
`Fig. 7 is a pressure-volume (p-V) diagram comparing the high-expan(cid:173)
`sion-ratio cycle with the conventional cycle when the charging effi(cid:173)
`ciencies of the two are equal. Fig. 8 shows the same sort of compari(cid:173)
`son when the compression end pressures are equal. When the
`charging efficiency is identical, delaying the closing of the intake
`valve raises the maximum pressure and increases the positive work,
`and also reduces pumping loss. With identical compression end pres(cid:173)
`sure, increasing the expansion ratio raises the theoretical efficien(cid:173)
`cy
`fll(lW:))(4X,X6Wh'..IM91
`
`0
`
`~ 1000
`
`~
`::,
`II)
`
`"' ~ 100
`
`10 ,__ _ _ L..-......J
`100
`1000
`10
`Cylinder volume (cc)
`
`Fig. 7 p-V Diagrams with
`Equivalent
`Charging Efficiency
`
`1000
`100
`10
`Cylinder volume (cc)
`
`Fig . 8 p-V Diagrams with
`Equivalent
`Compression End
`Pressure
`
`TOYOTA Technical Review Vol. 47 No. 2 Apr. 1998
`
`55
`
`Fig. 10 Relationship of Brake Mean Effective Pressure
`and Thermal Efficiency as Expansion Ratio and
`Compression Ratio Change
`
`BMW1081
`Page 3 of 19
`
`

`

`is delayed at the same time, knocking gradually diminishes and effi(cid:173)
`ciency improves. Therefore, if the brake mean effective pressure is al(cid:173)
`lowed to fall, the combination of high expansion ratio and delayed in(cid:173)
`take valve closing achieves high efficiency. Fig. 11 is an indicator
`diagram of actual measured results showing that the heat cycle illus(cid:173)
`trated in Fig. 7 and Fig. 8 was achieved.
`
`1000
`
`100
`
`4.2 Engine Structure
`
`Fig . 12 is a transverse sectional view of the high-expansion-r,
`engine. An aluminum-alloy cylinder block, offset crankshaft.• 1m,
`ladder-frame structure are used. The crankshaft has been made tt
`ner and lighter, and the load on the valve system springs has been
`duced, as has the tensile strength of the piston rings. The connec1
`rod/stroke ratio has been increased, and the intake inenia effect
`been reduced by using a small intake manifold. The engi_ne also u
`a slant squish combustion chamber. All of these features combin,
`achieve lighter weight, lower friction. and improved combustion.
`
`Conventional
`1.5-liter engine
`
`10 ....._~~~~~~~_...~~~~~~~---'
`1000
`100
`10
`
`Cylinder volume (cc)
`
`Fig. 11
`
`Indicator Diagram of Actual Measurements
`
`4. High-expansion-ratio THS Engine
`
`Fig. 12 Transverse Section of High-expansion-ratio Eng
`
`4. 1 Basic Specifications
`
`5. Experimental Results and Considerations
`
`Table 1 shows the main specifications for the high-expansion-ratio
`engine. The mechanical compression ratio is set to 13.5: I, but the ef(cid:173)
`fective compression ratio is suppressed to the range of 4.8: I to 9.3: I
`by using intelligent variable valve timing (VVT-i) to time the intake
`valve closing between 80° and 120° after bottom dead center (ABDC).
`The ratio of 4.8: I is obtained by the maximum delay of VVT-i and is
`used to counter vibration during engine restart, as explained below.
`
`Table 1 Design Specifications
`
`Engine model
`
`Displacement (eel
`
`Bore X stroke
`
`Maximum output
`
`Combustion chamber volume
`
`Mechanical compression ratio
`
`Effective compression ratio
`
`1NZ-FXE
`
`1497
`
`ll75X84.7
`
`43k~/4,000rpm
`
`30cc
`
`13.5
`
`4.8-9.3
`
`Intake valve closing timing
`
`80-120° ABDC
`
`Exhaust valve opening timing
`
`32° BBDC
`
`56
`
`This section summarizes the results of experiments cpnducte,
`the 1.5-liter high-expansion-ratio engine and some considerations
`ceming them .
`
`5. 1 Relationship of ExpaQsion Ratio and Brake Ther
`Efficiency
`··.
`
`Fig. 13 shows the relationship of ignition tinyng to torque ar
`brake specific fuel consumption (BSFC). · Expansion ratios of
`14: I, and 15: I were compared."iind it can be se'en that as the e>:
`sion ratio increases, the trace krroek ignition timing is delayed. \\
`15: I expansion ratio, the efficiency improves at the point of mini
`spark advance for best torque (MBT), but the expansion ratio i
`stricted by the knocking that occurs due to the high effective com
`sion ratio. The best results in terms of torque and BSFC wer•
`tained with an expansion ratio of 14: I.
`Fig. 14 shows the results of a study of thermal efficiency v
`engine output. A 14: I expansion ratio showed the best results
`the entire output range . Ul1imately. an expansion ratio of 13.5:
`chosen. taking into account such factors as the allowable variati
`
`BMW1081
`Page 4 of 19
`
`

`

`combustion chamber volume and the adhesion of deposits in the com(cid:173)
`bustion chamber, in order to leave a margin for pre-ignition.
`
`ventional engines and that the objective of reducing friction loss was
`achieved.
`
`1000 rpm
`
`Black points are trace knock
`
`120
`
`e
`~ 100
`.,
`::,
`
`6
`
`-o -D~
`E" ~ 0
`
`.....
`
`80
`
`6 Intake valve so· ABDC
`closing
`D Intake valve 90° ABDC
`closing
`
`260
`
`:c
`~
`~
`!:!}
`240 u u..
`
`VI
`CD
`
`1000
`
`2000
`
`3000
`
`4000
`
`Engine speed (rpm)
`
`220
`
`Fig. 15 Torque Improvement Effect of VVT-i
`
`80
`
`70
`
`E
`~ .,
`
`::,
`C"
`0
`I-
`
`60
`280
`
`:c
`.,,
`~ 260
`~
`u
`u..
`VI
`CD
`
`240
`
`220
`
`0
`
`Expansion ratio
`0
`D
`t::.
`
`13
`14
`
`15
`
`5
`
`10
`
`15
`
`Ignition advance (degrees BTDC)
`
`Fig. 13 Relationship of Ignition Timing and BSFC
`
`40
`
`35
`
`30
`
`0
`
`0
`D
`t::.
`
`14'
`15
`
`10
`
`20
`
`30
`
`40
`
`50
`
`Engine output (kW)
`
`0.2
`
`0.1
`
`io
`Q.
`~
`"' "' .2
`
`C
`.Q
`u
`~
`
`0 .._ ___ ,__ ___ .__ __ · ... • . ....L---..L--.J
`
`0
`
`1600
`
`3200
`
`4800
`
`6400
`
`Engine speed (rpm)
`
`Fig . 16 Comparison ofJ:=riction Loss·
`
`5.4 Reduction of Exhaust Emissions
`
`The advantages and disadvantages of the hybrid vehicle with re(cid:173)
`spect to cleaner exhaust emissions are summarized below.
`Advantages
`) By using the supplementary drive power of the electric motor, the
`system eliminates the light-load range, where concentrations of
`hydrocarbons in the emissions are high and the exhaust tempera(cid:173)
`ture is low.
`
`11
`
`r
`
`57
`
`Fig. 14 Expansion Ratio and Brake Thermal Efficiency
`
`5.2 Torque Improvement by VVT-i
`
`Full-load torque was adjusted using VVT-i. The results are shown
`in Fig. 15. An improvement in torque of 10% or more was made pos(cid:173)
`sible by advancing the intake valve closing by 10°. In THS, the en(cid:173)
`gine is controlled so that intake valve closing is advanced when the
`load requirements are high.
`
`5.3 Friction Loss
`
`As stated previously, the engine speed was lowered in an attempt to
`reduce friction loss. The measured resuhs are shown in Fig. 16. It
`can be seen that the friction loss for the high:expansion-ratio engine is
`at a consistently lower level than the cluster of points plotted for con-
`
`TovoTA Technical Review Vol. 47 No. 2 Ap.r. 1998
`
`BMW1081
`Page 5 of 19
`
`

`

`(2) By allocating a portion of the load to the electric motor. the system
`is able to reduce engine load fluctuation under conditions such as
`rapid acceleration. This makes it possible to reduce quick transients
`in engine load so that the air-fuel ratio can be stabilized easily.
`Disadvantages
`(I) Because the engine is used in the high-efficiency range. the ex(cid:173)
`haust temperatures are lower than for a conventional vehicle.
`(2) There is concern that the more the engine is stopped and restarted,
`the more unburned fuel will enter the exhaust system and the more
`the catalyst bed temperature will drop.
`Fig. 17 shows the ellhaust temperature distribution for the high-ex(cid:173)
`pansion-ratio engine. Although the exhaust temperatures are lower
`than for a conventional engine. a minimum temperature of 400°C is
`ensured for the engine operating range shown in the diagram. This is
`a temperature that can maintain the catalyst in an activated state.
`Fig. 18 shows the change in the catalyst bed temperature after the
`vehicle stops. In a conventional vehicle, where the engine continues
`to idle, the catalyst bed temperature slowly drops. But in the THS ve(cid:173)
`hicle, the influll of low-temperature exhaust gases can be avoided by
`stopping the engine, making it possible to sustain a comparatively
`gradual decline in temperature.
`Fig. 19 shows the levels of exhaust gases at the catalyst inlet.
`Hydrocarbons are at the same level as a conventional vehicle, which is
`thought to be due to the smaller volume and higher SN ratio of the
`combustion chamber. However, as ellplained previously, the catalyst
`is maintained in an activated state that is sufficient to ensure a high
`rate of catalyJic conversion.
`Exploiting the advantages cited above based on these results,
`Toyota optimized the system to achieve the voluntary emissions target
`of one-tenth of the current standard values.
`
`e
`~
`"'
`:::,
`I?"
`0
`t-
`
`120
`
`100
`
`80
`
`60
`
`40
`
`20
`
`0
`800
`
`THS engine operating range
`
`Exhaust temperature (°CI
`
`1600
`
`2400
`
`3200
`
`4000
`
`Engine speed (rpm)
`
`Fig. 17 Exhaust Temperature Map
`
`58
`
`f
`"'
`:i
`~
`"'
`a.
`E
`~
`-0
`"'
`D
`iii
`>
`
`m .. u
`
`600
`
`400
`
`200
`
`0
`
`0
`
`'
`
`..... -
`
`- - -
`-
`
`- --
`
`Engine stopped
`
`Idling at 1000 rpm
`
`5
`
`10
`
`15
`
`Time (min.)
`
`Fig. 18 Change in Catalyst Bed Temperature with
`Engine Stopped
`
`10 . 15 mode
`
`4r---------,
`
`"m
`C -~
`r - - - - - c
`"' >
`> I
`0 u
`
`C
`
`1.2
`
`e ,!!.
`E 0.8
`0 z
`0
`u
`u
`I
`
`X
`
`0.4
`
`2
`
`0
`
`co
`
`NOx
`
`0
`
`HC
`
`Fig. 19 Comparison of Emissions at Catalyst Inlet
`
`5.5 Vibration Countermea ... sures When Starting an
`Stopping
`
`Stopping the engine when the vehicle stops contributes greatly_
`fuel economy, realizing a 20% improvement in the 10-15 mode. (
`the other hand, problems have betn rais~d with vibration as the engi
`speed passes through the resonaru:e 'point of the drive train. as well
`vibration due to the brief continuation of the compression and ellpa
`sion cycle when the engine stops. The drive train _fesonance prob le
`is solved by using the motor to raise the engine' speed in a shon
`time. It was thought that the compression and expansion cycle cm
`be moderated by reducing the v~1J~e of air when the engine is st
`off. The VVT-i function is used to reduce the volume of the intake 1
`Fig. 20 shows floor vibration when the engine starts. The large a
`plitude of acceleration seen in area A in the diagram is due to the co
`pression reaction force. This amplitude can be reduced considerably.
`shown in area A', by using VVT-i to set the timing of intake valve cl,
`ing to 120° ABDC. The ,·ibration seen in area B arises from the ra;
`increase in engine torque after the engine· starts tiring. This is elimir
`ed by controlling the ignition timing delay. as shown in area B'.
`
`BMW1081
`Page 6 of 19
`
`

`

`C
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`e f 1000 r------+-----,,<=F=:::..---1
`,:, ., .,
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`0 '----lL-.-::~L--.....IL----lL----lL---.1
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`4i u
`u
`c{
`
`Intake valve closing timing
`o
`90°
`ABDC
`•
`114°
`125°
`A
`79•
`•
`
`.... --
`
`2
`
`..•... ----•----·-
`
`0 _____________ ..._ __ ..._ __ ...,
`
`0
`
`400
`
`800
`
`1200
`
`Engine speed (rpm)
`
`Time (sec.)
`
`Fig. 20 Vibration When Engine Starts
`
`Fig. 21 Relationship of Engine Speed and Cylinder
`Pressure
`
`5.6 Low-temperature Starting
`
`In the THS system, the generator is used as a starter motor to start
`the engine turning. For this purpose, the generator uses the large-ca(cid:173)
`pacity nickel-metal hydride battery as a power supply. However, as
`the temperature drops. the bactery power also drops, reducing the
`cranking speed. On the other hand, the significant delay in intake
`valve closing in the high-expansion-ratio engine reduces the compres(cid:173)
`sion end pressure (the maximum pressure within the cylinder) during
`cranking. The relationship betwe1;n cylinder pressure and engine
`speed is shown in Fig. 21, using intake valve closing timing as a para(cid:173)
`meter. Given the combustion characteristics of the engine, the maxi(cid:173)
`mum pressure at which ignition is possible is approximately 0.85
`MPa. In the THS system, the engine speed and intake valve closing
`timing are coordinated so that this pressure is maintained even under
`low-temperature conditions.
`
`5.7 Vehicle Fuel Economy
`
`Fig. 22 shows the efficiency distribution of the developed high-ex-
`pansion-ratio engine when it is combined with the THS system and
`
`/! driven in the 10 · 15 mode. In the low-output range the engine is
`
`stopped, so that it is used only in the high-efficiency range. Fig. 23
`shows the relationship between fuel economy and the charge balance
`of the battery before and after mode driving. In the hybr.d vehicle, the
`fuel economy changes as the ballery charges and discharges, so che
`vehicle's fuel economy is defined as the value when che charge bal(cid:173)
`ance is zero.
`Optimization of che vehicle's incegrated controls, including regener(cid:173)
`mive braking. allows the THS vehicle to attain almost twice the fuel
`economy of a conventional vehicle of the same class.
`
`10 · 15 mode
`
`20 t----..1...1':;._-+------+-------1 30
`
`0 .,
`~
`{';'
`C .,
`~ er ·
`~
`
`0
`
`Engine output (lq\'l
`
`Fig. 22 Engine Operating Range and Efficiency in
`10 - 15 Mode
`
`35
`
`30
`
`25
`
`-~
`i
`~
`>
`E
`0
`C
`8 Cl)
`4i
`~ u.
`
`20
`-0.2
`
`u
`
`I
`..
`
`~
`
`cu
`C dsi p::i::, ...
`' "
`
`00
`
`-0.1
`
`0.0
`
`0.1
`
`0.2
`
`Charge balance (Ahl
`
`Fig. 23 Charge Balance and Fuel Economy
`
`TOYOTA Technical Review Vol. 47 No. 2 Apr. 1998
`
`59
`
`BMW1081
`Page 7 of 19
`
`

`

`•
`
`6. Conclusion
`
`A lightweight, compact, high-expansion-ratio gasoline engine was
`developed for use in the internal-combustion/electric hybrid vehicle.
`(I) The engine output required to meet the vehicle's weight and per(cid:173)
`formance requirements was determined, and the engine displace(cid:173)
`ment was chosen to yield the optimum vehicle fuel economy from
`the high-expansion-ratio cycle.
`(2) A 1.5-liter high-expansion-ratio gasoline engine was developed as
`the primary power source, and it attained the target fuel consump(cid:173)
`tion rate of less than 230 g/kWh.
`(3) Emissions levels much lower than the current standard values
`were attained by optimum control of the motor and engine.
`(4) Vibration during engine starting and stopping was greatly reduced
`by using VVT-i.
`(5) The hybrid system achieved twice the fuel economy of a conven(cid:173)
`tional vehicle of the same class, while cutting the volume of CO)
`emissions in half.
`The authors wish to express their respectful appreciation to all
`those who cooperated in the development of this system. We particu(cid:173)
`larly wish to express our gratitude to the late Mr. Masahito Ninomiya
`for helping us to succeed in providing this engine to our-customers.
`
`• References
`
`(I) Yoshihiro Fujiyoshi, Urata, Suzuki, Fukuo: Study of . Non(cid:173)
`Throttling Engine Using Early Intake Valve Closing Mechanism.
`Report No. I. Society of Automotive Engineers of Japan (JSAE).
`Printed Materials for Presentations 924006, 924 1992-10
`(2) Shinichi Nagumo, Hara: Improved Fuel Efficiency by Control of
`Intake Valve Closing Timing. JSAE Paper 9540921 , Vol. 26 No.
`4, October, 1995
`(3) Richard Stone, Eric Kwan: Variable Valve Actuation Mechanisms
`and the Potential for their Application. SAE Paper 890673. 1989
`(4) T. Ahmad, M. A. Theobald (GMR): A Survey of Variable-Valve(cid:173)
`Actuation Technology. SAE Paper 891674, 1989
`(5) T. W. Asmus: Valve Events and Engine Operation. SAE Paper
`820749, 1982
`(6) Hitomi Mitsuo, Sasaki, et al. : Mechanism of Improving Fuel
`Efficiency by Miller Cycle and its Future Prospects. SAE Paper
`950974, 1995
`(7) James H. Tuttle: Controlling Engine Load by Means of Early
`Intake-Valve Closing. SAE Paper 820408, 1982
`(8) R. A. Stein, K. M. Galietti, T . G . Leone: Dual Equal YCT-A
`Variable Camshaft Timing Strategy for Improved Fuel Economy
`and Emissions. SAE Paper 95975. 1995
`(9) Naoharu Ueda, lchimaru, Sakai, Kanesaka: High Expansion Ratio
`Gasoline Engine Using Rotary Valve for Intake Manifold Control.
`Report No. 3. JSAE Printed Materials for Presentations 946 1994-
`
`60
`
`i
`i
`
`.i
`
`10. 9437458
`( IO)Shinichi Sano. Kamiyama. Ueda: Improving Thermal Efficie 1
`by Means of Cylinder Bore and Offset Crankshaft. JSAE Prin
`Materials for Presentations 966 1996-10
`
`• Authors
`
`T. TAKAOKA
`
`K. HIROSE
`
`T. UEDA
`
`Y. NOUNO
`
`H. TADA
`
`H. KANAI
`
`- --- ------ - ------ -- ---.. · -··
`
`. ···----- - -
`
`BMW1081
`Page 8 of 19
`
`

`

`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`FORD MOTOR COMPANY
`
`Petitioner,
`
`V.
`
`P AICE LLC & ABELL FOUNDATION, INC.
`
`Patent Owner.
`
`DECLARATION OF WALT JOHNSON
`
`I, Walt Johnson, hereby declare as follows:
`
`1.
`
`I am presently employed as the Patent and Trademark Resource Center (PTRC)
`
`Librarian at the Minneapolis Central Library. The Minneapolis Central Library is a PTRC
`
`located in Minneapolis, Minnesota. I have personal knowledge of the matters stated below. I am
`
`over 18 years of age, and I am competent to testify regarding the following.
`
`2.
`
`It is the normal course of business for the library services to index and catalog
`
`technical reference materials for incorporation into our facility in order to provide access to
`
`intellectual property information. Once received, a reference stamped with the date of receipt and
`
`placed on the shelf within a few days.
`
`3.
`
`Attached as Exhibit A to my declaration is a true and accurate copy of a
`
`technical article titled "A High-Expansion-Ratio Gasoline Engine for the Toyota Hybrid System"
`
`that was authored by T. Takaoka, K. Hirose, T. Ueda, Y. Nouno, H. Tada, and H. Kanai.
`
`BMW1081
`Page 9 of 19
`
`

`

`4.
`
`The first page of Exhibit A includes an imprint of the Minneapolis Public
`
`Library and Information Center's, which is now called the Minneapolis Central Library after a
`
`merger with the Hennepin County Library system, property stamp together with a stamped date
`
`of "May 2 _, 1998." The second digit of the date stamp is not clear; however, it is clear that the
`
`stamped date is between May 21-29, 1998. Therefore, I understand that the stamped date is May
`
`29, 1998 at the latest. This property stamp and date would have been placed on the volume at the
`
`time it was being processed by the library services at the Minneapolis Public Library and
`
`Information Center.
`
`5.
`
`I have knowledge that there existed no time between the processing date of
`
`around May 29, 1998 and December 23, 2014 when the technical reference attached as Exhibit A
`
`was not publically available at the Minneapolis Public Library and Information Center or the
`
`Minneapolis Central Library, except between August 2002 and May 20, 2006 while the library
`
`was in a smaller, temporary location during the contstruction of the new Minneapolis Central
`
`Library. Older issues of most magazines were not available to staff or public during this period.
`
`6.
`
`The technical reference attached as Exhibit A would therefore have been
`
`indexed and searchable by the general public since around May 29, 1998.
`
`7.
`
`The technical reference attached as Exhibit A would have been indexed and
`
`searchable by the general public well before September 1998.
`
`I declare under the penalty of perjury that the foregoing is true and accurate to
`
`the best of my knowledge.
`
`~3 P~c...-, ~01~
`Date
`
`- 2 -
`
`BMW1081
`Page 10 of 19
`
`

`

`EXHIBIT A
`EXHIBIT A
`
`1111111
`
`BMW1081
`Page 11 of 19
`
`

`

`M I N ~/ E AP .J LIS PU B L IC L I B R A R Y
`INFORMATION CENTER
`. AND
`
`1
`
`,·
`
`..
`
`,.
`
`r f
`
`I .
`
`-
`
`·,
`
`',
`
`;~
`
`STACKS
`
`p
`
`'f··
`?
`
`.
`
`' ~.....
`
`BMW1081
`Page 12 of 19
`
`

`

`1:
`j;
`lj
`
`Contents
`[> Special Edition for Prevention of Global Warming -CO2 Reduction(cid:173)
`Not Only as a Businessman, but as a Citizen
`··· .. ··By Akio Matsubara .......................................................................................................................................................... .
`, CO2 Reduction in Automotive Development
`···· .. ·By Naoto Kushi·· .............................................................................................................................................................. .
`, Fuel Efficiency Improvement of Gasoline Engine Vehicle
`·······By Nobutaka Morimitsu··························· .. ·······················································································································
`, Development of Fuel Economy SW-20 Gasoline Engine Oil
`·······By Kenyu Akiyama/ Hiromi Kawai/ Shinichi Sugiyama·········"················································-.................................... .
`, Contributions of Automatic Transmission to Fuel Economy
`·······By Sinya Nakamura/ Masahiro Kojima/ Katsumi Kohno ............................................................................................... .
`, Development of D-4 Engine
`"·····By Zen.ichiro Mashiki/ Souichi Matsushita/ Takeshi Gouno ......................................................................................... ..
`, Electric Vehicle "RAV4 EV"
`·· .. ···By Masao Kinoshita/, Sadahiro Kimura ............... : ............... , .. : ........................................................................................ .
`Introduction of EV Commuter "e-com"
`....... By Makoto Yamada/ Keiji Kogaki/ Toshiyuki Sekimori/ Tetsuhiro Ishikawa ............................................................... .
`• A Development of Toyota Hybrid System
`....... By Shinichi Abe/ Takeshi Kotani/ Ryuji Ibaraki/ Kazuo Tojima/ Sumikazu Shamoto/ Akira Sakai ........................... ..
`, A High-Expansion-Ratio Gasoline Engine for the TOYOTA Hybrid System
`.... ···By Toshifumi Takaoka/ Katsuhiko Hirose/ Tatehito Ueda/ Yasushi Nouno/ Hiroshi Tada/ Hiroshi Kanai ................. .
`• Production Engineering Development for EV, HV Units
`....... By Ken Tanoue/ Hiroshi Miyazaki/ Yasutomo Kawabata/ Toshiaki Yamamoto/ Takao Hirose/ Hajime Nakagawa· .. ·······
`• Development of Electric Vehicle Powered by Fuel Cell
`·······By Yasuhiro Nonobe/ Yoshio Kimura····························· .. .............................................................................................. .
`• CO2 Reduction Activities in TMC Production Process
`··· .. ··By Hidehiro Ono/ Wataru Sato/ Tomoki Nakagaki/ Takeo Sakai ................................................................................. ..
`
`,
`
`[> Technical Paper
`• An Automatic Offsetting Method of Composite Surfaces
`....... By Hiroyuki Kawabata/ Yukitaka Fujitani/ Junji Ishida/ Hiromi Morisaki .....................................................................
`• Development of TOYOTA New BEAMS 1UZ-FE Engine
`··· .. ··By Kenji Watanabe/ Tetsuji Asahi/ Minoru Iwamuro/ Kunihiko Satou/ Tsutomu Hiyoshi/ Shigeo Kikofr..................
`• A Development of Easy-Column Shift
`....... By Yoshitaka Sato/ Harumi Minoshima/ Minoru Makiguchi ........................................................................