Page 1 of 28
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`BOSCH-DAIMLER EXHIBIT 1012
`
`BOSCH-DAIMLER EXHIBIT 1012
`
`Page 1 of 28
`
`

`
`INTEFHNDUSTRY EMISSION CONTROL
`
`INTRODUCTION
`
`The Inter-Industry Emission Control Program (IIEC) was formed by Ford Motor Company and the Mobil Oil
`Corporation in April. 196?, as a multimillion dollar, three-year cooperative research effort on automotive emission
`control, with Ford as Project Manager. Soon after its inception, five other oil companies joined the program, and
`in July. 19614. MISC‘ became international. when three Japanese automobile manufacturers and one ltalian auto-
`mobile producer joined as cooperative research partners. The IIEC membership includes:
`
`American Oil Company
`Atlantic Richfield Company
`Fiat S.p.A._
`Ford Motor Company — Project Manager
`Marathon Oil Company
`Mitsubishi Motors Corporation
`Mobil Oil Corporation
`Nissan Motor Company, Ltd. (Datsnnl
`The Standard Oil Company l_Ohio_:u
`Sun Oil Company
`Toyo Kogyo Company. Ltd.
`
`QOOOIOIIIUI
`
`Subsequently, arrangements were made for
`AG. and Toyota Motor Co., Ltd.
`
`IIEC‘ research results to be made available to Volkswagenwerk
`
`three and one half years of the Program the llEC' member companies conducted joint research
`For the First
`studies to develop experimental Iiardware and fuel systems to meet the very low emission targets established by
`the IIEC. These emission targets as compared to an uncontrolled car were:
`
`IIEC
`
`Exhaust Emission Targets
`gin.-"mile
`
`Typical Uncontrolled Vehicle
`gm.-‘mile
`
`Ht‘
`(‘D
`
`NO,‘
`
`t'J.8'-_’
`7. I
`
`t'l_6R
`
`13-16
`83-90
`
`3.5-?
`
`The above targets were established in aeeordance with the Federal Test Procedure (F..T.P.l
`that time.
`
`in existence at
`
`The principal research results of the experimental efforts of the IIEC Program in attempting to reach its own
`targets on the (7-mode '3-eyelel FTP as well as the initial
`test results obtained on a revised test procedure and
`driving schedule (CV3) were reported in eight separate SAE papers presented in January l9':'l. The eight SAE
`papers are available in :1 SAE Special Publication #36 I.
`
`Since the earlier report. the IIEC has heen conducting extensive research efforts in an attempt to meet its revised
`emission objectives which are based on the very severe I976 vehicle emission standards established by the Clean
`Air Act Amendment of December 3 l. l9?tl.
`
`low vehicle mileage are based on a very minimal anticipated
`These new IIEC emission targets required at
`depreciation in emission control perform:-mce with mileage accumulation. The new low mileage emission targets
`referenced to the vehicle emission standards required for [976 are:
`
`Page 2 of 28
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`Page 2 of 28
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`

`
`IIEC
`
`Low Mileage Exhaust Emission Targets
`CV5 CIH gmlmile
`
`1976
`
`Exhaust Emission Targets
`CVS CIH gmfmile
`
`HC
`co
`NOX
`
`0.19
`1.5
`o.13*
`
`* (0.26 wfo use of a N0; catalyst)
`
`0.41
`3.4
`0.4
`
`The research results of the last sixteen months of development by the IIEC are documented herein in seven
`separate SAE papers. In addition, three additional papers by Volkswagenwerk A.G. and Toyota Motor Co.. Ltd.
`are also included.
`
`Page 3 of 28
`
`‘l._
`
`J‘.'l—‘["["I"'1_'I_‘l”‘l”"l_'f“'l”‘l“?J”L;“L4Lia9,
`
`Page 3 of 28
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`

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`IF...1pl1r|1_|jp|1_rv1,|1,'jr1r.1F.-1,1,1,1.1,1.111,_.
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`Page 4 of 28
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`Page 4 of 28
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`

`
`TABLE OF CONTENTS
`
`Introduction
`
`Status Report on HCICO Oxidation Catalysts for Exhaust Emission Control
`F. W. Snyder — Mobil Research & Development Corp.
`W. A. Stover — Mobil Research & Development Corp.
`H. G. Lassen —— Ford Motor Company
`NO,‘ Reduction Catalysts for Vehicle Emission Control
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`Paper No.
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`c — Low Emission
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`. 720484
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`G. H. Meguerian —— American Oil Company
`E. H. Hirschberg ~ American Oil Company
`F. W. Rakowsky —- American Oil Company
`C. R. Lang —— Ford Motor Company
`D. N. Schoci-L ——- Ford Motor Company
`Methods for Fast Catalytic System Warm-Up During Vehicle Cold Starts .
`W. E. Bernhardt —— Volkswagenwerk AG
`E. Hoffmann —- Volkswagenwerk AG
`Engine Testing of Catalysts ——- Conversion Versus lnlet Conditions .
`P. Gser — Volkswagenwerk AG
`D. H. Pundt — Volltswagcnwerk AG
`W. Buttergeit —— Volkswagenwerk AG
`Mitsubishi Status Report on Low Emission Concept Vehicles .
`Y. Kaneko ~ Mitsubishi Motors Corp.
`Y. Kiyota —— Mitsubishi Motors Corp.
`Economical Matching of the Thermal Reactor to Small Engin
`Concept Vehicles
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`Y: Nakajima — Nissan Motor Co.. Ltd.
`Y. Hayashi —— Nissan Motor Co.. Ltd.
`K. Sugihara — Nissan Motor Co.. Ltd.
`Fiat Status Report On Low Emission Concept Vehicles .
`Carlo Pollone — Fiat S.p.A.
`Toyo Kogyo Status Report on Low Emission Concept Vehicles .
`K. Tanalca —— Toyo Kogyo Co.. Ltd.
`M. Akutagawa — Toyo Kogyo Co.. Ltd.
`K. Ito —— Toyo Kogyo Co.. Ltd.
`Y. Higashi — Toyo Kogyo Co._. Ltd.
`K. Kobayashi — Toyo Kogyo Co.. Ltd.
`Toyota Status Report on Low Emission Concept Vehicles .
`T. lnoue —— Toyota Motor Co.. Ltd.
`K. Goto — Toyota Motor Co.. Ltd.
`K. Matsurnoto — Toyota Motor Co., Ltd.
`Ford Durability Experience on Low Emission Concept Vehicles .
`R. M. Campau —- Ford Motor Company
`A. Stefan —— Ford Motor Company
`E. E. Hancock —- Ford Motor Company
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`Page 5 of 28
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`Page 5 of 28
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`

`
`Methods for Fast
`
`Catalytic System
`
`Warm-Up During
`
`Vehicle Cold Starts
`
`W. E. Bernhardt
`
`and E. Hottmann
`VOLKSWAGENWERK AG
`
`INTRODUCTION
`
`To achieve the emission targets prescribed by law for
`1975/76 a number of emission concepts with conven-
`tional internal combustion engines and emission control
`systems have been examined by the automotive indus-
`try. Catalytic converters,
`thermal reactors and a com-
`bination of tltese two have been considered as emission
`control systems ti)‘. Low emission values have been
`
`attained with these concepts when the engine is under
`warm working condition. However,
`the difficulties
`
`lie mainly in the warm-up phase during cold vehicle
`start—up.
`
`To improve the over-ail eliectiveness of catalytic sys-
`tems at vehicle start-up. extensive experimental
`tests
`were carried out during the warm-up phase on various
`after burning systems by the Research Department of
`the Volkswagenwerk AG. The intent of this paper is to
`illustrate the utility of improving the warrn-up charac-
`teristic of catalytic emission control systems for achiev-
`ing very low emission levels.
`
`ABSTRACT
`
`
`
`During vehicle cold start, emissions. mass flow rates. and catalytic converter space velocities vary by orders of
`magnitude. Therefore. catalytic exhaust" control systems must he designed to operate at high efficiency almost from
`the moment of engine start-up. Catalysts must reach their operating temperature as quickly as possible. Therefore.
`the utility of different methods for improving the warm-up characteristics of catalytic systems is illustrated.
`
`A very elegant method to speed the warm-up is the use of the engine itself as a “preheatcr" for the catalytic con-
`verters. High exhaust gas enthalpy to raise exhaust system mass up to its operating temperature is obtained by the
`use of extreme spark retard, stochiometrie mixtures. and fully opened throttle. Intensive studies to investigate the
`effects of concurrent changes of spark timing and air/fuel mixtures on exhaust gas temperature. enthalpy. NO; and
`HC emissions are discussed.
`
`Finally. NO,. catalyst characteristics are dealt with. because the NO. catalyst is the first in a dual-bed catalytic
`system. The NO,‘ catalyst should have high activity, low ignition temperature, and good warm-up performance. If
`the NO; catalyst has a fast warm-up rate. this would result even in a significant improvement in the warm-up charac-
`teristic of the I-IC/C0 bed.
`
`
`
`*Number in (
`
`)
`
`indicates reference at end of paper.
`
`Page 6 of 28
`
`Page 6 of 28
`
`

`
`J"_lT‘_T'“_l”'_l"'1“I“I"l‘l‘l‘Il'l‘l‘l'l'l'l'l‘
`
`WARM-UP METHODS FOR CATALYTIC SYSTEMS
`
`Catalytic emission control systems described in this
`paper operate mainly with the dual—bed
`catalytic
`process. The lirst bed contains the reduction catalyst
`which reduces the oxides of nitrogen {NO_..) by carbon
`monoxide
`{CO}. hydrogen {H2}. and hydrocarbons
`(HC) which are present
`in the exhaust gases. The
`reaction between NO. and C0 will only take place
`
`in
`the amount of oxygen (02) present
`providing that
`the exhaust gas is strictly limited to low concentrations.
`This oxygen limitation is met by adjusting rich fuel/air
`mixtures.
`
`The second catalyst bed contains the oxidation cata~
`Iyst which burns the carbon monoxide and hydrocarbons
`after introducing secondary air between the first and
`second beds. The quantity of secondary air is set high
`enough to ensure that
`there is excess oxygen for all
`driving conditions.
`
`illustrates a dual-bed axial-Ilow converter.
`Figure 1
`Such a concept using fresh catalysts when tested accord-
`ing to the CVS cold-hot
`test procedure gave emission
`values which were still
`twice as high as the exhaust
`emission standards specified for model year 1976. The
`results would be considerably better if
`the catalytic
`emission system could be wartned up very quickly from
`
`the moment of cold engine start-up. Methods to speed
`the warm-up are listed below:
`
`' Reduce the heat capacity of the exhaust system be-
`tween the engine and the dual bed converter.
`
`' Reduce the heat capacity of the catalyst. use smaller
`catalyst quantities. and smaller catalyst particles.
`
`' Mount the converter very near to the engine exhaust
`valves.
`
`'
`
`Introduce secondary air in front of the first bed dur-
`ing the initial 120 seconds after cold engine start—up:
`then switch the secondary air to the connecting pipe
`between NO. and HC/CO beds (staged secondary
`air) .
`
`Even when these features were used.
`
`the dual-bed
`
`system illustrated in Figure 1 could not reach the targets
`of 0.41 gm. HC/rni., 3.4 gm. C0/mi.. and 0.4 gm.
`NO, mi. as proposed in the Federal Register for 19%.
`
`It is particularly difiicult to fulfill the emission stan-
`dard for oxides of nitrogen as the temperature in the
`NO, bed increases very slowly in systems which are
`designed to allow an adequate residence time for the
`exhaust gases.
`In Figure 2 is illustrated the mid-bed
`temperature of a VW radial-llow converter with a 1.3
`liter N0; bed during the CVS cold start. It
`is plain to
`
`lllllll BEII CATALYTIC CONVERTER
`IAXIAL FLOWI
`
`
`
`INSPECTION HOLES
`
`I.l.'lUVEH PLATE
`
`EXHAUST
`GAS OUT
`
`EXHAUST
`GAS IN
`
`HE/CD CATALYST BED
`
`
`
`
`
` tttu,.t:ArALvsr sen W
`
`SECONDARY AIR
`
`Page 7 of 28
`
`Figure 1
`
`2
`
`Page 7 of 28
`
`

`
`llll; lllll-BEIJ TEMPERATURE Ailll 00ll0ENTRlT|0ll IJIJRIRE
`lI0l|J START PORT|0ll 0E INS TEST
`
`VW 1.7 LITER {TYPE 4}. RADIAL FLOW DUAL-BED CONVERTER, PELLETED CATALYSTS
`
`SPEED-KM/HR
`
`SECONDARY AIR SWITBHED
`TD BETWEEN BEDS
`
`‘I00
`
`TEMP.— °B
`
`ND,‘ MID-
`BED TEMP.
`
`EXHAUST
`
`POOR RED UCTIDN
`
`{LEAN MIXTURE]
`
`GOOD REDUCTION
`
`TRIDH MIXTURET
`
`soon
`
`4000
`
`3000
`
`2000
`
`1000
`
`START-UP
`
`_ 50
`
`H 150
`
`200
`
`250
`
`TIME — SEC
`
`Figure 2
`
`ignition temperature of approx.
`the catalyst
`see that
`250°C was reached in the pelleted NO, catalyst bed
`after 195 seconds in spite of the use of the staged secon-
`dary air feature. The ammonia problem can also be seen
`in Figure 2 although this is not being dealt with in this
`connection. For more detailed information refer to
`Meguerian (2).
`
`To illustrate the problems of catalytic exhaust emis-
`sion control systems Figure 3 shows the tail pipe emis-
`sions as well as the exhaust gas flow rate during the
`first 240 sec. of a CVS cold start test. Both the concen-
`
`trations and the mass flow rate vary by orders of mag-
`nitude during the CVS cold start test procedure. Further-
`more, the concentrations of C0 and HC are particularly
`high during the tit-st 80 see. For this reason, catalytic
`emission control systems must be designed to operate
`
`that means high reduction and
`with high efficiency,
`conversion rates, as quickly as possible after the engine
`start-up. The catalysts should reach their operating
`temperatures within 20 see. so that the emissions which
`are produced during the warm—up period of the engine
`can be controlled as quickly as possible.
`
`To do this. further methods for improving the warm-
`up characteristics of dual-bed systems should be in-
`vestigatcd.
`
`One method which promises success is a thermal
`reactor acting as a "p1'eheater" for improving catalytic
`converter pcrfot'nutnce. The thermal reactor is located
`
`at the cylinder heads. When starting with a rich fuel/air
`mixture. oxidation of carbon monoxide and hydro-
`carbons after adding air. ensures rapid warm-up of the
`
`Page 8 of 28
`
`lulvl
`
`Page 8 of 28
`
`

`
`l'l'l'l"l'l‘l‘l‘l‘J”'.lf7JLl;lLllLlLJLl'—'_
`
`[IVS Blllll STAIN RAW EHISSIBNS Ill BlllclPARlSllll WITH VEll|lIl.E
`SPEED Allll EXHAUST GAS Flfllll RATE
`
`VEHICLE VW TYPE 4.1.7 LITEFI ENGINE
`
`ilflfll]
`
`2000
`
`|1}mm
`1500
`
`N03 -
`PPM
`
`Ht: —
`
`l
`‘
`
`-ltL
`
`AL ,,
`
`GAS
`
`FLOW *
`
`I115
`
`I].5{I
`
`0.25
`
`I]
`
`50
`
`35
`
`[I
`
`3 TI
`'2'
`3
`
`12
`
`8 4 I
`
`]
`
`SPEED -
`MPH
`
`ctt— %
`
`CD2—%
`
`0
`
`an
`
`an 120 160 Ztlll 240
`
`ll
`
`40
`
`B0
`
`120 lfifl 200 240
`
`TIME —SEC
`
`TIME — SEC
`
`Figure 3
`
`* STANDARD CUBIC METEFHMIN
`
`catalyst. In this system. secondary air is introduced in
`front of the thermal reactor at
`the cylinder head. and
`the reduction catalyst works as an oxidation catalyst in
`the starting phase. Due to the burning of high HC and
`CO emission levels directly after start-up a rapid warm-
`up of the after burning system and therefore a rapid
`attainment of operating tcmperatttre is ensured.
`
`is not necessary during
`A catalytic reduction of NO.
`the cold start phase because the engine operating tem-
`perature during this period is not high enough to pro-
`duce very high NO. emissions. After the catalysts in
`both beds have reached their operating temperatures
`(100-120 see. after CVS cold start—up'}.
`the thermal
`reactor must be switched off. This is brought about by
`the transfer of secondary air introduction to the connect-
`ing manifold between the first and second catalyst beds.
`
`Figure 4 illttstrates a catalytic emission control system
`together with major hardware components which has
`been developed for research purposes. It consists of a
`monolithic dual-bed converter. series connected thermal
`reactor. by-pass
`system. exhaust gas
`recirculation
`{EGR} , EGR cooler. regulating valve, and EGR filter.
`The efiiciency of such an emission control concept can
`be improved by the introduction of an additional igni-
`tion system in the thermal reactor. By enrichment of the
`air/fuel mixture, an improvement can be obtained as
`
`Page 9 of 28
`
`can be seen in Figure 5. With 10% rich fuel/air mix»
`tures (AXF : 13.0), the exhaust gas temperature at the
`thermal
`reactor outlet
`reaches
`300°C.
`five
`to six
`seconds earlier
`than with normal mixture strength
`{A/F : I6.0}.
`
`This high exhaust gas temperature increases the
`reactor warm-up rate. too. This means that the catalysts
`also reach their operating temperatures of about 300°C
`at least five seconds earlier.
`
`Another method of improving the warm-up rate of
`the catalytic system with series connected thermal
`reactors is to cause an ignition failure of a single cylinder
`charge (which contains approx. 20,000 ppm HC) and
`at
`the same time to increase the idling speed of the
`engine together with wide open throttle. The technique
`produces an increased [low rate of exhaust gases with
`high unburned components during the cold start phase:
`the chemical energy of which can be converted into high
`exhaust enthalpy. This comparatively rich fuel/air mix-
`ture can be ignited in the reactor by an additional spark-
`plug. With an automatic control device.
`the ignition
`failure of a particular cylinder can be controlled in
`accordance with the firing order. After the exhaust gas
`has attained the operating temperature required by the
`catalysts the ignition system will revert to normal.
`
`Page 9 of 28
`
`

`
`CIIMIIIIIEII REACTIIII-ERR-CATALYST SYSTEM
`MAIUR IIAIIIIIRRE CIIMPIIIIEIITS
`
`SECONDARY AIR INJECTION
`
`SECONDARY AIR PUMP
`
`EER ON-OFF VALVE
`
`W
`
`ELECTRONIC
`CONTROL UNIT
`
`sun FILTER
`
`is
`“
`
`
`
`MDNIJLITHIC run,
`CONVERTER
`
`5';If
`
`REACTOR
`
`EGR SYSTEM
`
`EGR COOLER
`
`MONOLITHIC NO;
`CONVERTER
`
`NOBLE METAL HCKCO CONVERTER
`
`BY- PASS SYSTEM
`
`REACTOR
`
`Figure 4
`
`INFLUENCE CE RICH AIR-FUEI MIXTURE IIII REACTOR IIUTIET TEMPERATURE
`EUR BETTER SYSTEM IIIRRM-UP
`
`IUD CU IN THERMAL REACTOR
`WITH ADDITIONAL IGNITION
`
`SYSTEM IN THE REACTOR
`
`WITHOUT WARM - UP SPARK RETARD
`
`OUTLET
`
`REACTOR
`
`TEMP. —°C
`
`0
`
`an
`
`an
`
`120
`
`160
`
`200
`
`240
`
`TIME — SEC
`
`Figure 5
`
`Page 10 of 28
`
`Page 10 of 28
`
`

`
`Figure 6 shows the results of an engine cold start test
`employing this warm-up system. The illustration shows
`the time dependence of the exhaust temperature in the
`reactor core and at the reactor outlet as a function of
`
`throttle opening. The test was carried out at an engine
`speed of 2800 rpm. The throttle valve angle was in-
`creased lrom 5° to 35°. A maximum speed governor
`controlled the ignition failure. It can be seen in Figure
`6. for example, that with a throttle valve opening of
`35° a reactor outlet temperature of 360°C is achieved
`in 10 sec. Even when considering the heat loss of the
`exhaust system between the thermal reactor and the
`catalytic system.
`it can be ensured that
`the operating
`temperature of the Iirst bed can be reached in a very
`short interval of time.
`
`Especially when operating under rich fuel/air con-
`ditions with thermal reactors mounted at
`the cylinder
`heads temperatures could be produced which are above
`the melting temperature of the monolithic materials.
`such as Cordierite (Mg2AE4SlSO|fiJ. Mullite {3Alg0--
`2Si0_»). and Alumina
`ta-A1303).
`In Figure 7.
`the
`monolithic catalyst reached temperatures of more than
`l350°C. It can be seen by the figure that the center of
`the monolithic catalyst has been melted when operating
`
`of the thermal destruction of the material could lay in
`the unequal distribution of the active components on
`the support material. This unequal disttibtttion of
`material, as for example 010, could have led to a drastic
`reduction of the melting temperature from I350 down
`to 975°C. Similar symptoms in the outer coating were
`observed during the aging process of catalysts by I. F.
`Rod1(3}.
`
`In place of the thermal reactors, monolithic noble
`metal catalysts could be employed as warm-up elements
`because the majority of the HC and CO emissions pro»
`duced by an engine are emitted in the first two minutes
`of the 42-min. CV5 cold-hot test. while the NO. emis-
`
`sion in general is produced over the whole test period.
`For this reason, a monolithic HC/CO converter at each
`side of the engine which reduces the high carbon mon-
`oxide and hydrocarbon raw emissions with high elli-
`ciency could be used to improve the warm-up character-
`istic. Due to the good cold start performance and the
`low ignition temperature.
`the platinum monolith is
`particularly suitable. The ignition temperature for C0
`is approximately between 200 and 280°C and for l-lC
`{hexane} between 240 and 340°C.
`
`together with a front mounted reactor. Tests hate
`proved that a too high inlet concentration of HC/C0 is
`not the cause of this high bed temperature. The cause
`
`To give a complete presentation of warm-up possi-
`bilitics. other more sophisticated methods for rapid
`warm-up of catalytic systems should be mentioned.
`
`EFFECT [IF lIllNlRllllE|l IGNITION FAILURE [IN REACTOR WARM-llP
`ASA Flllltillllll lli THRIITTLE IIPENINR
`
`8|] CU IN THERMAL REACTOR WITH SPARKPLUGS IN THE
`INLET TUBES, IDLE SPEED 2800 RPM, IGNITIDN FAILURE
`CONTROLLED BY A MAX SPEED GDVEBNDR
`
`lllllll
`
`Bflll
`
`ans
`
`TEMP.—
`
`son
`
`on
`
`"T
`
`NTHBOTTLE ANGLE
`--'
`35° tzHALF THROTTLE}
`F150
`
`5° {NORMAL OPERATION)
`
`0
`
`HI
`
`tlfl
`
`lifl
`
`RD
`
`TDD
`
`120
`
`TIME - SEC
`
`Figure 8
`
`6
`
`Page 11 of 28
`
`Page 11 of 28
`
`

`
`MIINIILIIHIB BATALYSI FAILURE
`During Rapid Warm-upPeI1urmance
`
`Page 12 of 28
`
`Figure 7
`
`Page 12 of 28
`
`

`
`
`
`
`
`l‘l‘l*l"J‘_l'_t‘_t‘_t“_t"‘_l"_l“*_l""_l"_l’“.
`
`One such approach involves the use of a gasoline
`heater,
`the other approach involves an electric heater.
`An electrically heated I-ICXCO radial-flow converter in
`which high temperature resistance heating rods were
`installed was tested within the IIEC Program (4).
`These heating rods were capable of heating the first
`layer of the catalytic bed (approx. 0.5 lb.)
`from the
`ambient
`temperature to 300°C within 30-40 sec. at
`start-up. Power
`requirements were available from
`vehicle electrical system. Similar results were obtained
`by the VW Research Department with pelleted catalysts
`in axial-llow converters which were however supplied
`by an external electrical system. The power available
`from the battery alone was not suflicient.
`
`in most cases the gasoline heater has the disadvantage
`of not being able to operate against the relatively high
`exhaust gas back pressures. A further disadvantage is
`that an auxiliary heater could produce considerably
`high emissions. Without
`taking the engine emissions
`into consideration. the following table shows the values
`produced during a CV5 test by a particular heating
`system:
`
`HC 0.58 gm./mi.
`
`CO 0.42 gm./mi.
`
`NO, 0.03 gm./mi.
`
`It may be surprising that for HC this is more than
`40% above the 1975 target, while the C0 emission is
`approx. 12% and the N0. emission is approx. 8% of
`the emission s1andat'ds proposed for 1976. Fortunately,
`a properly designed gasoline heater operating only 100
`to 120 see. after engine start-up has considerably lower
`emissions.
`
`reaction
`improving the initial
`Another method of
`temperature of the catalytic system is to increase the
`exhaust gas temperature by altering the ignition timing
`into the region after T.D.C. By the use of extreme re-
`tarded timing at vehicle start-up for example. the cata-
`lyst operating temperature of 250°C was reached 25
`sec. earlier in the CVS test" than by normal
`ignition
`timing. The influences which the ignition timing has
`upon the combustion process (exhaust gas temperature
`and exhaust gas emissions} are discussed in more detail
`in the next chapter. Based on extensive single cylinder
`measurements the utility of this warm-up technique is
`illustrated because of
`its particular
`importance for
`speeding the warm-up performance of catalytic systems.
`
`WARM-UP TECHNIQUE BY SPECIAL
`ENGINE OPERATION
`
`Only by employing after-burning systems. can the ex-
`tremely low emission targets for model year 1975/76
`be reached. Therefore, one of the most important tasks
`
`Page 13 of 28
`
`of the internal combustion engine is to ensure high effi-
`ciency almost
`immediately after engine start-up by
`changing the engine conditions especially for this re-
`quirement.
`It has been found that under appropriate
`operating conditions the engine itself is able to act as
`a preheater for the catalytic system. Warm-up spark
`retard and an increased idling speed of the engine with
`full open throttle lead to higher exhaust temperatures
`and thereby to a greater enthalpy of the exhaust gases.
`so that the after burning system could be brought rapidly
`
`up to its operating temperature.
`
`Figure 8 shows schematically an internal combustion
`engine as an open thermodynamic system. If steady flow
`is assumed the application of the First Law of Thermo-
`dynamics gives important information about possibili-
`ties of increasing the exhaust gas enthalpy (see Figures
`3 and 9) .
`
`As shown in the equations in Figure 9 the total chem-
`ical energy of the exhaust gases can be used to increase
`the exhaust gas enthalpy if
`the shaft work is zero
`(WI) : 0) . In practice this operation condition cannot
`be achieved because the engine could not overcome its
`own mechanical friction. The maximum heat of the
`exhaust gases ((1.2) max is therefore not at the no work
`condition, but at an indicated output which is appro-
`priate to the mechanical friction of the engine. A second
`factor is the quantity of the exhaust gas llow rate which
`can be increased by opening the throttle. In an engine
`the condition We : 0 can be attained by altering the
`ignition timing to ‘‘retard’'. In this case the energy re-
`lease rises very late so that the work clone on the piston
`becomes less.
`
`To illustrate the influence of the ignition timing on
`the combustion process more clearly, Figure 10 should
`be considered. This figure illustrates the results of a
`thermodynamic analysis of two combustion processes
`at low load. The combustion cycles differ only in the
`ignition timing (9° B.T.C. as opposed to normal adjust-
`ment of 27"‘ B.T.C.} whereas other engine parameters
`such as airX fuel ratio and volumetric efficiency remained
`equal. Essential differences can be seen already in the
`pressure-time history (upper diagram). In the case of
`extreme retarded timing the maximum pressure is re-
`duced from 16.5 - I05 to 7.8 -
`l(}5Pa (pascal. newton)’
`sq. meter} at 20° and 50° A.T.C., respectively. The
`expansion process of the working fluid can be noticed
`very late. runs at comparatively high pressure level and
`due to the opening of the exhaust valve it is cut off at
`a high pressure. Due to this energy loss to the ambient
`(that is loss of the work done on the piston) the indi-
`cated mean effective pressure was
`reduced from
`3.90 - 105 to 3.05 -
`l05Pa. This result can be taken
`directly from the energy release diagram (lower dia-
`gram) .
`
`Page 13 of 28
`
`

`
`APPIICATIIIN IIF FIRST LAIII CF THERAIIIIIYNAIAICS
`TII AN INTERNAL CIIMBIISTIIIN ENCINE
`
`Open Stea:Iv—F|uw Svstem
`
`
`
`I112
`
`Ii12—W12 = In I hz-h1 +‘/z{ V23-V15-'II
`
`I-112-HEAT,W12—-WI]R|(, rn-MASS FLOW RATE, h—EI\ITHALPY
`PER UNIT MASS. ‘J-VELOCITY, SUBSIIRIPT a—"AI'o‘IBlENT".
`
`Figure 8
`
`IIF THERMIIIIYNAAIICS TII
`APPIICATIIIN OF FIRST IAIII
`SENSIBIE HEAT III THE EXHAUST CASES
`
`INCREASE THE
`
`If No Work W12 ls Done By The Engine The Sensible Heat E112
`Reaches Its Maximum
`
`W12=U
`
`
`
`f112=rh[h2-h1+%lV22—\-H21]
`
`2
`ha=h1+!E—_
`
`A—lJUTLE'l'AREA.
`
`
`O.12=|'I‘I[h2+'/2V22—I1aI
`vz =rnuAg-92}:
`0-nemsmr
`
`ri13
`.
`_
`=-
`-
`[112 m(h2 haI+Am2‘p2}2
`
`Up 3 Tip {II ;
`
`t-TEMP;
`
`T.'|J—SPEC|FIC HEAT AT CONSTANT PRESSURE
`
`f'112=rhCn{t2—taI+‘/2
`
`.133
`
`(A2 - P232
`
`{SAME SYNIBU LS AS IN FIGURE BI
`
`Figure 9
`
`Page 14 of 28
`
`Page 14 of 28
`
`

`
`IIIFIIIEIIIIE Ill Ililllllllll TIMING IJN THE VAIIIIIIIIIN [IF PRESSURE Allll
`ENERGY lllllllllli
`IIIIMBIISTIIIII
`
`SINGLE CYLINDER ENGINE, "J'W1.fi LITEFI WITH MECHANICAL FUEL INJECTION,
`ENGINE CHDKING CONDITIONS, ENGINE SPEED 1500 PRNI
`
`EXHAUST GAS WARM-UP RATE EE°HlGHER l 646 V3. 580“ Cl
`
`TIMING 210 are
`TIMING 9031::
`
`25 x1|J'-5
`
`zn
`15
`in
`
`s D
`
`PRESsURE'Pa
`
`11.15 x1[I'3
`
`
`
`RELEASED ENERGY -
`|<W—HFI
`
`0-10
`
`0.05
`
`0
`
`-
`
`“E”
`95'-5”‘
`
`H‘
`" \-nsr HEAT RELEASE — an
`
`90
`
`TD!)
`CFlANKANGLE—DEGHEE
`
`Figure 10
`
`the period in
`Due to the late energy release rise.
`which the high temperatures are produced in the exhaust
`gases is considerably shortened. For this reason the
`heat loss to the cylinder walls during combustion is less.
`The same quantity of fuel
`is converted into energy in
`both cases, but
`in the case of extreme spark retard
`the piston work L. and the heat
`loss to the walls
`clue = On ~ QH is reduced. and the internal energy of
`the working gases U. : On — L.
`is increased by the
`appropriate amount. The exhaust gas temperature is
`thereby increased by 66"C from 530 to 64€>"C. The
`exhaust gas emissions are thereby also strongly influ-
`enced;
`the HC emission is reduced from I32 ppm to
`60 ppm by the high exhaust temperature. and the NO.
`emission is suppressed from [888 ppm to T20 ppm due
`to the retarded ignition timing.
`
`investigation a VW 1.6 liter
`For the experimental
`single cylinder engine with a prodttction type combus-
`tion chamber was used. A mechanical
`fuel
`injection
`system was chosen with which optimum fuel/air ratios.
`good mixture preparation, and an indcpendance from
`the distributor setting was available.
`
`The measurement of the exhaust gas temperature was
`carried out
`in the exhaust with an insulated thermo-
`couple of 1.5 mm. O.D. The holding device for the
`thermo-element was titted with a radiation shield.
`
`ID
`
`The tests began with an increased idling speed of
`2500 rpm and were later continued at 1500 rpm. The
`engine speeds were selected with respect to the highest
`possible exhaust flow rate. After adjusting the ignition
`timing the individual measuring points were chosen to a
`particular value in relation to the air flow rate. while
`the required airXfuel ratio was regulated by the fuel
`quantity. Deviations from the mean effective pressure
`p....~ : 0 had to be balanced out by adiusting the supplied
`air and fuel flow rates in stages.
`
`In addition to the measured exhaust gas temperatures
`
`Figure It shows the HC and NO, emissions as well as
`the exhaust gas enthalpy as a function of airfluel ratio
`and ignition timing. These results are in good agreement
`with the theory. As expected the exhaust gas tempera-
`ture increased very rapidly when the ignition timing
`was retarded to a region after T.D.C. However, due to
`alteration of the ignition timing the indicated output
`was decreased. as already rnentionecl. In order to keep
`the engine running the cylinder charge was repeatedly
`increased as
`the timing became more retarded until
`finally the throttle was fully open. Therefore. the lean
`limit in the ignition region after T.D.C. is given as the
`left hand limit on the performance diagrams of Figure
`I 1. The highest temperatures measured at the lean limit
`were 794°C at the engine speed of I500 rpm and 912°C
`at 2500 rpm. The lean limit with spark advance is
`
`Page 15 of 28
`
`Page 15 of 28
`
`

`
`ENGINE WARM-IIP PEREBRMANBE TEST
`
`Engine Speed 1500 RPM, Steady State, No Load.
`
`THROTTLE ADJUSTMENT
`
`EXHAUST GAS
`
`EXHAUST GAS
`ENTHALPY — KCALKHH
`
`2500
`
`1500
`
`21100
`
`1000
`
`5|]
`
`VDLMETFIIC
`EFFICIENCY
`
`/-
`
`|j— VULUMETHIC
`EFFICIENCY
`
`0 0
`\.
`o’¢"o"19o?¢’-.
`. 0.{_6)9,6 4' avg
`
`ATE
`
`TDE
`
`BTC
`
`ATE
`
`CFIANKANG LE — DEGREE
`
`Page 16 of 28
`
`Figure 11
`
`11
`
`
`
`
`
`REIZIPFIDCALEEIUIVALENCERATIO
`
`Page 16 of 28
`
`

`
`dependent on the air/fuel ratio in the same manner as
`it
`is with spark retard. However.
`the criteria for this
`lean limit is not the throttle opening but the breakdown
`of the combustion cycles which results in a rapid in-
`crease of the HC emission.
`
`The exhaust gas temperature diagram in Figure 1]
`illustrates the influence of the air-Xluel ratio and the
`
`ignition timing on the exhaust gas temperature. The
`exhaust gas temperature reaches its maximum at a
`reciprocal equivalence ratio ol’ 1M) : 1.0 because the
`combustion temperature is highest at stoichiometric mix-
`tures.
`
`The increase of air/fuel ratio at a constant spark ad-
`vance brings the exhaust gas temperature up to a max-
`imum at greatest possible air/fuel ratio.
`
`This is explained by the postponement of the com-
`bustion process into the expansion stroke which is in
`turn caused by the lower llame speed at lean mixtures.
`Furthermore.
`the volumetric efliciency increases as the
`A/F ratio becomes larger. The low exhaust tempera-
`tures at rich mixtures are attributed to the cooling eflect
`of the fuel in very rich mixtures.
`in combination with
`the volumetric cflicicncy, however, the largest influence
`on the exhaust gas temperature is exerted by the spark
`timing which brings about a large increase in the ex-
`haust gas temperature.
`
`As mentioned above. the volumetric eiliciency for the
`desired indicated output
`is dependent on the spark
`timing and increases from about 0.25 with spark ad-
`vance to a full load value of over 0.8 with spark retard.
`see Figure ll (bottom). The curves of constant volu-
`metric elficiency have the same tendency as the curves
`of constant exhaust gas temperature so that the desired
`objective of providing the hottest possible exhaust gas
`in largest possible quantities is achieved by the spark
`retard. This result is shown clearly by the enthalpy dia-
`gram. The increase in fuel flow corresponding to the
`increase in volumetric ellicicncy with spark retard raises
`the exhaust gas enthalpy (which is
`related to the
`enthalpy at ambient
`temperature} to a maximum of
`about 2750 kcal./hr. at 1500 rpm {Figure 1 I} whereas
`it is approximately 5600 ltcal./hr. at 2500 rpm.
`
`In the enthalpy diagram only the sensible heat portion
`of the exhaust energy is illustrated. The -chemical energy
`still contained in the exhaust gas, particularly when
`there is a shortage of air. is not taken into account. By
`the use of appropriate devices
`(i.e.
`thermal
`reactor
`with secondary air injection)
`this energy can be used
`to warm-up the converters in the start-up phase.
`
`In Figure it one can see that the spark timing has a
`very intensive inlluence on the composition of the ex-
`haust gases. The HC emi