United States Patent
`Griese
`
`[191
`
`[II]
`
`3,799,134
`[451 Mar. 26, 1974
`
`[54] COMBUSTION ENGINE WITH QUICK
`ARRANGEMENT FOR ITS EXHAUST GAS
`CLEANING DEVICE DURING COLD OR
`IDLE RUN
`Inventor: Wolfgang Griese, Gaimersheim,
`Germany
`
`[75]
`
`[ 7 3] Assignee: Volkswagenwerk AktiengeseUschaft,
`Wolfsburg, Germany
`
`(22] Filed:
`
`Dec. 11, 1972
`
`( 21] Appl. No.: 313,869
`
`( 30]
`
`Foreign Application Priority Data
`Dec. 14, 1971 Germany ............................ 2161946
`
`[52 J U.S. Cl. ......................... 123/119 A, 123/117 A
`[ 5 I]
`Int. Cl... ............................................ F02p 5/04
`[58] FieldofSearch ......... 123/ll7R, ll7A, ll9A
`
`[56]
`
`3,687,120
`3,507,260
`
`References Cited
`UNITED STATES PATENTS ·
`Lenz ............................... 123/117 A
`8/1972
`4/1970
`Walker ........................... 123/119 A
`
`Primary Examiner-Laurence M. Goodridge
`Assistant Examiner-Ronald B. Cox
`Attorney, Agent, or Firm-Ernest F. Marmorek
`
`ABSTRACT
`[57]
`A combustion engine with an exhaust gas cleaning ar(cid:173)
`rangement operable at predetermined temperature
`and placed in the exhaust gas conduit of the engine,
`such predetermined temperature is attained by the ex(cid:173)
`haust gas cleaning arrangement through the heat of
`
`the exhaust gases, a device for adjusting the ignition
`timing and the fuel supply to the engine during a cold
`start thereof or during an idle running phase of opera(cid:173)
`tion thereof for delivering exhaust gases having an in(cid:173)
`creased temperature for quickly heating up the clean(cid:173)
`ing arrangement including a pair of switching contacts
`serially connected with respect to each other in a cir(cid:173)
`cuit, a pair of magnetically operated solenoid valves
`connected parallel with respect to each and series with
`respect to the switching contacts, a suction pipe sup(cid:173)
`plying fuel-air mixture to the engine with a butterfly
`valve for controlling the quantity of the fuel and air
`mixture, a conduit branch bypassing the butterfly
`valve, one of the magnetic valves is coupled into the
`branch conduit for effecting opening or closing
`thereof, a low pressure conduit connected to the suc(cid:173)
`tion pipe, a device for adjusting the ignition timing
`connected to the low pressure conduit, the other of
`the magnetic valves is coupled to the low pressure
`conduit for effecting the opening or closing thereof, a
`thermostat for sensing the temperature of the exhaust
`gas cleaning arrangement and connected for operating
`one of the switching contacts for effecting energiza(cid:173)
`tion of the magnetic valves, a cam fixedly coupled
`with the butterfly valve for effecting the actuation of
`the other of the switching contacts, the magnetic
`valves receiving energizing current when both of the
`switching contacts are actuated, whereby an enriched
`fuel-air mixture is supplied to the engine through the
`pipe-conduit when it is opened by one of the magnetic
`valves, and the ignition timing device is set "delayed"
`by the adjusting device in response to a pressure con(cid:173)
`dition in the low pressure conduit when the other of
`the magnetic valves opens the conduit during the idle
`running operation of the engine.
`7 Claims, 2 Drawing Figure
`
`BOSCH-DAIMLER EXHIBIT 1004
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`Page 1 of 6
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`PAT£NTEDMAR261914
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`3, 799,134
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`8
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`23
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`21
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`Fig.1
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`3 -...... L
`2--o
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`19
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`Fig.2
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`9
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`Page 2 of 6
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`3,799,134
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`2
`The ignition point or instant at a maximum possible
`fuel supply can be "delayed" to such an extent, that
`the combustion of the air-fuel mixture will deliver only
`such amount of mechanical energy which is just needed
`5 to keep the combustion engine running. The larger part
`of the energy which is freed by the combustion, will be
`converted into heat within the exhaust gas at a very
`high enthalpy and, which can be used for heating up the
`exhaust gas cleaning arrangement to its operating tern-
`! o perature.
`
`1
`COMBUSTION ENGINE WITH QUICK
`ARRANGEMENT FOR ITS EXHAUST GAS
`CLEANING DEVICE DURING COLD OR IDLE RUN
`
`FIELD OF THE INVENTION
`The present invention relates to an arrangement for
`the adjusting of the fuel supply and of the timing of a
`combustion engine during its idle run as a function of
`the temperature thereof, in order to attain -the produc(cid:173)
`tion of exhaust gases having high temperature for use
`in the quick heating up of an exhaust gas cleaning ar(cid:173)
`rangement to its operating temperature.
`
`BACKGROUND OF THE INVENTION
`In order to meet the stringent requirements with re(cid:173)
`spect to the cleaning the exhaust gases of combustion
`engines, it became a common practice to attach ex(cid:173)
`haust gas cleaning arrangements to combustion en(cid:173)
`gines. Such exhaust cleaning arrangements will oper- 20
`ate, however, satisfactorily only when
`they have
`reached their operating temperature. It is therefore, of
`primary importance that the exhaust gas cleaning ar(cid:173)
`rangement could be brought up to their operating tem(cid:173)
`perature especially during the cold start of the combus(cid:173)
`tion engine when the exhaust gas has a very high con(cid:173)
`tent of atmosphere contaminants. The exhaust gas
`cleaning arrangement can be heated up either by elec(cid:173)
`trical heating arrangements, or by burning an air-fuel
`mixture within the cleaning arrangement itself or using
`the heat of the hot exhaust gases by passing them
`through the cleaning arrangement as they come from
`the combustion engine.
`The electrical heating arrangements require a consid(cid:173)
`erably high electrical energy supply which cannot be
`satisfactorily supplied by the batteries and generators
`conventionally used in motor vehicles. When electrical
`heating arrangements are used for the heating of the
`exhaust gas cleaning arrangement, one must, therefore,
`provide for an excess dimensioning for the electrical 40
`energy supplying units.
`When the exhaust gas cleaning arrangements are to
`be brought to their operating temperature by burning
`in them the mixture of air and fuel, then in order to pre(cid:173)
`pare such air-fuel mixture, one must provide a specially 45
`constructed preparing unit. It should be noted that by
`the burning of air-fuel mixture within the exhaust gas
`cleaning arrangement itself during its bringing up to the
`operating temperature thereof, there will be additional
`exhaust gases present in which the contaminants are
`present in high ratio.
`It appears, therefore, the simplest of them all to bring
`the exhaust gas cleaning arrangements to their operat(cid:173)
`ing temperature, the use of the exhaust gases them- 55
`selves coming from the combustion engine. The higher
`is, under this condition, the enthalpy and the tempera(cid:173)
`ture of the exhaust gas, the quicker one is able to heat
`up the exhaust cleaning arrangement. It is generally
`known that when the ignition delay of the air-fuel mix- 60
`ture of the combustion within the operating cylinder is
`increased, the temperature of the exhaust gases in(cid:173)
`creases, however, the power delivered by the combus(cid:173)
`tion engine will decrease. The energy which is freed by
`burning an air-fuel mixture becomes, under conditions 65
`of increasing the ignition delay, converted to a lesser
`extent into mechanical work, and becomes converted,
`to a greater extent, into heat present in the exhaust gas.
`
`50
`
`SUMMARY OF THE INVENTION
`It is therefore, an object of the present invention to
`provide arrangement which is capable of adjusting the
`IS ignition timing for "delayed," as a function of the tem(cid:173)
`perature of the exhaust gas cleaning arrangement and,
`at the same time to provide for a maximum possible
`fuel supply during the idle run or cold start of a com-
`bustion engine.
`According to the present invention a pair of switch-
`ing means are placed in a common electrical circuit in
`a series connection with respect to each other and, also
`in a series circuit with a pair of parallel connected mag(cid:173)
`netic valves which are operable electrically, one of the
`25 magnetic valves after being energized will open a by(cid:173)
`pass air channel bypassing the choke or butterfly valve,
`while the other of the magnetic valve means will open
`a low pressure channel branching off from the main
`suction pipe of the engine and leading to the distributor
`30 and causes the adjusting the ignition timing for "de(cid:173)
`layed," one of the switching means being operable by
`a thermostat which in the cold state will keep the asso(cid:173)
`ciated switching means closed, while the other switch(cid:173)
`ing means is operable by a cam means arranged on the
`35 shaft of the butterfly valve and which keeps the asso(cid:173)
`ciated switching means closed in the idle run position
`of the choke valve.
`When the combustion engine is in idle run and is also
`in cold state, both series connected switching means
`are closed according to the provisions of the present
`invention. One of the switching means, as mentioned
`above, is kept closed by a thermostat, when the ther(cid:173)
`mostat is in a position corresponding to the cold opera(cid:173)
`tional state. On the other hand, as soon as the thermo(cid:173)
`stat becomes warmed up, then the switching means be(cid:173)
`comes opened. The other switching means is closed by
`a caroming disc arranged on the choke valve shaft when
`the choke valve is in a position corresponding to the
`idle run. When the choke valve is pivoted, together
`therewith the above mentioned caroming disc becomes
`moved by the operation of the accelerator away from
`its idle run position, then the second switching means
`becomes opened. Consequently, both parallel con(cid:173)
`nected magnetic valve means become energized only
`then when both switching means are closed. In the
`event only one of the switching means becomes
`opened, then the current supply to both of the mag(cid:173)
`netic valve means is still interrupted. When both of the
`magnetic valve means become energized, then an air
`channel bypassing the choke valve or butterfly valve
`and a low pressure channel leading to the distributor
`becomes open. The air which is sucked in by the oper(cid:173)
`ating cylinders through the bypassing channel will
`cause a corresponding fuel supply to be delivered and
`the low pressure channel will cause an adjustment in
`the ignition timing and will set it for "delayed" timing.
`When the desired temperature has not yet been
`
`Page 3 of 6
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`

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`3,799,134
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`4
`then switch 1 is opened. It is noted that this switch 1
`can be constructed by the thermostat 27 itself, which
`then can, in its cold state, short the series circuit, while
`in the warm state, can open it up. The detailed opera(cid:173)
`tion of switches 1, 2 and the associated magnetic valves
`4 and 5 will be described in more detail in connection
`with FIG. 2.
`Still with reference to FIG. l, it is seen that the switch
`means 2 is actuated by a caroming disc 7 which is ar(cid:173)
`ranged on the shaft of the butterfly or choke valve 6 of
`the combustion engine and such caroming disc 7 in the
`preferred embodiment is a quarter segment of a full cir(cid:173)
`cular disc. The caroming disc 7 on its outer circumfer(cid:173)
`ence at one end of the arch thereof has a cam 8 formed,
`which in the idle run of the combustion engine engages
`switch 2 and keep switch 2 closed. When the butterfly
`valve 6, as described in more detail in connection with
`FIG. 2, is pivoted out from its idle run position, then the
`caroming means 7, which is fixedly connected there(cid:173)
`with, will rotate the cam portion 8 out of engagement
`with the switch 2, so that the switch 2 becomes opened.
`
`3
`reached and the engine is still in its idle run, it is possi-
`ble with the help of the control arrangement according
`to the present invention to deliver an additional quan(cid:173)
`tity to the combustion engine and to set the ignition
`timing for "delayed" so that the energy which is freed 5
`by the combustion of the enriched air-fuel mixture will
`be converted to a greater extent into heat within the ex(cid:173)
`haust gas with a high enthalpy and to a lesser extent, it
`becomes converted into mechanical work. The compo(cid:173)
`nent accounting for the mechanical energy will be kept I 0
`only sufficiently large in order that the combustion en(cid:173)
`gine could be just kept running. In the event, however,
`if the combustion engine is to deliver some power, then
`the accelerator is pressed down and thereby the butter-
`fly or choke valve will be moved out of its idle run posi- 15
`tion. By the pivoting of the butterfly or choke valve,
`one of both of the above mentioned switching means
`becomes opened so that the current supply to both of
`the magnetic valves is interrupted, As a result, both of
`the above mentioned valves become closed so that the 20
`increased fuel supply is interrupted as well as the igni(cid:173)
`tion timing is set back again to "advance."
`In order to attain a reliable switching on and off of
`the magnetic valve means which leads to a change in
`the operational state of the engine, the thermostat is 25
`placed either in the exhaust gas conduit of the combus(cid:173)
`tion engine or in the exhaust gas cleaning arrangement.
`The thermostat can, however, be placed on any other
`characteristic point within
`the combustion engine
`which is capable of delivering a characteristic tempera- 30
`ture which is representative of the the temperature
`within the exhaust gas cleaning arrangement.
`The arrangement according to the present invention
`can be manufactured inexpensively and it is simple in
`its construction. The termostat is a bimetal bar.
`
`35
`
`Turning now to FIG. 2, it is seen that in a schematic
`illustration a cylinder 9 of a combustion engine is
`shown in which a piston 19 is arranged for sliding
`movement. The combustion engine cylinder 9 is sup-
`plied with fuel mixture through a suction pipe 11 in
`which a choke or butterfly valve 12 is arranged and is
`connected for operation by an accelerator pedal, not
`shown in the drawing. The fuel supply itself is shown
`only schematically at 17 and which is supplied in a
`quantity which is a function of the air quantity passing
`through the suction pipe 11.
`The cylinder has an input valve 13 and an exhaust
`valve 14 which passes the exhaust gases into an exhaust
`gas conduit 15, into which an exhaust gas cleaning ar(cid:173)
`rangement 16, such as an exhaust gas cleaning cataly(cid:173)
`zator is coupled.
`In order that the exhaust gas cleaning arrangement
`40 16 could be brought quickly to its operating tempera(cid:173)
`ture when the combustion engine is started up in a cold
`state, the invention provides that, under the condition,
`when the engine is in its idle run, an abnormally high
`quantity of fuel-air mixture should be burned in the op-
`45 erating cylinder 9 of the combustion engine. The larger
`portion of the energy freed through the combustion be(cid:173)
`comes converted into exhaust gas heat having a very
`high enthalpy which can be then used for a quick heat-
`50 ing up of the exhaust gas cleaning arrangement 16.
`In order to accomplish the above, the combustion en(cid:173)
`gine, according to the present invention, is provided
`with a channel 18 bypassing the butterfly valve 12 and
`which is operated on by the magnetic valve 5 by either
`being closed or opened thereby. From the suction pipe
`11 below the butterfly valve 12 a low pressure channel
`19 branches off, which goes to a membrane box 20 for
`performing thereby an adjustment of the position of the
`ignition timing device 21 in response to the pressure ex-
`60 isting in the conduit 19, which can be opened or closed
`by the magnetic valve 4. Such membrane boxes 20 are
`well-known in the art in connection with their use to
`adjust the timing instants in combustion engines, and
`reference should be had in this respect to pages 376
`65 through 383 of the book "Automotive Electrical
`Equipment" by William H. Crouse, Third Edition,
`published by the MacGraw Hill Book Company, New
`York. In Section 245 thereof, there is a detailed de-
`
`BRIEF DESCRIPTION OF THE ORA WING
`The invention will become more readily apparent
`from the following description of a preferred embodi(cid:173)
`ment thereof shown, by way of example, in the accom(cid:173)
`panying drawing in which:
`FIG. 1 is a rather schematic block diagram illustrat(cid:173)
`ing the principle of the present invention; and
`FIG. 2 is a schematic diagram illustrating in more de(cid:173)
`tail the operative connections within the device accord(cid:173)
`ing to the present invention.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`With reference to FIG. 1, it is seen that a pair of elec(cid:173)
`tric switching means 1 and 2 are connected in series in
`an electrical circuit which is supplied with energizing
`current by a source of electrical energy~. In the same
`series circuit a pair of magnetic valves 4 and 5 are in(cid:173)
`cluded, but they are connected parallel with respect to
`each other. The magnetic valves 4 and 5 can have any
`well-known construction such as, for 'instance, de(cid:173)
`scribed on pages 4-5 through 12-8 of the "Tool Engi(cid:173)
`neers Handbook," Second Edition, published by the
`MacGraw Hill Book Company, New York. In this refer(cid:173)
`ence especically on pages 12-6 thereof, an electro(cid:173)
`magnetically operated valve is described with a sole(cid:173)
`noid actuation.
`The electric switch 1 is operated on by a thermostat
`27, as can be seen in FIG. 2, and particularly when the
`thermostat 27 is in the cold state, switch 1 is closed. On
`the other hand, when thermostat 27 is in its warm state,
`
`55
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`Page 4 of 6
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`

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`3,799,134
`
`5
`scription of arrangements used to adjust the timing of
`the ignition by using sub-pressures. In contrast to the
`provisions according to the present invention, the igni(cid:173)
`tion time according to the above mentioned publica(cid:173)
`tion is adjusted for "advance" according to the pres- 5
`sure in the suction pipe, whereas the invention requires
`that the ignition time is adjusted for "delayed" accord(cid:173)
`ing to the pressure in the sub-pressure conduit 19 by
`the closing of the conduit 19 on the other side of the
`membrane 20, in order to accomplish the required con- 10
`ditions for quickly heating up the exhaust gas cleaning
`arrangement 16 during the idle run of the combustion
`engine, that is, to set the timing for "delayed."
`Notwithstanding the schematic showing of FIG. 2, it
`is seen that the sub-pressure or low pressure conduit 19 15
`is connected with the housing of the membrane box 20
`from which an operating rod 23 extends and is coupled
`to the distributor 21 in order to adjust the timing in re(cid:173)
`sponse to the pressure condition existing in the conduit
`19, if the magnetic valve 4 is opened. The distributor 20
`21 then supplies the energy for the spark plug 24 of the
`combustion space by a conductor 25.
`The thermostat 27 measures the temperature at a lo(cid:173)
`cation indicated by 26 which, for example, can be in
`the form of a thermo-element placed, as indicated, into 25
`the exhaust gas conduit 15, directly before the exhaust
`gas cleaning arrangement 16. The thermostat 27 oper(cid:173)
`ates then the switching means 1 as described in connec(cid:173)
`tion with FIG. 1.
`The arrangement according to the present invention
`operates as follows:
`During a cold start of the combustion engine, at
`which the exhaust gas cleaning arrangement 16 is also
`cold, the thermostat 27 will keep the switch 1 closed.
`When simultaneously the butterfly valve 12 is also in its
`idle run position, then the cam 8 will keep the switch
`2 closed and, therefore, current is supplied to the mag(cid:173)
`netic valves 4 and 5. The energization of the magnetic
`valves 4 and 5 will lead to the opening of their asso(cid:173)
`ciated conduits 18, 19, respectively. Through conduit 40
`18 a larger quantity of air-fuel mixture will then be de(cid:173)
`livered into the cylinder 9 of the combustion engine,
`where it is ignited "delayed" as accomplished by the
`timing adjusting device, including the connecting rod
`23, within the distributor 21, which is coupled through 45
`the low pressure conduit 19 connected to one side of
`the membrane 22, while the adjusting device is con(cid:173)
`nected to the other side of the membrane 22 of the
`membrane housing 20.
`It can now be appreciated that when both of the
`above mentioned channels or conduits 18, 19 are open,
`as a result, the combustion engine will receive an en(cid:173)
`riched air-fuel mixture and the timing of the ignition is
`set for "delayed." The energy which is freed by the 55
`burning of the air-fuel mixture in this case will be only
`partly used to perform mechanical work, while the
`major part of it will be converted to heat up the exhaust
`gases. The exhaust gases will have then a high enthalpy
`and a high temperature so that the exhaust gas cleaning 60
`arrangement 16 will assume its operating temperature
`very quickly.
`As soon as the required temperature has been at(cid:173)
`tained by the cleaning arrangement 16, the thermostat
`26, 27 will open the switch 1 so that the energizing cur- 65
`rent to both of the magnetic valves 4 and 5 will be inter(cid:173)
`rupted. In this case the pipe 18 and the low pressure
`conduit 19 become closed by the magnetic valves 4 and
`
`50
`
`6
`5, respectively, which has its consequence in that the
`increased supply of an enriched air-fuel mixture to the
`engine will be interrupted and the ignition time will be
`set bach to "advance." Thereafter the combustion en-
`gine will be controlled in the usual fashion, exclusively
`by the positioning of the butterfly valve 12.
`In the event there is a need for a power delivery by
`the combustion engine in its cold state, then the accel(cid:173)
`erator will be pressed down and, thereby, the butterfly
`valve 12 becomes pivoted out of its idle run position.
`By pivoting the butterfly valve 12 from its idle run posi(cid:173)
`tion the switch 2 becomes opened so that even if switch
`1 is closed, the current to the magnetic valves 4 and 5
`becomes interrupted. Then also in this case, the com(cid:173)
`bustion engine will be operated in a conventional fash(cid:173)
`ion.
`As has been demonstrated with the help of the con-
`trol device according to the present invention, it be(cid:173)
`comes extremely simple to bring up the exhaust gas
`cleaning arrangement 16 to a high operating tempera(cid:173)
`ture very quickly even during the cold starting phase of
`the engine operating or during its idling and with the
`help of which very hot exhaust gases will stream
`through the cleaning arrangement 16 and will bring it
`quickly to its operating temperature. Under the provi(cid:173)
`sions of the present invention, the energies which are
`freed by the burning process and by supplying a maxi(cid:173)
`mum possible fuel quantity to the engine, will become
`used in an optimum fashion for the warming of the ex-
`30 haust gases and thereby, to the warming of the exhaust
`gas cleaning arrangement. By appropriately dimension(cid:173)
`ing the conduit 18, the cold and idle run operation can
`be controlled in a desirable fashion by controlling the
`quantity of the delivered air-fuel mixture to the engine.
`
`35
`
`I wish it to be understood that I do not desire to be
`limited to the exact details of construction shown and
`described, for obvious modifications will occur to a
`person skilled in the art.
`Having thus described the invention, what I claim as
`new and desire to be secured by Letters Patent, is as
`follows:
`1. In a combustion engine, an exhaust gas cleaning
`arrangement operable at predetermined temperature
`and placed in the exhaust gas conduit of the engine,
`such predetermined temperature is attained by said ex(cid:173)
`haust gas cleaning arrangement through the heat of the
`exhaust gases, a device for adjusting the ignition timing
`and the fuel supply to the engine during a cold start
`thereof or during an idle running phase of operation
`thereof for delivering exhaust gases having an in(cid:173)
`creased temperature for quickly heating up said clean(cid:173)
`ing arrangement, said device comprising a pair of
`switching means serially connected with respect to
`each other in a circuit, a pair of magnetically operated
`valve means connected parallel with respect to each
`and series with respect to said pair of switching means
`in said circuit, a suction pipe means for supplying fuel(cid:173)
`air mixture to the engine, a valve means mounted in
`said suction pipe means for controlling the supply of
`the fuel and air mixture, a pipe conduit means compris(cid:173)
`ing a branch of said suction pipe means and bypassing
`said control valve means, one of said magnetic valve
`means being coupled with said pipe-conduit for effect(cid:173)
`ing opening or closing thereof, a low pressure conduit
`means connected to said suction pipe means, means for
`adjusting the ignition timing connected to said low
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`Page 5 of 6
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`3,799,134
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`8
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`cleaning arrangement.
`4. The combination as claimed in claim 1, wherein
`said thermostat means is a bimetal bar.
`5. The combination as claimed in claim 1, wherein
`said first and second switching means are closed by said
`thermostat means and said camming means, respec(cid:173)
`tively, in the cold and idle running condition of the
`combustion engine.
`6. The combination as claimed in claim l, wherein
`said control valve means is a butterfly valve means and
`is connected to the accelerator of the engine in a con(cid:173)
`ventonal manner, said camming means being pivoted
`with said positioning of said butterfly valve means.
`7. The combination as claimed in claim 1, wherein
`said low pressure conduit branches off from said suc(cid:173)
`tion pipe means, upstream of said control valve means,
`said low pressure conduit including a membrane means
`responsive to the pressure in said low pressure conduit
`means, operating means coupling said membrane to
`said adjusting means for adjusting the ignition timing in
`response to the pressure existing in said low pressure
`conduit means when said low pressure conduit means
`is opened by said other magnetic valve means.
`* * * * *
`
`7
`pressure conduit means, the other of said magnetic
`valve means being coupled to said low pressure conduit
`means for effecting the opening or closing thereof, a
`thermostat means for sensing the temperature of said
`exhaust gas cleaning arrangement and connected there 5
`for operation to one of said switching means for effect(cid:173)
`ing energization of said magnetic valve means, a cam(cid:173)
`ming means fixedly coupled with said control valve
`means for effecting the actuation of the other of said
`switching means, said magnetic valve means receiving 1 o
`energizing current when both of said switching means
`are actuated, whereby an enriched fuel-air mixture is
`supplied to the engine through said pipe-conduit means
`when it is opened by one of said magnetic valve means,
`and said ignition timing means is set "delayed" by said 15
`adjusting means in response to a pressure condition in
`said low pressure conduit when the other of said mag(cid:173)
`netic valve opens said conduit during the idle running
`operation of said engine.
`2. The combination as claimed in claim l, wherein 20
`said thermostat means is placed into the exhaust gas
`conduit of said combustion engine.
`3. The combination as claimed in claim 1, wherein
`said thermostat means is placed in said exhaust gas
`
`25
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`30
`
`35
`
`40
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`45
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`50
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`55
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`60
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`65
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`Page 6 of 6