U.S. patent number 3,799,134 [Application Number 05/313,869] was granted by the patent office on 1974-03-26 for combustion engine with quick arrangement for its exhaust gas cleaning device during cold or idle run.
This patent grant is currently assigned to Volkswagenwerk Aktiengesellschaft. Invention is credited to Wolfgang Griese.
United States Patent |
3,799,134 |
Griese |
March 26, 1974 |
COMBUSTION ENGINE WITH QUICK ARRANGEMENT FOR ITS EXHAUST GAS
CLEANING DEVICE DURING COLD OR IDLE RUN
Abstract
A combustion engine with 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 the exhaust 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 increased temperature for quickly heating up the
cleaning arrangement including a pair of switching contacts
serially connected with respect to each other in a circuit, a pair
of magnetically operated solenoid valves connected parallel with
respect to each and series with respect to the switching contacts,
a suction pipe supplying 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
suction 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 energization 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 condition in the low pressure conduit when the other of
the magnetic valves opens the conduit during the idle running
operation of the engine. 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
production of exhaust gases having high temperature for use in the
quick heating up of an exhaust gas cleaning arrangement to its
operating temperature. BACKGROUND OF THE INVENTION In order to meet
the stringent requirements with respect to the cleaning the exhaust
gases of combustion engines, it became a common practice to attach
exhaust gas cleaning arrangements to combustion engines. Such
exhaust cleaning arrangements will operate, however, satisfactorily
only when they have reached their operating temperature. It is
therefore, of primary importance that the exhaust gas cleaning
arrangement could be brought up to their operating temperature
especially during the cold start of the combustion engine when the
exhaust gas has a very high content of atmosphere contaminants. The
exhaust gas cleaning arrangement can be heated up either by
electrical 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 considerably 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 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 prepare such air-fuel mixture, one must
provide a specially 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 operating temperature, the use of
the exhaust gases themselves coming from the combustion engine. The
higher is, under this condition, the enthalpy and the temperature
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 mixture of the combustion within the
operating cylinder is increased, the temperature of the exhaust
gases increases, however, the power delivered by the combustion
engine will decrease. The energy which is freed by burning an
air-fuel mixture becomes, under conditions 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. 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 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 temperature.
SUMMARY OF THE INVENTION It is therefore, an object of the present
invention to provide arrangement which is capable of adjusting the
ignition timing for "delayed," as a function of the temperature 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 combustion engine. According to the present
invention a pair of switching 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 magnetic valves which are operable electrically, one of
the magnetic valves after being energized will open a bypass 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 and causes the adjusting the ignition timing for
"delayed," one of the switching means being operable by a
thermostat which in the cold state will keep the associated
switching means closed, while the other switching means is operable
by a cam means arranged on the shaft of the butterfly valve and
which keeps the associated 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 thermostat is in a position
corresponding to the cold operational state. On the other hand, as
soon as the thermostat becomes warmed up, then the switching means
becomes opened. The other switching means is closed by a camming
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 camming 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 connected 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 magnetic 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
operating 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 reached and the engine is still in its idle run, it is
possible with the help of the control arrangement according to the
present invention to deliver an additional quantity to the
combustion engine and to set the ignition timing for "delayed" so
that the energy which is freed by the combustion of the enriched
air-fuel mixture will be converted to a greater extent into heat
within the exhaust gas with a high enthalpy and to a lesser extent,
it becomes converted into mechanical work. The component accounting
for the mechanical energy will be kept only sufficiently large in
order that the combustion engine 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 butterfly or
choke valve will be moved out of its idle run position. 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 increased fuel
supply is interrupted as well as the ignition 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 placed either in
the exhaust gas conduit of the combustion 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 temperature 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.
Inventors: |
Griese; Wolfgang (Gaimersheim,
DT) |
Assignee: |
Volkswagenwerk
Aktiengesellschaft (Wolfsburg, DT)
|
Family
ID: |
5827918 |
Appl.
No.: |
05/313,869 |
Filed: |
December 11, 1972 |
Foreign Application Priority Data
|
|
|
|
|
Dec 14, 1971 [DT] |
|
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2161946 |
|
Current U.S.
Class: |
60/284; 123/588;
60/285; 123/438; 123/406.7 |
Current CPC
Class: |
F01N
3/18 (20130101); F02D 37/02 (20130101); F02D
9/00 (20130101); F02P 5/155 (20130101); F02M
23/00 (20130101); Y02T 10/40 (20130101); Y02T
10/12 (20130101); Y02T 10/146 (20130101); Y02T
10/46 (20130101); F02D 2700/0241 (20130101) |
Current International
Class: |
F01N
3/18 (20060101); F02D 37/00 (20060101); F02M
23/00 (20060101); F02D 37/02 (20060101); F02D
9/00 (20060101); F02P 5/155 (20060101); F02P
5/145 (20060101); F02p 005/04 () |
Field of
Search: |
;123/117R,117A,119A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Goodridge; Laurence M.
Assistant Examiner: Cox; Ronald B.
Attorney, Agent or Firm: Marmorek; Ernest F.
Claims
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 exhaust 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 increased temperature for quickly heating up said
cleaning 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-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 comprising 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 effecting 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 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 for operation to one of said
switching means for effecting energization of said magnetic valve
means, a camming means fixedly coupled with said control valve
means for effecting the actuation of the other of said switching
means, said magnetic valve means receiving 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
adjusting means in response to a pressure condition in said low
pressure conduit when the other of said magnetic valve opens said
conduit during the idle running operation of said engine.
2. The combination as claimed in claim 1, wherein 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 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, respectively, in the cold and idle running condition
of the combustion engine.
6. The combination as claimed in claim 1, wherein said control
valve means is a butterfly valve means and is connected to the
accelerator of the engine in a conventonal 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 suction 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.
Description
BRIEF DESCRIPTION OF THE DRAWING
The invention will become more readily apparent from the following
description of a preferred embodiment thereof shown, by way of
example, in the accompanying drawing in which:
FIG. 1 is a rather schematic block diagram illustrating the
principle of the present invention; and
FIG. 2 is a schematic diagram illustrating in more detail the
operative connections within the device according to the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIG. 1, it is seen that a pair of electric
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 3. In the same series circuit a pair of magnetic
valves 4 and 5 are included, 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, described on pages
4-5 through 12-8 of the "Tool Engineers Handbook," Second Edition,
published by the MacGraw Hill Book Company, New York. In this
reference especically on pages 12-6 thereof, an
electro-magnetically operated valve is described with a solenoid
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, 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 operation 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. 1, it is seen that the switch means 2
is actuated by a camming disc 7 which is arranged on the shaft of
the butterfly or choke valve 6 of the combustion engine and such
camming disc 7 in the preferred embodiment is a quarter segment of
a full circular disc. The camming disc 7 on its outer circumference
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 camming means 7, which is fixedly connected
therewith, will rotate the cam portion 8 out of engagement with the
switch 2, so that the switch 2 becomes opened.
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 supplied 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 arrangement 16, such as an exhaust gas
cleaning catalyzator is coupled.
In order that the exhaust gas cleaning arrangement 16 could be
brought quickly to its operating temperature 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 operating cylinder 9 of the combustion engine. The larger
portion of the energy freed through the combustion becomes
converted into exhaust gas heat having a very high enthalpy which
can be then used for a quick heating up of the exhaust gas cleaning
arrangement 16.
In order to accomplish the above, the combustion engine, 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 existing 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 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 description 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 ignition time according to the above
mentioned publication is adjusted for "advance" according to the
pressure in the suction pipe, whereas the invention requires that
the ignition time is adjusted for "delayed" according 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 conditions 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 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 response to the pressure condition existing in the
conduit 19, if the magnetic valve 4 is opened. The distributor 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 location indicated
by 26 which, for example, can be in the form of a thermo-element
placed, as indicated, into the exhaust gas conduit 15, directly
before the exhaust gas cleaning arrangement 16. The thermostat 27
operates then the switching means 1 as described in connection 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 magnetic
valves 4 and 5. The energization of the magnetic valves 4 and 5
will lead to the opening of their associated conduits 18, 19,
respectively. Through conduit 18 a larger quantity of air-fuel
mixture will then be delivered 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 the low
pressure conduit 19 connected to one side of the membrane 22, while
the adjusting device is connected 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 enriched air-fuel mixture and the timing of
the ignition is set for "delayed." The energy which is freed by the
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 arrangement 16 will assume its operating temperature very
quickly.
As soon as the required temperature has been attained by the
cleaning arrangement 16, the thermostat 26, 27 will open the switch
1 so that the energizing current to both of the magnetic valves 4
and 5 will be interrupted. In this case the pipe 18 and the low
pressure conduit 19 become closed by the magnetic valves 4 and 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 engine 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 accelerator 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 position 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 combustion engine will be
operated in a conventional fashion.
As has been demonstrated with the help of the control device
according to the present invention, it becomes extremely simple to
bring up the exhaust gas cleaning arrangement 16 to a high
operating temperature 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 provisions of the present invention, the
energies which are freed by the burning process and by supplying a
maximum possible fuel quantity to the engine, will become used in
an optimum fashion for the warming of the exhaust gases and
thereby, to the warming of the exhaust gas cleaning arrangement. By
appropriately dimensioning 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.
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.
* * * * *