U.S. patent application number 11/374022 was filed with the patent office on 2006-07-20 for fuel injection equipment, internal combustion engine, and control method of fuel injection equipment.
Invention is credited to Yoko Nakayama, Toshiharu Nogi, Yoshihiro Sukegawa.
Application Number | 20060157018 11/374022 |
Document ID | / |
Family ID | 29720306 |
Filed Date | 2006-07-20 |
United States Patent
Application |
20060157018 |
Kind Code |
A1 |
Nakayama; Yoko ; et
al. |
July 20, 2006 |
Fuel injection equipment, internal combustion engine, and control
method of fuel injection equipment
Abstract
A fuel injection equipment to control the instability of
combustion when the airflow is weak, and improve the fuel cost. A
fuel injection equipment for an cylinder injection type and spark
ignition type internal combustion engine that injects gasoline
directly to a combustion chamber, wherein the top angle at the
point of fuel spray in the pressurized atmosphere of absolute
pressure 0.5 MPa is from -10.degree. to 10.degree.. Further, the
fuel is injected at the compression stroke of the internal
combustion engine which installs the fuel injection equipment, and
said internal combustion engine is started.
Inventors: |
Nakayama; Yoko; (Hitachi,
JP) ; Sukegawa; Yoshihiro; (Hitachi, JP) ;
Nogi; Toshiharu; (Hitachinaka, JP) |
Correspondence
Address: |
CROWELL & MORING LLP;INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Family ID: |
29720306 |
Appl. No.: |
11/374022 |
Filed: |
March 14, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10612153 |
Jul 3, 2003 |
7021274 |
|
|
11374022 |
Mar 14, 2006 |
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Current U.S.
Class: |
123/298 ;
123/305; 239/463 |
Current CPC
Class: |
F02M 69/045 20130101;
Y02T 10/12 20130101; F02B 2023/103 20130101; Y02T 10/125 20130101;
F02B 2075/125 20130101; F02F 3/26 20130101; F02B 17/005 20130101;
F02B 2023/106 20130101; F02M 61/162 20130101; Y02T 10/123 20130101;
F02B 23/104 20130101; F02M 61/1806 20130101 |
Class at
Publication: |
123/298 ;
123/305; 239/463 |
International
Class: |
F02B 3/02 20060101
F02B003/02; F02B 3/04 20060101 F02B003/04; B05B 1/34 20060101
B05B001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 5, 2002 |
JP |
2002-196652 |
Claims
1. A fuel injection equipment for a cylinder injection type and
spark ignition type internal combustion engine that injects
gasoline directly to a combustion chamber, wherein the fuel
injection equipment including a valve for opening and closing a
fuel nozzle hole through which a lead spray is directed with
substantial penetration toward a plug with respect to an axis of
the valve and a main spray is directed with lesser penetration than
that of the lead spray toward a piston and away from the lead spray
and the top angle at the point of fuel spray in a pressurized
atmosphere of absolute pressure 0.5 MPa is from -10.degree. to
10%.
2. The fuel injection equipment according to claim 1, wherein fuel
injection valves which have a plurality of nozzle holes are
combined.
3. The internal combustion engine of the cylinder injection type
and spark ignition type that injects gasoline directly to the
combustion chamber where the fuel injection equipment that the top
angle at the point of fuel spray in the pressurized atmosphere of
absolute pressure 0.5 MPa exists in the range of -10.degree. to
10.degree. has been installed, wherein the fuel spray injected from
a plurality of nozzle holes of said fuel injection equipment is
directed into the direction of the sparking plug.
4. The internal combustion engine according to claim 3, wherein the
fuel distribution is biased from a central axis of the fuel
injection valve to the region of the plug side.
5. A method of controlling a fuel injection equipment for the
cylinder injection type and spark ignition type internal combustion
engine that injects gasoline directly to the combustion chamber,
wherein the fuel is injected at the compression stroke of the
internal combustion engine which installs the fuel injection
equipment that the top angle at the point of fuel spray in the
pressurized atmosphere of absolute pressure 0.5 MPa exists in the
range of -10.degree. to 10.degree..
6. The method according to claim 5, wherein the engine is started
by injecting the fuel at the intake stroke, and the injection of
fuel is switched to compression stroke after the engine speed
reaches that corresponding to the fast idling speed.
7. A fuel injection valve for a cylinder injection type and spark
ignition type internal combustion engine that injects fuel directly
to a combustion chamber through a nozzle hole, wherein a top angle
at the point of fuel spray in the pressurized atmosphere of
absolute pressure 0.5 MPa is from -10.degree. to 10.degree.,
comprising a nozzle hole, a valve seat in the upstream side of said
nozzle hole, the valve body which opens and shuts the fuel passage
by acting on said valve seats, and driving means for said valve
body, and further comprising swirl providing means that gives the
swirl movement to the fuel in the upstream side of said nozzle
hole, wherein a stage difference is provided in the downstream
aperture of said nozzle hole in the direction of the central axis
line of the injection valve.
8. The fuel injection equipment for a cylinder injection type and
spark ignition type internal combustion engine that injects
gasoline directly to a combustion chamber, wherein a top angle at
the point of fuel spray in the pressurized atmosphere of absolute
pressure 0.5 MPa is from -10.degree. to 10.degree., comprising a
nozzle hole, a valve seat in the upstream side of said nozzle hole,
the valve body which opens and shuts the fuel passage by acting on
said valve seats, and driving means for said valve body, and
further comprising swirl providing means that gives the swirl
movement to the fuel in the upstream side of said nozzle hole,
wherein a stage difference is provided in the downstream aperture
of said nozzle hole in the direction of the central axis line of
the injection valve, wherein at least one turn-ditch provided to
the swirl providing means is a first turn-ditch where the sectional
area of the flow path is larger than that of other ditches, wherein
the penetration of the lead fuel spray with the maximum spray
penetration in absolute pressure 0.5 MPa after 2.7 ms of the start
of the injection is long compared with the distance between the
fuel spray point of the fuel injection valve and sparking plug
electrodes, the lead fuel spray being directed to the neighborhood
of the sparking plug with fuel injection equipment installed in the
internal combustion engine.
9. The fuel injection valve according to claim 7, wherein the
penetration of the lead fuel spray with the maximum spray
penetration in absolute pressure 0.5 MPa after 2.7 ms of the start
of the injection is long compared with the distance between the
fuel spray point of the fuel injection valve and sparking plug
electrodes, the lead fuel spray being directed to the neighborhood
of the sparking plug with fuel injection equipment installed in the
internal combustion engine.
10. The fuel injection equipment for a cylinder injection type and
spark ignition type internal combustion engine that injects
gasoline directly to a combustion chamber, wherein the top angle at
the point of fuel spray in the pressurized atmosphere of absolute
pressure 0.5 MPa is from -10.degree. to 10.degree., further
comprising a nozzle hole, a valve seat in the upstream side of said
nozzle hole, the valve body which opens and shuts the fuel passage
by acting on said valve seats, and driving means for said valve
body; and further comprising swirl providing means that gives the
swirl movement to the fuel in the upstream side of said nozzle
hole, wherein a stage difference is provided in the downstream
aperture of said nozzle hole in the direction of the central axis
line of the injection valve, wherein at least one turn-ditch
provided to the swirl providing means is a first turn-ditch where
the sectional area of the flow path is larger than that of other
ditches, wherein the electrode of the sparking plug exists in the
fuel spray existence angular range of said lead fuel spray when the
angular range that said lead fuel spray exists on the circumference
of the circle where centers on a central axis of the fuel injection
valve and the position where the sparking plug electrode exists is
assumed to be an fuel spray existence angular range in the fuel
spray horizontal section.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a method of controlling the
fuel injection equipment, an internal combustion engine and a fuel
injection equipment.
[0002] In the Japanese Patent Application No. 2001-214744, it has
been described that an excellent, homogeneous air-fuel mixture can
be formed even when a large amount of fuel is necessary in the
homogeneous combustion, in the fuel injection equipment for an
cylinder injection type and spark ignition type internal combustion
engine which can execute the stratification combustion of the fuel
injection at the compression stroke and the homogeneous combustion
of the fuel injection at the intake stroke.
[0003] In the prior art, the best fuel spray form of the air guide
type cylinder injection is not referred. Further, the air-fuel
mixture cannot reach the sparking plug because the pressure in the
combustion chamber is high when the air-fuel ratio is made a lean
state to improve the fuel cost, and the stable combustion cannot be
performed. In a word, there is a limit in the improvement of the
fuel cost.
SUMMARY OF THE INVENTION
[0004] The present invention is performed to solve the problem in
the above-mentioned prior art.
[0005] An object of the present invention is to control the
instability of combustion when the airflow is weak, and improve the
fuel cost.
[0006] In an cylinder injection type and spark ignition type
internal combustion engine which comprises a combustion chamber
formed between a cylinder head and a piston, an intake valve and an
exhaust valve arranged in said cylinder head, a sparking plug, a
fuel injection valve arranged at angles with the horizontal plane
of the combustion chamber, and which injects gasoline directly to
said combustion chamber, the fuel injection valve that top angle
(.theta.) at the point of fuel spray in the pressurized atmosphere
(Absolute pressure:0.5 MPa) exists in the range of -10.degree. to
10.degree. is adopted.
[0007] Because it is possible to make fuel spray reach the plug
even when the airflow is weak, the stable combustion is obtained.
As a result, the combustion efficiency can be improved, and thus
the fuel cost can be improved.
BRIEF DESCRIPTION OF DRAWINGS
[0008] FIG. 1 is a perspective view of an engine according to the
first embodiment.
[0009] FIG. 2 is a sectional view of the engine according to the
first embodiment.
[0010] FIG. 3 shows the first fuel spray imaging equipment.
[0011] FIG. 4A and FIG. 4B show the second fuel spray imaging
equipment.
[0012] FIG. 5 shows a fuel spray characteristic.
[0013] FIG. 6 shows the definition of fuel spray.
[0014] FIG. 7 shows the result of air-fuel mixture simulation.
[0015] FIG. 8 shows the effect of penetration of lead fuel
spray.
[0016] FIG. 9 shows the effect of existence angle of lead fuel
spray.
[0017] FIG. 10 is a sectional view of the fuel injection valve.
[0018] FIG. 11 shows a fuel injection valve used in the first
embodiment.
[0019] FIG. 12 shows the fuel spray by the fuel injection valve of
FIG. 11.
[0020] FIG. 13 illustrates a first swirler improvement idea.
[0021] FIG. 14 shows the fuel spray when the swirler of FIG. 13 is
used.
[0022] FIG. 15 shows the fuel spray of FIG. 14 and positioning of
nozzle difference.
[0023] FIG. 16 illustrates a second swirler improvement idea.
[0024] FIG. 17 illustrates a third swirler improvement idea.
[0025] FIG. 18 illustrates an improvement idea for the nozzle
step.
[0026] FIG. 19 shows the fuel spray from the fuel injection valve
of FIG. 18.
[0027] FIG. 20 shows the first nozzle form at the point of the fuel
injection valve.
[0028] FIG. 21 shows the fuel spray by the first nozzle form.
[0029] FIG. 22 shows a second nozzle form at the point of the fuel
injection valve.
[0030] FIG. 23 shows the fuel spray by the second nozzle form.
[0031] FIG. 24 shows an engine system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] In the cylinder injection engine, the fuel injection valve
is provided at angle of 20.degree. to 50.degree. with the
horizontal plane of the combustion chamber and between two intake
ports of the combustion chamber. The airflow formed by the flow
generation means such as the swirl control valves which are
provided in the intake port is mixed with the fuel injected aiming
at the cavity provided to the piston when the stratification burns.
The air-fuel mixture is led to the sparking plug arranged in the
center part of the combustion chamber, and ignited. It is necessary
to provide for a necessary fuel spray requirement when the air-fuel
ratio is made a lean state to improve the fuel cost and perform the
stratification combustion in the cylinder injection type and spark
ignition internal combustion engine. However, there is a problem
that fuel spray do not reach the sparking plug because of the
increase in atmosphere pressure of the combustion chamber, and the
stratification combustion in the cylinder injection engine of the
side injection type becomes unstable when air-fuel ratio was made a
lean state for the fuel cost improvement. The fuel injection valve
which has the spray characteristic that the fuel spray reaches the
sparking plug even when the combustion chamber pressure is high is
used for that. In a word, the top angle at the point of fuel spray,
the penetration in the direction of the plug, and the range of the
existence of the fuel spray in the rotation direction of the fuel
injection valve are given. Further, to meet the requirement, the
fuel injection valve structure is changed.
[0033] An embodiment of the cylinder injection engine is shown in
FIG. 1 and FIG. 2.
[0034] An engine 30 is provided with an intake port 3 and an
exhaust port 4. The intake port 3 and the exhaust port 4 lead to
the combustion chamber respectively through an intake valve and an
exhaust valve 6. Numeral 2 designates a piston, 20 an electrode of
the sparking plug arranged in the upper part of the combustion
chamber, and 10 a fuel injection valve to inject the fuel directly
to the combustion chamber. The engine 30 has a board 22 which
partitions the intake pipe up and down and an airflow control valve
21 provided at the beginning point of the board. Thereby, forward
tumble airflow 50 toward the exhaust valve 6 from the intake valve
5 and toward the piston 2 is formed in the combustion chamber. The
strength of the airflow 50 can be changed according to the opening
of electronically controlled airflow control valve 21. The piston 2
has a shallow cavity to maintain the tumble airflow easily, the
sparking plug electrode 20 which sparks to burn is arranged in the
vicinity of the center of the combustion chamber, and the fuel
injection valve 10 which supplies the fuel directly to the
combustion chamber is arranged at the angle of about 36.degree.
with respect to the horizontal line between two intake valves 5
provided in the combustion chamber.
[0035] The fuel injection valve is a solenoid valve which opens and
shuts by the control signal from ECU 41. The coil of the fuel
injection valve operates when an injection signal from the ECU is
input to the fuel injection valve drive circuit 40, the plunger is
pulled up, and the fuel is injected to the combustion chamber. The
fuel injection valve used in this embodiment is made by working the
step to the point of the conventional swirl fuel injection
valve.
[0036] The fuel spray forms asymmetrical and conical fuel spray as
shown in FIG. 2. The fuel spray with large penetration directed to
the sparking plug is called lead fuel spray, and the fuel spray
with small penetration is called main fuel spray.
[0037] It is necessary to meet the under-mentioned fuel spray
requirement on the fuel spray unit performance to do the
stratification combustion during the idling and the low revolution
in the cylinder injection engine having the above-mentioned
configuration. In the vertical fault fuel spray form after 2.7 ms
from the beginning of the injection at the pressurized atmosphere
of absolute pressure 0.5 MPa by which the combustion chamber is
imitated,
[0038] 1. Top angle .theta. of the fuel spray must be the range of
-10.degree. to 10.degree.,
[0039] 2. Penetration L2 of the lead fuel spray must be larger than
distance L1 from the sparking plug electrode to the fuel injection
valve.
[0040] In the horizontal fault fuel spray form after 4.4 ms from
the beginning of the injection at the pressurized atmosphere of
absolute pressure 0.5 MPa by which the combustion chamber is
imitated,
[0041] 3. The sparking plug electrode must exist within the
existence angle .alpha. of the lead fuel spray.
[0042] The method of verifying the fuel spray and the definition of
the above-mentioned parameter is explained.
[0043] The configuration of an imaging equipment for the fuel spray
is shown in FIG. 3. The fuel pressure and the injection quantity in
the idling operating condition where it is most difficult to obtain
the stability of the combustion in the regular stratification
operation. In this embodiment, fuel pressure 7 MPa and injection
quantity 12.5 mcc are set as a representative condition. Fuel
injection valve 10 is arranged in the upper part of a fuel spray
container 78 with 300 mm or more in height and 200 mm or more in
diameter. The fuel is supplied from a fuel tank 74, pressured by a
fuel pump 75, and controlled to the fixed fuel pressure.
Afterwards, the fuel passes a high-pressure piping 76, and is
supplied to the fuel injection valve through fuel injection valve
drive circuit 40 to drive it. Further, this signal is branched, and
is made the shutter trigger for a high-speed and high sensitivity
camera 79. A picture is taken after the fixed delay (a vertical
section:2.7 ms and the horizontal section:4.4 ms). An optical
system branches the light from a halogen light source 70 through an
optical fiber 71. A sheet light 73 of about 5 mm in thickness is
made by a cylindrical lens. When the picture of fuel spray vertical
section is taken, the light is irradiated from two opposed
directions as shown in FIG. 4A, and when the picture of the
horizontal section is taken, it is as shown in FIG. 4B. The camera
is set up as shown in FIG. 4. Further, it is set that the section
where the halogen sheet light is irradiated includes the fuel spray
injected in the direction of the sparking plug when taking a
picture of a vertical section, and the light is irradiated to the
position which corresponds to the distance from the fuel spray
point to the sparking plug electrode in the combustion chamber when
taking a picture of the horizontal section. The scattered light by
the fuel spray on each section is taken a picture by the camera.
The shutter is set at a speed (ex. 222 .mu.s) of the extent where
fuel spray does not flow. The light intensity and the camera
aperture is set brightly within the range where the halation is not
caused. Further, the condition of the internal pressure of the
cylinder when injecting fuel is imitated, and the pressure in the
chamber 78 is assumed to be 0.5 MPa (absolute pressure). Further,
the fuel spray image taken a picture is processed by a picture
processing personal computer 80. When the highest brightness of the
image is assumed to be Imax, the brightness part of Imax of 40% or
more is the fuel spray existence part.
[0044] The example of the fuel spray taken a picture is shown in
FIG. 5. A: Atmospheric pressure vertical section (Delay=1.3 ms), B:
Atmospheric pressure horizontal section (Delay=1.8 ms), C:
Pressurized vertical section (Delay=2.7 ms), and D: A photograph of
pressurized horizontal cross section (Delay=4.4 ms). The fuel spray
used in this embodiment is fuel spray of a hollow cone form in the
atmospheric pressure, and the fuel spray concentrated part exists
in the sparking plug side (picture on the right hand). In the
pressurized atmosphere, the fuel spray in the direction of the
sparking plug becomes strong penetration and one in the direction
of the piston (picture on the left hand) becomes weak penetration.
Further, the fuel spray takes the form that the lead fuel spray 60A
toward the sparking plug and other main fuel spray 60B separate in
the pressurized horizontal cross section.
[0045] The definition of the spray characteristic is shown in FIG.
6 in an example of such fuel spray. The angle which the central
axis of the fuel injection valve and the line which connects the
part where spray penetration is large and the fuel spray point
makes is assumed to be .theta.1 in the pressurized vertical
section. When a plurality of parts where the spray penetration is
large exists, a part that is nearest to the sparking plug is
defined as the lead fuel spray. Further, when the angle which the
central axis of the fuel injection valve and the line which
connects the fuel spray point of the fuel injection valve and the
sparking plug electrode 20 makes is assumed to be .theta.2 in the
engine, the top angle .theta. in the fuel spray point is shown by
the under-mentioned expression. .theta.=.theta.1-.theta.2
[0046] Next, the distance between the fuel spray traveled point and
the fuel spray point which is defined by the above-mentioned as the
lead fuel spray is defined as lead fuel spray penetration L2.
[0047] Further, the existence angle .quadrature. of the lead fuel
spray is defined as the angular range that the above-mentioned lead
fuel spray exists on circumference 65, of which center is on the
central axis of the fuel injection valve and the position where the
sparking plug electrode 20 exists is included in the fuel spray
horizontal section (A-A section in figure).
[0048] The operation and the effect of the cylinder injection
engine according to this embodiment are explained. when the
cylinder injection engine is operating at the middle or the high
load, the ignition and combustion are done after the fuel is
injected during the intake stroke and the homogeneous air-fuel
mixture is formed. Because the time from the injection to the
ignition is long, the influence by the fuel spray form is a little.
On the other hand, because the time from the injection to the
ignition is short in the stratification combustion at the low load,
the influence by the spray characteristic is great. In the
stratification combustion of the engine of this configuration, the
injected fuel is given to the sparking plug by the tumble airflow
formed in the combustion chamber, and the stratification is formed.
Further, the flow toward the ignition plug is formed by the lead
fuel spray, and the main fuel spray is made to the stratification
to the plug in the low revolution condition in which the tumble
airflow is weak. However, when the air-fuel ratio is made a lean
state to improve the fuel cost, the pressure of the combustion
chamber rises, and it becomes difficult for the fuel spray to reach
the plug. The result of simulation for the distribution of the
air-fuel mixture is shown in FIG. 7. The main fuel spray is
decelerated due to the atmosphere pressure and cannot reach the
sparking plug though the lead fuel spray can reach the sparking
plug having large spray penetration. It is important to set to meet
the requirement of this embodiment the fuel spray form (the top
angle .theta. at the point of the fuel spray, the lead fuel spray
rotation angle .alpha., and the lead fuel spray penetration L2) in
the pressurized atmosphere where the compression stroke is
simulated, in order to make the lead fuel spray surely reach the
sparking plug. In the graph of FIG. 8, the lead fuel spray
penetration is designated in the ordinate, and the combustion
stability is designated in the abscissa. When the lead fuel spray
penetration L2 is short as shown in the photograph of (a), the
stable combustion region is not obtained. Oppositely, the fuel
spray for which some length is secured like (b) can give the stable
combustion. In a word, if the lead fuel spray can reach the
sparking plug, the stable combustion is obtained. Further, when the
fuel injection valve is rotated and installed as shown in FIG. 9,
the stable combustion becomes difficult because the direction of
the lead fuel spray shifts from the plug. A permissible value of
the rotation direction is .+-.5.degree. for this fuel injection
valve. However, it is generally important that the sparking plug
electrode exists within the range of the lead fuel spray existence
angle .alpha. because it is thought that this value has sensitivity
in the lead fuel spray existence angle .alpha..
[0049] It is possible to operate at the low revolution in the
super-lean stratification state where the air-fuel ratio is 40 or
more by meeting the above-mentioned fuel spray requirement, and to
improve the fuel cost.
[0050] FIG. 10 is a block diagram of the fuel injection valve used
for the above-mentioned embodiment. The operation of the fuel
injection valve is explained. The valve body 14 is pressed against
the valve seat 15 by a spring 63, and the seal is done when the
valve is closed. The magnetic circuit is formed by a coil 61 when
an open valve signal is given by the electronic control unit, and
the valve body 14 rises by the electromagnetic force generated in
the direction where a magnetization part 62 of the valve body is
lifted. The fuel flows in from the upper part of the fuel injection
valve, passes a passage 63 in the valve body, and reaches the
nozzle. Swirler 12 by which the turn is given to the fuel is
arranged in the nozzle 11. The fuel is injected from the space
between the valve body 14 and the valve seat 15 to the combustion
chamber through nozzle hole 16 after passing ditch 13 provided in
the swirler. The nose form of the nozzle of the fuel injection
valve is shown in FIG. 11. The step 17 is provided on around the
half position of the nozzle hole. Thereby, the discontinuity part
and the fuel concentrated part are formed in a part of the hollow
fuel spray injected from the conventional turn type fuel injection
valve. FIG. 12 shows the fuel spray form under the atmospheric
pressure formed with the nozzle hole of FIG. 11. The above figure
shows a vertical section, and the figure below shows a horizontal
section. One of the fuel spray from this fuel injection valve
becomes discontinuous, and the opposing side of the fuel spray
forms a fuel concentrated part. The position and the amount of this
fuel spray distribution can be changed by the size and the position
of the step of the nozzle. Said embodiment are the one to direct
the fuel concentrated part to the sparking plug.
[0051] In said embodiment, the combustion can be stabilized by
assuming the fuel spray characteristic absorbed with the individual
dispersion of fuel spray. In the structure of FIG. 11, there is a
problem that the direction of the lead fuel spray shifts by the
misalignment by the working. One width of the turn-ditches 13 of
the swirler 12 is expanded, and the fuel amount which flows in is
increased as shown in FIG. 13. As a result, the fuel spray can be
formed so that there may be the fuel deflection in one direction as
shown in FIG. 14. The fuel concentrated part can be obtained stably
by setting a direction (b) of the fuel spray and a direction (a) of
nozzle step 17 as shown in FIG. 15. In a word, it is thought that
the lead fuel spray penetration can be stably secured.
[0052] Similarly, it is possible to make easy to form the
discontinuity part of the fuel spray with the lead penetration
securing by eliminating the wide ditch and the ditch at the
opposing side as shown in FIG. 16.
[0053] In two said methods of changing the swirler structure, the
method of changing not the width of the ditches of the swirler but
the height of the ditch as shown in FIG. 17 can be thought. This
problem is evaded by changing the height of the ditch though in the
expansion of the width of the ditches, there is a problem that the
swirl force decreases when expanded in the direction of the center
of the swirler. The effect is similar to said method.
[0054] The number other than four may be used without trouble, and
the size of ditches more than one may be changed in these methods.
Further, both of the ditch width and the ditch height may be
changed.
[0055] It is possible to expand the lead fuel spray existence angle
.alpha. as another means for the combustion stabilization. The
unstable combustion due to the displacement of the installation of
the fuel injection valve can be recovered by the fuel spray
form.
[0056] It is effective for the expansion of the lead fuel spray
existence angle .alpha. that the step provided at the nozzle hole
is provided not at rights but at angle of 0.degree. to 30.degree.
with respect to the vertical angle. The fuel concentration can be
eased by applying the angle as shown in FIG. 19, and the lead fuel
spray becomes to exist widely. However, because there is fear that
the lead penetration L2 decreases by distributing the flow, the
lead fuel spray existence angle .alpha. can be expanded with
securing the lead fuel spray penetration by combining the swirler
form shown in FIG. 13, FIG. 16, and FIG. 17 and the nozzle
configuration of FIG. 18.
[0057] Further, there is a porous fuel injection valve as other
injection valve structures to achieve said embodiment. A lot of
holes 16 of the minute diameter of about o0.05 to 0.3 mm are
arranged in the nozzle 11 as shown in FIG. 20, and the fuel spray
injected in the multi-directions as shown in FIG. 21 (a) is formed.
Various fuel sprays can be formed according to the number, the
size, and the direction of the nozzle hole. Further, it is easy to
control the direction of the fuel spray because the fuel spray
rolling decrease caused by the difference between the inside and
outside pressures of fuel spray as the swirling fuel spray is not
caused. Said embodiment can be achieved by designing to meet the
demand of the top angle at the point of the fuel spray 100 in the
figure, the lead fuel spray penetration, and the lead fuel spray
existence angle, and installing the fuel injection valve so that
the fuel spray 100 may be directed to the plug. It is effective
that the fuel spray injected from two or more holes is centralized
in the direction of the plug and the flow distribution is expanded
as shown in FIG. 21 (b) in order to expand the lead fuel spray
existence angle, although the flow distribution of one fuel spray
is narrow in the porous fuel injection valve. However, because the
interference with fuel spray combines the fuel spray to each other
and leads to the expansion of the particle size, it is necessary to
suppress interference to the minimum.
[0058] Further, it is desirable that the amount of fuel spray on
the piston side from the central axis of the injector is small, and
the fuel spray amount centralizes to the plug side to as shown
ideally in FIG. 22 and FIG. 23. Especially, because it is difficult
to suppress the penetration in the porous fuel injection valve, the
fuel spray directed to the piston side collides with the piston,
and becomes the factor of hydrocarbon and the smoke. Therefore, the
fuel spray is arranged so that the fuel spray may be centralized to
the plug side and the installation accuracy of the fuel injection
valve should not become severe, namely, the lead fuel spray
existence angle .alpha. can be greatly taken. In the swirler on the
upstream in the porous fuel injection valve, it is not required
that the ditch is arranged in the direction where the fuel
turns.
[0059] The cylinder injection type internal combustion engine
described in the above-mentioned is installed in, for example, the
system shown in FIG. 24.
[0060] Another embodiment is explained.
[0061] There is a problem that a large amount of harmful exhaust
constituent such as unburnt hydrocarbon etc. which originate in the
fuel adhesion on the piston and the cylinder, because the injection
is executed at the intake stroke at the cold start-up. Because the
fuel is flowed directly to the sparking plug without the assistance
of the piston wall and the airflow in the cylinder injection type
internal combustion engine described in the above-mentioned
embodiment, the combustion in the stratification can be performed
even at start-up in which the airflow is weak. The fuel adhesion on
the piston and the cylinder walls is decreased by the start-up in
the stratification combustion. Therefore, the exhaust performance
at start-up is improved, and the temperature of catalyst can be
raised at the early stage. As a result, the effect that the
purification efficiency of the catalyst is improved and the exhaust
is decreased is achieved.
[0062] Further, the influence by the combustion change at the
start-up in the stratification combustion is worried. Therefore, it
is also effective to raise the exhaust gas temperature by switching
to the lean stratification combustion in the course of the
temperature rise process of the catalyst after fast idling speed is
obtained even when the start-up in the homogeneous combustion is
done, and to raise the temperature of the catalyst at the early
stage.
[0063] Further, the fuel is divided into two times or injected at
the intake stroke and the compression stroke. The fuel injected at
the compression stroke is ignited, and the flame spread speed is
delayed by the super-lean air-fuel mixture formed by the injection
at the intake stroke. As a result, the heat generation is delayed,
exhaust gas temperature is raised, and the catalyst is raised at
the early stage.
[0064] Further, the airflow and the support of the piston form are
made a minimum, the stratification is achieved according to the
spray characteristic, and the fuel spray generation means to do the
stability combustion can be provided.
[0065] Further, unstable combustion is controlled by making the
combustible mixture a stratification in the vicinity of the
sparking plug under the condition where the airflow is weak. As a
result, fuel cost can be improved according to the embodiment. That
is, the air-fuel mixture comes to reach the sparking plug even when
the air-fuel ratio is lean, and the combustion stabilization and
the fuel cost improvement can be achieved.
[0066] The instability of combustion can be controlled even when
the airflow is weak according to the present invention, the fuel
cost can be improved.
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