CA1115149A - Air-fuel mixture supply system - Google Patents
Air-fuel mixture supply systemInfo
- Publication number
- CA1115149A CA1115149A CA330,058A CA330058A CA1115149A CA 1115149 A CA1115149 A CA 1115149A CA 330058 A CA330058 A CA 330058A CA 1115149 A CA1115149 A CA 1115149A
- Authority
- CA
- Canada
- Prior art keywords
- lever
- throttle valve
- temperature sensitive
- engine
- fuel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
- F02M69/04—Injectors peculiar thereto
- F02M69/042—Positioning of injectors with respect to engine, e.g. in the air intake conduit
- F02M69/043—Positioning of injectors with respect to engine, e.g. in the air intake conduit for injecting into the intake conduit upstream of an air throttle valve
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M1/00—Carburettors with means for facilitating engine's starting or its idling below operational temperatures
- F02M1/08—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling becoming operative or inoperative automatically
- F02M1/10—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling becoming operative or inoperative automatically dependent on engine temperature, e.g. having thermostat
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An engine is provided with a fuel injector which is located to inject fuel into an intake passageway upstream of a throttle valve. The throttle valve is mounted on a throttle shaft on which a lever is mounted so as to open the throttle valve to a predetermined extent when moved.
The lever is mechanically connected to a wax pellet which is expandable to move the lever, when heated. The wax pellet is heated by means of an electric wire to which electric current is passed when an ignition switch is closed to start the engine.
An engine is provided with a fuel injector which is located to inject fuel into an intake passageway upstream of a throttle valve. The throttle valve is mounted on a throttle shaft on which a lever is mounted so as to open the throttle valve to a predetermined extent when moved.
The lever is mechanically connected to a wax pellet which is expandable to move the lever, when heated. The wax pellet is heated by means of an electric wire to which electric current is passed when an ignition switch is closed to start the engine.
Description
BACKGROUND OF THE INVENTION
This invention relates to an improvement in an air-fuel mixture supply system of an internal combustion engine, and more particularly to a device for improving the cold start and the warming up of an internal combustion engine provided with a so-called single point injection ' (SPI) type fuel supply system in which a plurality of engine cylinders are supplied with fuel injected from only a fuel injector.
During cold start of an internal combustion engine, or while the engine is operating for warming up, it is usual to increase the quantity of intake air to increase the engine output in view of an inadequate operation of the engine and large frictional resistance of various moving parts thereof. Such method has been adopted in all types of engines using a carburetor, and an electro-nically controlled fuel injection system or other fuel injection systems. Among these, in the engine using the fuel injection system, there is provided a valve device disposed in an air passage bypassing a throttle valve.
The valve device is opened or closed by means of a temperature sensitive element as a wax pellet or a bi-metal which deforms in response to the temperature of the engine, so as to increase the quantity of the intake air.
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However, such an arrangement causes following problems particularly in the engine using a SPI type fuel injection system in which the fuel is injected upstream of the throttle valve,which has been developed for the purpose of decreasing the number of the injectors.
- The air supplied through the bypass air passage is diffi-cult to weli admix with the air-fuel mixture thus deteriorating the distribution of the fuel to respective cylinders. Furthermore, in the engine using such the SPI type fuel injection system, atomization of the fuel ls deteriorated due to deposition of fuel on the throttle valve, and the deposited fuel drops intermittently thus failing to supply a mixture having a constant air-fuel ratio. This degrades not only the response characteristic of the engine speed to the running condition but also the distribution characteristic of the fuel thus decreasing the power output of the engine.
Otherwise, there has been proposed an engine using another type fuel injection system which is provided with a plurality of fuel injectors which are arran~ed to in-ject fuel on the downstream side of the throttle valve, for example into intake ports communicable with respec-tive cylinders. Such an engine does not encountered the above-mentioned problems. However, as is necessary to provide many fuel injectors, the construction of the fuel .
:
injection system becomes complicated and the manufac-turing cost of the engine increases.
SUMMARY OF THE INVENTION
.
In view of the above, the present invention con-templates to overcome the various drawbacks encounteredin conventional engines equipped with fuel injection systems, by arranging to open a throttle valve to a predetermined extent in response to low temperature condition of the engine to increase intake air amount, at cold start and warming up of the engine.
It is an object of the present invention to provide an improved air-fuel mixture supply system of an internal combustion engine, capable of rendering easier cold start and warming up of the engine, without any troubles and without raising the drawbacks in the conventional air-fuel mixture supply system.
It is another object of the present invention to provide an improved fuel supply system of an internal combustion engine provided with a SPI type fuel injection system, which can prevent the unequal power outputs among a plurality of engine cylinders to maintain stable engine running, preventing exhaust emission of unburnt components and deterioration of fuel consumption.
It is a further object of the present invention to provide an improved air-fuel mixture supply system of an l.lternal combustion engine provided with a SPI fuel injection system, by which the mixing of fuel and air is effectively achieved to form homogeneous air-fuel mixture, thereby improving fuel distribution to a plurality of engine cylinders.
According to the present invention there is provided an air-fuel mixture supply system for an internal combustion engine, comprising: means defining an intake passageway through which each combustion chamber of the engine is communicable with the atmosphere; a throttle valve pivotally disposed in said intake passageway; temperature sensitive means responsive to a .j temperature which is in relation to an engine operating condition, and taking a first state when said temperature is within a range where the engine is cold; connecting means for connecting said temperature sensitive means with said throttle valve to open said throttle valve to a predetermined extent when said temperature sensitive means takes said first state; and a fuel injector dis-posed to inject fuel into said intake air passageway upstream of said throttle valve.
The present invention will be further described by way of the accompanying drawings in which like reference numerals are assigned to like parts and elements throughout all the figures and in which:
Fig. 1 is a cross-sectional view of a preferred embodi-ment of an air-fuel mixture supply system according to this invention;
Fig. 2 is a front view, partly in section, showing an essential part of the system of Fig. l;
Fig. 3 is a side view of a throttle valve rotating mechanism of the system of Fig. l; and Figs. 4 and 5 are front views of other examples of the throttle valves rotating mechanisms usable in the system of Fig. 1.
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.- DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to Figs. 1 to 3 of the drawings, a preferred embodiment of an air-fuel mixture supply system (no numeral) according to the present invention is shown including a conduit 1 defining therein a throttle chamber
This invention relates to an improvement in an air-fuel mixture supply system of an internal combustion engine, and more particularly to a device for improving the cold start and the warming up of an internal combustion engine provided with a so-called single point injection ' (SPI) type fuel supply system in which a plurality of engine cylinders are supplied with fuel injected from only a fuel injector.
During cold start of an internal combustion engine, or while the engine is operating for warming up, it is usual to increase the quantity of intake air to increase the engine output in view of an inadequate operation of the engine and large frictional resistance of various moving parts thereof. Such method has been adopted in all types of engines using a carburetor, and an electro-nically controlled fuel injection system or other fuel injection systems. Among these, in the engine using the fuel injection system, there is provided a valve device disposed in an air passage bypassing a throttle valve.
The valve device is opened or closed by means of a temperature sensitive element as a wax pellet or a bi-metal which deforms in response to the temperature of the engine, so as to increase the quantity of the intake air.
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. .
However, such an arrangement causes following problems particularly in the engine using a SPI type fuel injection system in which the fuel is injected upstream of the throttle valve,which has been developed for the purpose of decreasing the number of the injectors.
- The air supplied through the bypass air passage is diffi-cult to weli admix with the air-fuel mixture thus deteriorating the distribution of the fuel to respective cylinders. Furthermore, in the engine using such the SPI type fuel injection system, atomization of the fuel ls deteriorated due to deposition of fuel on the throttle valve, and the deposited fuel drops intermittently thus failing to supply a mixture having a constant air-fuel ratio. This degrades not only the response characteristic of the engine speed to the running condition but also the distribution characteristic of the fuel thus decreasing the power output of the engine.
Otherwise, there has been proposed an engine using another type fuel injection system which is provided with a plurality of fuel injectors which are arran~ed to in-ject fuel on the downstream side of the throttle valve, for example into intake ports communicable with respec-tive cylinders. Such an engine does not encountered the above-mentioned problems. However, as is necessary to provide many fuel injectors, the construction of the fuel .
:
injection system becomes complicated and the manufac-turing cost of the engine increases.
SUMMARY OF THE INVENTION
.
In view of the above, the present invention con-templates to overcome the various drawbacks encounteredin conventional engines equipped with fuel injection systems, by arranging to open a throttle valve to a predetermined extent in response to low temperature condition of the engine to increase intake air amount, at cold start and warming up of the engine.
It is an object of the present invention to provide an improved air-fuel mixture supply system of an internal combustion engine, capable of rendering easier cold start and warming up of the engine, without any troubles and without raising the drawbacks in the conventional air-fuel mixture supply system.
It is another object of the present invention to provide an improved fuel supply system of an internal combustion engine provided with a SPI type fuel injection system, which can prevent the unequal power outputs among a plurality of engine cylinders to maintain stable engine running, preventing exhaust emission of unburnt components and deterioration of fuel consumption.
It is a further object of the present invention to provide an improved air-fuel mixture supply system of an l.lternal combustion engine provided with a SPI fuel injection system, by which the mixing of fuel and air is effectively achieved to form homogeneous air-fuel mixture, thereby improving fuel distribution to a plurality of engine cylinders.
According to the present invention there is provided an air-fuel mixture supply system for an internal combustion engine, comprising: means defining an intake passageway through which each combustion chamber of the engine is communicable with the atmosphere; a throttle valve pivotally disposed in said intake passageway; temperature sensitive means responsive to a .j temperature which is in relation to an engine operating condition, and taking a first state when said temperature is within a range where the engine is cold; connecting means for connecting said temperature sensitive means with said throttle valve to open said throttle valve to a predetermined extent when said temperature sensitive means takes said first state; and a fuel injector dis-posed to inject fuel into said intake air passageway upstream of said throttle valve.
The present invention will be further described by way of the accompanying drawings in which like reference numerals are assigned to like parts and elements throughout all the figures and in which:
Fig. 1 is a cross-sectional view of a preferred embodi-ment of an air-fuel mixture supply system according to this invention;
Fig. 2 is a front view, partly in section, showing an essential part of the system of Fig. l;
Fig. 3 is a side view of a throttle valve rotating mechanism of the system of Fig. l; and Figs. 4 and 5 are front views of other examples of the throttle valves rotating mechanisms usable in the system of Fig. 1.
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.- DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to Figs. 1 to 3 of the drawings, a preferred embodiment of an air-fuel mixture supply system (no numeral) according to the present invention is shown including a conduit 1 defining therein a throttle chamber
2 which forms part of an intake passageway (no numeral) which fluidly connects the atmosphere and the combustion chambers of an internal combustion engine (not shown), in this instance, of an automotive vehicle. Accordingly, the throttle chamber 2 is communicable with the combustion chambers of the engine so that intake air is inducted and flows therethrough in the direction of arrows in Fig. 1.
As shown, the throttle chamber 2 is bent substantially at right angles. A throttle valve 3 is rotatably dis-posed in the throttle chamber 2 and securely mounted ona throttle shaft 3A which is pivotally and rotatably : supported by the wall of the conduit 1.
A fuel injector 4 is provided to penetrate verti-cally through the upper horizontal wall of the throttle chamber 2 and secured to the horizontal wall by bolts 9 through a clamping member 5. The injector 4 is con-structed and arranged to inject fuel in the form of a hollow cone from its nozzle 4a immediately above the throttle valve 3 or into a space defined by the throt--tle valve 3 and the inner wall of the throttle :
chamber 2. As clearly seen from Fig. 2, one outer endof the throttle shaft 3A is connected to an acceleration pedal (not shown) to be rotated by an angle corresponding to the degree of depression of the pedal, whereas the other outer end is connected to a control lever 6 having integral lever arms 6a and 6b. One end of a coil spring 7 is connected to the control lever 6 and the other end of the spring 7 is secured to the outer wall of the conduit 1 so as to urge the throttle valve 3 to rotate in the clockwise (closing) direction in the drawing through the control lever 6 and shaft-3A. The arm 6a engages the outer end of an adjusting screw 8 threaded through a projection on the outer wall of the conduit 1 so as to control the fully closed position of the throt-tle valve. The other arm 6b is urged to engage a control pin 12 at the end of a control rod 11 of a temperature sensitive control device 10 by the force of the coil spring 7 provided for the purpose of closing ; the throttle valve. Thus, when the arm 6b moves to follow the axial movement of the control rod 11 of the temperature sensitive control device 10, the throttle valve shaft 3A is rotated through the control lever 6 The temperature sensitive device 10 comprises a casing 10A, a wax pellet 15 secured by a member 16 for fixing the pellet 15, and an electric heating wire 14 '' .
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surrounding the wax pellet 15 and embedded in a heat insulator 13. The pellet 15 is connected to the control rod 11 through a movable piston or connecting lever 17.
A guide member 18 is formed integrally with the control rod 11 and slidable along the inner wall surface of the casing lOA to facilitate the movement of the connecting rod 17 and the control rod 11.
The temperature sensitive device 10 further comprises a return spring 19 for urging the guide member 18 upward in the drawing, a stop 20 formed at the inner wall surface of the casing lOA to limit the downward stroke of the guide member 18. A stop 22 is provided to set the fully opened position of the throttle valve 3. The electric heating wire 14 is energized when an ignition switch 21 of the automotive vehicle is closed. The wire 14 is electri-cally connected through the switch 21 to an electric source (no numeral) such as a battery. It is advan-tageous to use a positive temperature coefficient thermister as the heating wire 14 which increases its ` 20 resistance when a predetermined temperature is reached.
The throttle valve control device described above operates as follows:
When the ignition switch 21 is closed, a starting - motor (not shown) of the vehicle is operated while at the same time the fuel is injected from the fuel injector 4. As diagrammatically shown in Fig. 1, the injected fuel spreads in the form of the hollow cone into the space defined by the throttle valve 3 and the inner wall surface of the throttle chamber 2 on the upstream side of the throttle valve 3.
At this time since the air velocity in the afore-mentioned space is extremely high, the fuel injected thereto is atomized into fine particles whereby atomi-zation is enhanced to decrease the amount of fuel deposited on the surface of throttle valve 3. Such an atomization of the fuel improves combustion at the time of starting the engine or during engine warming up, thus greatly contributing to saving fuel and purifying exhaust gases.
At the time of starting the engine from cold state, the wax pellet 15 contracts so that the connecting rod 17 and the control rod 11 are held in the upper position as viewed in Fig. 2 by the force of spring 19. Accord-ingly, the control pin 12 raises the arm 6b to rotate ; 20 the control lever 6 and the throttle valve shaft 3A
connected thereto in the counterclockwise direction as viewed in Fig. 2 to open the throttle valve 3 by a pre-determined degree thus increasing the quantity of intake air of the engine. At the same time, the quantity of the fuel ejected by the fuel injector 4 is also '' increased to increase the engine output. When starting the engine from the cold state or when operating the engine for warming up, the frictional resistance of various moving parts of the engine is increased due to the increase in the viscosity of the lubricant, so that for the purpose of overcoming this difficulty the engine output is increased to improve the starting performance and to accelerate the warming up of the engine.
When the ignition switch 21 is closed at the time of starting the engine, the electric heating wire 14 is energized to gradually heat. The wax pellet 15 then gradually increases its volume with the heating time to gradually lower the connecting rod 17 and the control rod 11 against the force of the return spring 19. As a consequence, due to the restoring force of the throttle ; valve closing spring 7, the control lever 6 is caused to follow up the descent of the control pin 12 for rotating the throttle valve shaft 3A in the clockwise direction toward the fully closed position until the arm 6a engages the adjusting screw 8. Thus, as the engine is warmed up, the degree of opening of the throt-tle valve 3 is decreased to decrease the quantity of the intake air and the quantity of fuel injection. When the warming up completes, the throttle valve 3 is fully closed in the same manner as in an ordinary idling operation. Thus, excessive fuel supply is prevented to save the fuel.
The thermal expansion coefficient and the material of the wax pellet 15 and the electric heating wire 14 are selected such that, at the time of completing the warming up, the guide member 18 comes to engage the stop 20 due to the thermal expansion of the wax pellet 15. As above described, where the electric heating wire 14 is formed of the positive temperature coeffi-cient thermister, as the temperature of the heating wireexceeds a predetermined high temperature, the resistance thereof increases to such a value that no current flows therethrough so that it is not necessary to provide any circuit interrupter for the electric heating wire 14.
After completion of the warming up and under normal - operation of the engine while hot, the wax pellet 15 is - in the expanded state so that during the idling operation of the engine, the arm 6a of the control lever 6 is in engagement with the adjusting screw 8. When a throttle valve rotating force (in the counterclockwise direction in Fig. 1) corresponding to the degree of depression of the acceleration pedal is applied to the opposite end of the throttle valve shaft 3A, the control pin 12 is disengaged from the arm 6b whereby the throttle valve 3 is freed.
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When the engine stops in cold season, the wax pellet 15 contracts so that in the same manner as in the case described above in which the engine is cold, the throttle valve is opened slightly to prepare for satisfactory cold - 5 starting.
Although in the foregoing embodiment, the wax pellet 15 contracts by sensing the low temperature of the atmos-phere to open the throttle valve and is caused to expand by the heat of the electric heating wire 7 which is energized in synchronism with the warming up, it will be understood that the invention is not limited to this construction. For example, instead of using the heat insulator 13 and the electric heating wire 14, the engine - coolant showing a temperature variation related to the engine temperature may be passed through the space occupied by these elements. Such modified arrangement can also attain the object of this invention.
Fig. 4 shows a modified embodiment of this invention in which the control lever 6 is divided into two parts, that is, a lever 31 including an arm 6b' and another lever 32 including an arm 6a'. The lever 32 is connected to the throttle valve shaft 32, while the lever 32 i5 rotatably mounted on the throttle valve shaft 3A so as to cause the lever 31 to engage an adjusting screw 33 threaded through the lever 32. Consequently, it is ' :
possible to adjust the relative angle between the levers 31 and 32 about the throttle valve shaft 3A by turning the adjusting screw 33. A slot 34 receiving the control pin 12 is provided at the free end of the arm 6b' so that the lever 32 follows the vertical movement of the control rod 11 to rotate about the throttle valve shaft 3A. An E-shaped clip ring 35 is secured to the end of the con-trol pin 12 to prevent disengagement thereof from the lever 31.
~- 10 This modified embodiment is more advantageous than the previous embodiment in that the accuracy of control of the throttle valve can be improved by adjusting or compensating the errors due to production of component elements and the error due to assembling by means of the adjusting screw 33. Moreover, as the control rod 11 is coupled t-o the control lever 6 in a manner described above at the time of warming up the engine, the control lever 6 is subjected not only to the force of the coil spring ~ but also to the downward movement of the control rod 11 due to the expansion or the wax pellet 15 so that the throttle valve perfectly follows the movement of the control rod 11 without being blocked on its way, thus - preventing an excessive increase of the engine speed.
Fig. 5 shows another modified embodiment of this invention which is different from the embodiment shown i ,a~
in Figs. 1 to 3 in that instead of the control pin 12, a cam 41 is attached to the lower end of the control rod 11 and that an adjusting screw 42 contactable with the cam surface is threaded through the arm 6b of the control lever 6 so as to adjus~ the relative position . between the cam 41 and the control lever 6 by turning the adjusting screw 42.
According to this modification it is not necessary to change the thermal expansion characteristic of the wax pellet 15 in accordance with type of the engine so that it is possible to use the same wax pellet for various types of engine by merely changing the contour of the cam 41. Thus, it is possible to set to any value the degree of opening of the throttle valve for a pre-determined temperature of the engine, thus increasingthe freedom of design. When a slippy substance such as teflon is coated on the surface of the cam 41, the con-tact friction between the cam 41 and the adjusting screw 42 can be minimized thereby permitting these members to smoothly move relative to prevent hysteresis.
As above described, according to this invention, the increase in the amount of air fuel mixture at the time of cold start of the engine is accomplished by the increase in the air quantity due to increase in the degree of opening of the throttle valve and by the increase in the quantity of fuel injected upstream of the throttle valve.
Accordingly, the admixing of the air and fuel and the distribution of the fuel among respective engine cylin-ders can be improved over the prior art in which a passage bypassing the throttle valve is operable for the purpose of increasing the quantity of the sucked air. Hence, it is possible to prevent the difference in ` engine output powers among respective engine cylinders as well as the discharge of the unburnt components.
Moreover, since the fuel injected into a space on the upstream side of the throttle valve is atomized by the air flowing through a gap between the throttle valve and the inner wall of the intake passageway, the atomizing characteristic is improved and the amount of fuel deposited on the throttle valve is decreased, thereby improving the admixing of air and fuel, the response characteristic to the operating condition of the engine, the distribution of the fuel amount-to respective engine cylinders and the fuel economy. This permits more precise control of the alr-fuel ratio as well as stabi-lization of the engine operation.
As shown, the throttle chamber 2 is bent substantially at right angles. A throttle valve 3 is rotatably dis-posed in the throttle chamber 2 and securely mounted ona throttle shaft 3A which is pivotally and rotatably : supported by the wall of the conduit 1.
A fuel injector 4 is provided to penetrate verti-cally through the upper horizontal wall of the throttle chamber 2 and secured to the horizontal wall by bolts 9 through a clamping member 5. The injector 4 is con-structed and arranged to inject fuel in the form of a hollow cone from its nozzle 4a immediately above the throttle valve 3 or into a space defined by the throt--tle valve 3 and the inner wall of the throttle :
chamber 2. As clearly seen from Fig. 2, one outer endof the throttle shaft 3A is connected to an acceleration pedal (not shown) to be rotated by an angle corresponding to the degree of depression of the pedal, whereas the other outer end is connected to a control lever 6 having integral lever arms 6a and 6b. One end of a coil spring 7 is connected to the control lever 6 and the other end of the spring 7 is secured to the outer wall of the conduit 1 so as to urge the throttle valve 3 to rotate in the clockwise (closing) direction in the drawing through the control lever 6 and shaft-3A. The arm 6a engages the outer end of an adjusting screw 8 threaded through a projection on the outer wall of the conduit 1 so as to control the fully closed position of the throt-tle valve. The other arm 6b is urged to engage a control pin 12 at the end of a control rod 11 of a temperature sensitive control device 10 by the force of the coil spring 7 provided for the purpose of closing ; the throttle valve. Thus, when the arm 6b moves to follow the axial movement of the control rod 11 of the temperature sensitive control device 10, the throttle valve shaft 3A is rotated through the control lever 6 The temperature sensitive device 10 comprises a casing 10A, a wax pellet 15 secured by a member 16 for fixing the pellet 15, and an electric heating wire 14 '' .
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surrounding the wax pellet 15 and embedded in a heat insulator 13. The pellet 15 is connected to the control rod 11 through a movable piston or connecting lever 17.
A guide member 18 is formed integrally with the control rod 11 and slidable along the inner wall surface of the casing lOA to facilitate the movement of the connecting rod 17 and the control rod 11.
The temperature sensitive device 10 further comprises a return spring 19 for urging the guide member 18 upward in the drawing, a stop 20 formed at the inner wall surface of the casing lOA to limit the downward stroke of the guide member 18. A stop 22 is provided to set the fully opened position of the throttle valve 3. The electric heating wire 14 is energized when an ignition switch 21 of the automotive vehicle is closed. The wire 14 is electri-cally connected through the switch 21 to an electric source (no numeral) such as a battery. It is advan-tageous to use a positive temperature coefficient thermister as the heating wire 14 which increases its ` 20 resistance when a predetermined temperature is reached.
The throttle valve control device described above operates as follows:
When the ignition switch 21 is closed, a starting - motor (not shown) of the vehicle is operated while at the same time the fuel is injected from the fuel injector 4. As diagrammatically shown in Fig. 1, the injected fuel spreads in the form of the hollow cone into the space defined by the throttle valve 3 and the inner wall surface of the throttle chamber 2 on the upstream side of the throttle valve 3.
At this time since the air velocity in the afore-mentioned space is extremely high, the fuel injected thereto is atomized into fine particles whereby atomi-zation is enhanced to decrease the amount of fuel deposited on the surface of throttle valve 3. Such an atomization of the fuel improves combustion at the time of starting the engine or during engine warming up, thus greatly contributing to saving fuel and purifying exhaust gases.
At the time of starting the engine from cold state, the wax pellet 15 contracts so that the connecting rod 17 and the control rod 11 are held in the upper position as viewed in Fig. 2 by the force of spring 19. Accord-ingly, the control pin 12 raises the arm 6b to rotate ; 20 the control lever 6 and the throttle valve shaft 3A
connected thereto in the counterclockwise direction as viewed in Fig. 2 to open the throttle valve 3 by a pre-determined degree thus increasing the quantity of intake air of the engine. At the same time, the quantity of the fuel ejected by the fuel injector 4 is also '' increased to increase the engine output. When starting the engine from the cold state or when operating the engine for warming up, the frictional resistance of various moving parts of the engine is increased due to the increase in the viscosity of the lubricant, so that for the purpose of overcoming this difficulty the engine output is increased to improve the starting performance and to accelerate the warming up of the engine.
When the ignition switch 21 is closed at the time of starting the engine, the electric heating wire 14 is energized to gradually heat. The wax pellet 15 then gradually increases its volume with the heating time to gradually lower the connecting rod 17 and the control rod 11 against the force of the return spring 19. As a consequence, due to the restoring force of the throttle ; valve closing spring 7, the control lever 6 is caused to follow up the descent of the control pin 12 for rotating the throttle valve shaft 3A in the clockwise direction toward the fully closed position until the arm 6a engages the adjusting screw 8. Thus, as the engine is warmed up, the degree of opening of the throt-tle valve 3 is decreased to decrease the quantity of the intake air and the quantity of fuel injection. When the warming up completes, the throttle valve 3 is fully closed in the same manner as in an ordinary idling operation. Thus, excessive fuel supply is prevented to save the fuel.
The thermal expansion coefficient and the material of the wax pellet 15 and the electric heating wire 14 are selected such that, at the time of completing the warming up, the guide member 18 comes to engage the stop 20 due to the thermal expansion of the wax pellet 15. As above described, where the electric heating wire 14 is formed of the positive temperature coeffi-cient thermister, as the temperature of the heating wireexceeds a predetermined high temperature, the resistance thereof increases to such a value that no current flows therethrough so that it is not necessary to provide any circuit interrupter for the electric heating wire 14.
After completion of the warming up and under normal - operation of the engine while hot, the wax pellet 15 is - in the expanded state so that during the idling operation of the engine, the arm 6a of the control lever 6 is in engagement with the adjusting screw 8. When a throttle valve rotating force (in the counterclockwise direction in Fig. 1) corresponding to the degree of depression of the acceleration pedal is applied to the opposite end of the throttle valve shaft 3A, the control pin 12 is disengaged from the arm 6b whereby the throttle valve 3 is freed.
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When the engine stops in cold season, the wax pellet 15 contracts so that in the same manner as in the case described above in which the engine is cold, the throttle valve is opened slightly to prepare for satisfactory cold - 5 starting.
Although in the foregoing embodiment, the wax pellet 15 contracts by sensing the low temperature of the atmos-phere to open the throttle valve and is caused to expand by the heat of the electric heating wire 7 which is energized in synchronism with the warming up, it will be understood that the invention is not limited to this construction. For example, instead of using the heat insulator 13 and the electric heating wire 14, the engine - coolant showing a temperature variation related to the engine temperature may be passed through the space occupied by these elements. Such modified arrangement can also attain the object of this invention.
Fig. 4 shows a modified embodiment of this invention in which the control lever 6 is divided into two parts, that is, a lever 31 including an arm 6b' and another lever 32 including an arm 6a'. The lever 32 is connected to the throttle valve shaft 32, while the lever 32 i5 rotatably mounted on the throttle valve shaft 3A so as to cause the lever 31 to engage an adjusting screw 33 threaded through the lever 32. Consequently, it is ' :
possible to adjust the relative angle between the levers 31 and 32 about the throttle valve shaft 3A by turning the adjusting screw 33. A slot 34 receiving the control pin 12 is provided at the free end of the arm 6b' so that the lever 32 follows the vertical movement of the control rod 11 to rotate about the throttle valve shaft 3A. An E-shaped clip ring 35 is secured to the end of the con-trol pin 12 to prevent disengagement thereof from the lever 31.
~- 10 This modified embodiment is more advantageous than the previous embodiment in that the accuracy of control of the throttle valve can be improved by adjusting or compensating the errors due to production of component elements and the error due to assembling by means of the adjusting screw 33. Moreover, as the control rod 11 is coupled t-o the control lever 6 in a manner described above at the time of warming up the engine, the control lever 6 is subjected not only to the force of the coil spring ~ but also to the downward movement of the control rod 11 due to the expansion or the wax pellet 15 so that the throttle valve perfectly follows the movement of the control rod 11 without being blocked on its way, thus - preventing an excessive increase of the engine speed.
Fig. 5 shows another modified embodiment of this invention which is different from the embodiment shown i ,a~
in Figs. 1 to 3 in that instead of the control pin 12, a cam 41 is attached to the lower end of the control rod 11 and that an adjusting screw 42 contactable with the cam surface is threaded through the arm 6b of the control lever 6 so as to adjus~ the relative position . between the cam 41 and the control lever 6 by turning the adjusting screw 42.
According to this modification it is not necessary to change the thermal expansion characteristic of the wax pellet 15 in accordance with type of the engine so that it is possible to use the same wax pellet for various types of engine by merely changing the contour of the cam 41. Thus, it is possible to set to any value the degree of opening of the throttle valve for a pre-determined temperature of the engine, thus increasingthe freedom of design. When a slippy substance such as teflon is coated on the surface of the cam 41, the con-tact friction between the cam 41 and the adjusting screw 42 can be minimized thereby permitting these members to smoothly move relative to prevent hysteresis.
As above described, according to this invention, the increase in the amount of air fuel mixture at the time of cold start of the engine is accomplished by the increase in the air quantity due to increase in the degree of opening of the throttle valve and by the increase in the quantity of fuel injected upstream of the throttle valve.
Accordingly, the admixing of the air and fuel and the distribution of the fuel among respective engine cylin-ders can be improved over the prior art in which a passage bypassing the throttle valve is operable for the purpose of increasing the quantity of the sucked air. Hence, it is possible to prevent the difference in ` engine output powers among respective engine cylinders as well as the discharge of the unburnt components.
Moreover, since the fuel injected into a space on the upstream side of the throttle valve is atomized by the air flowing through a gap between the throttle valve and the inner wall of the intake passageway, the atomizing characteristic is improved and the amount of fuel deposited on the throttle valve is decreased, thereby improving the admixing of air and fuel, the response characteristic to the operating condition of the engine, the distribution of the fuel amount-to respective engine cylinders and the fuel economy. This permits more precise control of the alr-fuel ratio as well as stabi-lization of the engine operation.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An air-fuel mixture supply system for an internal combustion engine, comprising: means defining an intake passage-way through which each combustion chamber of the engine is communi-cable with the atmosphere; a throttle valve pivotally disposed in said intake passageway; temperature sensitive means responsive to a temperature which is in relation to an engine operating con-dition, and taking a first state when said temperature is within a range where the engine is cold; connecting means for connecting said temperature sensitive means with said throttle valve to open said throttle valve to a predetermined extent when said temperature sensitive means takes said first state; and a fuel injector disposed to inject fuel into said intake air passageway upstream of said throttle valve.
2. A system as claimed in claim 1 in which said temperature sensitive means includes an expandable temperature sensitive element which takes a contracted state when the temperature of a portion in close proximity to said temperature sensitive element is within said range, and an elongate member connected to said temperature sensitive element and movable in response to the state taken by said temperature sensitive element.
3. A system as claimed in claim 2, in which said connecting means includes lever means connecting said elongate member to a throttle shaft on which said throttle valve is securely mounted, said throttle valve being opened to said predtermined extent by said lever means upon said contracted state of said temperature sensitive element.
4. A system as claimed in claim 3, further comprising heating means for heating said temperature sensitive element at least during engine starting so that said temperature sensitive element takes an expanded state upon which said throttle valve is fully closable by said lever means.
5. A system as claimed in claim 4, in which said heating means includes a heating wire located in close proximity to said temperature sensitive element, and electrically connected to an electric source through an ignition switch to generate heat when the ignition switch is closed.
6. A system as claimed in claim 5, in which said temperature sensitive element includes a wax pellet.
7. A system as claimed in claim 3, in which said lever means includes a lever securely mounted on said throttle shaft and having a lever arm which is connectable to an end of said elongate member.
8. A system as claimed in claim 3, in which said lever means includes a first lever securely mounted on said throttle shaft, and a second lever rotatably mounted on said throttle shaft and engageable with said first lever, said second lever having a lever arm which is movably connected to an end of said elongate member.
9. A system as claimed in claim 3, further comprising a cam member attached to said elongate member, wherein said lever means includes a lever securely mounted on said throttle shaft and having a lever arm contactable on the cam surface of said cam member.
10. A system as claimed in claim 1, in which said fuel injector is arranged to inject fuel generally in the form of a hollow cone toward the opening formed between the wall surface and the periphery of said throttle valve.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10141278U JPS5520604U (en) | 1978-07-25 | 1978-07-25 | |
| JP53-101412 | 1978-07-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1115149A true CA1115149A (en) | 1981-12-29 |
Family
ID=14299988
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA330,058A Expired CA1115149A (en) | 1978-07-25 | 1979-06-19 | Air-fuel mixture supply system |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5520604U (en) |
| AU (1) | AU520910B2 (en) |
| CA (1) | CA1115149A (en) |
| DE (1) | DE2926843A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57148046A (en) * | 1981-03-09 | 1982-09-13 | Toyota Motor Corp | Temperature sensing controller of carburetor |
| JPS58107849A (en) * | 1981-12-21 | 1983-06-27 | Toyota Motor Corp | Variable venturi carburetor |
| JPS58107828A (en) * | 1981-12-22 | 1983-06-27 | Toyota Motor Corp | Carburetor throttle valve aperture control device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5018532B2 (en) * | 1972-01-25 | 1975-06-30 |
-
1978
- 1978-07-25 JP JP10141278U patent/JPS5520604U/ja active Pending
-
1979
- 1979-06-11 AU AU47942/79A patent/AU520910B2/en not_active Ceased
- 1979-06-19 CA CA330,058A patent/CA1115149A/en not_active Expired
- 1979-07-03 DE DE19792926843 patent/DE2926843A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5520604U (en) | 1980-02-08 |
| DE2926843A1 (en) | 1980-02-07 |
| AU520910B2 (en) | 1982-03-04 |
| AU4794279A (en) | 1980-02-07 |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |