Transmission Controlled Throttle For Internal Combustion Engine

Abstract

A fuel supply system for an internal combustion engine utilizing an automatic transmission including a torque converter and a gear train has a carburetor with an inlet passage and a throttle valve therein. A sensing member is in a first position when the gear train is in a neutral position and a second position when the gear train is in a drive position. A throttle valve control slightly opens or closes the throttle valve in response to the sensing member. The throttle valve control operates to slightly open the throttle valve to hold the idling speed of the engine to a predetermined value when the gear train is in the drive position, thereby preventing the engine speed from decreasing due to the load.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates to improvements in the fuel supply system for internal combustion engines incorporating an automatic transmission.

In general, it is well known that if the idling speed of the internal combustion engine is raised, unburned detrimental components contained within the exhaust gas such as carbon monoxide or hydrocarbon is decreased in comparison with lower idling speed.

However, in an automobile in which an automatic transmission having torque converter and gear train is coupled to the internal combustion engine, if the gear train is transferred from neutral to drive position for normal travelling, the idling speed of the internal combustion engine is abruptly decreased. If the automatic transmission is shifted from neutral to drive position such as, for example, manually to first, second or reverse gear, or automatically shifted in position, the torque of the engine is transmitted from the engine through the torque converter, gear train to the wheels so that the engine abruptly receives the load with the result that the engine speed decreases. As a result, the combustion state of the fuel in the engine becomes worse so that the unburned detrimental components in the exhaust gas increase at the same time. In the worst case the internal combustion engine sometimes stops. Where the engine has a pump for feeding secondary air for purifying the exhaust gas, the quantity of the air discharge from the pump decreases so that it cannot supply sufficient secondary air to the exhaust system and further the unburned detrimental components contained in the exhaust gas increase. In order to overcome these disadvantages, if the idling speed of the engine in transmission drive position is raised, the idling speed of the engine in transmission neutral position becomes very high accordingly so that the fuel consumption of the engine becomes very high, which is not preferable. At the same time, the shock in case that the transmission is shifted from neutral to drive position, or the shock raised due to the abrupt completion of the power train from the rotating engine to the wheels becomes extremely large.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to eliminate the aforementioned disadvantages of the conventional system and to provide a novel and improved fuel supply system for an internal combustion engine in combination with an automatic transmission, having a throttle valve control means for opening the throttle valve of a carburetor in the drive position of the transmission to a greater extent than that in the neutral position thereof when the gear train is shifted from neutral to drive position, which may always hold the idling engine speed in neutral and drive positions to a predetermined value.

It is another object of the present invention to provide a fuel supply system for an internal combustion engine in combination with an automatic transmission having a switching means opening or closing when the gear train is shifted from neutral to drive position, a solenoid valve means connected to the switching means and opening or closing the vacuum from the inlet passage of a carburetor to a diaphragm device upon opening or closing of the switching means, said diaphragm device for increasing the throttle valve opening in the drive position of the transmission to a greater degree than that in the neutral position thereof by means of the diaphragm device.

BRIEF DESCRIPTION OF THE DRAWING

The other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawing, in which the FIGURE is a schematic view of one embodiment of a fuel supply system for an internal combustion engine according to this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference numeral 1 designates a throttle valve disposed in an air intake passage 2 of a carburetor for supplying an air-fuel mixture to an internal combustion engine 16. A lever 3 is fixed to a rotary shaft of the throttle valve 1, and spring 3d urges the throttle valve 1 to close position. A solenoid valve means 4 is connected to the intake passage 2 of the carburetor through a vacuum conduit 5 to a diaphragm device 6 through a vacuum passage 7. A diaphragm 8 is carried in diaphragm device 6 and a spring 9 is disposed within a vacuum chamber 10 for urging the diaphragm 8 outwardly. A rod 11 fixed to the diaphragm 8 urges the lever 3 clockwise.

The vacuum conduit 5 and vacuum passage 7 constitute a conduit for introducing the vacuum within the air intake passage 2 to the vacuum chamber 10 of the diaphragm device 6. The opening position (designated by a solid line in the drawing) of the throttle valve 1 during idling speed of the engine when the vacuum is not applied to the vacuum chamber 10 of the diaphragm device 6, is so provided, that the throttle valve opening becomes larger by a predetermined amount over that (shown by a dotted line in the drawing) for the throttle valve 1 during the idling operation of the engine when the vacuum within the vacuum chamber 10 is applied. The solenoid valve means 4 includes a solenoid coil 12 and a valve 15 driven by the solenoid. The solenoid coil 12 is connected to a source of electric power 14 through a switch 13. The switch 13 is opened or closed by a signal from a sensing means 18. The sensing means 18 is connected to the automatic transmission 17 for generating a first signal when the automatic transmission 17 is in a drive position and the second signal when the automatic transmission 17 is in a neutral position. When the solenoid 12 is energized, the passage consisting of the vacuum conduit 5 and vacuum passage 7 is opened by the valve 15 of the solenoid valve means 4. On the other hand, when the solenoid 12 is deenergized, the valve 15 closes the passage defined by the vacuum conduit 5 and vacuum passage 7. The switch 13 is so provided that it closes in the neutral position of the transmission while it opens in the drive position thereof.

If the gear train is shifted to the neutral position and the internal combustion engine is in idling operation, the switch 13 is closed by the second signal from the sensing means 18 with the result that the solenoid 12 is energized. Accordingly, since the valve 15 of the solenoid valve means 4 opens the passage formed by the vacuum conduit 5 and the vacuum passage 7, vacuum is applied to the vacuum chamber 10 of the diaphragm device 6. As a result, the rod 11 moves together with the diaphragm 8, so that the opening of the throttle valve 1 decreases as seen by the dotted lines in the drawing via spring 3d, with the result that in engine idling operation and in the neutral position of the gear train, the engine speed may be lowered as much as possible in order to remove the unburned detrimental component of the exhaust gas.

If the gear train is shifted from neutral to drive position, the switch 13 is opened by the first signal from the sensing means 18, with the result that the solenoid 12 is deenergized. Therefore, since the valve 15 of the solenoid valve means 4 closes the passage defined by vacuum conduit 5 and the vacuum passage 7, vacuum is not applied to the vacuum chamber 10 of the diaphragm device 6.

Thus, rod 11 is urged downwardly by spring 9 acting against spring 3a, so that the lever 3 rotates clockwise to open the throttle valve 1 to the solid line position in the drawing. If follows that the opening of the throttle valve in idling operation of the engine is larger by a predetermined amount than that in idling operation during neutral position of the transmission.

In operation of the thus constructed device in the automobile in which an automatic transmission having a torque converter and a gear train is disposed in the driving system for an internal combustion engine, the lever 3 for rotating the throttle valve 1 is controlled by the diaphragm device 6 connected through the conduit to the air intake passage 2 of the carburetor. The switch 13 opening or closing in response to the shift in the gear train between neutral and drive positions is connected to the solenoid valve means 4 opening or closing the conduit with the result that the opening of the throttle valve upon idling operation of the internal combustion engine in the drive position of the transmission becomes larger by a predetermined amount over that of the throttle valve upon idling operation of the internal combustion engine in the neutral position of the transmission. Accordingly, since the idling speed in the neutral position of the transmission is decreased as much as possible when the gear train is shifted from the neutral position to drive position, the shifting shock becomes very small. Further, when the transmission is shifted from neutral position to drive position the load for abruptly completing the power train is applied to the engine and, while normally the speed of the engine reduces and in extreme condition the engine tends to stall, since the opening of the throttle valve is increased by a predetermined amount, lowering the speed of the engine and the engine stalling are prevented, and the idling speed in the drive position is maintained substantially corresponding to the idling speed in neutral position. For this reason, this system may decrease the content of the unburned detrimental components contained in the exhaust gas upon idling operation of the engine in the drive position of the transmission.

It should be understood that the operation of the solenoid valve means 4 and the switch 13 may also be provided in such a manner that it may be reversely operated to the operation described as above. This means that the switch 13 is OFF in the neutral position so that the valve 15 of the solenoid valve means 4 opens the conduit, while the switch 13 becomes ON to close the valve 15. Such a constructed device may obtain the same advantage as the aforementioned device.

It should also be understood that the diaphragm device may be omitted so that the lever 3 is directly pushed by rod 15 moved by means of solenoid 12. Further, it should be also understood that shifting between the neutral and drive position of the gear train may directly control the throttle valve through the linkage mechanism. Further, it should be understood that the signal oil pressure shifting the gear train between the neutral and drive position may directly control the throttle valve.

Claims

What is claimed is:

1. A fuel supply system for an internal combustion engine having an automatic transmission comprising:

an air and fuel supply means for supplying a combustion mixture to the internal combustion engine including an inlet passage to the engine and a throttle valve therein;

sensing means operatively connected to the automatic transmission for generating a first signal when the automatic transmission is in a neutral position and a second signal when the automatic transmission is in a drive position; and

throttle valve control means operatively connected to said sensing means and responsive to the signals of the sensing means for positioning the throttle valve in the inlet passage in a relatively open position when the automatic transmission is in the drive position in response to said second signal and in a relatively closed position when the automatic transmission is in a neutral position in response to said first signal whereby the engine speed will be maintained when the engine is placed under the drive load by the automatic transmission.

2. The fuel supply system as set forth in claim 1, wherein the sensing means includes a two-position switch which opens upon shifting the automatic transmission from the neutral position to the drive position, the throttle valve control means including a diaphragm device having a conduit communicating with the inlet passage and a solenoid valve means connected in said conduit and being operatively connected to said switch for opening the conduit by closing the two-position switch, whereby the diaphragm device operates to close the throttle valve to maintain the idling speed of the engine to a predetermined value when the automatic transmission moves to the neutral position, and further including biasing means opposing said vacuum operated diaphragm means to move said throttle valve control means to a predetermined open position to open the throttle valve so as to prevent the engine speed from lowering due to the transmission load when the automatic transmission is shifted from neutral to a drive position, said conduit being blocked by said solenoid valve means.