WO1984000194A1

WO1984000194A1 - Fuel control for internal combustion engines

Info

Publication number: WO1984000194A1
Application number: PCT/AU1982/000101
Authority: WO
Inventors: Olin Prochazka
Original assignee: Prochazka Anezka; Olin Prochazka
Priority date: 1980-12-24
Filing date: 1982-06-24
Publication date: 1984-01-19
Also published as: AU7886481A; EP0112816A1

Abstract

An idle needle valve for a carburettor of an internal combustion engine having provision for controlling the position thereof with respect to the valve seat of the idle jet. The valve has a head stem element (5), a sleeve (2) and control means (6) for opening and closing the valve in response to selected engine operating conditions. The control means (6) may comprise vacuum responsive or electromagnetic means.

Description

FUEL CONTROL FOR INTERNAL COMBUSTION ENGINES

This invention relates to an improved fuel control arrangement for internal combustion engines and to apparatus having particular value for this purpose.

It is known in some operating conditions that an internal combustion engine can draw the fuel into its manifold which is not usefully used.

Such conditions conventionally include a case such as where an engine in a motor vehicle is used to deacrelerate the vehicle and in this situation the fuel can be drawn especially from the idle jet into the inlet manifold of the engine.

It is conventional that there is a device commonly known as a needle valve controlling access of the petrol or other fuel through the jet which is normally used to assist tuning of the engine for best performance.

There is value in providing that during such engine operating conditions that the fuel be stopped from flowing through at least the idle jet. The value in addition to improved fuel economy is that pollution can be reduced.

While in general terms this problem is known, there is difficulty in proposing an apparatus which is both very simple in terms of installation in even conventional carburettors, which can be installed therefore economically and which can have significant value in terms of several operating conditions of the engine.

According to this invention in one form then there is provided a controllable needle valve wherein the

needle valve comprises a needle valve element having a head and a stem, said head being adapted to seat in sealable manner on the valve seat of the idle jet, and a sleeve having an out thread surrounding said stem, said stem together with said head being slidably retained with respect to said sleeve, a means controlling the position of the said stem together with the said head with respect to the relative elongate position with respect to the sleeve so that the said head can be caused to close the idle jet upon selected engine operating conditions.

With such an arrangement, it is preferred that the position of the stem be governed in response to the degree of vacuum existing within the throat of the carburettor or in the inlet manifold which is one convenient way of determining that the selected operating conditions are occrring.

Accordingly there can be provided either a vacuum responsive switch coupled to an electro-magnet by which the position of the stem can be governed acting typically against a resiliant spring or in a further preferred form, the degree of low pressure existing can in itself be used against a selected resiliant pressure to directly control the position of the stem and hence the head acting to close off the idle jet.

It will now be seen that by providing a device which can in fact be a straight replacement of an existing needle valve, with of course external control mechanisms, it become a very simple matter to firstly modify an existing apparatus to incorporate this improvement and secondly with new carbur ettors, there is no major alteration necessary in terms of the substantial design work presently involved in the design of a carburettor to incorporate this modification.

According to a further improvement, if the arrangement is such that upon the engine being switched off, the needle valve closes the idle jet, fuel still within the conduit feeding the idle jet can be stopped and this can firstly provide at least some fuel saving but it can also limit an effect known as "dieseling" that can occur after a petrol engine has been switched off. In order for the invention to be more fully understood it will now be described with the assistance of drawings in which :

FIG. 1 shows in schematic form a first embodiment of the invention,

FIG. 2 shows a second embodiment and

FIG. 3 shows a third embodiment

In a first preferred form of the invention as shown in FIG. 1 there is shown in schematic form a needle jet control valve 1 shown in the position on a conventional needle valve controlling the idle jet but in this case molified so that there is a threaded stem 2 engaging the co-operatively threaded aperture 3 of a conventional carburettor arrangement 4.

Slidably retained within the sleeve 2 however and in such a way as to provide adequate liquid sealing between the respective sliding surfaces is a stem and head assembly 5.

The head portion of the assembly 5 is adapted to seat against the seat as shown under pressure of energized electromagnetic coil 6.

When solenoid 6 is energized the assembly 5 is extended out to close the idling needle seat. Solenoid 6 is controlled by the adjustable vacuum switch 9. When the vacuum decreases below 13 to 20 inches of mercury the solenoid coil 6 is de-energized resulting in needle 5 returning to its set position for idling. Spring 7 is not directly connected with the function of the needle assemblys. This spring 7 is solely for securing the device in a stationary position once adjusted. Should wiring or solenoid malfunction occur the needle assembly 5 will immediately return to the idling position and prevent the motor stalling.

Instead of the control being activated by the vacuum switch, this could easily be activated by a device dependant upon the speed of the vehicle, such as a tachometer or output, which can be mechanically driven by a rotating part of the engine, or electrically from the ignition system in known manner or electronic brain or computer.

The electrical supply can be by way of a switch through the ignition switch of the motor vehicle supplied from the battery through connection 12.

According to a second embodiment, this being shown at FIG. 2, the head and stem assembly 5 is held under the relative pressure caused by helical spring 13 so that it will assume a normally closed position with respect to an idle jet valve seat.

In this arrangement then, activation of the electromagnetic coil 6 will cause a slug secured to the end of the stem to be pulled back so as to pull the head of the head stem combination 5 against the pressure of spring 13.

With release of activation, spring 13 will extend and it is arranged that there is sufficient clearance between the respective parts to ensure that the head sealing of the idle jet valve seat.

A feature of this arrangement is that for normal running of the engine, the coil 6 will remain activated so that upon opening of the electrical circuit such as the turning off of the ignition switch in the motor vehicle, this will release the slug and allow spring 1. to push the head of the head stem combination 5 into the seal position. This ensures that there is minimal fuel thereafter available to be drawn into the air flow through the carburettor and hence will limit or stop dieseling of the engine.

In the embodiment shown in FIG. 3 there is the threaded sleeve 2 carries a body 14 of a diaphragm valve, the diaphrag 15 of the diaphragm valve being connected to the stem of the head stem combination 5, a helical spring 16 being arranged so as to cause the diaphragm 15 and accordingly the stem 5 to assume the normally open position when there is not sufficient vacuum available through conduit 8.

Having now described the specific forms of the invention which are preferred it will be seen that the invention can be applicable to those forms of a carburettor in which there is a separate passage leading to the idle needle jet valve, and which passage is provided with a control to prevent the flow of fuel to the passage when the engine has been stopped and when the ignition system has been turned off.

It will be appreciated that in a broader form, the concept of this invention is applicable to the further jets used in a carburettor so that even the minimal fuel loss caused through these being open can be reduced if desired.

With respect to the value in terms of a standard motor vehicle of conventional type having a modification such as that described has been found in a typical instance to be in the order of 10. fuel saving over a conventional suburban use cycle.

Saving in fuel usage could be greater in manually driven vehicles, compared to an automatic driven vehicle. Fuel flowing into the carburettor will be able to be promptly stopped whenever the foot is taken off the accelerator above typically 1000 to 1200 R.P.M. as would occur during manual gear changing or during de-acceleration. A feature of the arrangement is that where the idle jet will be closed upon switch-off of an engine, the fuel remaining within the conduit supplying the idle jet is also stopped from passing into the air stream so that this fuel will not pass through the engine and be dissipated generally into the atmosphere as unburnt fuel so that there is a distinct saving in pollution.

There is also the additional advantage that unburnt fuel will not pass through the cylinders of the engine having the result of perhaps washing the cylinder walls reducing oil on the cylinder walls upon switch-off of the engine.

For these reasons, there are significant advantages above even the fuel saving advantages that is both in respect of pollution minimization and engine life and further than this life of oil within the engine which will then be less dilluted by the unburnt fuel. A very significant advantage of this invention is that the needle valve for the idle jet can be adjusted according to normal techniques so that best idle conditions can be established.

No major modification of any carburettor or other facilities is necessary.

Claims

The Claims defining the invention are as follows :-

1. A controllable idle needle valve where in the idle needle valve comprises a needle valve element having a head and a stem, said head being adapted to seat in suitable manner on to the valve seat of the idle jet, and a sleeve having an outer thread surrounding said stem, said stem together with said head being slidably retained with respect to said sleeve, means controlling the position of the said stem together with the said head with respect to the relative elongate position with respect to the sleeve so that the said head can be caused to close the idle jet upon selected engine operating conditions.

2 . A controllable idle needle valve as in Claim 1. wherein said means controlling the position of the said stem together with the said head with respect to the sleeve comprise vacuum responsive means arranged to be responsive to a selected pressure either within the throat of a carburettor or the inlet manifold.

3. A controllable idle needle valve as in either of Claims 1. or 2. wherein electro-magnetic means are coupled to the said stem whereby to provide for control of the said relative elongate position with respect to the sleeve.

4. A controllable idle needle valve accordi00 to any one of the preceding Claims wherein there is a vacuum responsive switch adapted to be responsive to a lower than selected pressure within either the throat of the carburettor or an inlet manifold of the engine being controlled so as to effect a closure by the head against the valve seat of the idle jet while such selected lower pressure is being detected.

5. A controllable idle needle valve according to any one of the preceding Claims further adapted so as to assume a position with the head sealed in scalable manner against the seat of the idle jet upon a switching off of the engine.

6. An internal combustion engine including a carburettor having within it a controllable idle needle valve according to any one of the preceding Claims.

7. A controllable idle needle valve substantially as described in the Specification with reference to and as illustrated by FIG. 1 of the accompanying illustrations.

8. A controllable idle needle valve substantially as described in the Specification with reference to and as illustrated by FIG. 2 of the accompanying illustrations.

9. A controllable idle needle valve substantially as described in the Specification with reference to and as illustrated by FIG. 3 of the accompanying illustrations.

10. An internal combustion engine having a carburettor having a controllable idle needle valve according to any one of the last three preceding Claims.