FUEL CONTROL FOR INTERNAL COMBUSTION ENGINES

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 5. 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 10. 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 petro 1 or ct_.er fuel through the jet which is normally use to assist tunin 15. of the engine for best performance. There is value in providing that during such engirt operating conditions that the fuel be stopped from .lowing through at " least the idle jot. The value : n addition t - improved fuel economy is that pollution can be reduced. 20. 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 carbur¬ ettors, which can be installed therefore economic.. ' ly and which can have significant value in terms o. several operating 25. conditions of the engine. % According to this invention in one forr. then .here is provided a controllable needle valve wherein the _::le needle valve comprises a needle valve elcm„:.t havl * a _-oad and a stem, said head being adapted to sea 1 , in sen_.αble mann. 30. on the valve seat of the idle jet, and a sleeve h ving an out - threac. surrounding said stem, said _'.en to-jether -.'" ' th . • > _ he. 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 5. 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 10- in the inlet manifold which is one convenient way of deter¬ mining that the selected operating conditions are occ ring. Accordingly there can be provided either a vacuum responsive switch coupled to an electro-magnet by vhic ' .- the position of the stem can be governed acting typically 15. against α resiliant spring or in a further preferred form, the degree of low pressure existing can in itself be used again t a selected resiliant pressure to *_ * "rectly cont r ol the position of the stem and hence the head actir... to close off the idle jet. 20. 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 secondl with new carbur 25. 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 α further improvement, if the arrangement is such that upon the engine being switched off, -he reedle 30. valve closes the idle jet, fuel still within the conduit feeding the idle jet can be stopped and this can "irstly provide at least ome fuel saving but it can also limit an effect known as "dieseling" that can occur af er a petrol engine has been switched off. In order for the invention to be more fully urderstood it will now be described with the assistance of drawings in which : FIG. 1 shows in schematic form a first embodiment 5. 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 α needle jet control 10. valve 1 shown in the position on a conventional needle valve controlling the idle jet but in this case m lified so that there is a threaded stem 2 engaging the co-operatively threaded aperture 3 of a conventional carburettor arrange¬ ment 4. 15. Slidably retained within the sleeve 2 however _ιnd in such a way as to provide adequate liquid sealing betweer the respective sliding surfaces is a stem and head assembly 5. The head portion of the assembly 5 is adapted to seat 20. against the seat as shown under pressure of energized electro¬ magnetic 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 vacuurr decreases 25. below 13 to 20 inches of mercury the solenoid coil 6 is de-energized resulting in needle 5 returning to it? 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 5. 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, 10. which can be mechanically driven by a rotating part of the engine, or electrically from the ignition system in kncwr manner or electronic brain or computer. -' The electrical supply can be by way of α switch through the ignition switch of the motor vehicle supplied from the 15. battery through connection 12. According to α second embodiment, this being shown at FIG. 2, the head and ste assembly 5 is held under he relative pressure caused by helical spring 13 so toat it will assume α normally closed position with respect to an 20. idle jet valve seat. In this αrranger-ent then, activation of the electro¬ magnetic coil 6 will cause a slug secured to .-he 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. 25. 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 seαiir.;; of the idle jet valve seat. A feature of this arrangement is that for normal r_.:_:.incr 30. of the engine, the coil 6 will remain activated so -_. . :ιt -rvon opening of the electrical circuit such as the turning off of the ignition switch in the motor vehicle, this will rel_._tse the slug and allow spring I. to push, the he::.* of r_ * .- ho: ' -ten, combination 5 into seal j posi ti■- • ■:.. BAD ORIGINAL This ensures that there is minimal fuel thereafter available to be drawn into the air flow through the carbur¬ ettor and hence will limit or stop dieseling of the engine. In the embodiment shown in FIG. 3 there is the threaded 5. sleeve 2 carries α body 14 of a diaphragm valve, the diaphrag 15 of the diaphragm valve being connected to the stem o a 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 i * ? not 10. sufficient vacuum available through conduit 3. 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 15. 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 20.- used in a carburettor so that even the minimal fuel loss caused through these being open can be reduced if ..esired. With respect to the value in terms of a stan dard motor vehicle of conventional type having a modi ication such as that described has been found in a typical instance to be 25. in the order of 10. fuel saving over a conventional suburban use cycle. Saving in fuel usage could be greater in manually drive- vehicles, compared to an automatic driven vehicle. Fuel flowing into the carburettor will be able to be promptly 30. stopped whenever the foot is taken off the accelerator above typically lOOOto 1200 .P. . as would occur during manual gear changing or during de-αccelerα ion. A feature of the arrangement is that where the idle jet will be closed upon switch-off of an engine, the fu__i remaining within the conduit supplying the idle jet is also stopped from passing into the air stream so that this 5. 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 -f the engine 10. having the result of pernaps 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 15. 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. ._ very significant advantage of this invent-.3;. is -hat the needle valve for the idle jet can be adjusted acco - " " ' ng 20. to normal techniques so that best idle conditions can be established. Mo major modification of any carburettor or other facilities is necessary. BAD ORIGINAL

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 sard 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 com¬ prise 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 o f 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. Λ controllable idle needle valve according 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 carburetter or an inlet manifold of the engine being controlled so as f _ effect α closure by the head against the valve seat of the idle jet while such selected lower pressure is bei • .-_-. detected. BADORIGINAi 5. A controllable idle needle valve according to any one of the preceding Claims further adapted so as to assume a position witn the head sealed in scalable manner against the seat of the idle jet upon α switching off of the engine. 6. An internal combustion engine including a carbur¬ ettor having within it a controllable idle needle valve according to any one of the preceding Claims. 7. A controllable idle needle valve substantially as descri ed 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. £- . Λ controllable idle needle valve substantially a . described _n the Specification with reference to and as illustrated by FIG. 3 of the acccr. ponying illustrations. 10. An .. iternal combustion engine having a carburettor having a controllable idle needle valve according to any one of the last three preceding Claims.

Inventors: PROCHAZKA OLIN, PROCHAZKA, OLIN
Applicants: PROCHAZKA ANEZKA, PROCHAZKA OLIN, PROCHAZKA, ANEZKA, PROCHAZKA, OLIN
Application year: 1982
Main classification: F02M3
IPC codes: F02M3