DE3531486A1 - Method and device for feeding fuel to an engine - Google Patents

Abstract

A method for feeding a metered quantity of fuel to an internal combustion engine is described. The fuel is metered in a chamber, which may have the shape of a line, the metered quantity being varied according to the engine load. A pulse of a gas, for example air, is fed into the chamber in order to expel the fuel from the chamber and feed it to the engine by way of a nozzle. The quantity and/or the length of time in which the gas is fed into the chamber is varied as a function of the changes in the metered quantity of fuel.

Description

Pfenning, Meinig & Partner 3 5 3 _{U 8 6}

Dipl.-tng. J. Pfenning, Berlin

g - Dipl.-Phys. KH Meinig, Munich

* Dr.-lng. A. Butenschön, Berlin

DipHng. J. Bergmann, Munich Lawyer

Mozartstrasse 17th

D-8000 Munich 2

Phone: 089 / 530575-77

Telex: 186237 pmp

Fax: 089/530578 (Gr 2 + 3)

Kurfürstendamm 170

D-1000 Berlin 15

Phone: 030 / 8812008-09

Telex: 186237 pmp

Fax: 030/8813689 (Gr 2 + 3)

Telegrams: rope defense patent

August 30, 1985 Bg / Ko

ORBITAL ENGINE COMPANY PROPRIETARY LIMITED, Whipple Street, Balcatta, Western Australia, AUSTRALIA

Method and device for supplying fuel to a machine

353U86

JT]

Method and device for supplying fuel to a machine

The invention relates to the metering and supply of fuel to an internal combustion engine and particularly relates to those systems that use a pulse of gas to deliver a metered amount of fuel and / or inject. The invention is particularly applicable to fuel supply of machines for transportation vehicles that have frequent and significant load change conditions appear.

There is a growing need for less expensive and more fuel-efficient fuel injection systems for internal combustion engines. Traditional fuel injection systems used to have one High-pressure fuel pump and a high-pressure metering device are required in order to

"17th

achievable degree of fuel atomization and to enable handling of the hot fuel. Both requirements lead to high cost of the parts used due to the high standards required in production, the tight manufacturing tolerances and the expensive materials required.

The use of pneumatic fuel metering is described in SAE-Technische Mackay Communication No. 820351, and further details thereof are disclosed in U.S. Pat GB-PS 2 018 906 and 2 102 501 as well as in the G3 patent applications numbers 532 035 and 454 657. This use leads to a considerable reduction in the aforementioned Problems.

In the process of pneumatic fuel metering and injection, one in one Dosed amount of fuel located in the chamber by a gas pulse of high pressure from the Chamber pushed out and fed into the machine. This feed is preferably carried out via a flexible line to the suction pipe of the machine, but it can also be fed directly into the Combustion chamber done. Existing systems work in such a way that they gas at increased Provide pressure upstream of a valve at the gas inlet of the chamber and open the valve Open the instruction of a programmed electronic control unit. The duration of the valve opening was previously set for all dosed quantities of the fuel that can be expelled from the chamber by the gas pulse is kept constant, and that System was designed to last this

353U8S

was sufficient to provide the required metered amount of fuel with the maximum fuel requirement to deliver to the machine. The duration of the valve opening became more constant by a pulse Width controlled by the electronic control unit.

However, for a given machine to function satisfactorily, the system must be able to deliver fuel over a wide range of quantities. Under stationary Conditions, i.e. constant speed and load, require a fuel metering and -injection system a reduction ratio (turn-down ratio) of about 5 to 1, however, in the event of sudden increases in load, the machine may for a very short period of time Demand up to twice as much fuel as with a wide open throttle valve.

It can be assumed that, although a constant gas pulse length is sufficient, to expel the required amount of fuel from the chamber, which is actually with the dosed amount of fuel amount of gas supplied

decreases considerably with increasing dosed amounts of fuel. It is believed that this Decrease in the amount of air due to inertia and viscosity properties of the increased amount of fuel based, and it has an adverse effect on the actually delivered Amount of fuel, the quality of the fuel / air mixture and what is being delivered to the machine Atomization pattern.

353U86

It is therefore the object of the present invention to provide a method and a device for supplying fuel to an engine using compressed Throttle to provide improved engine response in load transition conditions result.

The present invention discloses a method of supplying fuel to a machine by feeding compressed gas into a chamber to produce a metered Expelling amount of fuel from this and by varying the amount of injected Gas depending on changes in the fuel consumption of the engine, so that if the demand for fuel increases, and the amount of gas also increases.

The increase in the amount of fuel fed into the chamber to drive off the metered amount of fuel The amount of gas with the increase in the amount of fuel results in additional available energy per unit weight of fuel to drive it out of the metering chamber and to be transported through the injector.

The increased amount of gas also serves to atomize and spray the gas emerging from the nozzle Fuel. Depending on the degree of increase in the amount of gas relative to the amount of fuel the specific energy remaining in the gas at the nozzle can also increase with the increase increase in the amount of fuel or at least over the major part of the fuel amount range under normal operating conditions

, 4b.
be kept essentially constant.

The change in the amount of gas can be in a linear relationship to the change in the amount of fuel take place; however, any other relationship can also be selected.

The amount of gas fed into the dosing chamber is determined by the pressure and temperature of the Affected gas upon entry into the Dosiefkammer. From a practical point of view however, it is not convenient to vary either the pressure or the temperature, in particular if one takes into account that these variations occur in a time interval of a few

*

Milliseconds must be carried out. That

The most suitable means of changing the amount of gas consists in changing the period of time in which the gas is fed into the metering chamber.
20th

In particular, a method for supplying fuel to a machine is provided, in which a metered amount of fuel in a chamber with a gas inlet

and a fuel outlet is provided and wherein the fuel is provided through the Fuel outlet expelled from the chamber and fed through a nozzle to the machine is, with the expelling and feeding of the

Fuel by feeding in gas

caused by the gas inlet into the chamber and the amount of gas fed in can be varied depending on the fuel requirements of the machine.
35

- Alfs

It is known that when a fluid, and in particular a liquid, passes through a conduit flows, a layer of the liquid forms on the inner surface of the pipe. The thickness of this layer depends on a number of factors that affect the viscosity of the Include liquid, flow rate and surface finish of the conduit. As the velocity of the liquid decreases, the thickness of the layer increases, and therefore, in the presently considered fuel metering system, it increases with decreasing speed the fuel supply to the amount of fuel in the stationary layer.

We therefore have an increase in the amount of fuel takes place without a corresponding increase in the amount of gas propelling the fuel, part of the fuel obtained by the rise is not fed to the engine, but rather used for the reinforcement of the stationary layer. Accordingly, with a Increasing the amount of fuel by increasing the amount of fuel propelling the fuel Air volume avoided a decrease in fuel speed and the thickness of the stationary layer can be kept essentially constant.

It is possible to reduce the thickness of the layer if the increase in the amount of air is sufficient is to increase the speed of the fuel. This can be beneficial in two ways. An increase in the amount of gas without an increase in the amount of fuel dosed leads to an increase in the fuel

ORlGINAL INSPECTED

material speed and thus a reduction the layer thickness. In this way, a limited increase in the amount of fuel fed to the nozzle can be achieved, without changing the actual dosage amount. This kind of increase in Supplying fuel to the engine can be useful when the demand for fuel increases is relatively small and of short duration.

On the other hand, if the amount of gas increases with an increase in the amount of fuel dosed is coupled and sufficient to increase the overall fuel velocity, then a reduction in the thickness of the fuel layer can occur, whereby the The amount of fuel supplied through the nozzle is further increased. This can be beneficial be when a big or rapid increase

is present in the fuel requirement. 20th

The amount of fuel can be dosed when it is introduced into the chamber or also through / and / or during the feed

of the gas into the chamber.
25th

The invention is described below with the aid of an exemplary embodiment shown in the figures explained in more detail. Show it:

Fig. 1 A fuel metering device,

FIG. 2 shows a sectional view along the line 2-2 in FIG. 1,

353U86

Fig.

Fig.

Figures 5a-5d

a flow diagram about the mode of action an electronic control unit to regulate the available fuel supply Gas quantity,

a diagram showing the change in the duration of the gas injection depending on fuel requirements, and

Diagrams showing the amount of fuel supplied in relation to each other to the gas supply.

According to Figures 1 and 2, the metering device has a device body 110 in which four individual metering units 111 arranged side by side are. The device is thus suitable for use in a four-cylinder engine, with each metering unit 111 is assigned to a separate cylinder. Fittings 112 and 113 are for a connection with a fuel supply line or a fuel return line, which are not shown are provided and communicate with corresponding fuel supply and fuel return chambers 60 and 70 within the device body for the delivery and return of fuel to or from each dosing unit 111.

Each metering unit 111 is equipped with its own fuel supply connection piece 114, with each of which a fuel supply line 108 is connected, which the

353U86

Direct individually metered amounts of fuel to an injection nozzle 18 (FIG. 2). the Nozzle is placed in a suitable position to feed the fuel to the engine deliver, for example in the suction pipe of the machine near the respective Cylinder air intake valve inserted. Further details of the device are in the US patent application No. 532 035 shown.

The device body 110 is preferably in the Arranged near the injection nozzle 18 and have the fuel supply lines 108 expediently a diameter of about 1.8 mm and a length in the range from 10 to 40 cm depending on the distance to the respectively assigned Cylinder.

Figure 2 shows in cross section a metering unit 11 with a metering rod 115, which extends into both an air feed chamber 119 and a metering chamber 120. Each of the four metering rods 115 crosses a common leak collection chamber 116, which through a cavity in the device body 110 and one attached thereto in a sealed manner Cover plate 121 is formed. The operation of the leak collection chamber 116 is not part of it of the present invention and is further described in referenced U.S. Patent Application No. 532 described.

Each metering rod 115 is hollow and is arranged to slide axially in the device body 110. The length, in which the metering rod 115 protrudes into the metering chamber 120 can be changed for setting

the amount of fuel that can be expelled from the metering chamber 120. A valve 143 is located at the end of the dosing rod 115 protruding into the dosing chamber 120 and is through a rod 143a supported and normally supported by a spring 145 which extends between the upper end of the hollow metering rod 115 and rod 143a is held closed Flow of the air through the inner bore of the metering rod 115 from the air injection chamber 119 to the dosing chamber 120 is controlled by the valve 143. When the pressure rises in the air supply chamber 119 to a predetermined value, the valve 143 is opened, so that air from the air feed chamber into the metering chamber 120 through the hollow metering rod 115 flow and expel the fuel located in the metering chamber 120 can.

The amount of fuel that can be expelled by the air corresponds to that between the air inlet point and the amount of fuel located at the fuel outlet point of the chamber, i.e. the amount of fuel between the valve 143 for the air supply and one located at the opposite end of the metering chamber 120 Supply valve 109.

Each of the metering rods 115 is provided with a Crosshead 161 coupled, which in turn is slidably arranged in the device body 110 with a Operating rod 160 is coupled. The operating rod 160 is connected to a motor 169 which is controlled as a function of the fuel requirements of the machine in order to generate the

353U86

Set the length with which the metering rods 115 protrude into the metering chambers 120. This also determines the position of the valves 143 for the air feed, so that the metered amount of fuel that is fed in by the air feed corresponds to the fuel requirement. The motor 169 is preferably a reversible linear stepper motor.

The fuel supply valves 109 are each operated in such a way that it depends on the pressure in the metering chamber 120 are then opened when the air from the air feed chamber 119 into the metering chamber 120 is fed in. When the air through the valve 143 into the metering chamber 120 flows, the supply valve 109 also opens, so that the air to the supply valve moves and expels the fuel from the metering chamber through this valve. The valve 143 is kept open until sufficient air is fed in to expelling the fuel from the chamber between valves 143 and 109; and through line 108 to injector 18 and continue through this to atomize any fuel that has passed through.

Each metering chamber 120 has a fuel inlet 125 and a fuel outlet 126 controlled by valves 127 and 128, respectively are to allow a flow of fuel from the inlet chamber 60 through the metering chamber 120 to the outlet chamber 70 to er-35

35 31Vi

-4ο-

possible. Each of the valves 127 and 128 is connected to an associated membrane 129 or 130, respectively. Valves 127 and 128 are held in an open position by spring pressure and closed when air is under Pressure on the respective diaphragms 129 and 130 via associated cavities 131 and 132 acts. Each of these two cavities is in constant communication with an air duct 133, and this is in constant communication with the air feed chamber 119 via a line 135.

Thus, when air under pressure enters the air feed chamber 119 and thus into the Dosing chamber 120 is fed in for supplying the fuel, then the Air also on the membranes 129 and 130, so that the valves 127 and 128, the fuel inlet 125 and the fuel outlet 126 close.

The control of the air supply to the air injection chamber 119 via the line 135 and to cavities 131 and 132 via the Line 133 is timed to the duty cycle of the machine by one of solenoid operated valve 150 controlled. A common air supply line 151, which can be connected to a compressed air source via a connection piece 153, runs through the device body 110 and each has branches 152 for air to the respective valve 150 of each metering unit

111 to deliver.
35

ORIGINAL INSPECTED

353 1 4 δ ο

Typically, a spherical valve body 159 is under the action of springs 170 stored so that there is a flow of air from the air supply line 151 into the line 135 prevented and the line 135 connects via an outlet 161 to the atmosphere. if the solenoid is energized, the force of the springs acting on the valve body 159 becomes 170 is reduced and the valve body is opened by the pressure of the air in the air supply line 151 pushed back, so that air from this in the lines 135 and can flow.

The timing of the energization of the solenoid of the valve 150 with the Machine cycle can be controlled via a suitable detector device 171, by a rotating element of the machine, for example the crankshaft or flywheel 172 or any other element that moves at one of the machine speed corresponding speed is driven, is, can be actuated. One for that purpose Suitable detector consists of an optical switch that has an infrared source and includes a photodetector with a Schmitt trigger.

It has heretofore been suggested that the duration the energization of the electromagnet 150 is invariable is, in particular, independent of the amount of fuel to be supplied and the machine speed. This fixed duration was chosen so that the maximum fuel requirement at the maximum machine

ORIGINAL INSPECTED

speed could be sufficient.

The operation of the electromagnet 150 is expediently controlled by a electronic control unit, which sends an electrical impulse of fixed duration to the Electromagnet delivers regardless of the fuel requirement of the machine. With such a Control has been found, however, that the actual amount of air that is used in each injection process with the fuel flows through the injector 18, with an increase in the amount of the supplied Fuel decreases.

It is believed that this phenomenon is due to changes in inertia and Viscosity properties occurs as a result of the increased fuel level. This can according to the present invention can be compensated by the duration of the excitation of the Solenoid 150 is enlarged at higher fuel levels, which also increases the size of the The period of time in which the gas is fed into the metering chamber 120 is increased and thus the amount of air required to propel the fuel into the pipe and its transport through the injector is available.

Figure 3 is a flow chart showing a typical operation of the electronic Control unit 192 (Figure 1) to carry out changes in the excitation duration of the Electromagnet 150 as a function of

ORIGINAL INSPECTED

353U86

the metered amount of fuel to be supplied to meet the fuel needs of the machine to suffice represents. The controller 192 is with the required relationship between programmed for the metered amount of fuel and the amount of air per injection process.

As Figure 1 shows, the actuating rod 160 carries a contact arm 190, which is fixed with a on the device body 110 arranged resistance

strip 191 cooperates. The contact arm 190 and the resistance strip 191 form a feedback potentiometer 198. The actuator rod 160 is with the metering rods 115 connected and changes the length with which they protrude into the metering chambers 120, and thus the metered amount of fuel supplied. The position of the contact arm 190 on the resistor strip and thus the output voltage of the feedback potentiometer are therefore directly proportional to the metered amount of fuel supplied.

The electronic controller 192 is programmed to run at regular intervals reads the voltage on the potentiometer 198 and thereby the position of the operating rod 160 and thus also the metered amount of fuel is determined. These

Voltage readings are conveniently made in Half a millisecond intervals.

After reading the voltage on the potentiometer, the control unit 192 determines the

"353U86

^ - duration of the electromagnet 150, which is required for the metered amount of fuel in accordance with the position of the actuating rod 160. If, at the point in time at which this determination is made by the control device, the machine is in the part of the duty cycle in which fuel is supplied, then a corresponding setting is made by the control device for the remaining duration of the energization. If the result of this adjustment is that the energization duration is reduced to zero, then the energization of the electromagnet is switched off by the control device, so that the supply of fuel and gas is stopped. However, if the remaining time is not reduced to zero, then the electromagnet remains energized and fuel and gas continue to be supplied. This sequence is repeated in the next half-millisecond period.

If at the time of determining the duration of energization of the electromagnet the machine itself is not in the part of their work cycle in which fuel is added, then the newly determined duration of excitation is saved. If within the then ongoing Half a millisecond period the machine in the part of its duty cycle occurs in which fuel is fed, then the electromagnet for the newly determined Period of time excited. In the event that the machine is not in the part during the half millisecond period their working cycle occurs, in which the fuel supply takes place, then becomes

353U86

at the end of this period repeats the sequence as described above.

Commercially available parts can be arranged and programmed to perform the functions required to follow the flowchart shown in FIG to realize. Other factors can also be introduced to vary the energization time of the electromagnet. at 10

When used in motor vehicles, a factor to consider may be voltage be the energy source exciting the electromagnet.

The voltage of the battery used in a motor vehicle can vary under operating conditions differ significantly from the nominal value of 12 volts. Significant voltage drops can occur in such time periods when large loads are applied to the battery, e.g. when starting the machine. To this drop in the excitation of the electromagnet To compensate for the available voltage, the duration of the excitation can be extended.

The electronic control unit 192 can thus embody a function in which the actual The voltage available at the electromagnet is compared with the nominal battery voltage and, in the event of a drop, the actual voltage Voltage compared to the nominal voltage an extension of the excitation time of the electromagnet he follows. The degree of this elongation in relation to the voltage drop

353U86

^x can be preprogrammed in the electronic control unit.

The energization time of the electromagnet can be expressed by the following equation: Pw _e = pw _{o +} Pw _bv + pw _act>

Here: PW mean the actual duration of excitation
PW the basic excitation duration

PW, the battery voltage compens

sation duration

ACT is the compensation period based on the position of the operating rod .

PW is usually the duration of arousal when ο

the machine is not loaded and it is around 12 to 15 milliseconds; the maximal The increase depending on the position of the operating rod is approximately in the range between 5 and 10 milliseconds, this increase being linear with the change in position of the operating rod runs. The increase in the duration of excitation due to a decrease in battery voltage is in the range of 0.5 milliseconds

announce per volt. The increase of 5 to 10 milliseconds depending on the position of the operating rod results in the maximum fuel supply under load transfer conditions and is considerably larger (in the region of 50%) than the one under stable Conditions when the throttle valve is fully open. The excitation time of the Electromagnet per working cycle is of course limited by the duration of the working cycle the machine and the time that

- Xh

is required to fill the metering chamber with fuel, which takes about 8 milliseconds lies.

For reasons of combustion efficiency, it is desirable to inject the Stop fuel at a fixed point in the machine's work cycle. if thus the energization time of the electromagnet varies and the time of termination of the Excitation is fixed, the variation is obtained in that the beginning of the excitation time can be changed accordingly. Figure 4 shows a typical change in the duration of exposure to air on the supplied Fuel in relation to the output voltage of the potentiometer, which is directly from the amount depends on the fuel supplied.

In the previous description, the energization time of the electromagnet was changeable depending on changes in the metered amounts of fuel. However, this is to the point understand that the purpose of changing this duration is to allow for a corresponding change in the amount of air that is available to feed the metered amount of fuel. Because the pressure the supplied air is kept constant by suitable pressure regulators and that normally occurring temperature fluctuations do not significantly affect the air density, the amount of air delivered to the dosing chamber is directly dependent on the period of time in which the air is available through the solenoid valve 150.

ORIGINAL INSPECTED

^χ When the engine is subjected to transient conditions that require a rapid increase in fuel delivery, it can be difficult to control a fuel metering and injection system to deliver the optimal amount of fuel. From the beginning of the transition, the first or the first two working cycles of each cylinder should preferably have a higher fuel supply than with the same nozzle valve opening in the steady state. This immediate enrichment of the fuel mixture is necessary in order to give the engine a reasonably quick response if the throttle valve is suddenly opened. It has been found that adequate transient response can be obtained when the engine utilizes the fuel metering system described by using the method to deliver the fuel

available amount of air is increased, regardless of an increase in the metered amount of fuel .

During the operation of the machine, the inner surfaces of the fuel supply path remain, which comprises the fuel supply line 108 and the associated injection nozzle 18, after each supply of fuel and air through injector 18 to the engine wetted by the fuel. During essentially stationary machine operation, i. E. in steady state or slight acceleration or deceleration, this has residual Wetting of the inner surfaces none 35

353U86

significant effect on the operation of the machine, since the remaining on the wetted surfaces The amount of fuel remains essentially constant and also that used for each feed operation Air volume is constant.

Figure 5a represents the for a machine transition with a required immediate Increase in the amount of fuel between injections 5 and 6 desired sequential fuel injections via the injection nozzle 18. FIG. 5b shows the fuel quantities typically supplied, wherein the fuel metering and injection system is designed so that in each of the twelve Injections the fuel is driven by the same amount of air. The degree the remaining wetting in the fuel supply line 108 increases with increased the amount of fuel dosed and the amount of fuel supplied via the injector gradually increases between injections 5 and 9. From * the first feed at the The new fuel metering amount is the amount of fuel delivered via the injection nozzle 18 less than that determined by the position of the metering rod 115 in the metering chamber 120 Dosing amount, as the amount of air available does not directly affect the increased amount of fuel can cope, so that an increase in the remaining wetting of the inner surfaces he follows. However, the amount of fuel remaining wetting line 108 is one Function of both the metered amount of fuel

in the dosing chamber as well as that for the feed 35

353U86

The amount of air used by the line and the injector is the amount of fuel used.

FIG. 5c is now considered, in which the same is dosed for each injection process The amount of fuel in the metering chamber is assumed. However, the amount of air was increased for injection process 6 compared to the air quantities in the other injection processes, by energizing the electromagnet for a longer period of time. In the injection process 6 there is more fuel out of the injection nozzle 18 than in the injection process 5, since the amount of fuel wetting the inner surfaces of the fuel supply conduit 108

·

has been reduced. In the case of injection process 7, less fuel is used than in the case of Injection process 5 supplied as some fuel remains in line 108, in order to restore the wetting of their surfaces to the previous extent. the subsequent injections deliver an amount of fuel using the normal amount of air through the injection nozzle, which the metered, in the metering chamber 120

equivalent amount.

Figure 5d represents a repetition of the transition conditions of the machine accordingly of Figure 5a, but with the exception that the system is now designed so that the increased amount of fuel is driven by an increased amount of air. During the injection process 6, the first injection process with the increased metered fuel and

Represents air volumes, the supply line remains 108 slightly less wetted than in the previous injection process 5, during the following injection processes 7, 8, 9 etc. retain the reduced degree of wetting. The effect on the amount of fuel supplied can be seen from FIG. 5d. The fuel enrichment the transition is obvious. This training also causes a desired one Fuel depletion in delay transitions ° as a result of increased residual wetting in the supply line 108.

The utilization of the reduction in the wetting of the inner surface of the fuel supply

*

tion line is preferably carried out in connection with the increase in the metered amount of fuel as shown in Figure 5d, especially when the machine is under a severe transition condition is exposed. However, both properties can be used individually. The electronic control unit 192 can be configured in such a way that it responds to a transitional condition that is otherwise than by the Position of the operating rod is detected,

responds in order to realize the wettability reduction capability, e.g. by detecting the rate of change in the position of the throttle valve.

° It should be pointed out that the invention does not apply to that described in the exemplary embodiment Device is limited, but to all fuel metering and / or ζ uführungssysteme

is applicable, which use a gas pulse, 35

353H86

-3L.
to propel a metered amount of fuel to be fed to a machine.

The metered amount of fuel depends on the engine load, the transition state, the engine cylinder size and the selected air / fuel ratio and is usually in the range of a few milligrams to about 100 milligrams or more per injection. Correspondingly, the can in the dosing chamber Preferred amount of air fed in per injection process over a range of 2 milligrams vary up to 10 or more milligrams. An approximate voltammetry ratio from air to fuel measured at standard temperature and pressure about 50: 1. The pressure of the air supplied is regulated, with the metering process usually is carried out at pressures in the range of 200 kPa to 1000 kPa or even higher.

The minimum trick is achieved in practice by the Determines the need for valve actuation and the supply of a sufficient amount of air, so 400 kPa is a common value. The maximum pressure is correspondingly determined by the

Desire for simple and effective sources of supply determined. When used in the In automotive engineering, it is desirable to use a single-stage compressor, as a result of which the maximum pressure is limited to around 800 kPa.

Under certain operating conditions of the machine it may be desirable to have the Increase the amount of air per injection process, although there is no corresponding increase in the

353U86

Amount of fuel takes place. Such a condition can occur during the startup process the machine is given in particular during a cold start. The extra air contributes to improved atomization, especially when the machine is cold and the evaporation is not supported by the heat of the machine.

The machine status, depending on which the air volume is varied, can be from the beginning the starting process can be influenced in such a way that the amount of air increases with the passage of time decreases until it falls below a predetermined limit. If as a benchmark for this

the machine temperature is selected, then the amount of air increases with increasing temperature decreased until the limit value is reached.

Claims (25)

Claims Method for supplying liquid fuel to a machine, characterized in that compressed gas is fed into a chamber (120) to expel a metered amount of fuel fs therefrom and that the amount of gas fed in depends on changes in the fuel requirement of the machine at least over a Part of the demand range is varied so that as the fuel demand increases or decreases, the amount of gas fed into the chamber (120) increases or falls.
15th 2. The method according to claim 1, characterized in that that the amount of gas fed into the chamber (120) by changing the duration the feed is varied. 3. The method according to claim 1 or 2, characterized in that the amount of gas fed is varied proportionally to the change in the amount of fuel to be expelled. 4. A method for supplying liquid fuel to a machine, characterized in that a metered amount of fuel is collected in a chamber (120) that the metered amount of fuel Depending on the fuel requirements of the machine, that compressed Gas is supplied into the chamber (120) to drive out the metered amount of fuel and for their feeding to the machine, and that the in the chamber (120) 353U86 The amount of gas supplied is varied - to supply of the fuel as a function of the changes in the metered amount of fuel over at least part of the range of machine fuel needs. 5. The method according to claim 4, characterized in that a body (115) in the chamber (120) protrudes and the change in the metered amount of fuel by controlling the extent in which the body (115) protrudes into the chamber (120) is effected, and that the amount of the gas delivered into the chamber (120) depending on the extent to which the Body (115) protrudes into the chamber (120), is varied. 6. The method according to claim 4, characterized in that the metered amount of fuel is measured before being fed to the chamber (120). 7. The method according to claim 5, characterized in that the change in the amount of the the displaceable fuel chamber (120) by adjusting the relative positions the gas inlet (143) into and the fuel outlet (109) from the chamber (120) causing the fuel capacity the chamber (12o) is changed between these positions. 8. The method according to claim 7, characterized in that the position of the gas inlet (143) into the chamber (120) relative to the position of the fuel outlet (109) therefrom will. 9. The method according to claim 4 or 5, characterized in that the amount of in the Chamber (120) fed gas is varied by changing the duration of the feed. 10. A method for supplying a metered amount of liquid fuel to an internal combustion engine, characterized in that a Chamber (120) is filled with fuel, one with her and one in one Nozzle (18) terminating conduit (108) has selectively openable outlet (109) connected, that gas is fed into the chamber (120) to drive off the fuel the chamber (120) after opening the outlet 009) that the feeding of the gas is continued at a pressure at which the Fuel is propelled in line (108) and conveyed out through nozzle (18), that the amount of by the feeding of the gas into the chamber (120) can be expelled Fuel is controlled according to the fuel requirements of the engine, and that the amount of gas fed into the chamber (120) as a function of changes is varied in the amount of fuel expelled from the chamber (120). 11. The method according to claim 10, characterized in that that controlling the amount of expellable fuel by adjusting the relative positions of the gas inlet (143) in and of the fuel outlet (109) is effected from the chamber (120), increasing the fuel capacity of the chamber (120) is varied between these positions. * 12. The method according to claim 11, characterized in that that the position of the gas inlet (143) in the chamber (120) relative to the position of the fuel outlet (109) from the Chamber (120) is moved.
5 13. Device for feeding a metered amount of liquid fuel into a machine, characterized in that a chamber (120) with a selectively openable outlet (109), ^ a device (127) which can be actuated to feed the fuel into the chamber (120), in order to fill this in preparation for the feed, one for the effective feed of Gas in the chamber (120) actuatable device to the fuel from this after To expel opening of the outlet (109), means for controlling the amount of the fuel that can be expelled from the chamber (120) as a function of the fuel requirement, and means for changing the amount of that fed into the chamber (120) Gas as a function of fuel requirements, such that with an increase the amount of fuel increases the amount of gas, are provided. 14. The device according to claim 13, characterized in that that the chamber (120) is formed from two bodies, of which at least one is movable relative to the other in order to change the volume of the chamber. 15. The apparatus according to claim 14, characterized in that the outlet (109) in one of the body and a gas inlet (143) through 353U86 in which the gas can be fed into the chamber in which the other body is provided, whereby the relative positions of the outlet (109) and the gas inlet (143) by relative Movement between the bodies is adjustable to the amount of the infeed to control the gas expensible fuel. 16. The apparatus according to claim 14, characterized in that the means for changing the amount of gas means (198) for determining the relative positions of the two Body and means (192) responsive to the relative positions for controlling the amount of gas fed into the chamber (120). 17. The apparatus of claim 13 or 16, characterized characterized in that the device can be actuated to change the amount of gas fed in for controlling the duration of the feed of the gas into the chamber (120). 18. The device according to claim 13, characterized in that that the chamber (120) is provided with a gas inlet (143) through which the Gas can be fed into the chamber (120), and that the device for controlling the amount of the propellable fuel forming part of the chamber (120) and the gas inlet (143) containing body (115), which is movable relative to the outlet (109) in the chamber (120), so that the amount of can be expelled by the feed of the gas Fuel is determined by the position of the gas inlet (143). 19. The device according to claim 18, characterized in that that the device for changing the amount of gas includes a device (198) for determining the relative position of the gas inlet (143) in the chamber (120) and one on the relative position responsive means (192) for controlling the feed into the chamber Has amount of gas. 20. The device according to claim 13, characterized in that that a valve is provided for controlling the feed of the gas into the chamber and that the means for changing the amount of gas a device for opening the valve for a controlled duration and one on The fuel consumption of the machine responding device for setting the duration of the Has opening for each fuel supply process. 21. The device according to claim 20, characterized in that the valve is operated by an electromagnet (150) can be actuated and that the responsive to the fuel requirements of the machine Device for exciting the electromagnet (150) is designed for a period of time proportional to the fuel requirement. 22. A method for supplying fuel to a machine, characterized in that compressed gas is fed into a chamber (120) to generate a metered amount of fuel to drive out of this, and that the amount of gas fed into the chamber (120) as a function of changes in a selected one Machine condition is varied. 353U86 EJ 23. A method for supplying liquid fuel to a machine, characterized in that that a metered amount of fuel is collected in a chamber (120) that the metered amount of fuel varies depending on the fuel requirement of the machine is that compressed gas is fed into the chamber (120) to the metered amount of fuel driven out and fed to the machine, and that fed into the chamber (120) Amount of gas for supplying the fuel depending on the changes in a selected one Machine state is variable. 24. The method according to claim 22 or 23, characterized characterized in that the selected machine state is the machine temperature. 25. The method according to claim 22 or 23, characterized in that the selected machine state is the time that has elapsed since the start.