US2270410A - Means for automatically controlling the fuel injecting mechanism of internal combustion engines - Google Patents

Description

CAMNER Jan. 20, 1942. H. ca. 2,270,410

MEANS FOR AUTOMATICALLY CONTROLLING THE FUEL INJECTING MECHANISM OF INTERNAL COMBUSTION ENGINES Flled Nov '7, 1959 an uncertain control.

Patented Jan. 20, 1942 UNITED STATES PATENT OFFICE MEANS FOR AUTOMATICALLY CONTROL- LING THE FUEL INJECTING MECHANISM OF INTERNAL COMBUSTION ENGINES Hilding Gunnar Camner, Ektorp, Sweden, assignor to Aktiebolaget Atlas Diesel, Stockholm,

Sweden Application November 7, 1939, Serial No. 303,222 In Sweden June 1, 1938 4 Claims. (Cl. 123-140) In internal combustion engines it is desired to automatically time the fuel injection at changes of the number of revolutions of the engine. Thus,

at a greater number of revolutions the fuel in- Jection should take place earlier than at a lower number of revolutions.

shaped curved members, are used, which involvesa complication. It also often occur'sthat it is desired to change the feed pressure of the fuel, which means that the above mentioned motion transmitting means has no longer the desired action, but must be replaced by another means suitable for the changed pressure.

Devices have also been su gested, which are based on the utilization of the pressure changes.

in the suction pipe of the engine occuring at changes ofthe number of revolutions. However, such devices, which necessitate throttling of the suction pipe, have the drawback that they must work at very low pressures, which entails The present invention has forits object to avoid the above mentioned drawbacks and con sists essentially in that a servo-motor controlling the position of a member of the fuel injecting mechanism defining the time of injection is acted on by the-scavenging air.. The scavenging air is always at disposal and, since the pressure of same varies with the number of revolutions, the advantage is gained that the position of the injecting mechanism will be the desired one at any number of revolutions.

When running at a constant number of revolutions the scavenging pressure-varies with the torgue in such way that the said'pressure increases at an increased torque and vice versa, j

substantially depending -'on the fact that the back-pressure in the exhaust conduit of the engine increases and decreases with the torque.

Thus, by making the time for the fuel injection dependent on the scavenging air the further advantage is gained that when running at a cer- I tain constant number of revolutions the said I time will vary with the torque in such way that the injection occurs earlier at an increased torque, whereby a better combustion is obtained and also a greater torque can be taken out. At lower torques and when idling the injection occurs later and in this case no earlier ignition is required in order to eifect a complete combustion. The said later ignition brings about a more uniform and smooth. running of the engine, which is of a great importance particularly in idling.

The annexed drawing illustrates diagrammatically an embodiment of a device according to this invention. Fig.- 1 is a Side view showing the outlines of an ordinary internal combustion engine having the controlling device applied thereto. scale of the controlling device. i

Fig. 2a is a fragmentary section showinga part of the controlling device with damping means incorporated therein. I

Referring to the drawing, M designates the engine proper and P an ordinary scavenging air pump thereof driven by the engine in any ordinary convenient manner. The fuel pump mechaism, which also is of known type and need not be particularly described, is denoted by I and its cainshaft by 2, said shaft being driven by a drive shaft 3 drivenby the engine in any ordinary manner. The cam-shaft 2 is provided with axially disposed slots 4 and the drive shaft 3 with obliquely directed slots 5 meshing with correspondingly'arranged internal teeth in an axially displaceable coupling-sleeve 6. Freely mounted in an annular groove in said sleeve is a ring I provided with two diametrically opposed gudgeons 8, to which a double-armed forked lever 9 is applied, saidlever being swingably mounted on a stationary pivot Ill. The saidpivot may, if desired, be replaced by an adjustable eccentric in order tov change the relation of the arms of the forked lever 9. At its lower 'end the said lever is pivotally connected to the piston rod ll of a servo-motor, comprising here a cylinder l2 and a piston I3 movable therein. The cylinder chamber '14 at the one side of the piston communicates through a pipe IS with the scavenging air receiver of the engine or any part of the scavenging air conduit, whereas the chamber l6 7 at the opposite side of the piston through a pipe l'l may be in communication with the exhaustv conduit IQ of the engine at a place between the engine and a throttling member Illa in said conduit. Besides, the piston 1'3 is acted on by a Fig. 2 is a side view on an enlarged lows or the like.

spring l8 counter-acting the pressure in the cylinder chamber I.

When changing the number of revolutions of the engine or the torque,'the scavenging pressure takers-correspondingly, and the servo-motor-piston l3 will be moved in theone direction or the other. By means of the lever 9 the couplingsleeve 6 will thus be displaced in the one direction or the other and simultaneously brought to rotate relatively to the drive shaft 3 on account of the obliquely directed slots 5 and the corresponding intermeshing teeth. The said rotary motion is transmitted from the coupling-sleeve 6 to the cam-shaft 2 of the iniection pump l, whereby the time of the fuel injection will vary with the scavenging air pressure, 1. e. with the number of revolutions or the torque of the engine as above described.

the control. When throttling the exhaust gases,

the difference between the scavenging air pressure and the exhaust gas pressure will practically be unaltered, and thus the throttling will not affect the control.

Evidently, the invention is not limited to any.

certain .type of fuel injecting mechanism, and the motion transmitting means between the servo-motor and the control member of the fuel injecting mechanism can be of any desired kind.

This is true also of the servo-motor, which, for I instance, can be provided with a membrane, bel- If desired, the piston of the servo-motor or the axially dispiaceable coupling- I sleeve may also be provided with suitable dampingmeans in order-to prevent oscillations, particularly when idling or running at low loads. One such form'ofdamping means is illustrated in Fig. 2a by way of example, being of the general form disclosed in my'co-pending application Ser. No. 303,221; In this arrangement the servo-motor Piston l3 has a dash pot/piston 20 secured ing air pump driven by t e engine,a fuel injecting' mechanism, means for driving said mechanism from said engine including a member shiftable to vary the timing of fuel injection with respect to the cycle of operation of the engine, and means for automatically timing the fuel injection in accordance with changes of the number of revolutions of the engine or the torque, the lastmentioned means comprising a servomotor having a movable part acted on by the scavenging air and in operative connection with said member, said connection being arranged to cause the timing to be advanced upon increase in said number of revolutions or torque, and vice-versa.

2. In an internal combustion engine, a scaven ing air pump driven by the'engine, a fuel injecting mechanism? means for driving said mechanism from said engine including a member shiftable to vary the timing of fuel injection with.

respect to the cycle of operation of the engine, and means for automatically timing the fuel injection in accordance with changes of the number of revolutions of the engine or the torque, the last-mentioned means comprising ,a servomotor having a movable part acted on by the scavenging air and also in opposition thereto by the exhaust gas pressure and in operative connection with said member, said connection being arranged to cause the timing to be advanced upon increase in said number of revolutions or torque, and yice-ver a. r

3. In an ternal combustion engine, a scaven ing air pump driven by the engine, a fuel injecting mechanism, means for driving said mechanism from said engine including a member shiftable to vary the timing of fuel injection with respect to the cycle of operation of the engine, means for automatically timing the fuel injection in accordance with changes of I the number of revolutions of the englneor the torque, the

last-mentioned means comprising a servo-motor" having a movable part acted on by the scavenging air and in operative connection with said member, and a damping device in connection with said movable part, said connection being arranged to cause the timing to be advanced upon increase in said 'number of revolutions or torque, and vice-versa.

4. In an internal combustion engine, a scavenging air pump driven by the engine, a fuel injecting mechanism, means for driving said mechanism from said engine including a member shiftable to vary the timing of fuel injection with respect to the cycle 0; operation of the engine, means for automatically timing the fuel injection in accordance with changes of the number 0 revolutions of the engine or the torque, the lastmentioned means comprising a servo-motor having a movable part acted on by the scavenging air and in operative connection with said member, said connection being arranged to cause the timing to be advanced upon increase in said I

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