US2390143A - Controlling or regulating device for internal-combustion engines - Google Patents

Description

Dec. 4, 1945. 3. WUNSCH I 2,390,143

CONTROLLING OR REGULATING DEVICE FOR INTERNAL-COMBUSTION ENGINES Filed Jan. 26, 1940 Q Int/era dor- 60/00 Wan/$09 &2 :2

Patented Dec. 4, 1945 CONTROLLING R REGULATING DEVICE FOR INTERNAL-COMBUSTION ENGINES Guido Wiinsch, Berlin-Wannsee; Germany;

\ vested in the Alien Property Custodian Application January 26,1940, Serial No. 315,835

In G

1 Claim.

This invention relates to improvements in or relating to controlling or regulating devices for internal combustion engines of the kind in which an air quantity regulating element and a fuel regulating element are provided for controlling the air supply and the fuel feed, respectively.

ermany January 27, 1939 be used for maintaining a constant pressure drop at the air controlling element so that the air quantity is merely dependent on the cross section adjusted by the air controlling element. In other The invention aims at providing means for-- controlling the pressure drop determining the inflowing air quantity regardless of any pressure fluctuation in the intake conduit resulting from pressure fluctuations in the combustion chamber of the engine. I

A further object of the invention is to provide means for simultaneously adjusting the air controlling element and the fuel controlling element and for maintaining a constant pressure drop at said air element as well as at said fuel element. In this way the position of the air element and of the fuel element, respectively, is proportional to the amount of air or fuel flowing in.

Another object of my invention is to provide means for the avoidance of an overcharging of the engine as soon as the air controlling element reaches its terminal open position.

Other aims, advantages and objectso'f my invention will now be more fully explained with reference to the accompanying drawing which is a sectional view of an embodiment of the invention comprising an air controlling element and a throttling member in the air intake conduit.

tity are correlated at all engine loads in order to ensure an economic operation of the engine. To this end it does not suflice to positively couple the air member and the fuel member so as to ensure a simultaneous adjustment of both said members. In this manner a correct ratio between the air quantity and the fuel quantity can only be obtained if the pressure drop at the air controlling member and that at the fuel controlling member remain constant in all positions of said members. In the well known de ices of this type this condition is not existent du to the fact that the influx of the combustion air into the combustion chamber. of the engine fluctuates with the number of revolutions, wherefore the coupling of the air controlling element and the fuel controlling element referred to is inadequate.

In order to eliminate this drawback, the present invention aims at providing pressure sensitive means responsive to the pressure in the air intake conduit in front of the air controlling element for automatically controlling the pressure drop determining the inflowing air quantity in the intake conduit regardless of any pressure fluctuation resulting from the pressure variation in the en ine's combustion chamber.

The pressure sensitive means referred to may words, the air quantity supplied is always proportional to the position of said element.

Referring now to the drawing there is shown an embodiment of the invention. The air intake conduit I leading to the engine (not shown) is provided with a butterfly valve 2 rotatably mounted about a fixed axle 3. Fastened to the axle 3 is a cam 4 engaging one end of a lever 5, the other end of which engages a fuel control needle 6 a spring 1 holding in engaging relation the lever 5 andthe cam 4. The lever 5 has an axle 8 supported in any convenient manner by the conduit I. I

A rod 9 linked with the cam 4 may be manually operated for adjusting the valve 2 and the fuel needle 6 in response to the engine load. If for instance the rod 9'is moved in the direction of the arrow 1:, the valve 2 will be further opened and at the same time the lever 5 moves in a clockwise direction so that the spring I further lifts the needle 6, thereby increasing the fuel cross section.

It may be pointed out that the controlling curve 40. of the cam 4 may be formed in accordance with any desired variation of the fuel-air ratio upon the simultaneous adjustment of the valve 2 and the needle 6. It may, for instance, be desirable to enrich the fuel-air mixture as a function of the cross section controlled by the valve 2.

The fuel enters a float chamber ill of the well known type comprising a float for maintaining a constant level in said chamber. A channel ll leads from said chamber to the needle 6 and communicates with the conduit l2 which in turn communicates with the conduit I so that the fuel controlled by the needle 6 enters into the combustion air flowing through the intake conduit I.

According to the invention, beside the butterfly valve 2 a second or auxiliary valve I3 is provided in the conduit i behind the valve 2. The valve l3 will be automatically controlled in such manner that the pressure drop atthe main valve 2 (to be manually adjusted) remains constant in.

The device described operates as follows: Be it assumed that the suction behind the valve I3 increases due to an increase in the number of revolutions. Such a change of suction will likewise result in a suction increase in front of the valve I3, i. e. behind the main valve 2, whereby the pressure drop at 2 will be increased. Any pressure variation in front of I3 acts upon the diaphragm I4. In case of a suction increase, the pressure variation exerts a force on the diaphragm in the direction toward the conduit I, so that an anti-clockwise rotation is imparted to the valve I3. Therefore the cross section controlled thereby will be decreased and. accordingly the suction between I3 and 2 will again be decreased until the predetermined pressure drop to be maintained at 2 is restored.

As will be readily understood from the foregoing, the valve I3 does not only control the pressure drop at the main valve 2, but likewise that at the fuel needle 6, since the conduit I2 is connected to the part of the intake conduit I in which the pressure is maintained constant by means of the valve I3.

As described above, the pressure in the conduit I in front of the auxiliary valve I3, and thus the pressure drop beyond the main valve 2, may be maintained constant by controlling the auxiliary valve I3, 1. e., by varying the cross section determined by said valve. Upon an increase in the cross section at the main valve 2, the pressure between this valve and the auxiliary valve I3 increases, so that under the influence of the diaphragm I4 the valve I3 will be opened. As will be readily understood, such a pressure control by.

means of the valve I3 is possible only until the valve I3 reaches its full open position. If the pressure between 2 and I3 is in this position not yet restored to the pressure determined by the spring II, the desired pressure regulation by means of I3 is no longer possible so that under these conditions the pressure drop at the main valve 2 does not remain constant.

In order to overcome this difficulty, the invention aims at providing additional means for closing the main valve 2 and the fuel valve 6 as soon as the auxiliary valve I3 approaches its full open position. In the embodiment shown in Fig. 1 this additional means comprises, a stud fixed to the diaphragm II in the chamber I8, said stud engaging upon a nearly full right-hand stroke of the diaphragm a lever 2|, the lower end of which is forced against a stop 23 by means of a spring II. The lever 2I is linked to the rod 9 and connected to any suitable controlling rod 24 to be manually operated by a gas lever or pedal 26.

Upon depression of the pedal 26, the level 2i rocks about the stop 23 as a pivot point and opens the main valve 2 and the fuel valve Ii. Therefore the pressure between the valves 2 and I3 increases.

and the diaphragm I 4 is displaced to the right, thereby further opening the auxiliary valve I3 until the pressure in the diaphragm chamber I6 is restored to its pressure value determined by the initial tension of the spring II. Accordingly the pressure drop beyond the main valve 2 remains constant in the new position of the valve 2. Upon the valve 2 being further opened, the auxiliary valve I3 approaches its full open position and the stud 20 comes into contact with the lower end of the lever 2I. If in this position the pressure between 2 and I3 increases further and the diaphragm I4 shifts the lower end of the lever 2I to the right, thereby lifting the lever from the stop 23 and overcoming the resistance of the spring II. In this manner the pivot point of the lever 2I will be displaced from the stop 23 to the link 25 (provided that the pedal 23 does not change its position) thus imparting to the lever 2I a counterclockwise movement resulting in turn in a counterclockwise movement of the main valve 2 and a closing movement of the fuel valve 3. The decrease of the cross section at 2 thus produced is followed by a decrease of the pressure between 2 and I3. Therefore the pressure drop beyond 2 again reaches its predetermined value in spite of the fact that the valve I3 can no longer influence this pressure.

In order to ensure the operation described, the strength of the spring I1 is such that the lever 2I remains in contact at 23 during the controlling movements by means of the gas lever or pedal 23, while on the other hand the resistance of the spring II' may be overcome by the'spring II. In this respect it is to be noted that the above mentioned spring I is only provided for maintaining a contact between the cam 4 and the lever 5, so that the spring 1 need only possess a strength which is very feeble compared with that of the springs I1 and I1.

If the'motor operates under normal conditions, the main valve 2 rocks about a middle position so that the valve I3 does not reach its full open position either. Accordingly, under normal conditions the stud 20 does not contact with the lever 2I, and the stop 23 acts as a stationary pivot point.

In an idling condition, the main valve 2 and the auxiliary valve I3 are substantially closed, so that the diaphragm I 4 and the stud 20 are at their left-hand extremity.

If, however, the motor is at a standstill, the main valve 2 is closed, yet in lack of any suction in the air conduit I the pressure between 2 and I3 is equal to the atmospheric pressure, so that the diaphragm I 4 is at its right-hand extremity in which the spring I1 is compressed and the lower end of the lever 2| lifted from the stop 23.

What is claimed is:

An air-fuel ratio control device, for internal combustion engines having an air supply conduit, a fuelchamber and a fuel conduit connecting said chamber with said air supply conduit, comprising a main air valve in said air supply conduit; a fuel valve controlling said fuel conduit and operatively connected to said air valve; an auxiliary air valve in said air supply conduit, downstream of the said main air valve and the connection of said fuel conduit and said air supply conduit; pressure responsive means having a chamber communicating merely with said air supply conduit between said main and said auxiliary air valves, said auxiliary valve being operatively connected with said pressure responsive means, to be adjusted by the differential pressure in the air supply conduit and the atmosphere, for maintaining substantially constant the pressure in said air supply conduit between said main and said auxiliary air valves; means for manually and simultaneously controlling said main air valve and said fuel valve; and an auxiliary means connected with said pressure responsive means and to be controlled thereby, for independently moving said main air valve in closing direction when said auxiliary air valve is fully open.

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