DE958439C - Additional device for carburettor for internal combustion engines - Google Patents

Description

Additional device for carburettors for internal combustion engines The invention relates to a development of a 'part of the subject matter of patent application S 34508Ia / 46c2 forming carburetors for internal combustion engines, in which for relief the commissioning of these motors in a warm state at a low point of the Inlet line an outlet is provided. To from this line at least one To dissipate part of the fuel that has accumulated in it above this deep point has, this outlet being controlled by a closure system such that it is open when the engine is at a standstill and closed when the engine is running. In the Hazptpatent application solutions are described in which the actuation of the locking system z. B. by an electric current acting in an electromagnet or by a Fluid pressure or by the negative pressure prevailing in the inlet line.

The invention relates to a very simple solution to the task of actuation of the relevant locking system.

There are already known carburetors in the return line of the Have a collecting channel to a fuel container a valve. With these well-known Arrangements, however, the valve is such built in that the suction line is in free communication with the outside air if there is overpressure in this suction line occurs. It will be seen later that such overprints can arise in certain cases explained in more detail.

This locking system can be used in carburetors and especially in downdraft carburetors be installed, in which in the suction line in the direction of flow after the spray nozzle and the throttle valve and in front of the lowest and / or hottest point of the intake line a collecting groove with a drainage pipe for the downflow along the walls of this pipe liquid fuel are provided. A valve is installed at the end of the drain line, which connects to the outside air when the engine is switched off and when the engine is running Motor interrupts this connection.

According to the invention, a disc valve known per se is used for this purpose used, but when the engine is at a standstill, the valve disk 27 is between two Sitting 2,8,: 29 is held in suspension by an elastic system, spring 30 and so in a known way the connection between the intake pipe and the outside air produces while the engine is running, depending on whether there is a in the intake line There is underpressure (normal operation) or overpressure (exceptional operating state), the valve disc comes to rest on one, 28, or the other, 29, seat.

The invention is exemplified below with reference to the drawing explained.

Fig. I shows a vertical schematic section according to the invention trained carburetor; Figure 2 is a section along line 11-II of Figure i.

The invention is in its application to a downdraft carburetor for Combustion engines shown with a conventional inlet line.

The arrangement contains a main line i with a throttle valve 2, in front of or behind which the spray device 3 is located. This line is downstream connected to the inlet pipe 4 of the engine, and an air filter 5 is appropriate attached at the entrance of this line.

The device is with one at a deep point in the inlet duct attached outlet, which from this line at least part of the Is to discharge fuel in liquid or vapor state, which is has accumulated in the line above this lowest point, being used for control this outlet a closure system is provided which is operated so that it is open when the engine is at a standstill and closed when the engine is running.

For this purpose z. B. behind the actual carburetor in the wall of one perpendicular part of the inlet line an annular groove 6 is provided, which the trickling down Catches fuel and prevents it from penetrating further down the line. These Groove is z. B. mounted in a flange 7, which is between the carburetor and the inlet pipe is located. The bottom of this groove 6 is connected to a discharge channel8 in connection, which collects the fuel from the groove to a chamber 26 which contains an outlet provided with the above closure system is.

According to the invention, the closure system is now provided by a valve flap 27 is formed, which lies between two seats 28 and 29, which are connected to the channel 8 or are in communication with the outside space, the valve flap 27 in the rest position is kept away from these two seats simultaneously by a spring 3o.

The seats 28 and 29 are expediently above and below the valve flap. The seat 29 communicates at the bottom with an outlet opening 3i, and the spring 3o is arranged under the valve flap 27 so that it is in the rest position Holds valve flap expediently halfway between the two seats. Further are guides 32 to prevent excessive lateral displacement of the Valve flap provided.

The above arrangement works as follows: When the engine is at a standstill, the valve flap 27 assumes the position indicated in the figure, since the spring 30 has such a free length that the valve flap cannot be pressed onto the seat z8 by the spring.

The line 4 is therefore directly above the chamber with the outside space 26 and the opening 31 in connection. The liquid fuel entering the groove 6 is discharged through the channel 8 and the opening 31 and thus flows out of the line 4 to the outside.

Incidentally, it should be noted that, as in the case of the main patent, the channel 8 must have a sufficiently large cross-section (on the order of 8 mm clear width), otherwise a possible violent development of steam z. B. in the chamber 26 the drainage would prevent the liquid contained in this channel 8 down, so that the device does not work properly.

If, on the other hand, the channel has a sufficient cross-section, the Liquid does not form a plug due to capillary tension in the channel and flows despite the formation of vapors in the chamber 26 down into this.

When the engine is running, the connection with the outside space must be maintained at all times be closed. Now, however, two different operating states are possible.

The negative pressure in the line 4 can be relatively large and continuous be. Then the valve flap 27 is sucked in by this negative pressure and on their Seat 28 pressed, making the device tightly closed and any air ingress into the line is prevented.

As a result of the delayed closure of the inlet valves, however, can also a slight backflow in line 4 occurs after each intake cycle. These Appearance is very common at low speeds and heavy loads, though the line feeds four cylinders or fewer. The valve flap 27 then does not remain more on her seat 28 as everyone Backflow a slight overpressure in the inlet line, which only lasts for a short time, but does not is negligible.

In order to prevent the air-fuel mixture from being pushed back outwards under these conditions, the valve flap 27 then rests against the action of the spring 30 against its other seat 29.

The valve flap 27 is therefore under any operating conditions pressed either against their seat 28 or against their seat 29, so that the connection between the line 4 and 'the outside space is always interrupted.

When the engine is at a standstill, however, the valve flap 27 takes the in Fig. R indicated position .and sets the groove 6 freely in connection with the outside space.

Claims (1)

PATENT CLAIM: Additional device for carburetors according to patent application S 34508Ia / 46C2, especially for downdraft carburetors, in which a collecting groove with a drain line is provided in the suction line in the direction of flow after the spray nozzle and the throttle valve and in front of the lowest and / or hottest point of the suction line to collect and discharge liquid fuel flowing down the walls of this pipe, a valve being provided at the end of the discharge pipe which ensures the connection with the outside air when the engine is switched off and interrupts this connection when the engine is running, characterized by "d'ass this valve is a known disk valve, but when the engine is at a standstill, the valve disk (27) between two seats (28, 29) is held in suspension by an elastic system (spring 3o) and so in a known manner the connection between the intake line and the outside air, while during the current Mon tor, depending on whether there is underpressure (normal operation) or overpressure (exceptional operating state) in the intake line, the valve disc comes to rest on one (28) or the other (29) seat. Considered publications: Swiss patent specification No. 267 779; U.S. Patent No. 2,5o2,968.