DE1092253B - Device for operational monitoring of the injection pressure in internal combustion engines - Google Patents

Description

To maintain normal operation and to achieve full work performance fuel injection engines require the proper functioning of the Jet of fuel under pressure injecting nozzles into the combustion chamber of the engine continuously to be able to monitor.

A lack of regularity in the mentioned supply of operating fluids as well as the resulting pressure changes are often the cause of malfunctions, which must be found quickly, in order to be able to remedy the defects causing such malfunctions immediately.

Manometric and mechanical indicators are used to monitor the injection pressure and electrical pressure indicators are known. However, these known devices have the Disadvantage that more or less complicated measuring devices are necessary for monitoring do not offer any security against damage caused by sudden occurrence of impermissibly high pressures. This avoids the invention by using a device for monitoring the operation of the injection pressure in internal combustion engines with a pressure sensing device in the fuel injection line providing electrical pulses According to the invention it is proposed that the pressure sensing device from two structurally into one unit summarized spring-loaded piston pressure switches, one of which is designed so that he triggers a warning signal if the injection pressure fails, while the other is designed so that he in the event of an impermissibly high injection pressure, another warning signal is triggered, whereby it is also known per se Way as a safety valve opens a drain.

The invention is therefore a simple, between the fuel pump and the corresponding Nozzle-switched device through which the liquid fuel that feeds the nozzle flows. Of the Pressure acts on a piston which, after overcoming the resistance of a spring, starts the electrical circuit an electrical interruption device closes and thus a corresponding green control light for Brings light up; if this is constantly lit, the fuel supply is taking place regularly. As soon but the green control lamp goes out as a result of the reduction in fuel pressure, indicating that it is on the occurrence of an operational defect, which can be attributed to a pressure loss in the fuel pump, to fluctuations in the injection jet :, for breakage of the closing spring, for leaks in the pump valve seal or the like. is due. The engine must then be switched off immediately and the operating defect repaired immediately.

Facility for operational monitoring
the injection pressure in internal combustion engines

Applicant:

ίο Ramon Serra Subirana

■ and Roberto Cottino Molino,
Barcelona (Spain)

Representative: Dr.-Ing. H. Negendank, patent attorney,
Hamburg 36, Neuer Wall 41

Claimed priority:
Spain from March 16, 1956 and February 7, 1957

Ramon Serra Subirana and Roberto Cottino Molino,

Barcelona (Spain),
have been named as inventors

As soon as the fuel nozzle becomes clogged for any reason, the pressure of the increases liquid fuel immediately. In this case, the excess pressure in the apparatus brings one to one higher than the normal injection pressure calculated safety diaphragm for bursting a duct closes, after the release of which allows the entry of the fuel into a small cylinder is, at the end of which a piston is provided, which is in motion by the above-mentioned excess pressure offset, the circuit of a second interruption device closes and thus a red, den The control lamp indicating a malfunction lights up. The postponement of the said At the same time, the piston allows the fuel to be drained via a fuel that enables it to be recovered Derivation.

The aforementioned membrane can also be made up of a displaceable piston and a ball Locking device to be replaced. In this case the ball is in its spring tension final position held, the tension of the spring at a slightly higher than normal Injection pressure is calculated and overcome,

009 630/130

as soon as the said pressure exceeds the permissible limit. A simultaneous shift then occurs the ball as well as the piston, whereby the drainage by means of the ball seat downstream bores of the fuel causing the excess pressure through a discharge channel will.

In the drawing, the apparatus according to the invention is shown, for example. It shows

Fig. 1 is a longitudinal section through the apparatus,

Fig. 2 shows a section with another embodiment of the pressure switch protecting against overpressure and

Fig. 3 is a partial view of ^r in Fig. 2 depicted \ orrichtung in a larger scale.

As Fig. 1 shows, the apparatus consists of a double-T-shaped center piece 1, in which a longitudinal channel is provided for the normal flow of fuel. The fuel enters at one end A of the center piece, which is connected to the fuel pump by a corresponding pipe, and exits again at the opposite end B, onto which a feed pipe connected to the fuel nozzle is screwed.

The middle piece 1 also has two further channels C and D running transversely to the longitudinal channel.

Two threaded sockets 2 and 3 are screwed onto the center piece 1. One indicating the pressure drop Pressure switching device is housed inside the sleeve 2, namely a piston 4 is provided here, whose stroke is limited by a circular disk 6 forming a single piece with it, which is too a pin is extended, which is screwed onto the outlet mouth of the sleeve 2 by an inside Sleeve 8 housed coil spring 7 is surrounded.

The tension of the spring 7 is calculated in such a way that as long as the pressure of the fuel liquid flowing through the line D and acting on the piston 4 corresponds to the normal injection pressure, it allows a displacement of the piston 4, the extension pin of which closes an electrical contact device 13 and thus the control lamp V lights up, which shows the normal functioning of the fuel nozzle with its green light.

However, if as a result of any occurring at the nozzle or the fuel pump feeding it Operating defects, the injection pressure decreases, the spring 7 expands and allows a backward displacement of the piston 4, whereby the circuit is interrupted. This state is indicated in Fig. 1.

If the circuit mentioned is interrupted, the green light goes out, indicating a loss of pressure and thus the existence of an operational defect in the fuel system.

The device protecting against overpressure is located inside the sleeve 3. The latter is also screwed onto the center piece 1 and has a cylindrical bore in its longitudinal axis, the front inlet opening of which is closed by a safety membrane 12 connected between it and the channel C of the center piece 1 . The bursting pressure of this membrane is calculated in such a way that it can withstand a higher than the normal injection pressure, but bursts as soon as the said pressure exceeds a certain limit.

When the fuel nozzle is clogged, the pressure in the conduit C increases , causing the safety diaphragm 12 to burst, so that the fuel flows unhindered into the cylinder of the sleeve 3 and acts on the piston 5, which is advanced and an electrical contact device by means of an extension pin 13 'closes. This turns a red control light R on. Brought on, which thus indicates an increase in pressure. During the displacement of the piston 5, the latter compresses a helical spring 10 provided inside an extension of the sleeve 3, one end of which is supported in a sleeve 11. The latter serves to guide the pin which actuates the contact device 13 '.

Between the coaxial sleeves 3 and 11 is a sealed by two sealing washers 14 Ring socket connected as a drain line 9.

The extension of the sleeve 3 is provided with a transverse hole for a connection between the Manufacture cylinder of the sleeve 3 and the discharge line 9. When the piston 5 is displaced under the action of the overpressure, the fuel causing this overpressure can be discharged through the discharge pipe 19 and be regained.

When the red control light lights up, it indicates a defect caused by an increase in pressure.

Instead of the safety membrane 12, the closing mechanism shown in section in FIG. 2 and in an enlarged view in FIG. 3 can also be used. This consists of a ball 23 that closes the connecting channel between the fuel line C and the cylinder 20 provided in the sleeve 3. The ball 23 rests on the front end of a piston 18 which, by means of an insert 21, prevents the liquid from entering the interior of the cylinder 20 .

The piston 18 is under the action of a surrounding it and between its head end and a the rear end of the cylinder 21 final guide sleeve 17 tensioned helical spring 10 ' constantly pressed against the opening to be locked.

Usually, i. H. as long as the pressure of the injected fuel is a very specific one beforehand does not exceed a specified safety limit, the tension of the spring 10 'holds the ball 23 in its Supply line C final position, but if there is an excess pressure, then the voltage is the called spring overcome, so that a retreat of the ball 23 takes place and the liquid with overpressure in the small, opposite the front end of the piston 18 existing, the said ball serving as a seat chamber 22 flows in. From there, the liquid then penetrates through the channels 24, 24 ' (see Fig. 3) into the interior of the cylinder bore 20 provided in the sleeve 3, whereby the liquid via the interposed and with the mentioned cylinder of the sleeve 3 in connection 19 drains.

The overpressure setting the ball 23 in motion and overcoming the tension of the spring 10 'causes the piston 18 to retreat until the pin 16 provided at its end comes into contact with the pin 15 of the electrical contact mechanism 13', causing the red control lamp R to Illuminated and an impermissible pressure increase is displayed.

In terms of its composition, the device is designed for easy assembly and disassembly by only removing the sleeves 2, 3, 8, 11 in order to replace the safety membrane 12 or to be able to control the functioning of the pistons, springs and contacts .

Claims (4)

Patent claims: 1. A device for monitoring the operation of the injection pressure in internal combustion engines with an electrical pulse-generating pressure sensing device in the fuel injection line, characterized in that the pressure sensing device consists of two spring-loaded piston pressure switches (4, 5) which are structurally combined to form a unit, one of which ( 4) is designed in such a way that it triggers a warning signal (V) if the injection pressure fails, while the other (5) is designed in such a way that it triggers another warning signal (R) if the injection pressure is inadmissibly high, while at the same time being known per se Way as a safety valve opens a drain (19). 2. Device according to claim 1, characterized in that the piston (4,5) with electrical Contacts work together in such a way that if there is a pressure drop, this indicates normal operation Signal (V) goes out of operation, while signal (R) comes into operation when the permissible pressure is exceeded. 3. Device according to claim 1 or 2, characterized in that the moved at overpressure Piston (5) is housed in a cylinder, which has a resistance to the maximum permissible Pressure calculated bursting membrane (12) is separated from the injection line. 4. Device according to claim 1 or 2, characterized in that the moving at excess pressure A ball valve (23) is connected upstream of the spring-loaded piston (18), which during normal operation the connection between the injection line and the cylinder (12) of this piston (18) closes. Considered publications:
German Patent Nos. 535 404, 714992;
British Patent Nos. 431113, 561495. 1 sheet of drawings © O09 630/130 10.60