DE911793C - Method for operating internal combustion engines with gaseous fuels and device for carrying out the method - Google Patents

Description

Method for operating internal combustion engines with gaseous Fuels and equipment for carrying out the method The invention relates processes for operating internal combustion engines with gaseous fuels, 7.B. starting from pressurized, pressurized liquefied or pressureless gases, as well as facilities for carrying out the process.

When operating internal combustion engines with pressure-liquefied, Pressurized or pressureless flammable gases is the relaxed gas over a metering orifice added to the engine's intake air. The mixing ratio from gas to air remains over the entire speed and load range of the Motor almost constant.

It is known that with stoichiometric combustion neither the highest Performance even lowest consumption can be achieved. The highest performance one Motor results in about i o o / o lack of air, the greatest economy, however at about 10 per cent. excess air. In order to achieve the highest performance, therefore, the composition must be of the gas-air mixture to be matched to an air deficiency of about i o%, while , at part load to achieve the lowest consumption, the mixture for excess air can be adjusted. This results in maximum performance in full load operation and in Lowest consumption achieved at partial load.

With modern carburetors for liquid fuel this is part load correction already introduced by automatic partial load correction devices. The partial load correction has already been proposed for gas fuels such that the The amount of gas added to the combustion air by throttling the Gas metering in partial load operation has been reduced. Another suggestion is by increasing the gas throttle cross-section after the Engine to achieve an increase in maximum power., Being used to control a Controller is used.

The proposal of the invention now goes as follows: Change the mixing ratio carry out from fuel gas to air in such a way that initially the fuel gas more or less, in each case a relatively small amount of air (correction air) is supplied and then this mixture of gaseous fuel and correction air with the proportionally large amounts of air are mixed together to produce the final mixture. if A particularly low-air mixture is required for full load operation is the amount reduce the added correction air to zero, d. H. the supply of correction air to turn off the fuel gas.

Such a procedure has the considerable advantage that it is used for setting the desired mixing ratio only requires a relatively small amount of air, namely the correction air, needs to be regulated, with this control on can easily be done continuously.

The amount of correction air supplied should be in full load operation be so low that a mixture with a deficit of air is fed into the system, while at part load operation a gas-air mixture with more or less excess air is fed to the engine.

A preferred embodiment is used to carry out the method one that works automatically. Partial load correction device, in which the correction of the Composition of the gas-air mixture by adding correction air to the gas flow after the expansion of the pressurized fuel gas and before the final Mixing with the combustion air and the activation and deactivation of this correction air additive automatically by the one prevailing in the intake pipe of the engine behind the throttle valve Negative pressure is reached.

The level of the negative pressure in the intake pipe depends on the throttle valve position and the speed of the engine. When the throttle valve position is fully open, i.e. at At full load, the vacuum in the intake manifold is low, when it is partially or completely closed Dirosselklappe, i.e. in the partial load range, on the other hand, is considerably higher. Those differences at the level of the negative pressure, allow the automatic control of the partial load correction device such that by the high. Underpressure in the partial load range actuates a device that releases the flow of correction air.

According to a preferred embodiment, the opening is in the supply line the correction air is sealed directly by a membrane that is affected by the negative pressure is acted upon in the intake pipe.

Further details of the method of the invention and that for the Implementation of the method used device emerges from the description the preferred embodiment of the invention shown in the drawing.

Fig. I shows in section one in the supply system of gaseous Fuel and air to a built-in engine control device for leaning the mixture of gaseous fuel and air supplied to the engine according to the invention, while FIG. 2 shows in section the control device according to FIG. i in the state of addition of additional air.

The engine is gaseous expanded fuel through the pipe i fed. Between the line r and the air intake line 8 of the engine is the Control device built in.

The control device io is connected to the line i through a line 3 in connection. This line 3 can be closed by a membrane 5.

In the closed state (Fug. I) is a connection of the line i with the outside air does not exist, so that a mixture of the gaseous fuel takes place with air only via line 8. The proportions are chosen so that a over-rich mixture, e.g. B. with about 5 to 100,10 lack of air, generated and the engine is fed.

On the other hand, if the membrane 5 does not close the mouth of the line 3 (Fug. Z), a connection with the outside air is created via line 9, and it flows through the line 9 and the line 3 air in. the line i a below Diluting the gaseous fuel with air and making the final leaner Mixture of gaseous fuel and air.

The membrane 5 is against its seat, closing the mouth of the line 3, pressed by a spring 7, the pressure of which can be adjusted by a screw 6 can. In the sense of the spring, closing the mouth of the line 3, a negative pressure acts in line i. Against the action of the spring 7, the pressure of the outside air acts in the Line 9 (and possibly: an overpressure of the gaseous fuel in, the Line i). In addition, the pressure of the spring and a negative pressure in the line act i overcoming, .on the membrane 5, the negative pressure in the intake line 8 of the engine via line a, in such a way that at high negative pressure in line 8, the membrane 5 withdrawn from its seat against the action of the spring 7 and thus the line 3 is put in connection with the line 9 for the outside air, so that the gaseous Air is supplied to fuel in line i until the negative pressure in. the suction line 8 is so small that the spring 7, the membrane 5 on its seat under closing .the mouth of the line 3 presses, so that air out of the line 9 can no longer flow in.

The flowing in through the line 9 when the mouth of the line 3 opens Amount of air can be adjusted by setting a regulating screw .l, which is used as a Throttle valve acts, can be measured and regulated as required. Instead of .such a regulating screw; can also be a nozzle, preferably an exchangeable one Nozzle.

The amount of air added is measured so that the lowest specific fuel consumption.

The control device for supplying additional air can be from the line system for the supply of gaseous fuel and air to the internal combustion engine so that it does not require any special suspension or fastening.

Claims (1)

PATENT CLAIMS: i. Process for the operation of internal combustion engines while supplying a mixture of fuel gas and air with variable proportions, characterized in that, in order to set the desired ratio of gas to air, which differs according to full load and partial load, the fuel gas initially with a greater or lesser amount, in each case Correction air is mixed with a relatively small amount and only then is added to the relatively large amount of main combustion air, preferably with a gas-air mixture with a deficit of air in the engine in full load operation, while in the partial load range a gas-air mixture with more or less excess air, preferably below stepless regulation; the mixing ratio, is supplied. z. Device for carrying out the method according to claim i, characterized by controlling the addition of the correction air to the fuel gas by the negative pressure prevailing in the intake pipe of the engine. 3. Device according to claim z, characterized by the opening of the correction air supply line being directly closed by a control membrane. ¢. Apparatus for carrying out the method according to claim 1 and claims a and 3, characterized by a control chamber formed as part of the gas line between the pressure reducer for the fuel gas and the intake line of the engine. Referenced publications: German patent specification No. 186258.