DE2623371A1 - DEVICE FOR HEATING THE FUEL-AIR MIXTURE OF A COMBUSTION ENGINE - Google Patents

Description

Applicant: Turbo hot gas generators ^v

Gesellschaft m.b.H & Co

Patent exploitation limited partnership Goethe-Str. 17, 4356 Herten-We sterholt

Device for heating the fuel-air mixture of an internal combustion engine

The invention relates to a device for heating the, Fuel-air mixture of an internal combustion engine with controlled spark ignition, consisting of one in partial load operation between the carburetor and the intake manifold of the engine, the exhaust gas-heated heat exchanger in which the mixture under the intake vacuum of the engine is heated with multiple deflections and swirling.

Such devices are used by evaporation of the fuel droplets contained in the mixture, a complete To achieve combustion in the cylinder of the engine. This is intended to reduce the CO and NO content in the exhaust gas. Which he-

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Warming the mixture is particularly useful when the engine is running at part load, because here in the Hegel during the Compression stroke the temperature required for complete evaporation of the fuel is not reached, so that In the subsequent combustion stroke, the combustion is incomplete and only a low combustion temperature is reached.

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According to the prior art (Dt-OS 1 526 657) ^ st one Apparatus of the type mentioned is known in which the residence time of the mixture in the heat exchanger is extremely short, so that here only partial evaporation of the fuel present in the mixture takes place. And evaporate here essentially only the low-boiling components, while the higher-boiling components mostly also are viscous, precipitate and accumulate in the heat exchanger. The result is that the heat exchanger and the downstream pipe system with evaporation residues already after a relatively short operating time. set.

According to the prior art, devices of the type mentioned are also known in which the flow paths in the heat exchanger are so long that the mixture is heated to a temperature above the upper boiling limit of the fuel will. Complete evaporation of the constituents that can be settled takes place here. During the evaporation process remain in addition to the settable components

non-settable substances return, for the most part consist of carbon (oil coke) and a very small proportion of inorganic components (ash). These too Residues clog the heat exchanger and the connected pipe system after a relatively short operating time.

* “This process runs faster, the more impure it is

"- · is fuel used. Finally, at Ero

** heating of the mixture to just above the upper boiling limit of the fuel used, there is a risk that the mixture in the following line system will again be below the upper one

Boiling limit cools so that the higher-boiling components condense and are reflected in the pipeline system.

For the reasons indicated, devices of the type mentioned at the beginning have not proven themselves in practical operation and consequently also cannot establish itself on the market, even though the heating of the mixture causes it Significantly better exhaust gas values, lower fuel consumption and higher performance can be achieved.

It is therefore the object of the invention to develop the device of the type mentioned at the outset in such a way that
there are no deposits in the heat exchanger or in the downstream pipe system that would impair continuous operation
form.

To solve this problem, the invention, based on a device of the type mentioned at the outset, proposes that the flow path of the mixture in the heat exchanger is dimensioned so long that the mixture extends well above the boiling point of the fuel, in particular to 25o to 50 ... 0
becomes overheated.

Surprisingly, in the device according to the invention Even with continuous operation, there are no harmful deposits in the heat exchanger or in the downstream pipe system from # This is essentially due to the fact that, due to the relatively high temperature, the

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organic substances that make up the largest proportion of the non-separable components make up, are degraded. What this degradation is due to not yet clarified. There is probably a gradual oxidation at the comparatively high temperature with the oxygen present in the mixture. But it is also possible that these substances gradually are hydrogenated and evaporate in this form. As a result of the overheating of the mixture in the heat exchanger, the temperature and the heat content of the mixture is so high that one. Cooling in the following pipe system below the upper one There is no need to fear the boiling limit of the fuel. As a result, there is also one in this area Condensation of high-boiling components does not take place. Only those that cannot be settled remain in the heat exchanger Inorganic constituents (metals, salts, silicates) return in the form of ashes that adhere firmly to the Wallungai of the heat exchanger deposits. However, the volume of these components is so small that the Heat exchanger need not be feared during the life of an engine.

As tests have shown, when using a

J? Device according to the invention also in partial load operation

4> complete combustion takes place in the engine, so that CO

^ is no longer detectable in the exhaust gas and the NO values

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^{N> decrease} a minimum. Since the inorganic non-settable crt

Components are retained in the heat exchanger, these and their reaction products are no longer present in the exhaust gas.

keep. Due to the relatively strong heating of the Mixture, it was to be expected that the volumetric efficiency of the internal combustion engine would decrease. In fact, however - at least in partial load operation - an increase in the volumetricη efficiency achieved because due to the more complete combustion, the volume of the burned gas increases by a greater amount than the volume of the mixture as a result of heating to relatively high temperature. Surprisingly, the mixture will Heat exchanger not ignited despite the relatively high temperature of its heat transfer surfaces. this is essentially due to the negative pressure prevailing in the heat exchanger.

To in the heat exchanger also the completely evaporated Switching off the mixture of suspended solid particles is in the A Sirahl nozzle through which the mixture flows is expediently arranged in the heat exchanger, the jet of which is directed onto a collecting chamber before the opening of which the beam is deflected laterally, in particular at right angles. In the jet nozzle the completely evaporated mixture, in which solid particles may still be floating, is accelerated to a high speed accelerated. The solid particles accelerated to high speed fly in the area of the jet deflection straight ahead and are therefore deposited in the collection chamber.

When using the device according to the invention on a

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Engine with a simple carburetor is provided that the heat exchanger via a pipe to the intake duct is connected between the carburetor and the engine, which is in front of a controlled flap arranged in the intake duct branches off from the intake duct and opens into the intake duct behind the flap, the flap being controlled in this way is that it is closed in partial load operation and open in full load operation. By this arrangement, ensures that the entire sucked-in mixture is passed through the heat exchanger during partial load operation it in full-load operation, in which complete combustion is ensured even without the heat exchanger, directly from the Carburetor enters the engine's intake manifold. However, a partial flow of the mixture is also used in full-load operation passed through the heat exchanger and added to the mixture. This very highly heated partial flow of the mixture promotes the perfect ignition of the mixture in the cylinder. The partial flow through the heat exchanger is achieved by that the open flap also has a certain throttling effect, so that a pressure difference between the two connections of the pipeline in which the heat exchanger is located. In addition, the partial flow through the Heat exchanger increased by the injector effect of the mixture flowing through the intake duct.

The flap is expediently _{controlled by the β} · negative pressure generated by the motor.

When using the device according to the invention in

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connection with a register carburetor is provided «. that the The heat exchanger is located between the partial load stage of the register carburetor and the intake manifold of the engine, while the Full throttle of the register carburetor is connected directly to the intake port of the engine. This is at Partial load operation automatically draws the entire intake mixture flow through the heat exchanger. At full branch on the other hand Most of the sucked-in mixture arrives directly from the carburetor into the intake manifold of the engine during a Partial flow flows through the heat exchanger.

Particular advantages result when using a device according to the invention on a rotary piston engine where the mixture is passed through the heat exchanger both in part-load operation and in full-load operation. As is well known, in rotary piston engines the combustion must take place much faster than reciprocating piston engines, because here the dwell time between the ignition point and the discharge of the burnt gas is considerably shorter is. This can significantly reduce the incineration time can be achieved in a simple manner with a device according to the invention. Tests have shown that when using the device according to the invention on a rotary piston engine whose fuel consumption can be significantly reduced, wherein at the same time the emission of incompletely burned exhaust gases is avoided.

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-JB-

In order to avoid, when using the device according to the invention, the engine dies when the accelerator is suddenly released, it is also provided that in the actuating mechanism of the carburetor a retarding the reset process Delay element is arranged. In this way it is avoided that when you take the accelerator away, it is only sparsely over the mixture flowing into the idle nozzle is initially held to fill the vacuum of the heat exchanger. By the The delay element follows the lowering of the mixture supply gradually so that the vacuum in the heat exchanger is filled can without depriving the engine of the minimum amount of mixture required for idling operation.

An embodiment of the invention is explained in more detail below with reference to the drawing, in which

1 shows a heat exchanger according to the invention in longitudinal section,

Fig. 2 shows the intake duct with the flap arranged therein and

3 shows the actuating device for the flap

demonstrate.

In FIG. 1, the heat exchanger is designated in its entirety by the reference number 1. It consists of a cylindrical Muffler in which the exhaust gas enters via inlet connection 3 and exits via outlet connection 4. In the interior of the muffler 2 there are helically wound line sections through which the mixture to be heated flows 5, which are washed around from the outside by the exhaust gas. In these

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Line sections 5, the mixture arrives via a connecting piece 6, which protrudes from the outside into the interior of the muffler 2. In the helically wound Line sections 5 is given a strong swirl to the exhaust gas stream to be heated, so that the mixture any heavier droplets located are thrown against the outer walls of the line sections 5 and evaporate there.

At the end of the line sections 5 there is a jet nozzle 7, the jet of which is directed onto a collecting chamber 8. ^{1 In} front of this collecting chamber 8, the jet emerging from the jet nozzle 7 is sharply deflected by at least 90 °, so that heavy solid particles in the jet are shot into the collecting chamber 8 and are deposited there. The heated mixture, which has been completely freed from fuel droplets and solid particles, emerges from the heat exchanger 1 ″ at a connection piece 9.

As can be seen from Figure 1, the flow path of the mixture in the heat exchanger is extremely long, so that there is a relatively long residence time of the mixture in the heat exchanger. This residence time is sufficient to heat the mixture on the walls of the pipe sections 5 heated by the exhaust gas to well above the upper boiling limit of the fuel contained in the mixture, for example to temperatures between 25o and 500 ⁰ C. At these temperatures, not only the liquid components of the mixture completely evaporated, but rather

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the non-boiling components are also broken down except for a small amount of ash. This ash residue is stored on the walls of the line sections 5 or in the collecting chamber S.

In Figure 2, the connection of the heat exchanger 1 shown in Figure 1 is between the carburetor 1o and the Intake port 11 of the engine located intake duct 12 is shown. A flap is located in the intake duct 12 13, which is operated via an operating lever 14, such as is explained in more detail below. Before the flap 13 branches' from the intake duct 12 a pipe 15 which is used for connection 6 of the heat exchanger 1 leads. A pipeline 16 opens into the intake duct 12 behind the flap I3 a, which is connected to the connection piece 9 of the heat exchanger 1.

As can be seen from FIG. 2, when the flap 13 cLas is closed, the entire mixture flows through the heat exchanger 1. If the flap I3 is open, on the other hand, the largest flows Part of the mixture directly from the carburetor 1o into the intake manifold 11 of the motor, while only a small partial flow flows through the heat exchanger 1.

In Figure 3, the actuation of the flap I3 is illustrated. The actuating lever 14 of the flap I3 is for this purpose with a piston 17 in connection, which is in a cylinder liner 18 slides. The pressure chamber 19 of this cylinder liner 18 is acted upon by the vacuum generated by the engine,

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that the flap I3 opens in full ^{load operation and V} is closed in partial load operation.

- patent claims -

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Claims (1)

Claims M.) device for heating the fuel-air mixture of an internal combustion engine with controlled spark ignition, comprising switched from a case of partial load operation between the carburetor and the intake manifold of the engine, abgasbehei-e last heat exchanger in which _t the mixture standing under the intake vacuum of the engine, multiple deflection and swirling is heated, characterized in that the flow path (5) of the mixture in the heat exchanger (1) is so long that the mixture is overheated well above the boiling temperature of the fuel, in particular to 25o to 500 ° C. 2. Apparatus according to claim 1, characterized in that in the heat exchanger (1) one of the mixture flowed through jet nozzle (7) is arranged, the jet of which is directed to a collection chamber (8), before the opening of the Beam deflected sideways, especially at right angles "** will.
O cd 3 device according to claims 1 or 2, ° characterized in that the heat exchanger (1) has a ^ J Pipeline (15j16) to the intake duct (12) between the carburetor (1o) and Hohciir air> 3 <? Scfy.o.SseK ι is that in front of an im ORIGINAL INSPECTED Intake duct (12) arranged controlled flap (13) branches off from the intake duct (12) and opens into the intake duct (12) behind the flap (13), the flap (13) is controlled such that it is closed in partial load operation and is open in full load operation. 4-, device according to claim 3, characterized in, that the flap (13) is controlled by the negative pressure generated by the motor. 5. Device according to claims 1 or 2, when used in connection with a register carburetor, characterized in that the heat exchanger (1) between the partial load stage of the register carburetor and the intake manifold (11) of the engine, while the full load stage of the register carburetor is connected directly to the intake port (11) of the engine. 6. Device according to claims 1 or 2 _t, characterized by the use on a rotary piston engine, the mixture being passed through the heat exchanger (1) both in part-load operation and in full-load operation. 7 · Device according to one or more of claims 1 to 6, characterized in that in the actuating mechanism of the carburetor (1o) a delay element delaying the resetting process is arranged. 709849/0252