Method and device for improving the combustion efficiency of an internal combustion engine

TITLE A METHOD AND DEVICE FOR IMPROVING THE COMBUSTION EFFICIENCY OF AN INTERNAL COMBUSTION ENGINE DESCRIPTION

The invention is concerned with a method and device for inserting a small amount of rare earth containing mixture or composition based on Cerium into a combustion chamber, particularly the combustion chamber of an internal combustion engine with spark ignition or compression ignition, to improve its combustion efficiency.

While the mechanism of Cerium oxidation catalysis is not completely understood, the following discussion explains the catalytic activity of Cerium in solid crystalline form: the action of a catalyst is measured by its ability to react reversibly with both the fuel used and with the oxygen. It is further required that these reversible surface reactions do not irreversibly change the catalytic material and that the amount of the pure oxygen be quite small.

Cerium oxides normally exist in the ״Fluorite lattice structure, each Cerium oxide being equidistantly surrounded by eight oxygen ions in the corners of a cube, while each oxygen ion is surrounded by four Cerium ions at the corners of a regular tetrahedron. In this normal state each Cerium ion is quadrivalent.

Cerium can also exist in several valences: however, Ce-0₃, in which the Cerium is trivalent, has a normal crystal lattice which the Cerium ions lie near the centre of a distored octahedron of regular oxygen ions, a seventh oxygen ion above one of the octahedral faces. This is an a-M₌0₃ lattice, in which the distance between Cerium and oxygen ions is not always the same and the lattice therefore represents different bonding energies.

Still a third modification of these oxides exists at high temperatures. This is known as the C-MgOj lattice, in which the oxygen ions are arranged approximately at the corners of a cube around the cation, but two are missing and the other four are at distances which necessarily adjust for this.

It is possible then for Cerium to co-ordinate six, seven or eight oxygen ions with approximately equal ease. Since there is little if any volume of phase change involved, the resulting surface structure can absorb or release oxygen ions at will over a broad temperature range.

In essence, then, a combustion catalyst is one which, by increasing the probability of contact between fuel and oxygen, decreases the temperature threshold of combustion and also increases the combustion rate.

DE-A 29 32 603 discloses a device in which a rare earth metal composition finely dispersed in an aqueous solution is introduced into the air intake manifold of an internal combustion engine. The use of an aqueous solution gives rise to a strange problem and since the storage space available is usually severely limited in the case of the use of such device in an automobile, it is necessary frequently to refill a storage reservoir with the aqueous solution.

The problem underlying the invention is to provide a method device of simple design and structure, by which a rare earth mixture or composition may be continuously introduced in small amounts during a long operation period, without (or with a minimum of) maintenance and refill work, into the combustion chamber of an internal combustion engine.

This problem is accomplished by a device as mentioned above, in which a container, which has an air-permeable dry filling of rare earth in powder form, communicates via an opening with the atmosphere and via a suction connection or line either with a vacuum line, or directly, with the combustion chamber of the engine.

Preferably the opening to atmosphere is formed by one end of a tube, which communicates with the filling via at least one orifice, wherein an air filter may be arranged within the tube adjacent the opening and wherein a throttle is arranged downstream of the air filter within the tube.

In the device of the invention a pressure below atmospheric pressure is induced by means of the vacuum line into the tube. Thereby air is sucked from the container via the orifice, which conveys a small amount of the powder via the tube and the vacuum line into the combustion chamber.

The filter acts as a flow-barrier finely to divide the particles of the powder to be sucked into the tube and defines a relatively large surface, i.e., of the filter surface facing the filling. This large surface area avoids undue localizing and the attendant risk of clogging the filter. The filter is preferably formed as a filter screen in a cylindrical shape which is arranged transversely to the tube and communicates with its one end or foot with the orifice in the tube.

The container may be dimensioned to accept an amount Of the filling which is sufficient for the whole lifetime of the internal combustion engine. However, as the space in modern automobiles is limited, a container dimensioned for a filling sufficient for a restricted operation time, e.g., corresponding to 80,000 km running distance for a passenger car, may be installed. In the latter case, the container may be arranged removably in the engine compartment of an automobile so that it can be exchanged against a fresh container. The container may also have a refilling opening for renewal of the filling.

The device of the invention enables the addition a small amount of a rare earth mixture or composition in a dry state to the air intake of an internal combustion engine avoiding the carrying and filling of a solvent, thereby avoiding the necessity of regularly replacing the solvent after short time periods and/or the additional space necessary for a solvent container in the automobile.

Two particularly advantageous compositions of the following analysis give the composition by weight of mixtures which may be used in the invention.

1. The particle size of the materials will be as small as possible, and could range from 60 mesh down to as low as 0.5 micron. Preferably the particle size is no larger than 325 mesh. Such particles can be produced by milling.

2. The compositions used should contain as high a percentage of Cerium Oxide (Ce 0₂) as can be readily and economically achieved, taking into account the practical difficulties involved in separating the various rare earth oxides.

The Ceria content, by weight in the mixture can be from 30% up to practically 100%.

By introducing a small amount of the mixture into the air intake, the harmful pollutants, particuarly that of CO, CO₂, HC and N0_x are reduced, and the combustion is improved so that an effect comparible to that of a controlled catalytic converter is achieved, but with much less expenditure.

It is an important advantage of a device of the invention that it can be fitted to existing automobiles even when driven by engines using unleaded fuel. Of course, the device may be used in engines driven by other conventional fuels for internal combustion engines.

The vacuum line might be the intake manifold of the engine. It is however, also possible to connect the suction line directly with the combustion chamber. In that case a check valve may be provided in order to ensure that the container communicates with the combustion chamber only during, the intake period of the engine.

The device of the invention may likewise be applied to .0(,^ spark ignition or compression ignition engines and also to stationary internal combustion engines.

Particularly in applications for large combustion engines, like locomotive, ship or stationary engines it is preferred to transport the rare earth powder particles by a motor-driven conveying means in the vicinity of a suction opening of the suction line.

Embodiments of the invention are illustrated in more detail in the following with reference to the accompanying drawings in which:Fig. 1 is a diagram of a first embodiment of a device according to the invention connected to the intake manifold of an internal combustion engine;

Fig. 2 is a sectional view of another embodiment of the invention in more detail;

Fig. 3 is a perspective view of a mounting bracket for mounting the device of Fig. 2 on a housing wall in an engine compartment of a vehicle or the like, and

Fig. 4 is a sectional view of still another embodiment.

In Fig. 1 an internal combustion engine 1 has an intake manifold 2 and an exhaust manifold 3. A container 4 contains an air-permeable filling 5 of a rare earth oxide mixture in powder form. A space 6 above the filling in the container has at least one flow barrier 7 and communicates via a suction line 8 with an air intake manifold 2. A tube 10 which is fixed to the container and has a lower end extending into the container and filling 5, has an orifice at the inside end of the tube communicating with the filling 5 near the bottom of the container 4 and an upper end with an opening 11 to atmosphere. Downstream of the opening 11 an air filter 13 and a throttle 12 is arranged in the tube 10. Atmospheric air sucked via the suction line 8 enters the opening 11 and flows via the throttle bore 12, the tube 10 and the orifice 9 into the filling 5, passes said filling and the flow barrier 7, where a turbulent motion is imparted to the air such that rare earth oxide particles are taken up by the air and conveyed through the suction line 8 in the air intake manifold 2 and thereupon into the combustion chambers of the cylinders of the internal combustion engine.

The container 4 may be exchanged when empty, e.g., after an operation period of the engine corresponding to 80,000 km, against a freshly filled container. Alternatively, the container 4 may be recharged through a refilling opening, not shown.

Instead of the air intake manifold 2 any other vacuum line which communicates with the combustion chamber can be chosen for the transport of air through the filling 5, for instance the vacuum line of a carburettor, a vacuum line of fuel injection system, an air-fuel-mixture-intake line etc. To enable economic operation it is preferred that no energy is used for the transport of air through the container and into the combustion chamber additional to the flow energy which is produced and available anyway in an internal combustion engine.

In Fig. 2 the same parts or parts having a similar effect to those in Fig. 1 are designated by the same reference numerals.

A tube 10 is inserted into a base 16 and fixed thereto by a screw cap 14 which forms an air filter housing for enclosing a filter material 13 (e.g. of carbon granules) in co-operation with a filter screen 13a. The screw cap 14 clamps a flange 10a of the tube 10 against base 16. Between the base 16 and the flange 10a on the one hand and the screw cap 14 and the base 16 on the other hand are inserted annular seals 30, 31. An opening 11 in the screw cap 14 accomplishes communication between the atmosphere and an inner space 10b of the tube 10 via a throttle 12, which is press-fitted into the end of the tube and has a throttle bore 12a, the diameter of which is e.g 0.5 mm. Variation in the amount of filling charge consumed is governed by the air stream sucked through the opening 11 and throttle bore 12a.

On its upper end the base 16 has a threaded connecting piece 17, on which is screwed a threaded boss 18 at the bottom end of the container 4. In a blind bore 16a inside of the connecting piece 17 of base 16, the bottom end 19 of . a cylindrically shaped filter screen 7 is inserted, said filter screen 7 passing through the total depth or j thickness of the filling 5. The filter screen 7 controls | the flow of air and filling particles through the bore 16a I in the base 16 and further through two orificies 9 into the tube 10, which is connected through a suction projection 8a to the suction line 8, which in this case might be formed by a flexible hose, not shown. Thus, when applying a pressure which is lower than the atmosphere pressure, via suction projection 8a, air containing a small amount of rare earth oxide particles will be sucked from the filling 5 in the container 4 through the filter screen 7, blind bore 16a, orifices 9 and tube inner 10b into the suction projection 8a and from there according to Fig. 1 into the intake manifold 2 or directly into the combustion chamber of the engine 1.

The following examples give the composition by weight of mixtures which may be used in the invention:

Example 1

Cerium Oxide 45.0%

Lanthanum Oxide 22.5%

Neodymium Oxide 17.9%

Praesodynium Oxide 5.7%

Thorium Oxide 0.25%

Sulfate as SO₃ 1.5%

Other Oxides (Y₌0₂₃Sc₌0₃) 2.9%

Phosphate at P₌0₃ 0.8%

Lime and Magnesia 1.0%

Example 2

Cerium Oxide 90.0%

Lanthanum Oxide 1.3%

Neodymium Oxide 1.3%

Praesodynium Oxide 0.4%

Other Rare Earth

Oxides 1.0%

Iron Oxide & Alumina 0.25%

Lime and Magnesia 4.0%

Silica 0.05%

Phosphate 0.5%

Sulphate 0.5%

Example 3

<td> Cerium Oxide</td><td> 45.6%</td>

<td> Lanthanum Oxide</td><td> 22.8%</td>

<td> Neodymium Oxide</td><td> 16.2%</td>

<td> Praesodymium Oxide</td><td> 4.7%</td>

<td> Other Rare Earth</td><td></td>

<td> Oxides</td><td> 5.7%</td>

<td> Thorium Oxide</td><td> 0.2%</td>

<td> Iron Oxide and</td><td></td>

<td> Alumina</td><td> 1.0%</td>

<td> Lime and Magnesia</td><td> 0.2%</td>

<td> Silica</td><td> 0.1%</td>

<td> Phosphate</td><td> 0.5%</td>

<td> Sulphate</td><td> 1-2.0%</td>

<td> Loss on ignition</td><td> 0-1.0%</td>

The preferred composition is that of Example 2 where the Cerium Oxide content is high and the Lanthanum Oxide content is as low as can be achieved as a practical matter. Thus while in Examples 1 and 3 the Lanthanum content is less than 25%, in Example 2 the Lanthanum Oxide content is much lower at less than 2%. The particle size will be no larger than 325 mesh and the powder will be produced by a milling process.

Fig. 3 shows a mounting bracket 20 for the adjustable screw connection of the device of Fig. 2 by means of screws 23 (Fig. 2) on a wall (not shown) in the engine compartment of an automobile. The mounting bracket 20 has a cranked supporting portion 22 to support the bottom of base 16. Two slots 21 having the shape of an arc of a common circle are dimensioned to accept screws 23, which are screwed into threaded bores at the bottom of base 16. Slots 21 allow j for adjustable mounting of the device in desired rotational !positions of base 16 and thereby of tube 10, in order to bring the suction projection 8a in a most favourable position for connection to the intake manifold 2.

I The amount of the filling 5 is dependent on the size

ו1 and fuel consumption of the internal combustion engine. Experiments have shown, that in a 1000 ccm-gasoline engine about 1.6 mg/km of filling should be charged to achieve the desired effect of reducing the pollutants sufficiently from the exhaust gas. After a driving distance of about 800 km the benefits of the device is evident and no increase in benefits would appear to occur after that time.

The device according to the invention may particularly be applied instead of a controlled catalytic converter in internal combusion engines using leaded fuel and in internal combustion engines, in which the use of a controlled catalytic converter would be too expensive.

The embodiment shown in Fig. 4 comprises a container

104 which has a housing part 134 containing a filling 105 of a rare earth powder, an air filter part 136 containing a filter material 113 (e.g. active charcoal granules) or filter mesh and having and a driving part 138 a transmission 125.

an opening 111 to the atmosphere, housing an electric motor 124 with

The air filter part 136 and the driving part 138 are each separated from the housing part partition walls

130, 132 respectively, which

134 by i

I comprise bearings 128 for supporting a central shaft 126, ί ;I which is driven by the motor 124. The inside of parts 134, i 136 and 138 normally is under atmospheric pressure. Filter p part 136 is connected to housing part 134 by an air opening

112, which might be covered by a membrane 112a, which is p urged against the opening 112 by spring force inherent in the membrane. The opening and the co-operating membrane have the effect of a throttling device.

On said central shaft 126 a wheel 120 is fixed, which has a radial part 120a and a conical part 120b. At the outer periphery of said conical part 120b conveying means 122 in the form of shovels or teeth are arranged around the periphery around the wheel 120. Instead of shovels or teeth any other means, for instance roughened surfaces may be provided which are apt to take up rare earth particles from said filling 105 when said wheel 120 travels through said housing part 134 thereby transporting said rare earth particles into the vicinity of a suction orifice 109 which passes through the wall 126 of the container 104 and communicates with a suction line connector 108a for communicating with a suction line 108, for instance a hose as shown in Fig. 4.

When the combustion engine is started, the motor 124 will be activiated to rotate shaft the 126 and wheel 120 at low speed (e.g 6 rpm). The conical part 120b acts as a paddle or shovel which urges the material to flow from the sides of the wheel 120 to its bottom into a region under the central part of wheel 120 such that rare earth particles are conveyed by the conveying means 122 on the periphery of the wheel 120 to a location close to the suction orifice 109 where the particles are taken up by means of the suction effect with the suction line 108. Thus the rare earth particles are positively conveyed and delivered to the combusion chambers of the combustion engine.

13׳

The embodiment of Fig. 4 is particularly useful in large combustion engines as used in locomotives, ships and as stationary engines of power plants or the like.