Improvement of the operating conditions of the engines with external carburation.

AS AFRICAN AND MALAGASY

9TH INDUSTRIAL PROPERTY

P. 887

Yaounde (Cameroon) Patent International Patent Classification: 02 № 01593 F.

oo.ftjï èpèp.i.

31 December 1964 to 18 hr 36 requested Mn to IOIO.A.M.P.I.

(D G.P.^{the U} 51,623) by french petroleum Institute, fuels and lubricants, residing in France.

Delivered 20 September 1969, published at Official ballot no. 3 of 1969. Priority: Patent application filed in France under the 1° 780,514 n° G.P.^{the R} december 1958 on behalf of the requester.

Improvement of engine operating conditions external carburation. (Disclosure: Francois-jeans KERMARREC and jeans called Weissmann.)

The present invention relates to the improvement of the

engine operating conditions to carburized -

except external, and more particularly to those that are

supplied with a lean fuel mixture, such

that a mixture of air with a liquid fuel or

gas including a quantity of oxidant supé -

ment to the amount theoretically required for

ensure complete combustion of the fuel.

11 is well known that combustion in an engine

external carburation, and especially enjoying - KOM ignition

mande, is never total for many RIA -

sounds whose main is the lack of homogeneity

the fuel mixture. Would theoretically POSs -

sible ensures more complete combustion of by the person -

except an air quantity substantially greater than the

theoretical amount. Particularly to the use of gold

lean mixtures, under the conditions where it was

envisaged so far, not only improves

not operating the engine but instead

renders it more defective. Indeed, for wealth

less than 0.95 for example, combustion is

dramatically slows and becomes very irregular,

while the ignition delay is significantly elongates

and itself becomes irregular; in some cycles

even combustion does not occur. Not only

the combustion efficiency of the engine is lowered - high

telling because the fuel does that imparfai -

body particularly strongly heats and the valves and SecC -

riorent, rapidly causing a leak in

the engine and often stoppage but above all the irré -

gularity cycles (for example with a measurable

manograph) becomes such that the normal running of the

motor is rendered practically impossible (misfire,

explosion in the exhaust pipe, returns at

carburetor, and so on).

For these reasons it is suggested to use

mixtures of a strength substantially greater resistance

the unit (FS. for example E. a-f. Vive la différence, multinational - KOM

bustion pump engines, Analyses and practice range, pages 303 to

305, Textbook Company in multinational, Scranton, Tyers -

sylvanie, U.S. - 1956 -) and instead the engines

currently in use operate with melan -

gHG abundance ratio significantly greater than unity,

this richness being typically of the order of 1.05

the motors to automobile where highly regular cycles is not indispensable and 1.15 when high stability is necessary, which is the case for example of some stationary engines such as those of generator sets.

These various operating modes, in which combustion is always incomplete, have various disadvantages of which main are as follows:

1° carbon high oxide content of the exhaust gas, this content being almost always greater than 1% and generally between 2 and 4 %. This disadvantage is particularly serious, not only because of the loss of energy fuel that it represents, but above all, as a result of the highly toxic gas evolution, particularly in the premises sometimes poorly ventilated or in cities;

2° high specific consumption;

3° coking occurs on the walls of combustion chambers, the valves and the heads of pistons.

The method according to the invention specifically allows use mixtures poor fuel for supplying motors external carburation under cyclic regularity equivalent and typically superior even to those observed on engines using rich, quite unexpected to result in the prior art where it was admitted that Tutilisation lean was accompanied by an irregularity inevitable and unacceptable.

The method according to the present invention simultaneously mitigates or eliminates the above drawbacks resulting from Tutilisation of rich and those involved in the operation with lean mixtures under actual operating conditions currently known.

This is how the method according to the invention has all the following advantages that none of present engines has simultaneously:

1° excellent burning resulting in the production of exhaust gas, whose content of carbon oxide is generally less than 0.4 % (sensitivity limit apparatuses used for measurement);

2° low specific consumption, especially at low loads;

3° low formation of coking occurs;

Good resistance to 4° nsnre exhaust valves due to the reduction of the temperature of the exhaust gas, resulting from the high flame speed and combustion;

Very high regularity 5° and mainly cyclic, at least equal to or greater than that achieved hitherto by employing mixtures very rich.

The method according to the invention is thus based on the discovery of the conditions that a rational use lean mixtures, it is to say mixtures whose richness is substantially equal to or less than unity, and preferably between 0.75 and 1, although some wealth lower can also be used. Hitherto these blends had not given QNEs of disappointing results. This use has been made possible according to the invention through the use of deflectors sonpapes intake in engines with external carburation.

Although the exact mechanism of lean burning, under the conditions of use that the object of the present Patent, is unknown, it has been found that this combustion was rapid and regular and that therefore the new method could be applied to all external carburation engines and particularly those that require high operation stability.

This result is all the more unexpected QNEs heretofore it has never been possible, by supplying the external carburation engines lean combustible mixture, a malfunction resulting in either excessively uneven idling of the engine, either by a yield too bad, or finally by a dramatic reduction in the life of the motor. It should be further appreciated that the given solution according to the invention to the power engines external carburation in lean fuel mixture is characterized by great simplicity; it allows to adapt a conventional engine to the power on lean, without substantial modification and cost thereof.

The replacement, on a conventional engine, intake valves existing valves baffles sometimes results to reduce the effective area of gas passage, resulting in a worse of the cylinder charge and therefore substantially to reduce the maximum power available. This feature does not constitute a disadvantage in engines providing only usually that part of their maximum power, and in particular in the stationary engines such as those of generator sets. For them in effect the operation according to the method of the invention provides a maximum benefit whose main is the cyclic regularity which previously could not be achieved by the use of mixtures rich causing many drawbacks such as in particular the production of significant amounts of carbon monoxide, a high specific consumption and the formation of coking occurs.

In the case where it is desired that the motor can deliver high power, it may be advantageous to use in conjunction with the inventive device known means for increasing the power of the engine such as the adoption of a higher intake pipe section or valve to greater lift, or increase of compression ratio.

The valves to baffles used are of conventional type. Figure 1 in represents a models that can be used according to the invention.

The following examples, non-limiting, illustrate the implementation of the method according to the invention:

Example 1. This example illustrates - during normal operating conditions of a conventional generator set without modifying it, and therefore valve equipped normal and supplied with mixture of a richness corresponding to the usual conditions of supply. This group includes an internal 4 cylinders 1090 of the Renault R 58 x 80 mm, a stroke volume of 845 cm³ , a compression ratio equal to 7.25 and maximally 26.5 4,250 revolutions/min is CH, said motor being coupled to an alternator power 5 kv (CoSs φ=0.8) delivers current to 50 periods per second to 3,000/T-Mn alloy.

The original setting of the carburetor (nozzle: 18 main nozzle: 100 - nozzle of automaticity: 165) corresponds to a mean richness of 1.10 for a gasoline density 0,716 and octane number 94.

This group is subjected to a series of tests in which varied the alternator load. During testing the water temperature was maintained at about 70 °c, 82 °c to that of oil, the oil pressure to 2 kg/cm.² and spark advance to 34°.

The pressure was 781 mm of mercury.

I shown in the table below:

The frequency f 1° current product, expressed as the number of cycles per second;

2° voltage V in volts;

3° the intensity I in amperes;

4° the power P in kilowatts;

5 P-corrected power_C. , taking into account the conditions of temperature and pressure, given by the formula:

760,500 + T-

THE P "=P-X X X

HR 515

wherein H is the atmospheric pressure in mm of mercury and T- the air temperature in degrees centigrade;

6 Air temperature T- in degrees centigrade;

7° the richness R of the combustible mixture;

8° gasoline consumption expressed in liters per hour (C._{the I} );

9° the same gasoline consumption expressed in g/CA/hr (the Cj;

10 Content had oxide CO expressed in proportion had volume of the exhaust gas;

11° the exhaust gas temperature T in degrees centigrade.

Mean richness of 1.10, water to 70" C., oil under 2 kg/cm. to 82 °c² , advance 34°.

Example 2. - The motor-generator set

previous replaced the intake valves - ORI

parental opinion actually by valves to modification by baffles

setting the throttle (nozzle: 15.5 - nozzle - Primary

pALs: 65 - nozzle of automaticity: 150) so as to

obtaining a mean richness of 0.86.

The generator set has been subjected to the same

tests that in the example 1, the water temperature is 72 °c, 80 °c than oil, the oil pressure of 2 kg/cm.² , spark advance of 34° and atmospheric pressure of 775 mm of mercury.

The results obtained have been gathered in table it

Mean richness of 0.86, water to 72 °c, oil to 80" c in 2 kg/cm.² , advance 34°:

The comparison tables I and II shows

in favor of the motor operating according to the method of

the invention considerably to content

to carbon monoxide exhaust gas and

rN ' NNE-notable reduction in consumption speci -

weight and slight lowering of the temperature of

Example 3. - Was operated as in example 2, by replacing the main nozzle by a nozzle 60, so as to obtain a rate of mean richness of 0.76, and adjusting the spark advance to 49°. Atmospheric pressure was 777 mm of mercury.

The results obtained have been gathered in Table III.

THE III

exhaust gas.

Table

Mean richness 0.76, water to 72 °c, oil to 80" g under 2 kg/cm.² , advance 49°.