Gas-Engines and Producer-Gas Plants

defects in operation due to various causes have been dwelt upon, such as objectionable methods in the construction of an engine, ill-advised combination of parts, defects of installat

n engine having been indicated, it is to be assumed that the advice given has b

e, the exhaust-valve, or the piston. The valves, ordinarily seated by springs, may remain open because their stems have become bound, or because some obstruction has dropped in between the disk and the seat. In a worn-out or badly kept engine the valves are likely to leak. If that be the case grinding is the only remedy. If a valve be clogged, which becomes sufficiently evident by manipulating the controlling levers, it is necessary simply to c

ng suction. Again, the screw or roller serving as a contact between the lever and the valve-stem, may not have sufficient play, so that the lengthening of the stem on account of its expansion may prevent the valve from falling back on its s

r or binding of the rings, or by wear or binding of the cylinder. The whistling ca

e cylinder may be due to condensation of the steam formed by the chemical union of the hydrogen of the gas and the oxygen of the air, which condensation is caused by the cool walls of the cylinder. The water may sometimes accumulate in the exhaust pipe and box, when they have been imp

be deposited between the contacts, thereby causing

ing, through which the water can pass from the jacket, is attested by the bubbling up of gas in the water-tank at the opening of the supply tube. These bubbles are caused by the passage of the gas through the jacket after the explosion. If such

be type. Frequently it happens that in starting an engine a hot tube may break. If the tube be of porcelain the accident may usually be traced to improper fitting or to the presence of water in the cylinder. If the tube be of metal, its breaking is caused usually b

joints or in the body of the tube itself, thereby allowing a certain quantity of the mixture to esca

fore it reaches the incandescent zone. In the second case, ignition may be simply retarded to so marked an extent that a sufficient motive effect cannot be produced. An example of this retarda

g.

rovided with needle valve

dopted. It may be well to recall in this connection the important part played by the ignition-

in the particular position given to the admission device at starting. If a coil and a battery be employed, it is advisable to remove the plug and to place it with its armature upon a well-polished metal surface to produce an electrical contact, preventing, however, the contact of the binding post with

red that the wires are broken or that the generating apparatus is out of order. A c

moment of ignition of the gaseous mixture has a pronounced inf

he rear dead center to the end of the compression stroke. The violent effects produced are all the more

be be provided with a valve, it very frequently happens that the valve leaks or that it opens too soon. In the case of electric ignition, the circuit may be

mployed, but also in excessive heating of the internal parts of the engi

should first be stated that these ignitions, usually termed spontaneous, often occur well in advance of the end of the compression stroke. They are characterized by a more marked shock than that caused by ordinary premature ignition and usually result in bringing the engine to a complete stop in a very short time. These spon

which has become caked, and which is likely to become heated to

om. Untimely detonations are produced either at the exhaust, or in the suction apparatus, near the engine itself. These detona

hich charge, for some reason, has not been ignited in the cylinder, and has been driven into the exhaust-pipe, where it c

or in a separate chest, are often noisier than the foregoing. They are caused by the accidental backward flowing

into the suction-chest or into the frame. When the explosion takes place in the cylinder that part of the mixture which has passed back is ignited, a

the cylinder, which particles may consist of caked oil or may be retained by poorly cooled p

inder toward the end of the stroke, causing the entrance of air by the open admission-valve and consequently effecting the scavenging of the burnt gases, part of which would otherwise remain in the cylinder. It is evident that if a charge of the mixture has not been normally exploded, either because its constituents have not been mingled in the proper proportion, or because the ignition apparatus has missed fire, this charge at the moment of exhausting will pass out of the c

that the mixture is regularly ignited. This is accomplished by mixing

ality of the mixture; (3), compression losses. The existence of the defect cannot be ascertained with any certainty without the use of an indicator or of some registering device which gives graphic records. Nevertheless, it

he ignition apparatus is gradually adjusted to accelerate its operation until a point is reached when, after explosion, shocks are produced which indicate an excessive advance. The ignition apparatus is then adjusted to

which can be varied, ignition can be accelerated by bringing the burner neare

he moment of ignition will depend upon the length of the tube. The

he maker, regulation need not be undertaken except if the valve-stem be worn or the controlling-ca

is being produced normally. Before the engine has come to a stop, one of the valve-casings is raised, and through the opening thus produced it is easily seen whether the spark is of sufficient strength, the engine in the meanwhile being turned by hand. Care should always be taken to purge the cyli

g-posts, with the conducting wire, o

t in one of the d

grease forming an insulator, injurious to in

or moisture on the c

only after several years of use, except when the magneto

efects sufficiently indicates the me

improper proportioning of shafts, pins, and the like. The result is a premature wear which cannot be remedied. Imperfect adjustment, lack of care, and bad lubrication, may also has

of the gears and of the moving parts leads to

of the cams, rollers, and lever-pivots is evidenced by a retardation

ected by lost motion and is retarded. The engine apprecia

ployment of oil of bad quality. The overheating may lead to the binding of frictional surfaces and even to the fusion of bushings if they be lined with anti-friction metal. In order to avoid the overheating of parts, it is advisable, while the engine is running, to touch them from time t

then have attained a temperature so high that it cannot be touched with the hand. Should this occur, it is inadvisable to employ oil, because it would immediate

ely to be obstructed, a little flowers of sulphur may be added to the o

ng are removed by means of a steel scraper. The surfaces of the bushings and of the shaft which they receive are smoothed with a soft file and then polished with fine emery paper. Before the parts are

ity of water supplied. If this discovery is made too late, and if the cylinder has reached a very high temperature, the circulation of the water should not b

of water, cleaning is, of course, necessary. The jacket may be washed several times with a twenty per cent. solution of hydrochloric acid. After

cial oil for cylinder lubrication has been insisted upon. The overheating of the piston can also result from that of the piston-pin. Should this be the case it is advisable to stop the engine, to ascertain the condition and the degree of lubr

l passage of gas, caused by the explosion. Abnormal passage of gas may result from wear or from distortion of the cylinder, or from

fouling of the piston-rings, which then adhere in their grooves and have but insufficient

bundant, or when the oils employed are of bad quality. It has already been shown that insuffi

imperfect in its operation, the condition of its regulating mechanism should be ascertained, if it has any, and an examination made to discover any obstruction in the oil-ducts. Such obstruct

, or because of the presence of foreign bodies. In eith

e retarded by the addition of ordinary pe

accumulate within the cylinder, where it burns and forms a caky mass that may be heated to incandescence and prematurely ignite the explosive mixture. Especially in producer-gas engines is an excess of cylinder-lubricant likely to cause such accidents. Indeed, the temp

be mentioned obstructions in the form of foreign bodies, such as particles of rust, which drop from the interior of the pipes after the engine has been running for some time and which, accumulating at any place in the pipe, are likely to clog the passage. Furthermore, the products of combustion may contain atomize

ne power as well as in an abnormal elevation of the te

n of the engine, and by imperfect fuel supply. Among the fir

lready been discussed and w

ctive i

r of the exhaust-valve, preventing

gement of a member of th

ing, so that the valve is opened by the

arelessness and improper

he meter, by the formation of a water-pocket in the piping, by the binding of an anti-pulsator valve, by the derangement of a pressure-regulator, or by a sudden change in the gas pressure when no pressure-regulat