CHAPTER VII_Gas and Petroleum Engines

ENGINES FOR USE WITH POOR GASES

_Simplex motor_ (Fig. 45).—Although this motor works equally well with

coal gas and oil, we have put off the description of it until now

because it has become associated particularly with the production of

poor gases, and by their help forms one of the most formidable rivals

of the steam engine.

The Simplex was invented in 1884 by MM. Edouard Delamare-Deboutteville

and Léon Malandin. In appearance it is of the usual four-cycle type.

A lateral shaft transmits the rotation of the crank-shaft to a small

crank which actuates the sliding valve. This sliding valve forms one of

the principal features of the engine, and consists of a sliding iron

plate pierced with two holes, one oblique regulating the ignition,

and the other straight forming the admission valve. The piston

having completed its first forward stroke comes back to compress the

explosive mixture, and the sliding valve having advanced puts it in

communication with a chamber containing two metallic points, between

which a continuous stream of electric sparks is made to flow. After

the explosion this cavity and the passage leading to it are filled with

burnt gas, which must be driven out to prevent a miss-fire at the next

stroke. This is effected by a small purging hole, through which they

are driven by a fresh charge entering the cylinder.

In earlier patterns of this engine an ingenious air governor was used,

but it has now been replaced by a fresh arrangement of a different

pattern. This governor (Figs. 46 and 47) consists of a double pendulum,

which takes up a vertical position because of the lower ball, seen in

the illustration, being the heaviest. The whole pendulum is pivoted on

a fixed bearing. The variation in the speed is obtained by a weighted

knife blade acting on the gas-valve. The sliding valve is provided with

a knife blade square at one end and pointed at the other, which catches

in a notch on the pendulum, and is held by it in position so that the

square end hits the end of the gas-valve and admits gas. If, however,

the speed of the engine be too great the sliding valve carries its

knife blade forward too soon and it does not catch in the notch, with

the result that no gas is admitted as the square end is too low. The

speed of the engine, therefore, tends to remain adjusted to the rate of

vibration of the pendulum, which is a fixed quantity. A self-starting

arrangement is provided by stopping the engine half-way back along the

compression stroke, so that it is only necessary to pass an electric

spark across for an explosion to occur and give it the necessary

starting impetus.

[Illustration: FIG. 45.—Simplex Gas Engine (Delamare-Deboutteville).]

[Illustration: FIGS. 46, 47.—Governor of the Simplex Engine.]

MM. Delamare-Deboutteville and Malandin were the first to construct

units of very great power. At the Havre Exhibition in 1889 they

exhibited a Simplex engine using Dowson gas, and in 1889 they exhibited

at the Paris Exhibition a 100 horse-power single-cylinder motor.

Their latest achievement in this direction is the erection of a 320

horse-power engine supplied by two Buire-Lencauchez gasogenes with poor

gas. This is the largest single-cylinder gas engine in the world. The

Simplex engine was the pioneer of motors using poor gas. The machine we

described was for use with coal gas, and some modification has to be

made in the parts when the motor is required to use gases of the Dowson

type. The economy is very good, only 580 litres of coal gas or 550

grammes of anthracite being used per horse-power hour.

[Illustration: FIG. 48.—Combined Simplex Engine and Buire-Lencauchez

Gas-Producer.]

_Gardie motor._—We have shown how poor gases are, beyond a shadow of a

doubt, cheaper than coal gas for the production of power. Many makers

have therefore attempted to use it by simply adding a gas-producing

plant to existing engines. Sometimes these motors were totally unsuited

for these cheaply produced gases, and the result has been failure from

miss-fire or irregular speed. The Crossley, Niel, and Andrews motors

are exceptions, and a few others have also given fairly good results.

We described in the previous chapter the ingenious gasogene devised by

M. Gardie of Nantes; the motor which is constructed for use with it is

rather novel. It has two cylinders placed side by side, a compressing

pump and reservoir for compressed air. The gaseous mixture arriving at

a high temperature from the gasogene passes into the cylinders, and

is mixed with a volume of air coming from the reservoir; these gases

are compressed to about 100 lbs. on the square inch. At the entrance

to the cylinders are placed two igniters of platinum heated to a

white heat by an electric current at starting, but the temperature

is afterwards maintained by the combustion. During the admission the

gaseous mixture burns without any explosion and without raising the

pressure, but considerably increasing in volume. At the commencement

of the stroke the pressure in the cylinder is therefore the same as in

the compressor, but it soon decreases by virtue of the expansion and

driving forward of the piston.

After having exhausted themselves in doing work the gases pass out

into a regenerator, which communicates their heat to the air for

admission. The valves are actuated by a horizontal shaft placed above

the cylinders; the cams are three in number corresponding to three

valves, of which two regulate the admission of gas and air to a

chamber in which they are mixed. The third valve opens the exhaust.

This arrangement is not unlike that adopted by MM. Forest and Gallice

for their marine oil engines.

The cylinders are surrounded by water jackets for cooling purposes,

aided by air which can enter the front end when the piston is moving

in its backward stroke. The hottest portion is therefore that situated

at the valve end, and in which the explosion takes place. This portion

is surrounded by a closed chamber forming a boiler, where steam is

formed for use in the gas plant; the steam is superheated in a spiral

coil placed on the top of the gasogene. As we have already stated,

this system of gas production avoids the ammoniacal products, which

are a constant source of trouble in other engines. The drawback lies

in the compressor, which uses up about one-third of the indicated

power, but the speed is exceedingly constant, and averages about 175

revolutions per minute. The consumption of gas is not very high,

probably owing to the amount of heat which is absorbed from the waste

gases, usually lost. A number of other engines exist of a similar type

to the Gardie motor, such as the Shaw, Woodburg, Crowe, Buchett, and

others, which cannot, however, consume poor gases, and which have not

any distinguishing features worth mentioning.

_Bénier motor gasogene_ (Figs. 49 and 50).—We have described the Bénier

gasogene, and we will now complete the description by a short notice

of the motor associated with it. This motor works on the Dugald-Clerk

cycle, and in general arrangement is not unlike the Dugald-Clerk

motors. A special compressing cylinder is provided cast in one with

the motor cylinder, and the cranks are set at 90° degrees apart from

one another. The pump is double, with two pistons coupled tandem-wise

in the same cylinder. One of these draws in the air and the other

forces the gas into the gasogene. The air and gas thus conducted by

different paths reach the mixing chamber placed behind the motor

cylinder and provided with a valve. The motor cylinder has exhaust

ports perforating the walls, and which are uncovered by the piston when

it has moved through five-sixths of the forward stroke. It remains open

during the remaining sixth and the first sixth of the return stroke.

At this moment the two piston pumps have forced into the cylinder the

air and gas which they contain. The mixture enters through a valve

and a perforated plate, which thoroughly mixes them in the cylinder.

During the return stroke the piston, having closed the exhaust ports,

compresses the explosive mixture till the end of the stroke. Ignition

then takes place, and the explosion drives the piston forward, and the

products of combustion escape to the air directly the exhaust ports are

uncovered by the piston.

[Illustration: FIGS. 49, 50.—Bénier Engine and Gas Plant (sectional

plan and elevation).]

By this arrangement it might happen that the explosive mixture

introduced into the cylinder might escape by the open exhaust valves.

M. Bénier has obviated this difficulty by a novel device. Pure air is

first admitted, driving out the products of combustion; the explosive

mixture which follows is only admitted when the ports are closed. This

result is obtained by properly regulating the supply of air and gas

from the pump. One explosion therefore occurs in every revolution.

The Bénier engine is constructed in sizes up to 100 horse-power, and

also smaller ones of a few horse-power. A 5 horse-power motor consumes

800 grammes of anthracite per horse-power hour: this result is very

remarkable, because great difficulty has been found in working these

small engines at all with poor gas; the gas generator seems to work

badly when its dimensions are so small. A 15 horse-power motor only

consumes 600 grammes per horse-power hour. The Bénier combined plant

shown in Figs. 49 and 50 has received a most flattering reception on

the Continent, and there is good reason to believe that it will be very

much more widely used in the future. We close this chapter with a table

setting forth the relative merits and economy of a number of motors.

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Hugon (1866) | ” | 2·07 | 5400 ” | 2600 ” | 8·5 | ”

Langen and Otto | ” | ·46 | 660 ” | 1380 ” | 4·5 | ”

(1867) | | | | | |

Wittig and Hees | ” | 4 | 4960 ” | 1240 ” | 3·5 |Brauer

(1881) | | | | | |

Koerting- | ” | 2·18 | 2700 ” | 1275 ” | 3·7 |Schettler

Otto | ” | 8·34 | 9500 ” | 915 ” | 2·8 |Allard and

Dugald-Clerk | ” | 11·6 | 9700 ” | 877 ” | 2·5 |Sterne

(1884) | | | | | |

Lenoir (1885) | ” | 2 | 1320 ” | 655 ” | 1·9 |Tresca

Simplex (1885) | ” | 9·41 | 5580 ” | 593 ” | 1·1 |Witz

” ” | Dowson | 3·66 | 6040 ” | 3300 ” | ·7 | ”

| gas | | | | |

Lenoir (1885) |Carburet- | 4·15 | 2·7 ” | ·65 ” | 4·5 |Tresca

Benz (1885) | Coal gas | 5·1 | 3600 litres| 707 ” | 1·4 | ”

Atkinson (1888) | ” | 9·48 | 6000 ” | 618 ” | 1·3 |Society

Crossley(1888) | ” | 14·74 |10,800 ” | 765 ” | 1·5 | ” ”

Griffin (1888) | ” | 12·51 | 9500 ” | 786 ” | 1·5 | ” ”

Charon (1889) | ” | 4·17 | 2210 ” | 530 ” | 1·1 |Witz

Niel (1891) | Coal gas | 3·75 | 1250 ” | 402 litres| ·8 |Witz

Simplex (1889) | Poor gas | 75 |191 cub. met.| 2370 ” | ·7 | ”

” (1893) | ” |220 |110 kilg. | 500 grms. | ·3 |Leblan

Lenoir (1891) | Coal gas | 6 | 4260 | 710 litres| 1·5 |Lencauchez

Charon (1892) | ” | 7·5 | 4380 | 586 ” | 1·2 |Chauveau

| oil | | | | |

” (1891)|Russoline | 6·7 | 2 kilg. 700 | 428 ” | 1·9 | ”

Crossley (1892) | Dowson |148 | 415 kilg. | 280 ” | ·2 |Dowson

| gas | |(anthracite) | | |

Atkinson (1892) | ” | 16·7 | 6·6 kilg. | 455 ” | ·3 |Tomlinson

Schleicher-Schum| Poor gas | 92 | 55 ” | 596 ” | ·32 |Spanglon

Trusty |Petroleum | 4·3 | 1·83 ” | 440 ” | 2·2 |Beaumont

Delamare- |Lencauchez| 62 | 37 ” | 603 ” | ·2 |Bourdon

(1894) | | | | | |

Campbell (1895) |Petroleum | 6 | 2·4 ” | 400 grms. | 2·5 | ”

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The price of fuel has been calculated from prices current at the dates given.