Part 15
The action of the engine is as follows: as the piston moves outwards in its first stroke it sucks through the inlet valve a quantity of mixed air and gas, the proportions of which are regulated by special taps. The stroke ended, the piston returns, compressing the mixture and rendering it more combustible. Just as the piston commences its second outward stroke an electric spark passed through the mixture mechanically ignites it, and creates an explosion, which drives the piston violently forwards. The second return forces the burnt gas through the exhaust-valve, which is lifted by cog-gear once in every two revolutions of the crank, into the “silencer.” The cycle of operations is then repeated.
We see that during three-quarters of the “cycle”--the suction, compression, and expulsion--the work is performed entirely by the flywheel. It follows that a single-cylinder motor, to work at all, must rotate the wheel at a high rate. Once stopped, it can be restarted only by the action of the handle or pedals; a task often so unpleasant and laborious that the driver of a car, when he comes to rest for a short time only, disconnects his motor from the driving-gear and lets it throb away idly beneath him.
The means of igniting the gas in the cylinders may be either a Bunsen burner or an electric spark. Tube ignition is generally considered inferior to electrical because it does not permit “timing” of the explosion. Large cars are often fitted with both systems, so as to have one in reserve should the other break down.
Electrical ignition is most commonly produced by the aid of an intensity coil, which consists of an inner core of coarse insulated wire, called the primary coil; and an outer, or secondary coil, of very fine wire. A current passes at intervals, timed by a cam on the exhaust-valve gear working a make-and-break contact blade, from an accumulator through the primary coil, exciting by induction a current of much greater intensity in the secondary. The secondary is connected to a “sparking plug,” which screws into the end of the cylinder, and carries two platinum points about 1/32 of an inch apart. The secondary current leaps this little gap in the circuit, and the spark, being intensely hot, fires the compressed gas. Instead of accumulators a small dynamo, driven by the motor, is sometimes used to produce the primary current.
By moving a small lever, known as the “advancing lever,” the driver can control the time of explosion relatively to the compression of the gas, and raise or lower the speed of the motor.
The strokes of the petrol-driven cylinder are very rapid, varying from 1000 to 3000 a minute. The heat of very frequent explosions would soon make the cylinder too hot to work were not measures adopted to keep it cool. Small cylinders, such as are carried on motor cycles, are sufficiently cooled by a number of radiating ribs cast in a piece with the cylinder itself; but for large machines a water jacket or tank surrounding the cylinder is a necessity. Water is circulated through the jacket by means of a small centrifugal pump working off the driving gear, and through a coil of pipes fixed in the front of the car to catch the draught of progression. So long as the jacket and tubes are full of water the temperature of the cylinder cannot rise above boiling point.
Motion is transmitted from the motor to the driving-wheels by intermediate gear, which in cycles may be only a leather band or couple of cogs, but in cars is more or less complicated. Under the body of the car, running usually across it, is the countershaft, fitted at each end with a small cog which drives a chain passing also over much larger cogs fixed to the driving-wheels. The countershaft engages with the cylinder mechanism by a “friction-clutch,” a couple of circular faces which can be pressed against one another by a lever. To start his car the driver allows the motor to obtain a considerable momentum, and then, using the friction lever, brings more and more stress on to the countershaft until the friction-clutch overcomes the inertia of the car and produces movement.
Gearing suitable for level stretches would not be sufficiently powerful for hills: the motor would slow and probably stop from want of momentum. A car is therefore fitted with changing gears, which give two or three speeds, the lower for ascents, the higher for the level: and on declines the friction-clutch can be released, allowing the car to “coast.”
_B. Steam Cars._--Though the petrol car has come to the front of late years it still has a powerful rival in the steam car. Inventors have made strenuous efforts to provide steam-engines light enough to be suitable for small pleasure cars. At present the Locomobile (American) and Serpollet (French) systems are increasing their popularity. The Locomobile, the cost of which (about £120) contrasts favourably with that of even the cheaper petrol cars, has a small multitubular boiler wound on the outside with two or three layers of piano wire, to render it safe at high pressures. As the boiler is placed under the seat it is only fit and proper that it should have a large margin of safety. The fuel, petrol, is passed through a specially designed burner, pierced with hundreds of fine holes arranged in circles round air inlets. The feed-supply to the burner is governed by a spring valve, which cuts off the petrol automatically as soon as the steam in the boiler reaches a certain pressure. The locomobile runs very evenly and smoothly, and with very little noise, a welcome change after the very audible explosion motor.
The Serpollet system is a peculiar method of generating steam. The boiler is merely a long coil of tubing, into which a small jet of water is squirted by a pump at every stroke of the cylinders. The steam is generated and used in a moment, and the speed of the machine is regulated by the amount of water thrown by the pumps. By an ingenious device the fuel supply is controlled in combination with the water supply, so that there may not be any undue waste in the burner.
_C. Electricity._--Of electric cars there are many patterns, but at present they are not commercially so practical as the other two types. The great drawbacks to electrically-driven cars are the weight of the accumulators (which often scale nearly as much as all the rest of the vehicle), and the difficulty of getting them recharged when exhausted. We might add to these the rapidity with which the accumulators become worn out, and the consequent expense of renewal. T. A. Edison is reported at work on an accumulator which will surpass all hitherto constructed, having a much longer life, and weighing very much less, power for power. The longest continuous run ever made with electricity, 187 miles at Chicago, compares badly with the feat of a petrol car which on November 23, 1900, travelled a thousand miles on the Crystal Palace track in 48 hours 24 minutes, without a single stop. Successful attempts have been made by MM. Pieper and Jenatsky to combine the petrol and electric systems, by an arrangement which instead of wasting power in the cylinders when less speed is required, throws into action electric dynamos to store up energy, convertible, when needed, into motive power by reversing the dynamo into a motor. But the simple electric car will not be a universal favourite until either accumulators are so light that a very large store of electricity can be carried without inconvenient addition of weight, or until charging stations are erected all over the country at distances of fifty miles or so apart.
Whether steam will eventually get the upper hand of the petrol engine is at present uncertain. The steam car has the advantage over the gas-engine car in ease of starting, the delicate regulation of power, facility of reversing, absence of vibration, noise and smell, and freedom from complicated gears. On the other hand the petrol car has no boiler to get out of order or burst, no troublesome gauges requiring constant attention, and there is small difficulty about a supply of fuel. Petrol sufficient to give motive power for hundreds of miles can be carried if need be; and as long as there is petrol on board the car is ready for work at a moment’s notice. Judging by the number of the various types of vehicles actually at work we should say that while steam is best for heavy traction, the gas-engine is most often employed on pleasure cars.
_D. Liquid Air_ will also have to be reckoned with as a motive power. At present it is only on its probation; but the writer has good authority for stating that before these words appear in print there will be on the roads a car driven by liquid air, and able to turn off eighty miles in the hour.
_Manufacture._--As the English were the pioneers of the steam car, so are the Germans and French the chief manufacturers of the petrol car. While the hands of English manufacturers were tied by shortsighted legislation, continental nations were inventing and controlling valuable patents, so that even now our manufacturers are greatly handicapped. Large numbers of petrol cars are imported annually from France, Germany, and Belgium. Steam cars come chiefly from America and France. The former country sent us nearly 2000 vehicles in 1901. There are signs, however, that English engineers mean to make a determined effort to recover lost ground; and it is satisfactory to learn that in heavy steam vehicles, such as are turned out by Thorneycroft and Co., this country holds the lead. We will hope that in a few years we shall be exporters in turn.
Having glanced at the history and nature of the various types of car, it will be interesting to turn to a consideration of their travelling capacities. As we have seen, a steam omnibus attained, in 1830, a speed of no less than thirty-five miles an hour on what we should call bad roads. It is therefore to be expected that on good modern roads the latest types of car would be able to eclipse the records of seventy years ago. That such has indeed been the case is evident when we examine the performances of cars in races organised as tests of speed. France, with its straight, beautifully-kept, military roads, is the country _par excellence_ for the _chauffeur_. One has only to glance at the map to see how the main highways conform to Euclid’s dictum that a straight line is the shortest distance between any two points, _e.g._ between Rouen and Dieppe, where a park of artillery, well posted, could rake the road either way for miles.
The growth of speed in the French races is remarkable. In 1894 the winning car ran at a mean velocity of thirteen miles an hour; in 1895, of fifteen. The year 1898 witnessed a great advance to twenty-three miles, and the next year to thirty miles. But all these speeds paled before that of the Paris to Bordeaux race of 1901, in which the winner, M. Fournier, traversed the distance of 327-1/2 miles at a rate of 53-3/4 miles per hour! The famous Sud express, running between the same cities, and considered the fastest long-distance express in the world, was beaten by a full hour. It is interesting to note that in the same races a motor bicycle, a Werner, weighing 80 lbs. or less, successfully accomplished the course at an average rate of nearly thirty miles an hour. The motor-car, after waiting seventy years, had had its revenge on the railways.
This was not the only occasion on which an express service showed up badly against its nimble rival of the roads. In June, 1901, the French and German authorities forgot old animosities in a common enthusiasm for the automobile, and organised a race between Paris and Berlin. It was to be a big affair, in which the cars of all nations should fight for the speed championship. Every possible precaution was taken to insure the safety of the competitors and the spectators. Flags of various colours and placards marked out the course, which lay through Rheims, Luxembourg, Coblentz, Frankfurt, Eisenach, Leipsic, and Potsdam to the German capital. About fifty towns and large villages were “neutralised”--that is to say, the competitors had to consume a certain time in traversing them. At the entrance to each neutralised zone a “control” was established. As soon as a competitor arrived, he must slow down, and a card on which was written the time of his arrival was handed to a “pilot,” who cycled in front of the car to the other “control” at the farther end of the zone, from which, when the proper time had elapsed, the car was dismissed. Among other rules were: that no car should be pushed or pulled during the race by any one else than the passengers; that at the end of the day only a certain time should be allowed for cleaning and repairs; and that a limited number of persons, varying with the size of the car, should be permitted to handle it during that period.
A small army of automobile club representatives, besides thousands of police and soldiers, were distributed along the course to restrain the crowds of spectators. It was absolutely imperative that for vehicles propelled at a rate of from 50 to 60 miles an hour a clear path should be kept.
At dawn, on July 27th, 109 racing machines assembled at the Fort de Champigny, outside Paris, in readiness to start for Berlin. Just before half-past three, the first competitor received the signal; two minutes later the second; and then at short intervals for three hours the remaining 107, among whom was one lady, Mme. de Gast. At least 20,000 persons were present, even at that early hour, to give the racers a hearty farewell, and demonstrate the interest attaching in France to all things connected with automobilism.
Great excitement prevailed in Paris during the three days of the race. Every few minutes telegrams arrived from posts on the route telling how the competitors fared. The news showed that during the first stage at least a hard fight for the leading place was in progress. The French cracks, Fournier, Charron, De Knyff, Farman, and Girardot pressed hard on Hourgières, No. 2 at the starting-point. Fournier soon secured the lead, and those who remembered his remarkable driving in the Paris-Bordeaux race at once selected him as the winner. Aix-la-Chapelle, 283 miles from Paris and the end of the first stage, was reached in 6 hours 28 minutes. Fournier first, De Knyff second by six minutes.
On the 28th the racing became furious. Several accidents occurred. Edge, driving the only English car, wrecked his machine on a culvert, the sharp curve of which flung the car into the air and broke its springs. Another ruined his chances by running over and killing a boy. But Fournier, Antony, De Knyff, and Girardot managed to avoid mishaps for that day, and covered the ground at a tremendous pace. At Düsseldorf Girardot won the lead from Fournier, to lose it again shortly. Antony, driving at a reckless speed, gained ground all day, and arrived a close second at Hanover, the halting-place, after a run averaging, in spite of bad roads and dangerous corners, no less than 54 miles an hour!
The _chauffeur_ in such a race must indeed be a man of iron nerves. Through the great black goggles which shelter his face from the dust-laden hurricane set up by the speed he travels at he must keep a perpetual, piercingly keen watch. Though travelling at express speed, there are no signals to help him; he must be his own signalman as well as driver. He must mark every loose stone on the road, every inequality, every sudden rise or depression; he must calculate the curves at the corners and judge whether his mechanician, hanging out on the inward side, will enable a car to round a turn without slackening speed. His calculations and decisions must be made in the fraction of a second, for a moment’s hesitation might be disaster. His driving must be furious and not reckless; the timid _chauffeur_ will never win, the careless one will probably lose. His head must be cool although the car leaps beneath him like a wild thing, and the wind lashes his face. At least one well-tried driver found the mere mental strain too great to bear, and retired from the contest; and we may be sure that few of the competitors slept much during the nights of the race.
At four o’clock on the 29th Fournier started on the third stage, which witnessed another bout of fast travelling. It was now a struggle between him and Antony for first place. The pace rose at times to eighty miles an hour, a speed at which our fastest expresses seldom travel. Such a speed means huge risks, for stopping, even with the powerful brakes fitted to the large cars, would be a matter of a hundred yards or more. Not far from Hanover Antony met with an accident--Girardot now held second place; and Fournier finished an easy first. All along the route crowds had cheered him, and hurled bouquets into the car, and wished him good speed; but in Berlin the assembled populace went nearly frantic at his appearance. Fournier was overwhelmed with flowers, laurel wreaths, and other offerings; dukes, duchesses, and the great people of the land pressed for presentations; he was the hero of the hour.
Thus ended what may be termed a peaceful invasion of Germany by the French. Among other things it had shown that over an immense stretch of country, over roads in places bad as only German roads can be, the automobile was able to maintain an average speed superior to that of the express trains running between Paris and Berlin; also that, in spite of the large number of cars employed in the race, the accidents to the public were a negligible quantity. It should be mentioned that the actual time occupied by Fournier was 16 hours 5 minutes; that out of the 109 starters 47 reached Berlin; and that Osmont on a motor cycle finished only 3 hours and 10 minutes behind the winner.
In England such racing would be undesirable and impossible, owing to the crookedness of our roads. It would certainly not be permissible so long as the 12 miles an hour limit is observed. At the present time an agitation is on foot against this restriction, which, though reasonable enough among traffic and in towns, appears unjustifiable in open country. To help to convince the magisterial mind of the ease with which a car can be stopped, and therefore of its safety even at comparatively high speeds, trials were held on January 2, 1902, in Welbeck Park. The results showed that a car travelling at 13 miles an hour could be stopped dead in 4 yards; at 18 miles in 7 yards; at 20 miles in 13 yards; or in less than half the distance required to pull up a horse-vehicle driven at similar speeds.
_Uses._--Ninety-five per cent of motors, at least in England, are attached to pleasure vehicles, cycles, voiturettes, and large cars. On account of the costliness of cars motorists are far less numerous than cyclists; but those people whose means enable them to indulge in automobilism find it extremely fascinating. Caricaturists have presented to us in plenty the gloomier incidents of motoring--the broken chain, the burst tyre, the “something gone wrong.” It requires personal experience to understand how lightly these mishaps weigh against the exhilaration of movement, the rapid change of scene, the sensation of control over power which can whirl one along tirelessly at a pace altogether beyond the capacities of horseflesh. If proof were wanted of the motor car’s popularity it will be seen in the unconventional dress of the _chauffeur_. The breeze set up by his rapid rush is such as would penetrate ordinary clothing; he dons cumbrous fur cloaks. The dust is all-pervading at times; he swathes himself in dust-proof overalls, and mounts large goggles edged with velvet, while a cap of semi-nautical cut tightly drawn down over neck and ears serves to protect those portions of his anatomy. The general effect is peculiarly unpicturesque; but even the most artistically-minded driver is ready to sacrifice appearances to comfort and the proper enjoyment of his car.
In England the great grievance of motorists arises from the speed limit imposed by law. To restrict a powerful car to twelve miles an hour is like confining a thoroughbred to the paces of a broken-down cab horse. Careless driving is unpardonable, but its occasional existence scarcely justifies the intolerant attitude of the law towards motorists in general. It must, however, be granted in justice to the police that the _chauffeur_, from constant transgression of the law, becomes a bad judge of speed, and often travels at a far greater velocity than he is willing to admit.
The convenience of the motor car for many purposes is immense, especially for cross-country journeys, which may be made from door to door without the monotony or indirectness of railway travel. It bears the doctor swiftly on his rounds. It carries the business man from his country house to his office. It delivers goods for the merchant; parcels for the post office.
In the warfare of the future, too, it will play its part, whether to drag heavy ordnance and stores, or to move commanding officers from point to point, or perform errands of mercy among the wounded. By the courtesy of the Locomobile Company we are permitted to append the testimony of Captain R. S. Walker, R.E., to the usefulness of a car during the great Boer War.
“Several months ago I noticed a locomobile car at Cape Town, and being struck with its simplicity and neatness, bought it and took it up country with me, with a view to making some tests with it over bad roads, &c. Its first trip was over a rough course round Pretoria, especially chosen to find out defects before taking it into regular use. Naturally, as the machine was not designed for this class of work, there were several. In about a month these had all been found out and remedied, and the car was in constant use, taking stores, &c., round the towns and forts. It also performed some very useful work in visiting out-stations, where searchlights were either installed or wanted, and in this way visited nearly all the bigger towns in the Transvaal. It was possible to go round all the likely positions for a searchlight in one day at every station, which frequently meant considerably over fifty miles of most indifferent roads--more than a single horse could have been expected to do--and the car generally carried two persons on these occasions. The car was also used as a tender to a searchlight plant, on a gun-carriage and limber, being utilised to fetch gasolene, carbons, water, &c., &c., and also to run the dynamo for charging the accumulators used for sparking, thus saving running the gasolene motor for this purpose. To do this the trail of the carriage, on which was the dynamo, was lowered on to the ground, the back of the car was pulled up, one wheel being supported on the dynamo pulley and the other clear of the ground, and two bolts were passed through the balance-gear to join it. On one occasion the car ran a 30 c.m. searchlight for an hour, driving a dynamo in this way. In consequence of this a trailer has been made to carry a dynamo and projector for searchlighting in the field, but so far this has not been so used. The trailer hooks into an eye, passing just behind the balance-gear. A Maxim, Colt, or small ammunition cart, &c., could be attached to this same eye.