Engine cylinder

“ How to find which Cylinder Misses.—Endeavour first to ascertain which cylinder is the culprit. One method of doing this is to place your hand on each exhaust pipe while the engine is running. You will then get a bad burn from every one except that belonging to the faulty cylinder. A more convenient way—if electric ignition is fitted—is to stop the working of three out of four of the induction coils, changing about until you find the one that is at fault. It may be, however, that your engine has only one cylinder, or that all the cylinders miss occasionally. ”

“ On the revolution of the shafts the pistons reciprocate in their cylinders in much the same way as in an ordinary engine, and the valve arrangement is such that while each piston is receding from its cylinder the steam pressure is driving it, and during the in-stroke of each, its cylinder is in communication with the exhaust. There are thus four single-acting cylinders making each a double stroke for one revolution of the driving-shaft. The engine has no dead centres, and has been at 1,000 revolutions per minute. ”

“ Only one cylinder has been explained here, but most engines have several, each working at a different stage, so that the power is exerted on the shaft continuously. For instance, take a four-cylinder engine; on the instant that the first cylinder is exploding and driving the shaft, the second cylinder is compressing gas for the next explosion, the third is getting a fresh supply of gas, and the fourth is cleaning out the waste gas of the explosion of a second before. ”

“ The cylinders for a right handed propeller should be on the starboard side of the vessel, so that the pressure on the piston, when the engine is going ahead, shall be in a direction to lift the trunk in the cylinder, and thus act to relieve the gland and cylinder bore of the weight of the trunk and piston.
An oscillating engine is one in which the cylinder is mounted on bearings called trunnions, so that the cylinder can swing and keep its bore and the piston pointing to the crank at all parts of the engine revolution. This enables the connecting rod and slide bars to be dispensed with. ”

“ Multiple cylinder engines vary in the cylinder grouping or arrangement, the arrangement and number of cylinders depending on the service for which the engine is intended, the amount of vibration permissible, or the weight. The question of speed also introduces modifications in the design, but no matter what valve arrangement is adopted or what grouping of cylinders is 91used, a four stroke cycle engine performs the five events of suction, compression, ignition, expansion and exhaust in four strokes, in each and every cylinder. ”

“ As this Engine is of the Four Stroke Cycle Type, Each Cylinder Gives One Impulse per Revolution, or Two Impulses per Revolution for Both Cylinders. The Piston and Piston Rod Are Both Cooled by Water, and Are Supported by the Cross Heads so that Their Weight is Taken Off the Cylinder Bore.
An “opposed” type engine is in the most perfect mechanical balance of any engine as the crank shafts and connecting rods are not only on opposite sides of the crank-shaft, but make equal angles with the center line of the cylinders as well, at all points in the revolution. ”

“ After the cranks are on their places the keys may be fitted, care being taken that, if the crank last put on had to be moved to adjust it, the sides of the keyways be filed even, otherwise driving the key will tend to move the crank.
Fitting Engine Cylinders. [35] —When engine cylinders are made in quantities, as in locomotive building shops, a great deal of the fitting work is saved by the machine work; but when a single cylinder or a pair of cylinders only are to be fitted up it will not pay to make jigs and appliances; hence, they are usually fitted up entirely by hand. ”

“ Such a model, having a fixed cylinder, has not the friction of other types, and therefore it gives more power, size for size, than an oscillating engine, and does not get so easily out of order.
You must of course have a lathe, which I will therefore suppose you to possess; but should there not be a slide-rest to it, you must get the cylinder bored by a professional turner, for which he will charge about two shillings, according to the size of your castings. ”

“ The engine contains two cylinders—a power cylinder A and a displacer cylinder B. The function of the displacer cylinder is to take in a combustible charge of gas and air and transfer it to the power cylinder, displacing as it enters the exhaust gases of the previous explosion. A compression space G is formed at the end of the motor cylinder A. It is of conical shape and communicates with the displacer cylinder B by means of a large automatic lift valve which opens into the compression space from a chamber communicating by a pipe with the displacer cylinder. ”

“ The cylinders may be detached and changed if required, one size of bed answering for three different sizes of cylinder, which may vary only in diameter, the stroke being the same, so that the castings for engines of different power are the same except in the matter of the cylinders and pistons, and all the parts are interchangeable—a feature of modern engine building that cannot be too highly valued. ”

“ The “Crampton” engines—a great favourite in various parts of the continent, especially on the Northern of France Railway, but never in England—all have outside cylinders. The outside cylinder engine was very popular some twenty years ago, but the tendency of engineers, especially since the introduction of steel-cranks, is to revert to inside cylinders. Even at the Crewe manufacturing shops, where [191] formerly none but outside cylinder engines were built, engines with inside cylinders are now constructed. ”

“ I made myself comfortable on a grassy slope and proceeded to take the engine down. This I soon discovered was no mean task. It took nearly three hours to remove the cylinders. Woe be unto the man hereafter who puts nuts where they cannot be loosened or places cylinders where they cannot be removed save by an Indian sword-swallower! The result of my investigations was that I found the front piston in fragments, mainly in the bottom of the crank-case. The gudgeon pin was broken in half and the connecting rod was waggling about merrily in the cylinder. ”

“ In a two-cycle engine there is one working stroke in two traverses. For a given mean pressure the cylinder of a gas engine must be larger than a double acting steam cylinder. In single cylinder gas engines the crank effort is irregular; hence a heavy fly-wheel is required, or, a number of cylinders must be joined together, adding much weight. The motor does not start by the simple motion of a lever or valve. It has to be started by an auxiliary apparatus stored with energy enough to cause one working stroke. ”

“ However, by increasing the diameter of the screw and making it of such a form that very little or no atmospheric skin friction is encountered, a much better and cheaper engine of a totally different type may be employed. There is no reason why more than four cylinders should be used, but the stroke of the piston and diameter of the cylinder should be increased. ”

“ Pressure curves of actual engines are of the greatest value as they show the conditions within the cylinder at a glance and make it possible to detect losses due to leaks, poor valve settings, etc. These curves are traced by means of the INDICATOR which is an instrument consisting of a small cylinder which is connected to the cylinder of the engine, and an oscillating drum that is driven to and fro by the engine piston. The piston in the indicator cylinder is provided with a spring that governs its movements and communicates its motion to a recording pencil through a system of levers. ”

“ The difference of pressure on the two sides of the piston determines the tangent of the inclination of the tangent wheel which runs on the integrating cylinder; while the motion of the latter is made to keep time with that of the piston. In this case the number of evolutions of the cylinder measures the total amount of work done by the engine. The disk cylinder integrator may also be applied to find the total amount of work transmitted by shafting or belting from one part of a factory to another. ”

“ In all engines the most important parts are the cylinders, which must be well fitted. Boys who have a turning-lathe and the requisite practice in metal-turning can buy rough castings of all the parts of the engine for a few shillings and finish them up themselves. But as only a few of my readers may be so favoured, I will suppose that the cylinders are purchased ready for use. For these cylinders there is a great range in the prices quoted by different firms, the prices varying for the No. 4 cylinder from eight shillings at one firm to twelve shillings and sixpence at another. ”

“ The double cylinder and cross compound style have been very successfully adapted to traction engine purposes with certain advantages that no other style of traction engine has. With two cylinders and two pistons placed side by side, with crank pins at right angles on the shaft, there can be no dead centers, at which an engine will be completely stuck. Then sudden starting is liable to throw off the main belt. With a double cylinder engine the starting is always gradual and easy, and never fails. ”

“ But even between the best-lubricated surfaces, employing the most efficient metal as a bearing, some wear is bound to occur. The crank shaft of a four- or a six-cylinder motor is forged or sawed from one piece of steel, and with the accurate machining, finishing, and grinding to which it is subjected, it becomes an expensive part of the engine. ”

“ If the scavenging of the cylinder were complete, and the cylinder were to receive a full charge of fresh mixture for every stroke, the same mean effective pressure as is obtained with four-stroke cycle engines ought to be realised, and at an equal speed of rotation this engine should give twice the power obtainable from a four-stroke cycle engine of equal dimensions. ”

“ Our cylinder is to be horizontal, and the steam to work with equal force at each end. The mode by which we obtain (what I take the liberty of terming) a vacuum is, we believe, entirely new; as is also the method of letting the water into it, and throwing it off against the atmosphere without any friction. It is expected that the engine, which is a 12-inch cylinder, will move with a clear force of 11 or 12 cwt., after the frictions are deducted; this force is to act against a wheel of eighteen-inch diameter. ”

“ Inasmuch, however, as the engine weighs 44 tons empty and 51 tons in working order, and as all this weight is available for adhesion, this great cylinder power can be utilized. The cylinders are 6 ft. 10 in. apart from center to center, and they are well secured to the frames, as shown in Fig. 4. The frames are deep and heavy, being 1 3/8 in. thick, and they are stayed by a substantial box framing at the smokebox end, by a cast-iron footplate at the rear end, and by the intermediate plate stays shown. The axle box guides are all fitted with adjusting wedges. ”

“ In setting up a new engine it is obvious that if the flanges of the cylinder are planed parallel with its bore and at the proper distance from its axial line, and the pillow block is made of the proper height, a line stretched axially true with the cylinder bore will pass through the centre of bore of pillow-block brasses, or be equal in height from the engine bed ”

“ The high-pressure cylinder is smaller in diameter than the low-pressure cylinder, which is of such diameter that the power from the low-pressure cylinder is practically equal to that of the smaller high-pressure cylinder. For starting purposes, or when special effort is required, the driver can turn high-pressure steam into both cylinders. The idea of the compound engine is economy of the steam consumption, as more work is got out of the steam before its final release. ”

“ To test the alignment of an engine with stretched lines take out the piston and rod, and take off the connecting rod, then fasten a piece of iron at the open end of the cylinder so that it will hold a stretched line true with the axis of the cylinder bore. ”

“ There has been suction, compression (including ignition) , combustion, and exhaustion. It is evident that a heavy fly-wheel must be attached to the crank shaft, because the energy of one stroke (the explosion) has to serve for the whole cycle; in other words, for two complete revolutions of the crank. A single-cylinder steam-engine [Pg 92] develops an impulse every half-turn—that is, four times as often. In order to get a more constant turning effect, motor cars have two, three, four, six, and even eight cylinders. Four-cylinder engines are at present the most popular type for powerful cars. ”

“ The proportion of the length and diameters of the cylinders differ from those of land engines for a like reason: to save height, short cylinders with large diameters are used. Thus, in an engine of 200 horse-power, the length of the cylinder is sometimes 60 inches, and its diameter 53 inches: the valves and the gearing which work them, the air-pump, condenser, and other parts of the machine, do not differ materially from those already described in the land engines.
(h.) The action of machinery may be rendered more equable by using two engines, each of half the power, instead of a single one. ”