Cylinder (engine)

“ 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. ”

“ The cylinder is the heart and soul of the engine, being the seat and centre of its power. The steam is generated in the boilers, but while it remains there it remains quiescent and inert. The action in which its mighty power is expended, and by means of which all subsequent effects are produced, is the lifting and bringing down of the enormous piston which plays within the cylinder. This piston is a massive metallic disc or plate, fitting the interior of the cylinder by its edges, and rising or falling by the expansive force of the steam, as it is admitted alternatively above and below it. ”

“ We have now to notice the double cylinder engine constructed by Woolfs, which will be found, by reference to the diagram in the preceding page, to consist of a high pressure cylinder, connected with a condensing apparatus.
A and B represent the two cylinders, in the larger of which the steam is allowed to expand itself, after passing from the high pressure cylinder B. The steam, which in the first instance is of considerable elasticity, is admitted to the cylinder B, by the tube and valve E, and entering the cylinder above its piston, impels it to the bottom. ”

“ Tightness of the Cylinder.—The amount of power developed depends principally on the degree of compression to which the explosive mixture is subjected. The economical operation of the engine depends in general upon perfect compression. It is, therefore, necessary to keep those parts in good order upon which the tightness of the cylinder depends. These parts are the piston, the valves, and their joints, and the ignition devices whether they be of the hot-tube or electrical variety. In order to prevent leakage at the piston, the rings should be protected from all wear. ”

“ 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. ”

“ In 1890 he started to construct a double-cylinder engine, after having built various experimental engines, and decided that for transportation a single-cylinder was impracticable because its flywheel weighed too much. ”

“ 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. ”

“ 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 fact that force is given the cylinder at such wide intervals makes it necessary to have an extra heavy flywheel to keep the engine steady, and the double cylinder engine which can give a stroke at least every revolution is still better and is indispensable when the flywheel cannot be above a certain weight. ”

“ 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. ”

“ Besides the advantages gained by increasing the impulses, the mechanical balance of a multiple cylinder engine is always better than that of a single and is also much 60lighter in weight since less material is required to resist shocks of the explosions. ”

“ 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. ”

“ 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. ”

“ An instance of the weight reduction obtainable in using six cylinders instead of four is shown in Critchley’s list, for one of the four-cylinder engines developed 118.5 brake horse-power and weighed 1,100 lbs., whereas a six-cylinder engine by the same manufacturer developed 117.5 brake horse-power with a weight of 880 lbs., the respective cylinder dimensions being 7.48 diameter by 9.06 stroke for the four-cylinder engine, and 6.1 diameter by 7.28 stroke for the six-cylinder type. ”

“ Each cylinder with piston and piston-rod weighs no less than 38 tons, while each pair of cylinders with its crank, condenser, and air-pumps, forms in itself a complete and separate engine, and each of the four cylinders is so constructed that it can be, at once, disconnected when required, from the other three, so that the whole forms a combination of four engines, altogether complete in themselves, whether worked together or separately. ”

“ 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. ”

“ The heating of the top and bottom of the cylinders, I think, must be particularly important in a short-stroked engine working expansively. In a cylinder of 80 inches diameter and 40 inches stroke, having regard to the time of contact, the area of the bottom will be nearly equal in effect to the surface of the cylinder. ”

“ 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. ”

“ 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. ”

“ A.--It is not only in the boring of the cylinder that it is necessary to be careful that there is no change of figure, for it will be impossible to face the valves truly in the case of large cylinders, unless the cylinder be placed on end, or internal props be introduced to prevent the collapse due to the cylinder's weight. ”

“ 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. ”

“ 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. ”

“ The advantages of this arrangement are that the moving masses are perfectly balanced, the construction of the cylinder is very simple and especially adapted to high pressures, and the reaction of the gases, instead of being directed against a fixed part of the engine, is directed against a moving piston, thus reducing the strain on the structure. ”

“ These cylinders are driven by bevel wheels, so that each one is independent of its neighbor, and should any accident occur to one or more of the cylinders or wheels, the remaining ones can be run until a favorable opportunity arrives to repair the damage. A small separate double cylinder diagonal engine is fitted to this machine, the speed of which can be adjusted for any texture of cloth, and being of the design it is, will start at once on steam being turned one. The machine cylinders are rolled by a special machine for that purpose, and are perfectly true on the face. ”

“ 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. ”

“ The difference is that inlet takes place through hollow connecting-rods, which are ball-ended and fit into ball seatings. The cylinders oscillate, and the connecting-rods, being rigidly attached to the pistons, by their angularity during revolution form the inlet and exhaust mechanism. The propeller is geared up in the ratio 2: 1.
Fig. 145.—Three-cylinder Engine
The design is analogous to a very early French engine much in evidence in the early days in model experiments. ”

“ 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. ”

“ However many cylinders an engine may have, the magneto must be revolved from one point of sparking to the next in the interval between ignition in one cylinder and ignition in the next cylinder to fire. ”

“ 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 great bugbear staring the amateur mechanic in the face when he contemplates making a small steam engine is the matter of boring the cylinder. To bore an iron cylinder on a foot lathe is difficult even when the lathe is provided with automatic feed gear, and it is almost impossible with the ordinary light lathe possessed by most amateurs. To bore a brass cylinder is easier, but even this is difficult, and the cylinder, when done, is unsatisfactory on account of the difficulty of adapting a durable piston to it. ”