Fig. 77. Working Cylinder of Elyria Oil Engine.
Fig. 77. Working Cylinder of Elyria Oil Engine.
Fig. 77. Working Cylinder of Elyria Oil Engine.
It is claimed that the change from the ordinary four stroke cycle Diesel cycle has been accomplished with practically no loss of thermal efficiency, and that the elimination of the many moving parts of that type has done away with many of the operating difficulties. By the introduction of a false piston end and an unjacketed cylinder head, the loss of efficiency due to the lower compression is compensated by the reduction of heat loss to the jacket water. Because of the high temperature it is possible to burn the heaviest fuels with a maximum pressure not exceeding 400 pounds per square inch, and without trouble due to missed ignition at light loads. With a given cylinder capacity this heating effect has increased the output about 75 per cent. The loss due to the friction of the scavenging apparatus causes a fuel consumption of approximately 10 percent more than a standard four stroke Diesel.
Unlike the Diesel, this engine automatically controls the quantity of injection air admitted to the cylinder at different loads, the air corresponding with the amount of fuel injected. This is in marked contrast with the Diesel engine which admits a constant volume of air at all loads. In place of the usualcrank-case compression of the scavenging air met with in the ordinary two stroke cycle engine, the initial compression in the Elyria engine is performed by a “differential piston” which acts in an enlarged portion of the cylinder bore. This construction increases the volumetric efficiency from 70 percent, in the case of the marine type, to well over 90 percent, and it also does away with the bad effect of the compression on the lubrication of the main crank shaft bearings.
Fig. 78. Compressor Cylinder of Elyria Oil Engine.
Fig. 78. Compressor Cylinder of Elyria Oil Engine.
Fig. 78. Compressor Cylinder of Elyria Oil Engine.
The working piston and differential piston as shown by Fig. 77 is separate castings fastened together by four studs, and the piston pin is carried by the differential piston which acts as a cross-head, taking all of the side thrust from the main piston. The working piston is easily taken from the cylinder by removing the cylinder head and the four nuts that fasten it to the differential piston casting. The displacement of the differential piston is approximately 1.9 times the displacement of the working piston which is more than enough for thoroughly scavenging the cylinder and supplying air for combustion. The air suction is controlled by a piston valve which eliminates much of the loss encountered in the marine type of two stroke cycle.
In the figure may be seen the separate or auxiliary piston head which is bolted to the piston proper, a construction that greatly increases the working temperature, and allows a symmetrical form of piston. By removing the cap over the inletport, it is possible to inspect the condition of the six piston rings with removing the piston from the cylinder. Because of the clean burning of the fuel lubrication is easily effected by the force pump which supplies oil at three points around the cylinder wall.
Three stages of compression are employed for providing the air for fuel injection, the first stage being accomplished by the differential piston, and the remaining two stages by a separate air pump driven by an eccentric from the crankshaft. This cylinder also supplies the air for starting the engine, the air being taken from the second stage and piped to the storage tank. The suction of the second stage pump which receives its air from the differential pump (first stage) is controlled automatically so that it is possible to keep the supply tank at any desired pressure regardless of the pressure or amount of air used for the fuel injection. Air from the tank (at approximately 200 pounds pressure) is piped to the suction side of the third stage air pump. In this suction line is a valve, controlled by the governor, which regulates the amount of air admitted to the injection nozzle, and also the amount. This pressure at the nozzle will vary from 500 pounds per square inch to 1000 pounds depending on the load and the nature of the fuel. The high pressure air travels directly from the pump to the fuel valve casing, and is equipped with a safety valve and pressure gauge.
The fuel pump is driven by a Rites Inertia Governor located in the fly-wheel which varies the stroke of the pump plunger and gives a correct proportion of fuel to the load. This type of governor has been extensively used on high speed engines and is exceeding accurate. The fuel pump may be disconnected from the governor drive, and operated by hand when it is necessary to provide fuel for starting. The spray or injection valve is operated by a cam, which lifts the valve at the proper moment in a very simple manner. The valve proper is made of a single piece of steel with openings of ample size, so that there is no danger of clogging with the heaviest fuels. As the valve only lifts116of an inch, the amount of work required to operate the valve is very small.
Starting is accomplished by spraying cold gasoline into the cylinder through the fuel valve in the same manner that the heavier oil is fed during operation, and the ignition is performed by a high tension coil and batteries. No spark time device is used, so that a continuous shower of sparks is thrown intothe mixture during the starting period. Within a minute after the engine is started, the ignition switch may be opened, the gasoline cut off, and the heavy oil turned on for continuous running on full load. Starting by an electric spark avoids the inconvenience and danger of torch starting with a retort.
Cooling water is admitted around the compressor cylinder from which point it goes to the working cylinder, and is there discharged. Less water is required for this type of engine than for the ordinary gasoline engine, for with the water entering at 60°F, only 3 gallons per horse-power hour is used. With fuel oil weighing 7.33 pounds per gallon the makers claim a fuel consumption of .65 pounds per horse-power at the rated load. The amount of cylinder oil used does not exceed 1 pint per 100 horse-power hours, while the loss of the bearing oil is extremely small because of the return system.
The Remington Oil Engine is a vertical oil engine operating on the three port, two stroke cycle, and is an oil engine in the strict meaning of the word, the oil consumed being introduced into the combustion chamber as a liquid and gasified within this chamber.
The method of gasifying and igniting the charge of oil in the Remington Oil Engine is unique. Only clean air unmixed with any charge, is taken into the crankcase. This air is afterwards passed up into the cylinder and compressed until its temperature has raised to a point high enough to vaporize the oil which is injected into it. The charge of oil is then atomized into this hot compressed air and turns immediately into a vapor, which finds itself well mixed with the charge of air, comes in contact with a firing pin recessed in the head, ignite and burns. This method of having the oil well gasified and mixed with air before ignition begins, prevents the formation of carbon which is formed when oil not well gasified and mixed with air comes suddenly in contact with very hot surfaces.
This perfect system of gasifying the oil has the effect not only of preventing the formation of carbon in the cylinder, but also of increasing the mean effective pressure and therefore decreasing the amount of fuel necessary for doing a certain amount of work. The engine passes through its cycle of operations smoothly, and does not have to be constructed with excessive weight.
Fig. 79. Cross-Section of Remington Oil Engine.
Fig. 79. Cross-Section of Remington Oil Engine.
Fig. 79. Cross-Section of Remington Oil Engine.
The Remington Engine is of the valveless type, delivering a power impulse in each cylinder for each revolution of flywheel. The gases are moved in and out of the cylinder through ports uncovered by the movement of the piston, which itself performs also the function of a pump.
On the up stroke of the piston a partial vacuum is created in the enclosed crankcase, causing air to rush in when the bottom of the piston uncovers the inlet port seen directly under the exhaust port (23), Fig. 79. On the next down stroke this air is compressed in the crankcase to about four or five pounds pressure per square inch. Meanwhile the mixture of oil vapor and air already in the cylinder is burning and expanding. When the piston approaches the end of its down stroke, it uncovers the exhaust port (23), permitting the burnt charge to escape, until its pressure reaches that of the atmosphere. Directly afterward the transfer port on the opposite side of the cylinder is uncovered by the piston, thereby allowing a portion of the air compressed in the crankcase to rush into the cylinder, where it is deflected upwards by the shape of the top of the piston and caused to fill the cylinder, thereby expelling the remainder of the burnt charge. The piston now starts upward, compressing the fresh charge of air into the hot cylinder head. Near the end of the stroke, a small oil pump, mounted on the crankcase and controlled by the governor, injects the proper amount of oil through the nozzle (13), into the compressed and heated air.
Fig. 80. Remington Spray Nozzle.
Fig. 80. Remington Spray Nozzle.
Fig. 80. Remington Spray Nozzle.
This oil is atomized in a vertical direction through a hole near the end of the nozzle. It is therefore vaporized and gasified before there is a possibility of its reaching the cylinder walls.
The spray of oil is ignited by the nickel steel plug (12), which is kept red hot by the explosions because the iron walls surrounding it are protected from radiation by the hood (11).By the burning of the oil spray in the air the pressure is gradually increased and the piston forced downward, this being the power or impulse stroke. Near the end of the down stroke, the exhaust port is again uncovered and the burnt gases discharged.
Fig. 81. Fuel Pump and Mechanism of Remington Oil Engine.
Fig. 81. Fuel Pump and Mechanism of Remington Oil Engine.
Fig. 81. Fuel Pump and Mechanism of Remington Oil Engine.
The operations above described take place in the cylinder and crankcase with every revolution. Each upstroke of the piston draws fresh air into the crankcase and compresses the air transferred to the cylinder. Each down stroke is a power stroke, and at the same time compresses the air in the crankcase preparatory to transferring it to the cylinder by its own pressure at the end of the stroke.
The same volume of air enters the cylinder under all conditions, and the power is regulated by modifying the stroke of theoil pump, which may be done by hand or automatically by the governor in the flywheel. A separate fuel pump is provided for each cylinder when multiple cylinders are used, making it absolutely certain that each cylinder shall receive the same amount of fuel for a position of the control lever.
When starting the engine, the hollow cast iron prong rising from the cylinder head is heated by a kerosene torch, and when hot, a single charge of oil is admitted to the cylinder by working the hand pump. The flywheel is now turned backward, thereby compressing the charge which ignites the fuel before the piston reaches the highest position. After being started the engine, the torch may be extinguished.
Fig. 82. Two Cylinder Remington Oil Engine Direct Connected to Dynamo.
Fig. 82. Two Cylinder Remington Oil Engine Direct Connected to Dynamo.
Fig. 82. Two Cylinder Remington Oil Engine Direct Connected to Dynamo.
The governor is of the centrifugal type. It has an L-shaped weight, pivoted to the piece attached to the flywheel. As the engine speed increases, the weight tends to swing outward toward the flywheel rim, and thereby moves the arm attached to it so as to shift the cam along the crankshaft toward the left.
This cam turns with the shaft, and operates the kerosene oil pump. According to the position of the cam on the shaft, it will impart to the pump plunger a long or a short stroke, thereby injecting more or less oil into the cylinder. The lever pivoted on the bracket moves with the cam and is used forcontrolling the engine’s speed by hand. To stop the engine the handle of the lever is pulled towards the flywheel, thereby interrupting the pump action altogether.
The handle of the control lever can be fitted with an adjustable speed regulator when required. This device is for use on marine engines to enable the operator to slow down the engine. The speed regulator does not interfere with the action of the governor but acts in conjunction with it. Whatever the speed of the engine may be, it is under the control of the governor. The engine can be controlled from the pilot house if such an arrangement is desirable.
The fuel pump is made of bronze. The valves are made of bronze and are designed with very large areas. The plunger is made of tool steel. A bronze cup strainer is attached to the lower end of the pump to prevent sediment or foreign matter from reaching the pump valves. As a result of the care used in its construction, the fuel pump is not only very sensitive in measuring the oil required by the governor, but is also very strong and durable.
The nozzle through which the fuel is atomized into the cylinder is thoroughly water jacketed to prevent the formation of carbon within the nozzle. It is so constructed that the water jacket spaces and fuel spaces can be opened for inspection.
Lubrication of all the important bearing joints is effected by a mechanical force feed oiler, pressure feed oiler or by gravity sight feed oilers, depending upon the service for which the engine is designed. Oil is fed in this manner to the piston, the main bearings and the crankpin bearings. The oil for the crankpin is dropped from a tube into an internally flanged ring attached to the crank by which it is carried by centrifugal force to a hole drilled diagonally through the crank and crankpin to the centre of the bearing. This insures that all the oil intended for the crankpin shall reach it. This feature, as well as the use of the sight feed oiler itself, is in line with the best modern high speed engine practice, and is an important factor in the reliability of the engine.