Besides the two above distinct types there are three other kinds of systems derived from them, and these are (1) the splash circulating, (2) the splash and force feed and (3) the full force feed.
In the splash circulating system the oil is put into the sump, or reservoir of the crankcase. Troughs are cut in the floor of the crankcase and the flywheel which runs in the oil sump keeps the troughs full of oil; the connecting rods dip into them and splash the oil into the cylinders as before; the oil is also carried up and into the oil tube which oils the bearings.
Where the splash force feed system. is used the oil is forced by a pump through an oil tube into the crankshaft bearings and from these the oil drops back into the splash troughs in the crankcase and the con necting rod splashes it to all parts of the engine.
The full force feed system is the only one where the splash is not used. The oil is pumped from the sump through an oil tube to the bearings and then it MUM through ducts in the erank-webs to the crank pins and, finally, through hollow connecting The Construction of the Muffler —A motor car muffler is made on the same principle as that of a mo torcycle muffler but as room on a motor car is not at a premium it is made considerably larger.
A simple muffler consists of two or more pipes fixed one in the other; each pipe is closed at one end and holes are drilled through near the end that is closed, as shown in Fig. 52.
When the waste gases exhaust from the cylinders into the inside pipe they shoot to the end of it and then pass out of the holes into the second pipe; they next flow out of oppositely disposed holes, which change their direction, and finally they escape silently into the open air.
Hand and Electric Starters.—Motor car engines are started either (1) by hand or (2) by an electric motor.
Hand Starters.—A few small new cars and a lot of the old-timers have engines with ratchet handles to crank them, and these are thrown out of gear the instant the engines start.
The Electric Starter.—Every up-to-date engine is equipped with an electric starter, and this is formed of four pieces of apparatus, namely, (1) a storage battery, (2) an electric motor, (3) a motor drive, and (4) a starting switch, and these are connected up, as shown at A in Fig. 53.
The storage battery is formed of prepared lead plates, or girds, immersed in a weak solution of sul phuric acid, as shown at B. Three, six, or twelve cells of storage battery are generally used, and these must be charged with a current generated by a dynamo.
Now a dynamo and a motor are made exactly alike, and if you rotate the armature the machine will gen erate a current, and then it is called a dynamo; on the other hand if you pass a current through the machine it will rotate the armature and then it will be a motor.
The motor drive is the mechanical part of the starter; it is formed of a screw gear mounted on the projecting shaft of the electric motor; it meshes with teeth that are cut on the rim of the flywheel of the engine, as shown at C, and demeshes from it after the engine is started. It is shown complete at D.
The switch is a simple device for opening and clos ing the circuit. Now when you throw on the switch the storage battery energizes the motor and this screws the drive gear into the flywheel and turns it ; as soon as the engine has started, the motor drive demeshes automatically; you release the switch and the elec tric motor stops. When the engine is running the motor can then be driven by it, and it will then gen erate current and charge the storage battery.
Tice Knight Sleeve Engine.—To get rid of the noise that the poppet valves make, Knight invented an engine in which the inlet and exhaust porta are opened and closed by a sleeve that slides between the cylinder and the piston. It is shown in Fig. 54..