STEERING SYSTEM

The mechanism for transmitting the rotary motion of the steering wheel to the steering-gear arm is arranged in the steering-gear case. It is bolted to the frame. In case of a frameless construction, it is attached to a member of the body.

Many motor vehicles, especially passenger cars, are now equipped with the rack-and-pinion steering. It consists of a straight-guided rack arranged at right angles to the driving direction, and a spur-gear pinion, attached to the end of the steering column, engaged with the rack.

This type of steering requires a minimum of joints; as a result, it features long service life and minimum steering slack. It is especially used in case of axleless front-wheel suspension. A friction shock absorber is arranged behind the spur-gear pinion to prevent road shocks from being transmitted to the steering wheel.

The operation of the steering system should not require great effort. The force to be applied to the steering wheel depends on the load of the front wheels. In some special cases it is required to assist the driver's effort by means of a pneumatic or hydraulic servo-steering unit. Generally, this unit consists of a compressed-air cylinder. By means of the piston rod, its piston acts directly on the steering control arm of the front axle, while turning of the steering wheel guides the front wheels and additionally actuates the control valves of the compressed-air cylinder. Thus, rather effortless steering is achieved.

Furthermore, adherence to the specified type pressure is important for a good steering. Besides, troubles in the steering system may be traced back to wrong position of the front wheels.

TEXT 10

AIR CLEANER

Air is one of the three factors necessary to produce combustion.

Air consists of oxygen, nitrogen, and other gases. It is the oxygen in the air that is necessary for combustion.

During combustion the nitrogen and other gases pass through combines with two atoms of oxygen forming carbon dioxide (CO₂), which passes through the exhaust system as a gas.

With a rich gasoline mixture, carbon monoxide (CO), a poisonous gas consisting of one atom of carbon and one atom of oxygen, is formed because insufficient oxygen is available to form carbon dioxide. Two atoms of hydrogen from the gasoline with one atom of oxygen form water (H₂O). Approximately 11/3 gallons of water are produced for each gallon of gasoline burned.

Each pound of gasoline must be mixed with approximately 15 pounds of air or putting it another way, an engine at sea level operating at 70^o F. requires approximately 1250 cubic feet of air for each gallon of gasoline used.

Air, even during normal operation conditions, contains dust and abrasives that contaminate the lubricating oil, which is continuously circulated. These foreign substances damage there closely fitted parts; therefore, filtering devices have been installed to reduce the amount off foreign material entering the engine. One of them is the air cleaner.

A dry type air cleaner consisting of an air cleaner body, a filter element, and an air cleaner cover is mounted above the carburetor.

The filtering action of the air cleaner is accomplished by means of a dry filter element consisting of a band accordion pleated filter paper encased in a wire mesh screen. The air enters the air cleaner through the opening on the side, passes through a silencing clamber, then trough the filter. The cleaned air is deflected down to the carburetor. The dust particles air is trapped in the filter element as the air rushes trough it.

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