The Zenith Carburetter Company Limited was a British company making carburettors in StanmoreMiddlesex, founded in 1912 as a subsidiary of the French Société du carburateur Zénith.[1] In 1965,[2] the company joined with its major pre-war rival Solex Carburettors, and over time, the Zenith brand name fell into disuse. The rights to the Zenith designs were owned by Solex UK (a daughter company of Solex in France).
While better known for its much later products, Zenith produced carburettors that were standard equipment on some very early, brass eraautomobiles, including the Scripps-Booth.
Non-UK German Pierburg (Stromberg) carburettor in a Saab 90Non-UK German Pierburg (Stromberg) carburettor dashpotBritish made Zenith/Stromberg carburettors as installed on a 1969 Jaguar E-type 6cyl 4.2l engine
The Triumph Spitfire used Zenith IV carburettors in the North American market. In Australia, the CD-150 and CDS-175 models were fitted to the high-performance, triple-carburettored Holden Torana GTR-XU1.
Designed and developed by Dennis Barbet (Standard Triumph) and Harry Cartwright (Zenith) to break SU's patents, the Stromberg carburettor features a variable venturi controlled by a piston. This piston has a long, tapered, conical metering rod (usually referred to as a "needle") that fits inside an orifice ("jet") that admits fuel into the airstream passing through the carburettor. Since the needle is tapered, as it rises and falls, it opens and closes the opening in the jet, regulating the passage of fuel, so the movement of the piston controls the amount of fuel delivered, depending on engine demand.
The flow of air through the venturi creates reduced static pressure within it. This pressure drop is communicated to the upper side of the piston via an air passage. The underside of the piston is in communication with atmospheric pressure. The difference in pressure between the two sides of the piston creates a force tending to lift the piston. Counteracting this force is the weight of the piston and the force of a compression spring that is compressed by the piston rising; because the spring is operating over a very small part of its possible range of extension, the spring force approximates to a constant force. Under steady state conditions, the upward and downward forces on the piston are equal and opposite, and the piston does not move.
If the airflow into the engine is increased – by opening the throttle plate, or by allowing the engine revolutions to rise with the throttle plate at a constant setting – the pressure drop in the venturi increases, the pressure above the piston falls, and the piston is sucked upward, increasing the size of the venturi, until the pressure drop in the venturi returns to its nominal level. Similarly, if the airflow into the engine is reduced, the piston will fall. The result is that the pressure drop in the venturi remains the same regardless of the speed of the airflow – hence the name "constant depression" for carburettors operating on this principle – but the piston rises and falls according to the speed of the airflow.
Since the position of the piston controls the position of the needle in the jet, and thus the open area of the jet, while the depression in the venturi sucking fuel out of the jet remains constant, the rate of fuel delivery is always a definite function of the rate of air delivery. The precise nature of the function is determined by the tapered profile of the needle. With appropriate selection of the needle, the fuel delivery can be matched much more closely to the demands of the engine than is possible with the more common fixed-venturi carburettor, an inherently inaccurate device whose design must incorporate many complex fudges to obtain usable accuracy of fuelling. The well-controlled conditions under which the jet is operating also make it possible to obtain good and consistent atomisation of the fuel under all operating conditions.
This self-adjusting nature makes the selection of the maximum venturi diameter (colloquially, but inaccurately, referred to as "choke size") much less critical than with a fixed-venturi carburettor.
To prevent erratic and sudden movements of the piston, it is damped by light oil in a dashpot (under the white plastic cover in the picture), which requires periodic topping-up.
A major drawback of the constant-depression carburettor is its unsuitability in high-performance applications.[citation needed] Since it relies on restricting air flow to produce enrichment during acceleration, the throttle response lacks punch. By contrast, the fixed choke design adds extra fuel under these conditions using its accelerator pump.
A carburetor or carburettor is a device that mixes air and fuel for internal combustion engines in an appropriate air–fuel ratio for combustion. The term is sometimes colloquially shortened to carb in the UK and North America or to carby in Australia.
A float chamber is a device for automatically regulating the supply of a liquid to a system. It is most typically found in the carburettor of an internal combustion engine, where it automatically meters the fuel supply to the engine. However, this arrangement is found in many automatic liquid systems, for example the cistern of most toilets could be said to be a type of float chamber.
Aircraft engine controls provide a means for the pilot to control and monitor the operation of the aircraft's powerplant. This article describes controls used with a basic internal-combustion engine driving a propeller. Some optional or more advanced configurations are described at the end of the article. Jet turbine engines use different operating principles and have their own sets of controls and sensors.
Rootes Arrow was the manufacturer's name for a range of cars produced under several badge-engineered marques by the Rootes Group from 1966 to 1979. It is amongst the last Rootes designs, developed with no influence from future owner Chrysler. The range is almost always referred to by the name of the most prolific model, the Hillman Hunter.
The Jaguar XK is an inline 6-cylinder dual overhead camshaft (DOHC) engine produced by Jaguar Cars between 1949 and 1992. Introduced as a 3.4-litre, it earned fame on both the road and track, being produced in five displacements between 2.4 and 4.2-litres for Jaguar passenger cars, with other sizes being made by Jaguar and privateers for racing. A de-rated version was also used in certain military vehicles built by Alvis and Daimler.
The Sunbeam Alpine is a two-seater sports roadster/drophead coupé that was produced by the Rootes Group from 1953 to 1955, and then 1959 to 1968. The name was then used on a two-door fastback coupé from 1969 to 1975. The original Alpine was launched in 1953 as the first vehicle from Sunbeam-Talbot to bear the Sunbeam name alone since Rootes Group bought Clément-Talbot, and later the moribund Sunbeam from its receiver in 1935.
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Carburetor, carburettor, carburator, carburettor heat is a system used in automobile and piston-powered light aircraft engines to prevent or clear carburetor icing. It consists of a moveable flap which draws hot air into the engine intake. The air is drawn from the heat stove, a metal plate around the exhaust manifold.
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Miss Shilling's orifice was a very simple technical device made to counter engine cut-out in early Spitfire and Hurricane fighter aeroplanes during the Battle of Britain. While it was officially called the R.A.E. restrictor, it was referred to under various names, such as Miss Tilly's diaphragm or the Tilly orifice in reference to its inventor, Beatrice "Tilly" Shilling.
The Hillman Super Minx is a family car which was produced by Hillman from 1961 to 1967. It was a slightly larger version of the Hillman Minx, from the period when the long-running Minx nameplate was applied to the "Audax" series of designs.
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The Reece-Fish carburettor was a carburettor used by Mini Se7en racers in the 60s and 70s.
SU carburettors were a British manufacturer of constant-depression carburettors. Their designs were in mass production during most of the twentieth century.
Of the three types of carburetors used on large, high-performance aircraft engines manufactured in the United States during World War II, the Bendix-Stromberg pressure carburetor was the one most commonly found. The other two carburetor types were manufactured by Chandler Groves and Chandler Evans Control Systems (CECO). Both of these types of carburetors had a relatively large number of internal parts, and in the case of the Holley Carburetor, there were complications in its "variable venturi" design.
Société du carburateur Zénith was a French corporation specialized in the making of carburettors for both automotive and aerospace industries. Created in Lyon in 1909 by car manufacturer Rochet-Schneider, it was taken over in 1970 by German company DVG. One of the main carburettor manufacturers of the 20th century, it had factories in Lyon and abroad, including in the United States and the United Kingdom.
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