ENGINE FUEL PART 4

Maximum power is normally considered to be developed in a reciprocating engine with a air-fuel mixture ratio of approximately. 8:1. 12:1. 15:1.

One of the best ways to increase engine power and control detonation and preignition is to. enrich the fuel/air mixture. use water injection. lean the fuel/air mixture.

The device that controls the ratio of the air-fuel mixture to the cylinders is called a. throttle valve. mixture control. metering jet.

A punctured float in a float-type carburetor will cause the fuel level to. lower, and enrich the mixture. rise, and enrich the mixture. rise, and lean the mixture.

The primary purpose of the air bleed openings used with continuous flow fuel injector nozzles is to. provide for automatic mixture control. maintain constant fuel pressure. aid in proper fuel vaporization.

What component is used to ensure fuel delivery during periods of rapid engine acceleration?. Acceleration pump. Engine-driven fuel pump. Power enrichment unit.

A mixture ratio of 11:1 normally refers to. a stoichiometric mixture. 1 part air to 11 parts fuel. 1 part fuel to 11 parts air.

On an engine equipped with a pressure-type carburetor, fuel supply in the idling range is ensured by the inclusion in the carburetor of. a spring in the unmetered fuel chamber to supplement the action of normal metering forces. an idle metering jet that bypasses the carburetor in the idle range. a separate boost venturi that is sensitive to the reduced airflow at start and idle speeds.

An aircraft engine equipped with a pressure-type carburetor is started with the. primer while the mixture control is positioned at IDLE CUTOFF. mixture control in the FULL-RICH position. primer while the mixture control is positioned at the FULL-LEAN position.

If the main air bleed of a float-type carburetor becomes clogged, the engine will run. lean at rated power. rich at rated power. rich at idling.

Which of the following statements is true?. A positive displacement pump produces a continuous flow, but due to lack of a positive internal seal against slippage, its output will increase as pressure increases. In a positive displacement pump, slippage is substantial compared to the pump's volumetric output flow. If the output port were plugged, pressure would increase, and the pump pressure relief valve would close. In a positive displacement pump, slippage is negligible compared to the pump's volumetric output flow. If the output port were plugged, pressure would increase, and the pump pressure relief valve would open.

Most large aircraft reciprocating engines are equipped with which of the following types of engine-driven fuel pumps?. Rotary vane-type fuel pump. Centrifugal-type fuel pump. Gear-type fuel pump.

Which of the following best describes the function of an altitude mixture control?. Regulates the richness of the fuel/air charge entering the engine. Regulates the air pressure above the fuel in the float chamber. Regulates the air pressure in the venturi.

The back-suction mixture control system operates by. varying the pressure within the venturi section. varying the pressure acting on the fuel in the float chamber. changing the effective cross-sectional area of the main metering orifice (jet).

A pilot reports that the fuel pressure fluctuates and exceeds the upper limits whenever the throttle is advanced. The most likely cause of the trouble is. a ruptured fuel pump relief valve diaphragm. a sticking fuel pump relief valve. an air leak at the fuel pump relief-valve body.

The density of air is very important when mixing fuel and air to obtain a correct fuel-to-air ratio. Which of the following weighs the most?. 75 parts of dry air and 25 parts of water vapor. 100 parts of dry air. 50 parts of dry air and 50 parts of water vapor.

If fuel is found running from the carburetor with the engine not running, the likely cause is that the. float needle valve is not seated properly. float level is adjusted too low. main air bleed is clogged.

For what primary purpose is a turbine engine fuel control unit trimmed?. To obtain maximum thrust output when desired. To properly position the power levers. To adjust the idle RPM.

Idle cutoff is accomplished on a carburetor equipped with a back-suction mixture control by. introducing low pressure (intake manifold) air into the float chamber. turning the fuel selector valve to OFF. the positive closing of a needle and seat.

On a float-type carburetor, the purpose of the economizer valve is to. provide extra fuel for sudden acceleration of the engine. maintain the leanest mixture possible during cruising best power. provide a richer mixture and cooling at maximum power output.

Which of the following turbine fuel filters has the greatest filtering action of any present day filter type?. Micron filter. Plain screen mesh filter. Wafer screen filter.

The throttle valve of float-type aircraft carburetors is located. ahead of the venturi and main discharge nozzle. after the main discharge nozzle and ahead of the venturi. between the venturi and the engine.

Which statement is true regarding proper throttle rigging of an airplane?. The throttle stop on the carburetor must be contacted before the stop in the cockpit. The stop in the cockpit must be contacted before the stop on the carburetor. The throttle control is properly adjusted when neither stop makes contact.

Under which of the following conditions will the trimming of a turbine engine be most accurate?. High wind and high moisture. High moisture and low wind. No wind and low moisture.

What is the relationship between the accelerating pump and the enrichment valve in a pressure injection carburetor?. No relationship since they operate independently. Unmetered fuel pressure affects both units. The accelerating pump actuates the enrichment valve.

What should be checked/changed to ensure the validity of a turbine engine performance check if an alternate fuel is to be used?. Fuel specific gravity setting. Maximum RPM adjustment. EPR gauge calibration.

Which type of fuel control is used on most of today's turbine engines?. Electromechanical.. Mechanical. Hydromechanical or electronic.

It is necessary to control acceleration and deceleration rates in turbine engines in order to. prevent blowout or die-out. prevent overtemperature. prevent friction between turbine wheels and the case due to expansion and contraction.

A nine-cylinder radial engine, using a multiple-point priming system with a central spider, will prime which cylinders?. 1, 2, 3, 8, and 9. All cylinders. 1, 3, 5, and 7.

What is a characteristic of a centrifugal-type fuel boost pump?. It separates air and vapor from the fuel. It has positive displacement. It requires a relief valve.

Where physical separation of the fuel lines from electrical wiring or conduit is impracticable, locate the fuel line. below the wiring and clamp the line securely to the airframe structure. above the wiring and clamp the line securely to the airframe structure. inboard of the wiring and clamp both securely to the airframe structure.

One of the things a metering orifice in a main air bleed helps to accomplish (at a given altitude) in a carburetor is. pressure in the float chamber to increase as airflow through the carburetor increases. a progressively richer mixture as airflow through the carburetor increases. better fuel vaporization and control of fuel discharge, especially at lower engine speeds.

If an engine is equipped with a float-type carburetor and the engine runs excessively rich at full throttle, a possible cause of the trouble is a clogged. main air bleed. back-suction line. atmospheric vent line.

What are the positions of the pressurization valve and the dump valve in a jet engine fuel system when the engine is shut down?. Pressurization valve closed, dump valve open. Pressurization valve open, dump valve open. Pressurization valve closed, dump valve closed.