Chapter 21

Which does makes the volumetric efficiency of the reciprocating engine decrease? * Low cylinder head temperatures Improper valve timing Full throttle operation Sharp bends in the induction system High carburetor air temperatures When the piston reaches the bottom center it reverses direction and starts moving up on the compression stroke. TRUE OR FALSE? * Your answer What happens with the volumetric efficiency when the engine's heat increases? Your answer As an aircraft climbs, air density decreases, thereby decreasing the amount of air in the fuel/air mixture. This results in a vibrant air/fuel mixture which causes a reduction in engine power. TRUE OR FALSE? * Your answer

Answer the following statements by True or False: 1. Superchargers are used to increase the power of an IC engine by raising the intake pressure and thus allowing more fuel to be burned per cycle. 2. Scavenging is the process by which the oil rings scrape the lubricating oil from the cylinder wall and allow the oil to return to the oil pan. 3. The power output of a two-stroke engine equals that of a four-stroke engine for the same displacement. 4. After coolers are used after the compressor to drop the air temperature and thus increase its density. 5. The rotary engine has the advantages of better sealing of high pressure gases and less wear on seals.

A simple carburetor is adjusted for a 15.2:1 air-fuel ratio at sea level and 600F. Determine the air-fuel ratios at 10,000 feet, 16,000 feet and 20,000 feet altitudes. Ans. (a) 12.83; (b) 11.52; (c) 10.7

Identify the correct order of the cycles in the four-stroke engines analyzed in lab, with the first cycle beginning when the piston is at Top Dead Center and no air-fuel mixture is present in the combustion chamber. Combustion, Intake, Compression, Exhaust Intake, Compression, Combustion, Exhaust Intake, Combustion, Compression, Exhaust Intake, Combustion, Exhaust, Compression

I need the answer quickly

Which of the following is not a true statement about diesel engines?a. The operation and main components of a diesel engine are comparable to those of a gasoline engine. Diesel and gasoline engines are available as four- stroke combustion cycle engines. Diesel engines rely on glow plugs instead of spark plugs to initiate ignition. The compression ratio of diesel engines is typically three times that of a gasoline engine.

Which of the following are complexities that are ignored when assuming air-standard for an internal-combustion engine? Select all that apply. Variation of specific heat values with a change in temperature Changes in pressure during the power stroke (expansion) Changes in chemical composition due to combustion O Heat transfer through the piston or cylinder walls

tech a says that the float type carburetor is the least efficient design used on Briggs engines. Tech b says that Briggs carburetors typically have their mixture screws adjusted to 4 turns out. Who is correct?

How many degrees the crankshaft will rotate with both the intake and exhaust valves seated when the intake opens 20 deg. BTDC, the exhaust opens 55 deg. BBDC, intake closes 25 deg. ABDC, and exhaust closes 45 deg. ATDC. (TYPE NUMBERS ONLY, AND THE UNIT IS DEG. AND ANSWER IN WHOLE NUMBERS ONLY) * Your answer On a four-stroke cycle reciprocating engine, which strokes are both valves open? * Power Compression Intake Exhaust Ignition The primary concern in the firing order of the opposed engine is to keep the power impulses on adjacent cylinders as close as possible to obtain the most outstanding mechanical efficiency. TRUE OR FALSE? * Your answer A nine-cylinder engine with a bore of 5.5 inches and a stroke of 6 inches will have a total piston displacement of? (TYPE NUMBERS ONLY, AND THE UNIT IS CU. INCH AND ANSWER IN WHOLE NUMBERS ONLY) * Your answer