The Engine Flashcards
Valve overlap increases the ______ of charge induced into the cylinder, improves ______ of the waste gases, and aids ______ of the upper parts of the cylinder.
weight (or amount); scavenging; cooling
The onset of combustion at too early a point in the cycle through pre-ignition can lead to a loss of ______ and to serious engine ______.
power; damage
The heat energy from the combustion process causes the ______ of the gases in the confined space of the cylinder to rise suddenly, which pushes the piston down in the cylinder.
pressure
A two-stage energy conversion process is involved in the piston engine. ______ energy in the fuel is first converted to ______ energy by combustion, and then to ______ energy by the action of the piston.
Chemical; heat; mechanical
In aero engines, two ______ ______ are fitted to each cylinder to ignite the mixture at the right time.
spark plugs
In a typical piston aero-engine, the fuel-air mixture is ignited by ______ ______ situated on opposite sides of the cylinder head.
spark plugs
The pistons are normally cast from______ ______. Steel piston ______ seal the piston within the cylinder, preventing both the loss of combustion pressure and the passage of ______ into the combustion chamber.
aluminium alloy; rings; oil
Diesel engines use (compression / spark ignition). A typical system of preheating the combustion chamber to facilitate ignition when starting is to use ______ plugs.
compression; glow
The horizontally-opposed piston engine has its cylinders arranged (on each side of / above / below) the crankshaft?
on each side of
Valve lag involves the ‘late’ closing of the ______ valve on the induction stroke.
inlet
The camshaft rotates at (half / twice) the speed of rotation of the crankshaft.
half
Valve overlap involves the period when both valves are open for a short period around TDC at the end of the ______ stroke and at the beginning of the ______ stroke.
exhaust; induction
In the compression stroke, both valves are closed. The fuel-air charge becomes compressed and as a result its ______ rises considerably.
temperature
Cylinder heads are fitted at the top of each cylinder to enclose the ______ space. They are normally constructed of ______ alloy and also have a large number of ______ fins.
combustion; aluminium; cooling
During the induction stroke, the inlet valve is (closed / open). As the piston descends, pressure in the cylinder is (increased / lowered) and the fuel-air mixture flows in because the pressure in the intake manifold is (higher / lower).
open; lowered; higher
Valve lag allows more time for the fuel-air ______ to enter the cylinder.
charge
The piston engine burns a mixture of ______ and ______ in the combustion chambers.
fuel and air
One complete cycle of a four-stroke engine requires (one / two / four) complete revolutions of the crankshaft.
two
Detonation causes wildly oscillating ______ fluctuations within the cylinder and can lead to (overheating / overcooling), deterioration of ______ surfaces, and a (loss of / gain in) power.
pressure; overheating; bearing; loss of
In broad terms, a diesel aero engine can be expected to produce the same power as an (AVGAS / AVTUR) engine of more than (twice / three times / four time) its cylinder capacity.
AVGAS; twice
Cylinder barrels are normally constructed of ______ and have a large number of closely-spaced external cooling ______.
steel; fins
The connection between the connecting rod and the crankshaft is made through a (big end / main) bearing. The crankshaft is held in place by, and runs in, (big end / main) bearings.
big end; main
Pre-ignition is the ignition of the charge by some means (before / after) normal ignition is timed to occur.
before
The ideal spark advance will be somewhere between 45 and 5 degrees before TDC depending on a number of factors. To cope with these variables, most light aircraft engines have a fixed spark advance set at an optimum point of about ______ degrees before TDC.
25 degrees
