Basic Engines Review
What is the purpose of casting and forging numbers on a cylinder block and head?
It is a means of identification for the vehicle
What components determine firing order?
The camshaft and crankshaft determine firing order
How fast is the camshaft in relation to the crankshaft, how?
The camshaft is half the speed of the crankshaft because of gearing
In an engine with companion cylinders, if one cylinder is on the exhaust stroke , what is the companion on?
The companion is on the compression stroke
What is compression ratio?
The difference in volume in the cylinder from B.D.C. to T.D.C.
What is the formula used to calculate degrees of crankshaft rotation between power strokes?
720 degrees / # of cylinders
What is the mechanical efficiency on a gasoline engine?
90%
What is the difference between a cycle and a stroke?
A cycle is an operation from start to finish, a stroke is the movement of the piston from B.D.C. to T.D.C.
Which direction is the piston moving during each of the strokes?
-Down on intake -Up on compression -Down on power -Up on exhaust
Name the four events on a four stroke engine
-Intake -Compression -Power -Exhaust
What are the factors that influence compression ration?
-Piston dome size -Combustion chamber volume -Cylinder volume -Head gasket clearance -Deck clearance
How many camshaft revolutions are required to fire all the cylinders in a four stroke motor?
1 camshaft rotation or 360 degrees of rotation
What is the practical efficiency on a gasoline engine?
15%
What are the 4 degrees of bank on a 6 cylinder v-type motor?
15, 30, 60, and 90 degrees
How many crankshaft revolutions are required to fire all the cylinders in a four stroke engine?
2 crankshaft revolutions or 720 degrees
What is the thermal efficiency on a gasoline engine?
33%
If you know the C.I.D., how do you calculate the engine size in liters?
C.I.D. / 61.024
What is the formula to calculate C.I.D.?
C.I.D. = (Bore)^2 * .7854 * # of cylinders * stroke
What are companion cylinders?
Cylinders that travel from B.D.C. to T.D.C. together
In what types of engines are there companion cylinders?
Engines with an even number of cylinders
What is volumetric efficiency?
How well the motor breathes
What valve is hotter?
The exhaust valve
What valve is larger?
The intake valve
What is the purpose of the valves?
To allow allow air and fuel to flow in and exhaust to flow out
What is the purpose of the crankshaft?
To convert reciprocating motion into rotary motion
What is the purpose of a flat rate manual?
To get time estimates for jobs
What is the purpose of the camshaft?
To open and close the valves in the engine
What are the three types of four stroke motors?
V-type, inline, and horizontally opposed
From what position on the engine is the left and right bank determined on a v-type motor?
When behind the engine looking directly at the flywheel
What is valve overlap?
When both valves are open at the same time