Internal Combustion Engines Flashcards
When working on large engines it may be required to crawl into the engine or turn it over while performing checks. What extra precautions are take when performing these tasks?
Make sure to disable all starting motors, lock out tag out. Starting mechanisms may be pressurized gas on air injection or electric start motors.
What do you need to do when climbing into a crank case?
- inform workers you are entering
- pin, lock, and tag flywheel before entering
If flywheel has been removed or that have no provisions for locking what should you do?
Block engine under the throws of the crank shaft
Parts of an old engine image
Large stationary engines have one head per cylinder. Smaller engines may have?
One common cylinder head to cover all the cylinders
The block is?
Main structure of the engine that supports all working parts to keep them in alignment
Piston rings help seal the in the burning gases to harness as much energy as possible. But they also:
- Control oil consumption
- transfer heat from the piston to the engine block
Connecting Rod is between the piston pin(wrist pin) and?
Crankshaft
Crankshaft changes the linear motion of the piston to?
Continuous usable rotary motion
Camshafts (cams) do what?
Opens and closes the intake and exhaust valves.
Can have extra lobes on it to operate gas valves, air valves, or fuel injectors
Lobes of the of the cam push on _______, which push on the push rods and rocker arms.
Lifters
What is the purpose of the rocker arm?
Change the direction of motion and open valves
What is the purpose of a balancer?
Also known as harmonic balancer, vibration dampener, or torsional vibration dampener.
To reduce crankshaft torsional vibration
What is the purpose of timing gears?
Link the crankshaft, camshaft, balance shafts, ignition systems and other accessories so that all the events in the engine occurs at the correct time
Smaller engines use timing gears while larger engines use?
Chain or belt drives
The engine is a mechanical device that converts ___________ energy stored in a fuel to heat and then to mechanical energy.
Chemical
Engines can be external combustion such as a ________ or internal combustion such as_________.
Steam engine
Gas and diesel engines
What is a motor ?
A mechanical device that converts fluid or electrical energy into mechanical.
A over square engine has a?
(Many high speed engines in cars and small engines are over square)
Larger bore diameter than stroke length
Square engines have?
Same dimensions for bore diameter and stroke length.
Most diesel engines have a under square engine. What does this mean?
Has a longer stroke length than a bore diameter.
Piston displacement of an engine cylinder is the volume swept by the piston when making one complete stroke. What is the formula?
Piston displacement = area of bore x length of a stroke
What is the difference between piston displacement and engine displacement?
Engine displacement is the volume swept by all the pistons in the engine. This is how engines are measure.
Cubic inches, cubic centimetres or litres.
What is clearance volume?
Volume remaining above the piston at TDC.