Diesel Engines 1 Flashcards
What is happening during the induction stroke.
The inlet valve is open
The exhaust valve is closed
The piston is moving from top dead center to bottom dead centre sucking air in to the cylinder through the air intake.
What happens during the compression stroke?
Both valves are closed
The piston moves from bottom dead centre to top dead center compressing the air causing it to heat up then the injector sprays atomised fuel in to the cylinder just before the piston reaches TDC.
What happens during the power stroke?
After the fuel is injected it has a ignition delay before combusting forcing the piston down to bottom dead center turning the crankshaft.
What happens during the exhaust stroke?
The exhaust valve is open
The intake valve is closed
The piston moves from bottom dead centre to top dead centre to force the exhaust gases out of the exhaust manifold.
What is valve overlap and why do we use it?
Valve overlap is when the intake valve opens slightly near the end of the exhaust to push out all of the exhaust gases and cool the exhaust valve to prevent deformation
What are diesel engines used for in the RN?
1.Propulsion
2.Air compressors
3.Generating electricity
4.Fire pumps
Define the driven end of a engine.
The end of the engine with the flywheel which is connected to a load like a gearbox
Define the free end of a engine.
The end that is used to power ancillaries and control timing of them
What is the compression ratio of a desiel engine.
20:1
What does the engine block do?
It is the main body of the engine housing the cylinders and mounting ancillary components.
What is the job of the cylinder?
To be the compression chamber and dissapate heat from the piston and power stroke to the engine block.
How are cylinders labeled for inline engines?
They are labelled in series from the free end of the engine.
How are cylinders labelled in a v-engine?
The cylinders are separated into banks A and B.
Bank A is always on the left when looking from the free end the cylinders are the labeled in series in each bank
What is the role of the cylinder head?
To close of the combustion chamber and house the valves and fuel injectors.
What is the role of the cylinder head gasket?
A gasket between the cylinder head and engine block to prevent gas or fluid leaking it is also reinforced in high pressure areas with soft metals.