Diesel Engine Flashcards
The most commonly used prime mover
Diesel Engine
Available sizes of a Diesel Engine
Few to 10,000 hp
Relatively speaking, Diesel Engines are?
Small, Inexpensive, Powerful, Fuel Efficient, and Extremely Reliable if maintained properly
Modern Diesel engines came about as the result of?
Internal combustion principle by Sadi Carnot
Who is the inventor of Diesel Engines?
Dr. Rudolf Diesel
How do Diesel Engines operate?
The heat generated during the compression of the air-fuel charge caused ignition
What is the first fuel used on Dr. Diesel’s engine?
Coal Dust
What is the Compression pressure of the first Diesel engine?
1500 psi
How did the Diesel engine almost kill its inventor?
By exploding
What is the cause of the explosion of the first diesel engine?
Lack of cooling
What did Dr. Diesel use to improve the engine’s design?
Used oil as a fuel, added cooling water jacket around the cylinder, and lowering its compression to 550 psi
Production rights were sold to?
Adolphus Bush
(T or F) Diesel engines are heavier than gasoline engines of equal horsepower rating
True
How is the compression ratio measured?
By measuring how much the engine compresses the gasses in the engine’s cylinder
What is the Compression ratio of a gasoline engine?
Less than 10:1
What is the Compression ratio of an average gasoline engine car?
7:1
What is the range of Compression ratio of a diesel engine?
14:1 to 24:1
(T or F) Gasoline Engines are self-speed limiting
True
How are Gasoline engine’s speed controlled?
By butterfly valve in a carburetor
(T or F) Diesel Engines are self-speed limiting
F
(T or F) The air entering the Diesel engine always its maximum amount
T
(T or F) Diesel engines need speed limiters
T
What is the speed limiter used in a Diesel engine?
Governor
(T or F) Diesel engines need an ignition system
F
It is a single unit of cast iron block that provides oil and coolant passages and supports other parts of the engine.
Cylinder Block
This part is located at the bottom of the cylinder block and encloses the rotating crankshaft, counterweights, and directs returning oil into the oil pan.
Crankcase
It collects and stores the engine’s supply of oil.
Oil pan
It provides the engine the cylindrical structure needed to confine the combustion gasses and guides the engine’s pistons
Sleeve or Bore
How many types of cylinders are used on a diesel engine?
Two types
* Bored into the block (integral part)
* Machined steel sleeve (pressed into the block)
It is a type of sleeve that does not come in contact with a coolant.
Dry sleeve
It is a type of sleeve that does come in contact with a coolant.
Wet sleeve
It is the volume enclosed by the sleeve or bore
Combustion chamber
It is the diameter of the cylinder
Bore
It is a type of engine wherein all cylinders are in a row
In-line engine
It is a type of engine wherein it is arranged in two rows and set at an angle to align the common crankshaft
V-type
It is the group of cylinders making up one side
Bank of cylinders
It is a component that transforms the energy of the expanding gasses into mechanical energy
Piston
Pistons are commonly made out of?
Aluminum or Cast-iron alloy
It is a component that prevents the combustion gases and oil from bypassing
Piston rings
It is the coating used in piston rings
Chrome or molybdenum
How many piston rings do most Diesel engines have?
2 to 5
It is the ring that acts as a pressure seal
Top ring
It is the ring that acts as a wiper ring
Intermediate ring
It is the ring that acts as an oiler ring
Bottom ring
It is the part that connects the piston and crankshaft
Connecting rod
Connecting rods are made out of what material?
Drop-forged, heat treated steel
( T or F) Some diesel engine’s connecting rods have drilled down to the center to allow oil to travel from the crankshaft to the piston and piston pin
T
It transforms the linear motion of the pistons into rotational motion that’s transmitted to the load.
Crankshaft
The crankshaft rod bearing is _______ from the center of the crankshaft enabling it to convert the reciprocating motion of the piston into rotary motion of the crankshaft.
Offset/Eccentric
The crankshaft does not ride directly on the engine block but on a?
Special bearing material
The connecting rods also have _______ inserted between the crankshaft and connecting rods
Bearings
The crankshaft is drilled with ______ _______ to allow the engine to feed oil to the components
Oil passages
This is a component of a crankshaft that balances the weight of the connecting rods ensuring even force is applied during the rotation.
Counterweights
Three purposes of a flywheel
1st Reduces vibration by smoothing out the power stroke
2nd Mounting surface used to bolt the engine up to its load
3rd Allows the starting motor to engage and crank the engine
Functions of a cylinder head
1st Provides seal for the cylinder bore
2nd provide the structure holding the exhaust valves, fuel injector, and necessary linkages
Cylinder heads are manufactured in two ways, what are those?
1st bolted to the block
2nd cast as one piece
This part is mechanically opened or closed to admit or exhaust gas as needed.
Valves
It is a long bar with an egg-shaped eccentric lobe, one lobe for each valve and fuel injector
Camshaft
It is forced upside down as it follows the profile of the cam lobe
Follower
It is the linkages used to connect the valves and fuel injectors
Pushrods or rocker arms
It is applied to allow thermal expansion to happen in the rocker arm and valve
Valve lash
It is a series of gears which allows the camshaft to be driven by the crankshaft
Idle gears or timing gears
It compresses the incoming fresh air for delivery to the cylinders for combustion
Blower
Five supporting systems for a Diesel engine to operate
Cooling
Lubrication
Fuel injection
Air intake
Air exhaust
It is a support system to transfer waste heat out of the block and internals
Engine cooling system
This support system lets the parts to have a thin film of oil riding on it to reduce friction
Engine Lubrication
Two purposes of oil
Lubrication and cooling
It maintains oil pressure in the galleries and returns oil to the oil pan upon high pressure
Pressure relief valve
(T or F) In medium to large diesel engines the oil is also cooled before being distributed to the block
T
(T or F) The fuel system must deliver dirty fuel to the combustion chamber
F
Two purposes of fuel
Fuel for combustion
Cooling of the injectors
(T or F) The air entering the engine must be clean, full of debris, and cool
F
Types of Air filter
Wet - has a bath of oil
Dry - Made or paper, cloth, or metal screen
Why is the engine designed to intake cool air?
Cool air is more dense than hot air, it provides more oxygen per cylinder charge compared to hot air which has less dense air
Two functions of compressed air
1st increases the engine’s available power
2nd increase intake pressure
Types of Air Intake Systems
Turbocharging
Supercharging
Three functions of exhaust system of a diesel engine
1st Routes the spent combustion gases away from the engine
2nd Confines and routes the gasses to the turbocharger, if available
3rd Exhaust systems allows mufflers to be used to reduce engine noise
How much travel is between TDC and BDC, or equal to a one stroke
180 degrees
It is the total volume displaced by all the pistons during one stroke
Engine Displacement
It refers to the order in which each of the cylinder in a multi-cylinder engine fires
Firing Order
It is the volume remaining in the cylinder when the piston is at TDC
Clearance volume
How is the clearance volume calculated while having an irregular-shaped combustion chamber?
By filling it with a measured amount of fluid
Formula of Compression Ratio
Compression Ratio = (Displacement volume + Clearance volume) / Clearance volume
It is the power transmitted to the piston by the gas in the cylinders
Indicated Horsepower
Refers to the usable power delivered by the engine to the crankshaft
Brake Horsepower
It is the ratio of an engine’s brake horsepower to the indicated horsepower
Mechanical Efficiency
It is the measure of the engine’s ability to apply the power it is generating
Torque
