DIESEL ENGINE Flashcards
1
Q
Most power facilities require some type of _____ to supply mechanical power for pumping, electric power generation, operation of heavy equipment, and to act as a backup electrical generator for _______ during the loss of the normal power source.
A
PRIME MOVER, EMERGENCY USE
2
Q
T or F. Diesel engines are small, expensive, powerful, fuel efficient, and extremely reliable.
A
FALSE
INEXPENSIVE
3
Q
In the early 19th century, the modern engine came about as the result of the _________ principles first proposed by Sadi Carnot
A
INTERNAL COMBUSTION
4
Q
_____ applied Sadi Carnot’s principles into a patented method of combustion that has become known as the diesel cycle.
A
DR. RUDOLF DIESEL
5
Q
Dr. Diesel’s first engine run on ______ and used a compression pressure of _____ psi to increase its theoretical efficiency.
A
COAL DUST, 1500
6
Q
After recovering, Diesel tried again using _____ as the fuel, adding a cooling water jacket around the cylinder, and lowering the compression pressure to _____ psi.
A
OIL, 550
7
Q
Production rights to the engine were sold to _______.
A
ADOLPHUS BUSH
8
Q
A diesel engine, when compared to a gasoline engine of equal horsepower, is _____ due to stronger, heavier materials used to withstand the greater dynamic force from the ______ combustion pressure present in the diesel engine
A
HEAVIER, HIGHER
9
Q
T or F. The greater combustion pressure is the result of the higher compression ratio used by diesel engine
A
TRUE
10
Q
The measure of how much the engine compresses the gasses in the engine’s cylinder.
A
COMPRESSION RATIO
11
Q
In a diesel engine, compression ratio ranging from ____ to as high as ____ are commonly used.
A
14:1, 24:1
12
Q
______ engines are self-speed-limiting, due to the method the engine uses to control the amount of air entering the engine.
A
GASOLINE
13
Q
Engine speed is indirectly controlled by the ______ in the carburetor. It limits the amount of air entering the engine
A
BUTTERFLY VALVE
14
Q
In a carburetor, the rate of air flow dictates the amount of _____ that will be mixed with the air.
A
GASOLINE
15
Q
Diesel engines are not self-speed-limiting because the air/oxygen entering the engine is always the ______. Therefore, the engine speed is limited solely by the amount of fuel being _____ into the engine cylinders.
A
MAXIMUM AMOUNT, INJECTED
16
Q
Diesel engines require a speed limiter commonly called the _____, to control the amount of fuel being injected into the engine
A
GOVERNOR
17
Q
A diesel engine does not require an ______ because the fuel is injected into the cylinder as the piston comes to the top of its compression stroke.
A
IGNITION SYSTEM
18
Q
The _____ is a single unit made from cast iron
A
CYLINDER BLOCK
19
Q
The _____ is usually located on the bottom of the cylinder block
A
CRANKCASE
20
Q
The crankcase is defined as the _____ around the crankshaft and crankshaft bearings.
A
AREA
21
Q
The _____ is located at the bottom of the crankcase
A
OIL PAN
22
Q
The oil pan collects and stores the engine’s supply of ______.
A
LUBRICATING OIL
23
Q
One of two types of cylinders used in diesel engines is each cylinder is _____ into the block casting making the block and cylinders an integral part.
A
BORED
24
Q
T or F. In the second type of cylinders used in diesel engines, machined steel sleeve is pressed into the block casting to form the cylinder.
A
TRUE
25
The _____ provides the engine with the **cylindrical structure** needed to **confine the combustion gasses** and act as a **guide** for the engine's pistons.
CYLINDER SLEEVE OR BORE
26
A ____ sleeve is surrounded by the metal of the block and does **not come in direct contact** with the engine's coolant (water)
DRY
27
A ____ sleeve comes **in direct contact** with the engine's coolant.
WET
28
The **volume** enclosed by the sleeve or bore is called the ______ and is the space where the **fuel is burned**
COMBUSTION CHAMBER
29
In either type of cylinder, ***sleeved*** or ***bored***, the **diameter** of the cylinder is called the _____ of the engine and is stated in _____.
BORE, INCHES
30
In an ____ engine, **all cylinders** are in a **row**
IN-LINE
31
In a ____ engine, the **cylinders** are arranged in **two rows** set at an angle to each other that **align** to a **common crankshaft**
"V" TYPE
32
Each group of cylinders making up one side of the "V" is referred to as a _______.
BANK OF CYLINDERS
33
It transforms the energy of the **expanding gasses** into **mechanical energy**
PISTON
34
Pistons are made of ______ or _____ alloys.
ALUMINUM, CAST-IRON
35
To **prevent the combustion gases** from **bypassing the piston** and to **keep friction to a minimum**, each piston has several _____ around it.
METAL RINGS
36
Most diesel engine pistons have several rings, usually _____, with **each ring performing a distinct function**
2 TO 5
37
Functions of Piston Rings
1. Act **to reduce friction** by minimizing the contact area between the piston and the cylinder wall.
2. Act as the **pressure seal** (Top ring)
3. Act as a **wiper ring** to remove and **control the amount of oil film** on the cylinder walls (Intermediate ring)
4. Act as an **oiler ring** and ensures that a supply of **lubricating oil is evenly deposited** on the cylinder walls (Bottom ring)
38
It connects the piston to the crankshaft
CONNECTING ROD
39
Some diesel engine _____ are **drilled down** the center to allow oil to travel up from the crankshaft and into the piston pin and piston for lubrication
CONNECTING RODS
40
It transforms the **linear motion** of the pistons into a **rotational motion** that is transmitted to the load
CRANKSHAFT
41
Crankshafts are made of ______.
FORGED STEEL
42
The **rod bearings** are _____, or _____, from the center of the crankshaft.
ECCENTRIC, OFFSET
43
It converts the **reciprocating (up and down) motion** of the piston into a **rotary motion** of the crankshaft
OFFSET
44
The amount of offset determines the ______ (distance the piston travels) of the engine
STROKE
45
The crankshaft **does not ride** directly on the **cast iron block** crankshaft supports, but **rides** on ________ material.
SPECIAL BEARING
46
The connecting rods also have _____ inserted between the crankshaft and the connecting rods.
BEARINGS
47
The crankshaft is **drilled** with _____ that allow the engine to **feed oil** to each of the crankshaft bearings and connection rod bearings and up into the connection rod itself.
OIL PASSAGES
48
The crankshaft has **large weights** called ______, that **balance** the weigh of the connecting rods.
COUNTERWEIGHTS
49
It is located on one end of the crankshaft.
FLYWHEEL
50
Three Purposes of a Flywheel
1. Through its ***inertia***, it **reduces vibration** by smoothing out the power stroke as each cylinder fires
2. It is the ***mounting surface*** used to **bolt the engine up** to its load
3. On some diesels, it has ***gear teeth*** around its perimeter that **allow the starting motor to engage** and crank the diesel. **KICKSTART ROTATION**
51
Functions of Cylinder Heads
1. Provide the **top seal** for the cylinder sleeve or bore
2. Provide the structure holding exhaust valves (and intake valves where applicable), the fuel injector, and necessary linkages.
52
In one method to manufacture the cylinder heads, each cylinder has its own _______, which is **bolted** to the block. This method is used primarily on the _____ diesel engines.
HEAD CASTING, LARGER
53
The method of casting the cylinder head as **one piece** is used on _____ engines.
SMALLER
54
_____ are mechanically opened and closed to admit and exhaust the gases as needed.
VALVES
55
The valves are located in the _____ of the engine.
HEAD CASTING
56
It is the point at which the **valve** seals against the head
VALVE SEAT
57
A _____ is a long bar with **egg-shaped eccentric lobes**, one lobe for each valve and fuel injector.
CAMSHAFT
58
T or F. For a diesel engine to operate, all of its components must perform their functions at very **precise intervals** in relation to the motion of piston. Therefore, a **crankshaft** is used.
FALSE
**CAMSHAFT**
59
As the camshaft is rotated, the _____ is forced up and down as it follows the profile of the cam lobe.
FOLLOWER
60
The followers are connected to the engine's valves and fuel injectors through various types of **linkages** called _____ and _____.
PUSHRODS & ROCKER ARMS
61
The _____ transfer the **reciprocating motion** generated by the camshaft lobes to the valves and injectors, opening and closing them as needed.
PUSHRODS & ROCKER ARMS
62
Because an engine experiences fairly large changes in temperature, its components must be designed to allow for _____.
THERMAL EXPANSION
63
_____ is the term given to the "**slop**" or "**give**" in the valve train before the cam actually starts to open the valve.
VALVE LASH
64
The camshaft is driven by the **engine's crankshaft** through a series of gears called _____.
IDLER GEARS AND TIMING GEARS
65
T or F. To increase the flexibility in timing the valve opening, valve closing, and injection of fuel, and to increase power or to reduce cost, and engine may only have **one camshaft**.
FALSE
**ONE OR MORE**
66
T or F. In the larger engines, the intake valves, exhaust valves, and fuel injectors may **share a common camshaft** or **have independent camshafts**.
TRUE
67
This major component **compresses the incoming fresh air** for delivery to the cylinders for combustion, and is part of the air intake system.
BLOWER
68
(5) Diesel Engine Support Systems
1. **C**ooling
2. **L**ubricating
3. **F**uel Injection
4. Air **I**ntake
5. Air **E**xhaust
69
(4) Major Components of a Cooling System
1. Water Pump
2. Radiator or Heat Exchanger
3. Water Jacket
4. Thermostat
70
(2) Purposes of Engine Lubrication
1. To **lubricate** the bearing surfaces
2. To **cool** the bearings by absorbing the friction-generated heat
71
Oil is accumulated and stored in the _____ where one or more oil pumps take a suction and pump the oil through one or more oil filters.
ENGINE'S OIL PAN
72
The _____ clean the oil and remove any metal that the oil has picked up due to wear. The cleaned oil then flows up into the _____.
FILTERS, ENGINE'S OIL GALLERIES
73
A _____ maintains oil pressure in the galleries and returns oil pan upon high pressure.
PRESSURE RELIEF VALVE(S)
74
T or F. In **small** engines, the oil is cooled before being distributed into the block. This is accomplished by either an internal or external oil cooler.
FALSE
MEDIUM TO LARGE
75
T or F. Because diesel engines rely on injectors which are precision components with extremely tight tolerances and very small injection hole(s), the fuel delivered to the engine must be extremely clean and free of contaminants.
TRUE
76
(2) Purposes of a Fuel System
1. To **supply the fuel** to run the engine
2. To **act as a coolant** to the injectors
77
Because a diesel engine requires close tolerances to achieve its compression ratio, and because most diesel engines are either turbocharged or supercharged, the air entering must be _____, _____, and _____.
CLEAN, FREE OF DEBRIS, AS COOL AS POSSIBLE
78
(2) Types of Air Intake System
WET OR DRY
79
In a _____, the air is sucked or bobbled through a housing that holds a bath of oil such that the dirt in the air is removed by the oil in the filter. The air then flows through a **screen-type** material to ensure any entrained oil is removed from the air.
WET FILTER INTAKE SYSTEM
80
In a _____, paper, cloth, or a metal screen material is used to catch and trap dirt before it enters the engine (similar to the type used in automobile engines).
DRY FILTER SYSTEM
81
Aside from cleaning the air, the intake system is usually designed to _____ from as far away from the engine as practicable, usually just outside of the engine's building or enclosure.
INTAKE FRESH AIR
82
T or F. The reason for ensuring that an engine's air supply is as cool as possible is that cool air is **less** dense than hot air.
FALSE
MORE
83
T or F. Cool air provides more oxygen per cylinder change than less dense, hot air. Therefore, more oxygen means a more efficient fuel burn and more power.
TRUE
84
It is the component that directs the fresh air to each of the engine's intake valves or ports.
MANIFOLD OR AIR BOX
85
(2) Types of Air Intake System
1. Turbocharging
2. Supercharging
86
If the engine is turbocharged or supercharged, the fresh air will be compressed with a _____ and possibly _____ before entering the intake manifold or air box.
BLOWER, COOLED
87
_____ an engine occurs when an engine's own exhaust gases are forced through a turbine (impeller), which rotates and is connected to a second impeller located in the fresh air intake system.
TURBOCHARGING
88
(2) Functions of compressed air
1. Increase the engine's available power
2. Increase intake pressure
89
T or F. Turbocharging is commonly founds on high power four-stroke engines.
TRUE
90
This type of air intake system performs the same function as turbocharging an engine. The only difference is the source of power used to drive the device that compresses the incoming fresh air.
SUPERCHARGING
91
In a supercharged engine, the air is commonly compressed in a device called a _____.
BLOWER
92
T or F. Supercharging is more commonly found on **four-stroke** engines where the higher pressures that a supercharger is capable of generating are needed.
TWO-STROKE
93
(3) Functions of a Diesel Engine Exhaust System
1. The exhaust system **routes the spend combustion gases** away from the engine, where they are diluted by the atmosphere.
2. The exhaust system **confines and routes the gases** to the turbocharger, if used.
3. The exhaust system **allows mufflers** to be used to reduce the engine noise.
94
_____ are terms used to define the size of an engine.
BORE AND STROKE
95
It refers to the diameter of the engine's cylinder.
BORE
96
It refers to the distance the piston travels from the top of the cylinder to the bottom.
STROKE
97
This is the highest point of travel by the piston
TOP DEAD CENTER (TDC)
98
The lowest point of travel is called _____.
BOTTOM DEAD CENTER (BDC)
99
There are _____ of travel between TDC and BDC, or one stroke.
180 degrees
100
_____ refers to the total volume displaced by all the pistons during one stroke. This is usually given in cubic inches or liters.
DISPLACEMENT
101
Because the piston is connected to the crankshaft, any _____ of the piston corresponds directly to a specific number of _____.
LOCATION, DEGREES OF CRANKSHAFT ROTATION
102
It refers to the order in which each of the cylinder in the multicylinder engine fires (power stroke).
FIRING ORDER
103
It is the volume remaining in the cylinder when the piston is at TDC.
CLEARANCE VOLUME
104
T or F. Because of the **irregular shape** of the combustion chamber the clearance volume is calculated empirically by filling the chamber with a measured amount of fluid while the piston is at TDC. This volume is then added to the displacement volume in the cylinder to obtain the cylinders total volume.
TRUE
105
An engine's _____ is determined by taking the volume of the cylinder with piston at TDC and dividing the volume of the cylinder when the piston is at BDC.
COMPRESSION RATIO
106
_____ is the power transmitted to the pistons by the gas in the cylinders and is **mathematically calculated**.
INDICATED HORSEPOWER
107
_____ refers to the amount of usable power delivered by the engine to the crankshaft.
BRAKE HORSEPOWER
108
T or F. Indicated horsepower can be as much as **25%** higher than brake horsepower.
FALSE
15%
109
It is the ratio of an engine's brake horsepower and its indicated horsepower.
MECHANICAL EFFICIENCY
110
T or F. The mechanical efficiency of a four-cycle diesel is about 82 to 90 percent.
TRUE
111
_____ is a measure of the engine's ability to apply the power it is generating.
TORQUE
112
Fuel Rate
amount of fuel / power (kg/kW-h)
113
Heat Rate
energy chargeable / power (kJ/kW-h)
114
Thermal Efficiency
power / energy chargeable
115
Engine Efficiency
actual power / ideal power
