Ch1. Introduction to Diesel Engines

10. Stationary applications for Diesel engines include:

All of the above. •motorized pumps • starting units • industrial power takeoff units

2. Technician A says that when compared to a diesel, a gasoline engine delivers usable torque through a much wider rpm range. Technician B says gasoline engines also run quieter and offer faster acceleration. Who is correct.

Both

8. Technician A states that solidified wax can lead to fuel starvation or a no start condition. Technician B states that high temperatures can thin out diesel fuel and increase wear. Who is correct?

Both A and B

10. Define the terms mobile and stationary as they pertain to Diesel engine applications

In mobile applications, the engine propels the vehicle or machine upon which it is mounted from once location to another. In stationary applications, produce power from a fixed location for industrial use

9. All of the following are changes or systems designed in the last 10 years to improve the efficiency of Diesel engines except:

Inline fuel injection pumps

Nikolaus Otto

a German traveling salesman. engineer who successfully developed the compressed charge internal combustion engine which ran on petroleum gas and led to the modern internal combustion engine

Superchargers

a blower or pump which forces air into the cylinders at higher-than-atmospheric pressure. the increased pressure forces more air into the cylinder, thus enabling more fuel to be burned and more power to be produced. superchargers are dependent on engine speed and are most efficient at high engine speeds

Governor

a device that is used to sense changes in engine speed, then change the amount of fuel delivered to correct for the difference

Aftercoolers

a device used on turbocharged engines to cool air which has undergone compression

Sensors

a device used to detect a change in pressure, temperature, or mechanical movement and convert a reference voltage into a usable electrical signal

Emission Controls

employed to limit the discharge of noxious gases from the internal combustion engine and other components.

Diesel Fuel

contains more heat energy (BTUs or joules) than gasoline. much less volatile than gasoline.

2. List at least 4 reasons why Diesel engines are more efficient than gasoline engines

- the method of supplying fuel to the combustion chamber - the high compression ratio used in Diesel engines - the method of igniting the fuel in the combustion chamber - the grade and type of fuel used - the greater integral strength of Diesel engine components

1. Typical compression ratios used in heavy duty, high speed Diesel engines range between

13.5 and 22:1

6. What is the function of the governor in a Diesel engine?

A device capable of sensing engine speed and load and changing fuel delivery accordingly

8. What problems are associated with diesel fuel at both low temperatures and at very high temperatures?

At low temperatures, the wax in diesel fuel begins to solidify into crystals that can block fuel flow through filters, lines, and injectors. High fuel temperatures above 100degrees F (38degreesC) can also thin out the diesel fuel and reduce power output

7. Diesel fuel contains more ______ than gasoline

BTUs or Joules

6. All of the following are characteristics of Diesel engines except:

Diesel engines operate at lower compression ratios than gasoline engines

5. There is always an _____ of combustion air in a Diesel engine

Excess

3. In a Diesel engine, the _______ is not mixed with air prior to entering the combustion chamber

Fuel

4. In a Diesel engine, speed is controlled by regulating the amount of ______ delivered to the cylinder

Fuel

9. Who was the first engineer to develop a compact, reliable diesel fuel injection pump?

Robert Bosch

3. Technician A says unit fuel injectors are being used on Diesel engines because they are capable of attaining higher injection pressures that lead to reduced emissions. Technician B says that inline injection pumps are capable of attaining higher injection pressures than unit fuel injections. Who is correct?

Technician A only

4. Technician A says that aftercoolers are used to cool the diesel fuel that returns to the fuel tank from the injectors. Technician B says that aftercoolers are used to cool the air supplied to the engine so it is denser and contains more oxygen. Who is correct?

Technician B only

5. Technician A states that both four stroke and two stroke Diesel engines are used for high horsepower Diesel engines. Technician B states that only four cycle engines are used for high horsepower diesels. Who is correct?

Technician B only

7. All of the following are drawbacks to the Diesel engines except:

They offer faster acceleration than gasoline engines

Turbochargers

a turbine device that utilizes exhaust pressure to increase the air pressure going into the cylinders. used particularly in reference to movement of air in the cylinder and combustion chamber

Solid Fuel Injection

allows diesel fuel to be injected directly into the combustion chamber without using an air compressor

Electric Ignition

an automotive ignition in which electrical pulses are generated electronically, usually by transistors controlled by sensing devices, without the use of mechanically actuated breaker points

Power Takeoff (PTO)

an auxiliary drive that eliminates the need for a second engine to power any needed accessories

Four-Stroke Cycle

an engine design where a power pulse occurs every other revolution of the crankshaft. these strokes are 1. intake stroke 2. compression stroke 3. power stroke 4. exhaust stroke

Internal Combustion Engine

an engine that burns fuel within itself as a means of developing power

Two-Stroke Cycle

an engine that requires one complete revolution of the crankshaft to fire each piston once. an engine requiring only one complete revolution of the crankshaft to complete the cycle of events

Diesel Engine

an engine that uses diesel oil for fuel. a diesel engine injects fuel oil directly into the cylinders. the compression is so great that the air itself is hot enough to ignite the diesel fuel without a spark.

1. What is a Diesel engine?

an internal combustion engine that uses the heat of compression to ignite a fuel charge

Actuators

any output device controlled by a computer

Power Units

are mounted on a stand, transmitting their power to the load through a coupler or driveline

Computer

calculates the ideal fuel and engine settings for these conditions, and electromagnetic actuators to make the necessary adjustments

Unit Fuel Injectors

capable of attaining higher injection pressures that inline pump fuel injection systems

Compression

opposite of tension. reduction in volume, such as compressing a gas. also applying pressure to a spring to reduce its length

Compression Ignition

principle used in diesel engines to ignite an air-fuel mixture by using heat of compression

Stationary Applications

produce power from a fixed location for industrial use

Electronically Controlled Fuel Injection Systems

similar to those that have been adopted by the automotive industry for gasoline engines. they use sensors to monitor operating conditions, a computer to calculate the ideal fuel and engine settings for these conditions, and electromagnetic actuators to make the necessary adjustments

Stroke

the distance the piston moves between TDC and BDC

Mobile Applications

the engine propels the vehicle or machine upon which it is mounted from one location to another

Rudolf Diesel

the father of the diesel engine. invented the diesel engine

Intake Stroke

the portion of the piston's movement that is devoted to drawing air into the combustion chamber

Exhaust Stroke

the portion of the piston's travel that is devoted to expelling the burned fuel charge

Power

the rate at which work is being done

Compression Ratio

the ratio of the maximum volume in an engine cylinder with the piston at Bottom Dead Center to the minimum volume in the cylinder with the piston at Top Dead Center