Exam 9: Functions of High Pressure Fuel Systems

Which of the following is the most significant benefit of pilot injection?

Injection rate is reported in which of these values as compared with the delivery volume of the injection event?

Technician A says that fuel pressurized to thousands of pounds per square inch (psi) can easily penetrate the skin, causing bodily harm, blood poisoning, and even death. Technician B says that when checking for leaks from a high-pressure fuel system, use a small piece of cardboard or paper instead of the hand to detect the location of a leak. Who is right?

What is done when the road grade becomes steeper or additional freight and passengers are added to the vehicle?

In which of the following ways does the rate at which combustion occurs change when additional fuel is added to a cylinder?

A speed density algorithm is an example of a mathematical procedure used to calculate:

When referencing rate control of the injection system, the most meaningful definition is the quantity of fuel injected per:

How does pilot injection, also known as split-shot injection, reduce exhaust emissions?

What forms around the fuel droplet as it absorbs heat from the combustion chamber?

While discussing potential ways to increase power output from an engine, Technician A says that advancing injection timing a few degrees will increase power output. Technician B says that advancing injection timing a few degrees will reduce fuel consumption. Who is correct?

The discharge shape on mechanical fuel injection systems is achieved by using:

While discussing potential ways to increase power output from an engine, Technician A says that advancing injection timing a few degrees will increase power output. Technician B says that advancing injection timing a few degrees will reduce fuel consumption. Who is correct?

Using fine droplets also means that retarded injection timing can be used, to produce low:

Consider a diesel engine that has an increased load applied to it while its speed remains constant. Which of the following changes to injection timing would be expected?

While discussing the steps to perform when changing an injector in a late-model engine, Technician A says that uploading a fuel injector calibration code helps the engine to run more smoothly. Technician B says that replacing the old code with the one on the new injector enables the ECM to compensate for small variations to injection quantity unique to each injector. Who is correct?

The term "retarded injection timing" refers to injection timing occurring _________.

Two technicians are describing fuel atomization. Technician A says that the ignition delay period is also lengthened, leading to lower levels of combustion noise. Technician B says that finer atomization means fuel ignites sooner, burns faster, and burns more completely. Who is right?

What is observed when one or more cylinders are cut out and the engine maintains a set idle speed?

Technician A says that atomization can be reduced with high injection pressures. Technician B says that high pressure is necessary to break up the liquid fuel into a fine mist. Who is right?

While discussing the steps to perform when changing an injector in a late-model engine, Technician A says that uploading a fuel injector calibration code helps the engine to run more smoothly. Technician B says that replacing the old code with the one on the new injector enables the ECM to compensate for small variations to injection quantity unique to each injector. Who is correct?