Exam 30: Common Rail Systems

Technician A says that most transfer pumps used on diesel CR systems are of the external gear type. Technician B says that most transfer pumps used on diesel CR systems use a non-positive pumping principle. Who is correct?

Technician A says that an advantage of EHIs over standard hydraulic injectors, is the absence of injection lag. Technician B says that EHIs are capable of multipulse injections within a single cycle. Who is correct?

Technician A says that all current diesel CR fuel systems use a transfer pump. Technician B says that Caterpillar flange mount their transfer pump to the CR high pressure pump. Who is correct?

What component is used to control the actual rail pressure of a CR diesel fuel system?

What type of injectors are used in a typical diesel CR system?

What is used to time a Caterpillar CR fuel system high pressure pump to the engine?

How many plungers are used in the high pressure section of a Bosch radial piston pump?

Which of the following is another way of saying base timing when referring to multipulse capable, CR fuel systems?

Which of the following is the ECM output used to manage rail pressure at any given moment of operation in a diesel CR fuel system?

What is used to switch an electrohydraulic injector (EHI) used in a typical CR fuel system?

?Which of the following engine OEMs uses a Delphi CR fuel system?

What is the function of the admission valve used in some diesel CR fuel systems?

If actual rail pressure falls below desired rail pressure in a diesel CR system, which of the following should occur?

Technician A says that the ECMs used on commercial truck applications of diesel CR are networked on the CAN-C bus. Technician B says that the diesel engine ECMs used on automobile and light truck applications of diesel CR are networked exclusively by the J1939 bus.Who is correct?

Technician A says that the actuation voltage used to drive CR electrohydraulic injectors (EHIs) is typically around 100 volts when they use solenoid actuators. Technician B says that EHI piezo actuator resistance reading tend to be higher solenoid-actuated EHIs, for EHIs that use piezo actuators is usually much higher than 100 volts. Who is correct?

Technician A says that CR EHIs with piezo actuators respond faster to energization by the injector drivers than those with solenoid actuators. Technician B says that current CR EHIs using piezo actuators tend to be slimmer and more compact than those with solenoid actuators. Who is correct?

Technician A says that fuel delivery timing in diesel CR fuel systems is limited by cam profile. Technician B says that a major advantage of diesel CR systems is their ability to manage fuel injection pressures without regard to engine rpm. Who is correct?

Technician A says that in a diesel CR fuel system, the rail supplies all of the injectors required to fuel the engine. Technician B says that the rail pressures in a diesel CR fuel system are widely variable. Who is correct?

What type of high pressure pump do Caterpillar use in their CR fuel systems?

Technician A says that adaptive trim (A-Trim) evaluates and corrects EHI fuel flow at set intervals to ensure balanced cylinder fueling. Technician B says the A-Trim feature makes initial fuel flow programming (E-Trim/ QR-codes/ Cal-codes) unnecessary. Who is correct?