Exam 11: Hydraulic Nozzles

Technician A says that the nozzles used by DI combustion engines mix air and fuel faster and produce less combustion noise than nozzles used in IDI combustion engines. Technician B says that before the introduction of electronically controlled DI systems, IDI combustion engines produced less noise with fewer emissions and had higher maximum engine rpm than DI combustion engines did. Who is correct?

Technician A says that injection lag or delay is the time between the start of injection pressurization and the point when fuel is actually being delivered. Technician B says that the needle lift sensor provides an electrical signal to the electronic control module (ECM) that indicates nozzle-valve movement. Who is right?

Which of the following is not indicated by a distorted spray pattern?

Which of the following increases wear on nozzle valves and seats?

Compared to non-electronic DI engines, IDI engines had the advantage of operating at higher speeds with lower air-fuel ratios, noise, and noxious emissions due to the ability of the IDI chamber to rapidly:

The pressure required to open the nozzle valve of an injector, when compared to the pressure required to keep it open, is ______________.

A cylinder misfires under all load and speed conditions with burned piston crowns. Which of the following could be the cause?

Technician A says that nozzle opening pressure (NOP) is adjusted with selective shims placed on top of the nozzle spring. Technician B says that NOP is electronically controlled in some of the latest injectors. Who is correct?

What process enhances flow characteristics by removing resistance to fuel flow but also permits, in performance applications, increased fuel delivery?

Which of the following is NOT a benefit of finer atomization?

Hydraulic nozzles are composed of a nozzle valve and nozzle body. Technician A says that the needle valve is the valve in the nozzle that seals the end of the nozzle tip when it is not injecting fuel. Technician B says that there are 4 basic types of nozzles. Who is right?

Which of the following conditions is caused by a weak nozzle spring?

Technician A says that nozzle opening pressure (NOP) is adjusted with selective shims placed on top of the nozzle spring. Technician B says that NOP is electronically controlled in some of the latest injectors. Who is correct?

Which type of nozzle is used in a direct injection combustion?

Using which of the following, positioned beneath the nozzle, may also be helpful to evaluate spray angle and the uniformity of the spray pattern?

Technician A says that servo-hydraulic injectors use hydraulically balanced nozzle valves. Technician B says that servo-hydraulic injectors require piezoelectric actuators. Who is correct?

Injection delay is caused by _________.

The subject of balanced multi-orifice injectors is being discussed. Technician A says that the Delphi E3 unit injector is an example of a nozzle with electronically controlled variable NOP (Nominal Opening Pressure). Technician B says that some injectors use hydraulically balanced nozzle valves with servo actuators, but can also electronically vary nozzle opening until injection pressures. Who is right?

Technician A says that a driver may be correct when they report that an engine has less power after the injector has been replaced. Technician B says that fuel consumption should decrease after replacing worn-out injectors. Who is correct?

Technician A says that DI combustion chambers use pintle spray nozzles. Technician B says that only multi-orifice nozzles are used in DI combustion engines. Who is correct?