MDE Unit 5 injectors Flashcards

Purpose of the Delivery Valve in Bosch or Jerk Type Fuel Injection Pumps

Question: What is the purpose of the delivery valve in Bosch or Jerk type fuel injection pumps?

B) To prevent fuel leakage back into the pump after injection

Effects of Advanced Fuel Injection in Four-Stroke Engines

Question: What are the effects of advanced fuel injection in a four-stroke engine?

B) Improved power output and reduced exhaust emissions

Preventing Fuel Spray from High-Pressure Pipe Failure in Scroll Type Fuel Injection Pumps

Question: In scroll type fuel injection pumps, how is fuel oil prevented from spraying out if the high-pressure pipe fails in service?

A) By using a pressure relief valve to divert excess fuel

1. Operation of a Diesel Engine Fuel Nozzle

Question: What is the primary function of a diesel engine fuel nozzle?

B) To inject fuel into the combustion chamber at high pressure

Question 2: Which defect in a fuel injector can cause fuel to leak into the combustion chamber continuously?

C) Leaking nozzle seals

Question 5: What is a possible defect in fuel injectors that may result in a rough engine idle and excessive exhaust smoke?

B) Leaking nozzle tip

Effects of Low Compression Pressure in Four-Stroke Engines

Question: What are the effects of low compression pressure in a four-stroke engine?

A) Increased fuel consumption and reduced power output

3. Fuel Nozzle Construction

Question: Which component of a diesel engine fuel nozzle is responsible for controlling the spray pattern of the fuel?

A) The nozzle tip

5. Common Issues with Diesel Fuel Nozzles

Question: What is a common issue that can affect the performance of a diesel engine fuel nozzle?

A) Clogged nozzle orifices

Understanding Atomization

Question: What is meant by atomization in the context of diesel engine fuel injection?

B) The process of breaking down fuel into fine droplets for efficient mixing with air

Question 3: What defect can lead to erratic engine operation and knocking?

A) Incorrect spray pattern

Fuel Metering in Scroll Type Fuel Pumps

Question: How does a scroll type fuel pump meter fuel for high and low loads?

C) By varying the displacement of the scroll mechanism

Defects in Main Engine Fuel Injectors

Question 1: What is a common defect in fuel injectors that results in poor engine performance and increased exhaust smoke?

A) Clogged nozzle orifices

4. Effects of Fuel Pressure on Nozzle Operation

Question: How does high fuel pressure affect the operation of a diesel engine fuel nozzle?

B) It increases the spray pattern's spread and improves atomization

2. Purpose of Fuel Atomization

Question: Why is fuel atomization important in a diesel engine fuel nozzle?

B) To ensure the fuel mixes thoroughly with air for efficient combustion

Components of a Scroll Type Fuel Pump

Question: Which of the following labels the MAIN components of a scroll type fuel pump?

A) Scroll mechanism, camshaft, delivery valve, and pump housing

Purpose of the Delivery Valve in Scroll Type Fuel Injection Pumps

Question: What is the purpose of the delivery valve in scroll type fuel injection pumps?

C) To prevent backflow of fuel from the high-pressure side to the low-pressure side

Fuel Metering in Scroll Type Fuel Pumps

Question: How does a scroll type fuel pump meter fuel for high and low loads?

C) By varying the displacement of the scroll mechanism

Controlling Delivered Fuel Quantity in Bosch or Jerk Type Pumps

Question: In Bosch or Jerk type fuel injection pumps, how is the delivered quantity of fuel oil controlled?

C) By changing the position of the plunger within the pump cylinder

Understanding Penetration

Question: What does the term "penetration" refer to in the context of diesel engine fuel injection?

A) The depth to which fuel droplets penetrate into the combustion chamber

Effects of Retarded Fuel Injection in Four-Stroke Engines

Question: What are the effects of retarded fuel injection in a four-stroke engine?

A) Increased engine knocking and reduced power output

Varying Delivered Quantity in Scroll Type Fuel Injection Pumps

Question: In scroll type fuel injection pumps, how is the delivered quantity of fuel varied?

C) By modifying the position of the scroll or cam mechanism

Defects in Diesel Engine Fuel Nozzles

Question: What are some defects that diesel engine fuel nozzles may encounter during service? (Select THREE)

A) Clogged nozzle orifices, B) Leaking nozzle seals, D) Corrosion or erosion of the nozzle tip

Question 4: Which defect in a fuel injector can cause reduced fuel efficiency and increased fuel consumption?

B) Poor injector atomization

Main Components of a Fuel Injector Nozzle

Question: What are the MAIN components found in a cross section through the nozzle of a fuel injector? (Select THREE)

A) Nozzle tip, C) Needle valve, E) Spring

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