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HET2 > 203f - Diesel Engine & Fuel Testing & Adjusting > Flashcards

203f - Diesel Engine & Fuel Testing & Adjusting Flashcards

1
Q

A properly tuned engine has what benefits? (4)

A
  • Low exhaust emissions
  • Efficient engine operation - fuel economy
  • Maintains rated power output
  • Reliable and maximum service life

203f pg. 2

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2
Q

An engine tune-up could include what services?

A
  • Valve & injector adjustment
  • Governor adjustment
  • Engine brake adjustment
  • Injection pump timing check
  • Injector nozzle test

203f pg. 2

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3
Q

Governors are designed to work through the full range of throttle travel. If throttle linkage wear affects the range of travel, what should be done before making adjustments?

A

Replace the throttle linkage

203f pg. 5

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4
Q

What do some throttle linkages use that allows full throttle travel regardless of engine movement in the chassis?

A

A spring-loaded overtravel device

203f pg. 5

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5
Q

What does a fuel injector cut-out test consist of?

A

Momentarily crack open one injection line at a time with engine running. A cylinder that exhibits no change in rpm indicates a faulty injector or other issues in that cylinder.

203f pg. 8

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6
Q

How could an infrared thermometer be used to test for misfiring cylinders?

A

Check exhaust manifold temperature at each cylinder. A drop of more than 50 degrees Celsius indicates a cylinder that is not firing correctly.

203f pg. 9

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7
Q

How is injector back leakage tested?

A

Bring the pressure up to 2000psi and let drop to 1500psi. Time the pressure drop.

203f pg. 10

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8
Q

What is the maximum allowed variation in cracking pressures between a set of injectors?

A

50 psi

203f pg. 11

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9
Q

What is injector nozzle chatter?

A

A series of popping or chattering sounds caused by the rapid pulsation of the needle.

203f pg. 12

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10
Q

How is injector needle seat to face leakage tested?

A

Maintain pressure at 150-200 psi lower than cracking pressure. Time for 10 seconds and check for leakage. There should be no leakage.

203f pg. 12

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11
Q

Why is injector back leakage important?

A

Back leakage fuel cools and lubricates the injector

203f pg. 13

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12
Q

To properly test and diagnose an engine for performance, you must put the engine under _____.

A

Load

203f pg. 14

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13
Q

What three basic components to dynos have?

A
  • A power absorption unit
  • A load control
  • A torque-measuring device

203f pg. 14

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14
Q

Two common types of load cells used in heavy-duty diesel engine dynos are:

A
  • Hydraulic
  • Electric

203f pg. 14

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15
Q

In a water brake dyno, engine power output is converted to ______ in the load cell.

A

Heat

203f pg. 15

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16
Q

What style of dyno has a permanent frame on the shop floor and requires long setup time?

A

Stationary dyno

203f pg. 18

17
Q

What style of dyno is usually compact, has integral instrumentation, and minimal hookup?

A

Portable dyno

203f pg. 17

18
Q

What style of dyno is embedded in the shop floor and has a set of rollers to support the rear wheels of the vehicle?

A

Chassis Dyno

203f pg. 19

19
Q

What style of dyno is typically used in the agricultural industry?

A

PTO dyno

203f pg. 20

20
Q

What units are engine power output typically measured in?

A
  • Horsepower (hp)
  • Kilowatts (kW)

203f pg. 21

21
Q

What units are engine torque output typically measured in?

A
  • Pound-feet (lb-ft)
  • Newton meters (Nm)

203f pg. 21

22
Q

Why should engines be operated at their rated horsepower level?

A

Ensures that it performs at maximum efficiency.

203f pg. 22

23
Q

How do most diesel engine manufacturers rate the fuel economy of an engine?

A

Brake Specific Fuel Consumption (BSFC). The amount of fuel used per hour per brake horsepower.

203f pg. 23

24
Q

How much should a naturally aspirated engine be de-rated at 1000 feet above sea level?

A

3%

203f pg. 23

25
Q

What should be inspected on a vehicle before performing any dyno tests?

A
  • Vehicle powertrain
  • Suspension
  • Tire condition

203f pg. 25

26
Q

What four main uses are there for dyno testing?

A
  • Testing engine performance
  • Diagnosis
  • Troubleshooting
  • Break-in after a rebuild

203f pg. 26

27
Q

What four basic steps should be followed when performing engine diagnosis?

A
  • Gather relevant information
  • Perform operating tests to verify the problem
  • Determine possible causes
  • Perform tests based on the results of your diagnosis

203f pg. 27

HET2 (29 decks)

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