ATASA 5 Electronic Fuel Injection

ATASA 5 th Electronic Fuel Injection ATASA 5 TH Study Guide Chapter 30 Pages 899921 Electronic Fuel Injection 68 Points

Please Read The Summary

1. EFI systems are ________ controlled and designed to provide the correct _________ ratio for all engine loads, speeds, and temperature conditions.

ATASA 5 th Electronic Fuel Injection

Computer Mechanical Hydraulic

2. The ideal air/fuel ratio is called the _________________ ratio and consists of 14.7 parts of air to 1 part of fuel by weight. Note: Different fuels have different stoichiometric ratios.

Stoichiometric Basic Advanced



3. The stoichiometric ratio allows the ____________ converter to work most efficiently.


Catalytic Cadillac Catatonic

3. The stoichiometric ratio allows the ____________ converter to work most efficiently.

Catalytic Cadillac Catatonic


Catalytic Converter Efficiency

4. A _________ _________ system determines the amount of air entering the engine with input from the MAP (manifold absolute pressure) (piezo resistive Vref) sensor and the RPM sensor.


Speed Density Mass Air Flow Carbureted

5. Most engines use a _________ __________ system (MAF) to measure the amount of incoming air.

Mass Air Flow Mass Fuel Flow Mass Any Flow


6. During __________ ________, EFI systems rely on input from various sensor before adjusting the air/fuel ratio. (warm coolant, time running, & using active upstream HO2S signals)


Open Loop Closed Loop Fail Safe

7. During ________ ________, EFI systems deliver fuel according to predetermined parameters held in the PCM’s memory. (cold coolant, time running, & ignoring inactive upstream HO2S signals)


Base Command

Exhaust Base Pulse

Width

Working at Base Fuel Trim

Number is Zero .450 volts

Feedback System in Closed Loop Mode



Rich Command

Lean Exhaust

Pulse Width Δ

Richened Fuel Trim Positive #’s

.1 to .4 volts Low Numbers Lots of Oxygen Lean Exhaust




Rich Exhaust

Lean Command

Pulse Width Δ

.5 to .9 volts

Less Oxygen

Leaned Out Fuel Trim

Negative #’s


8. Fuel _______________ are solenoids with movable armatures that pulse on when electricity flows through their internal coil of wire. This action delivers a spray of atomized fuel.

Relays Transformers Solenoids


9. Orings on injectors seal them into the intake ________________ and the fuel __________.

Manifold, Rail


10. Injectors are fed ______________ voltage and are pulsed on by the PCM controlling the driver circuit ground.

Battery 5 VRef Secondary


11. The length of time that a PCM grounds the injector to turn it on is called ________ _________.

Pulse Width Fuel Trim Duty Cycle


Injector Signature or Voltage Waveform

Injector Current Ramp Waveform

12. Injector pulse width is expressed in _________________ of ontime. (Fuel Trim = adjustment)

Nanoseconds Milliseconds Seconds


12. Injector pulse width is expressed in _________________ of ontime. (Fuel Trim = adjustment)

Nanoseconds Milliseconds Seconds


13. Pulse width can range from 1 to 10 milliseconds. Cold starting requires a ________ pulse width.

Shorter Medium Longer


Clear Flood Base

Lean Rich

14. Idle speed is controlled by ________________ a certain amount of airflow past the throttle plate.


Surrounding Bypassing Rejecting

15. __________ ______ _____________ motors (IAC) are stepper motors used to control idle rpm.


Idle Air Control Idle Speed Control Idle Shut Down



16. Throttlebywire systems use a throttle actuator motor (TAC) instead of an IAC. True or False


17. The ________ ____________ sensor (MAF) calculates the mass of a given amount of air by multiplying its volume by its density. (measured & expressed in grams/second or # per minute)


Mass Air Flow

18. Base pulse width of injectors can also be determined by a ___________ ____________ _____________ (MAP) sensor which calculates engine load using manifold vacuum.


Manifold Absolute Pressure

19. At closed throttle the engine has a ____ MAP value. At WOT a ______ MAP value is produced…Opposite of Vacuum!!

Low, High High, Low Little, No


20. MAP output is the ____________ of what is measured on a vacuum gauge.

Opposite Same Reciprocal


21. The MAP signal is also used to inform the PCM when the ______ valve is open since introducing exhaust into the intake manifold would affect pressure in the manifold.

EGR PCV CNP


22. The MAP signal could be used to determine turbo boost. True or False


EGR Raises Manifold Pressure

Turbo Boost Really Raises Manifold Pressure

23. Manifold Absolute Pressure equals the _______________ pressure minus the intake manifold ______________. Expressed in inches of mercury (Hg”) BARO – VAC = MAP

Barometric, Vacuum Vacuum, Barometric Sea Level, Gravity


minus

24. Signals from the exhaust gas ________ (O 2 S) sensors are the main input to adjust the A/F ratio.

Oxygen Hydrogen Krypton


Voltage Range:

.1 to .9 Volts DC

100 mV = Lean Exhaust Results in: Rich Fuel Trim Command

900 mV = Rich Exhaust Results in: Lean Fuel Trim Command


B1 S1 HO2S Upstream = PreCAT AirFuel Ratio Management

B1 S2 HO2S Downstream = PostCAT Catalyst Efficiency Monitor

Exhaust Flow


ATASA 5 th Electronic Fuel Injection 25. Low voltage at the HO 2 S is a ______ exhaust indicator resulting in a rich

injector command

Lean Stoichiometric Rich

26. High voltage at the HO 2 S is a ______ exhaust indicator resulting in a lean injector command.


Lean Stoichiometric Rich



Catalyst Efficiency Comparison of Upstream & Downstream HO2S

A good CAT should have a flat pattern on the S2 HO2S


27. Intake ______ temperature sensors (IAT) are necessary since ________ air is more dense than warm air, it can burn more fuel than the same volume of warm air.

Fuel, Cold Air, Cold Heat, Cold


28. The engine ___________ temperature sensor (ECT) signals the need for cold A/F enrichment.

Fuel Air Coolant


29. The ____________ position sensor (TPS) is a potentiometer.

Coolant Intake Throttle


30. The highly important _______________ position sensor (CKP) monitors engine speed.


Camshaft Crankshaft Balance Shaft

31. The _________________ position sensor is used to synchronize the timing of injector pulses.


Camshaft Crankshaft Balance Shaft

32. ____________ mode sets injector pulse width using MAF, IAT, ECT, & TPS.

Starting Open Loop Closed Loop


33. _________ mode can be either open loop or closed loop based on ECT, HO 2 S, and TPS.


Starting Run WOT

34. A system with 0 milliseconds of pulse width during cranking is in ________ ________ mode.


Closed Loop Deceleration Clear Flood

35. There are also ________________ & _______________ modes to respond to rapid TPS change.

Acceleration, Deceleration Liftoff, Splashdown Intake, Exhaust



36. Adjustments made to base pulse width are called fuel ________. A positive fuel trim is an increase in pulse width. A negative fuel trim is a decrease in pulse width.

Trip Trim Brim


37. ______ term fuel trim (STFT) represents changes made immediately in response to HO 2 S signals.

Short Medium Long


38. _____ term fuel trim (LTFT) represents changes made to a new base pulse width by STFT trends.


Short Medium Long

39. STFT is __________ when the ignition is turned off. LTFT remains in the PCM memory.

Reset Rebuilt Refused


40. Low pressure _____ systems used 1 or 2 injectors above a throttle plate centrally located atop the intake manifold. Throttle body injection was the transition from carburetors to port injection.

TBI CMFI TRI


41. ______________ injection (MPI) locates the injectors close to the valves in the intake manifold, but pulses all injectors at the same time or in banks on engines with V cylinder arrangements.

Multiport Multicylinder Multirail


42. ______________ (SFI) controls each injector separately, firing just before the intake valve opens.

Sequential Special Supersonic


43. Port injection systems have a ___________ _______ to control the amount of incoming air.


Throttle Body Air Injector Throttle Pedal

44. Idle speed is adjustable with a screw on the port injection throttle body. True or False


45. Injectors are fastened to the fuel ________ which is a fuel manifold or distribution device.

Rail Snail Tail


46. Fuel pulsation __________ are used on some rails to reduce fluctuations and to quiet operation.

Dampers Tampers Hampers


47. Vacuumsensitive fuel pressure _________________ maintain constant pressure drop of the injectors.

Restrictors Regulators Resonators


48. On Throttlebywire systems, a throttle actuator __________ responds to input from accelerator pedal position sensors (APP). There are redundant APP and TPS in a throttlebywire system.

Motor Engine Pedal



49. CMFI uses individual ________ _____________ for each cylinder controlled by a single injector and a fuel pressure regulator mounted right on the CMFI module.

Poppet Nozzles Poppet Valves Poppet Sodas


50. CMFI injector pressure is regulated very accurately between ____ to ____ psi. This eliminates vapor lack tendencies, but makes the system sensitive to low fuel pressure problems.

37 43 psi 48 56 psi 54 64 psi


51. ____________ __________ _________ (GDI) has advantages over SFI, such as precise delivery and the system’s ability to learn the fuel type & adapt to another stoichiometry.


Gasoline Direct Injection Great Direct Injection Good Direct Injection

52. GDI injectors deliver fuel ____________ into the high pressures & high temperatures in the cylinder.

Directly Indirectly Easily


53. Piezoelectric injectors that rely on stacked _____________ have a faster response time than solenoidtype injectors. They react so fast that they can pulse multiple times in one engine stroke.


Crystals

54. GDI fuel rail pressures can range from ______ to ______ psi!

435 1,885 psi


55. GDI can operate in ______ burn, _____________, or ______ __________ mode.

Lean, Stoichiometric, Full Power


56. For increased mileage, GDI can run as lean as 60:1 using ____________ charge combustion.

Nullified Stratified Pacified


57. GDI engines can operate at higher _____________ ratios without the need for high octane fuel.

Compression Air:Fuel Axle


58. To meet OBDII standards, diesel engines use __________ rail injection systems with many of the same inputs as gasoline engine and piezoelectric injectors. Rail pressures are 2,000 to 25,000 psi!


Common Uncommon NonCommon







A. System Voltage B. Injector On C. Injector Off D. Inductive “Kick”

B to C. Pulse Width


www.picotech.com This is an amazing site for Automotive Diagnostics!

Under the Automotive Heading, go to the Waveform Library!!



http://www.cf.ac.uk/engin/staff/pjb/source/GDIanim.gif

Click Here!



Manometer or UTube. Contains Mercury (Hg) measured in Inches


Abbreviation Full name of sensor Type of sensor MAF Mass Air Flow [ ] active (freq gen) [ ] passive MAP Manifold Absolute Pressure [ ] active [ ] passive TPS Throttle Position Sensor [ ] active [ ] passive ECT Engine Coolant Temperature [ ] active [ ] passive IAT Intake Air Temperature [ ] active [ ] passive KS Knock Sensor [ ] active [ ] passive CKP Crankshaft Position [ ] active [ ] passive CMP Camshaft Position [ ] active [ ] passive EGO Exhaust Gas Oxygen [ ] active [ ] passive (B1 S1) Bank 1 – Stream 1 HO2S (PreCAT) HEGO Heated Exhaust Gas Oxygen [ ] active [ ] passive (B1 S2) Bank 1 – Down Stream (PostCAT)


MAF MAP Hot Wire or Hot Film

High Frequency Generator PiezoResistive (3wire)

5 Volt Reference


TPS KS 5Volt Reference (3 Wire)

Potentiometer PiezoElectric Generator

Quartz Crystal


IAT

ECT Negative Temperature Coefficient (NTC) Thermistors 5 Volt Reference (2Wire)


CKP CMP Permanent Magnet Generators (2Wire) Analog Output

Or HallEffect Generators (3Wire) Digital Output



HO2S

Galvanic Cell Uses Zirconia exposed to 2 Different Atmoshperes to Produce Voltage


Voltage Range:

.1 to .9 Volts DC

100 mV = Lean Exhaust Results in: Rich Fuel Trim Command

900 mV = Rich Exhaust Results in: Lean Fuel Trim Command



WideRange Air:Fuel Sensor




ATASA 5 Electronic Fuel Injection

Documents