Session 5: Regular Servicing of MPFI System
Module 2: Serviceability, Replacement or Repair of Engine Components
Textual Question-Answers
Check Your Progress
Fill in the blanks
1. The Multi Point Fuel Injection (MPFI) system is advantageousbecause it provides a more uniform ……………. to each cylinder, resulting in minimized power differences between cylinders.
Ans: air–fuel mixture.
2. The Mass Air Flow (MAF) sensor is responsible for monitoringthe intake air flow, which is crucial for correcting the Air Flow Mapand regulating …………………Ans: fuel injection.
3. The Coolant Temperature Sensor (CTS) is a type of ……………. that changes resistance as the engine’s temperature changes, helpingdetermine the engine’s temperature.
Ans: thermistor.
4. The Rail Pressure Sensor (RPS) is located on the fuel commonrail and its primary function is to monitor and decide the ………… ofthe fuel injector.
Ans: injection pressure.
Multiple Choice Questions
1. What is the primary advantage of the Multi Point Fuel Injection(MPFI) system over a single-point injection system?
A) Improved engine vibration
B) Lower fuel consumption
C) Increased exhaust emissions
D) Enhanced cold start performance
Ans: B) Lower fuel consumption
2. Which component of the MPFI system is responsible for receiving signals from various sensors and sending control signals to actuators?
A) Throttle Position Sensor (TPS)
B) Crankshaft Position Sensor
C) Oxygen (O2) Sensor
D) Engine Control Module (ECM)
Ans: D) Engine Control Module (ECM)
3. Which sensor changes resistance based on the temperature of thecoolant and helps in regulating engine performance?
A) Throttle Position Sensor (TPS)
B) Crankshaft Position Sensor
C) Coolant Temperature Sensor (CTS)
D) Mass Air Flow (MAF) Sensor
Ans: C) Coolant Temperature Sensor (CTS)
4. What is the main function of the EGR Vacuum Modulator in theMPFI system?
A) To control exhaust emissions
B) To monitor intake vacuum
C) To regulate fuel pressure
D) To control EGR flow
Ans: D) To control EGR flow
Answer the following questions
Q1. What is the full form of MPFI?
Ans: Multi Point Fuel Injection.
Q2. What are main components of MPFI?
Ans: Fuel tank, fuel pump, fuel filter, fuel injectors, fuel rail, throttle body, sensors, actuators, and Engine Control Module.
Q3. What are the advantages of MPFI over Conventional System?
Ans: MPFI provides better fuel economy, uniform fuel distribution, improved engine performance, lower emissions, and smooth engine operation.
Q4. What are the disadvantages of MPFI over Conventional System?
Ans: MPFI system is costly, requires skilled technicians for maintenance, and involves complex electronic components.
Q5. What precaution to be taken while working on MPFI system?
Ans: The battery should be disconnected, fuel pressure should be released, proper tools should be used, and cleanliness must be maintained to avoiddamage to sensors and injectors
Q6. What is Sensor?
Ans: A sensor is a device that detects physical or chemical changes and converts them into electrical signals for the ECM.
Q7. What is Actuator?
Ans: An actuator is a device that receives signals from the ECM andperforms an action such as opening or closing valves or controlling fuel injection.
Q8. What is ECM?
Ans: ECM is the Engine Control Module that processes input signals fromsensors and controls actuators to ensure optimum engine performance.
Q9. Write the two names of sensor used in MPFI.
Ans: Throttle Position Sensor and Coolant Temperature Sensor.
Activity
1. Make a list of advantages of MPFI system
Ans:
S. No. Advantage
1. Better fuel efficiency
2. Reduced exhaust emissions
3. Smooth engine operation
4. Improved cold starting
5. Make a poster showing different stages from 1 to 4 of multipointinjection fuel as per valve timing.
Ans: The poster should show fuel injection stages during intake valveopening, atomization of fuel, mixing of air and fuel, and fuel delivery to thecombustion chamber with proper valve timing.
Try yourself.
