This set of Automotive Engine Auxiliary Systems Multiple Choice Questions & Answers (MCQs) focuses on “ Petrol Injection”.
1. Which among the following tunes the fuel delivery to achieve the correct fuel ratio?
a) Float valve
c) Oxygen sensor
d) Temperature sensor
Explanation: The ECU uses the information from the sensors to fine-tune the fuel delivery to achieve the just correct fuel ratio. The sensors monitor the mass of air entering the engine and also the amount of oxygen in the exhaust.
2. Which among the following is defined as the amount of time the injector stays open and also determines the amount of fuel supplied to the engine?
a) Flat spot
b) Pulse radiation
c) Pulse width
d) Dark pulse
Explanation: The amount of time the injector stays open determines the amount of fuel supplied to the engine it is called the pulse width. This time duration and the amount of fuel flowing into the combustion chamber is controlled by the ECU.
3. Which among the following is not a factor affecting the pulse width?
a) Coolant temperature
b) Oxygen level in the exhaust
c) Base pulse width
d) Muffler explosion
Explanation: The factors affecting the pulse width are the base pulse width, the coolant temperature and the factors for oxygen level in the exhaust.Whereas the muffler explosion takes place due to the unburnt fuel In the engine, which completes its combustion in the muffler.
4. Which type of control valve is used in the operation of the injector?
Explanation: The Petrol is injected by an electronically controlled valve, called an injector. The injector has nozzles on its circumference through which the petrol or gasoline is sprayed into the combustion chamber which is controlled by the ECU.
5. Which among the following is not an advantage of petrol injection?
a) Fuel consumption is less
b) Rapid response to throttle
c) High-quality fuel distribution
d) Low efficiency
Explanation: The advantages of petrol injection are high-quality fuel distribution, fuel consumption is less, the engine to throttle control is very rapid, etc. Whereas the petrol injection system provides more efficiency.
6. Which of the following is not a component of a petrol injection system?
a) Injection pump
b) Injection nozzle
d) Compression ring
Explanation: The injector is made up of a precise fuel injection pump, injection nozzle through the fuel enters the combustion chamber and pipelines are provided for each cylinder. Whereas the compression ring has no part in the petrol injection system.
7. How is the air-fuel mixture for full power mode?
d) Very lean
Explanation: Fuel – air mixture is made richer in the full power mode and the fuel is sprayed in during the intake stroke which is controlled by the ECU. The ECU controls the amount of fuel injected based upon the airflow into the engine.
8. Where is the injector placed in the direct injection system?
a) Intake manifold
b) Next to the inlet valve
c) Inside the cylinder
d) Near the throttle body
Explanation: The fuel injector is placed directly into the cylinder and sprayed as per the ECU signal. The intake valve allows only the air into the combustion chamber and the fuel is sprayed – indirectly through an injector.
9. In which of the following stroke concerning ultra-lean mode the fuel is injected?
Explanation: In the ultra-lean mode the fuel is injected later on as the piston is moving up on its compression stroke. This forces the fuel-air charge right up to the spark plug points for the best burning condition. The combustion takes place partly in the cylinder and party in the shaped piston crown.
10. How is the time given for the mixing of air and petrol concerning the port injection system?
c) No time
d) Has no effect
Explanation: In the port injection the injection is made in such a way that it gives more time for the mixing of air and petrol moreover the system is more precise than throttle body type since the fuel delivery does not depend upon air to carry the fuel through the intake manifold.
11. Without any fear of which of the following higher compression ratios can be adopted in the petrol injection system?
a) Ignition lag
b) After burning
d) Flame propagation
Explanation: In a fuel injector a very high-quality fuel distribution is obtained due to which higher compression ratios can be adopted without and danger of detonation occurring. Whereas the ignition lag, after burning and flame propagation are the process of combustion.
12. How many numbers of a circuit are required in the computer to control injection in a Throttle body injection?
Explanation: The computer requires just one circuit to control the process of injection in a vehicle. Thus this is a less costly but less precise system. Never the less the throttle body injection controls the fuel better than the carburetor.
13. How is the piston crown created in a direct injection to help a minimum of air and fuel before combustion?
b) Swirling vortex
Explanation: In a direct injection the piston crown is designed in such a way that it creates a swirling vortex to help mix the fuel and air before combustion. The piston crown also has a cavity on it for ultra-lean-burn conditions.
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