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The CORRECT choice is (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.

Correct option is (b) 1

The EXPLANATION is: 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.

Correct answer is (c) Detonation

For explanation I would SAY: 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.

The correct option is (c) INSIDE the cylinder

To EXPLAIN I would SAY: 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.

The correct OPTION is (a) Rich

To explain I would say: 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.

Right option is (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.

Correct option is (d) Low efficiency

Best 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.

Correct answer is (d) Muffler explosion

To explain I would say: 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.

Correct option is (B) Electrical

To explain: 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.

The correct OPTION is (c) Pulse width

The best 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.

Correct choice is (d) Idle adjuster

To elaborate: Apart from the idle adjuster and throttle adjustment the other adjustments which are provided are accelerating pump, metering rod, floats,ETC which MUST be performed as laid down in the user MANUAL.

Right ANSWER is (B) Ecu

Best 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.

Correct choice is (d) STALLING of the engine

Easiest explanation: The EXTRA rich mixture can be recognized by Hugh fuel consumption, surging while idling, loud MUFFLER explosion and BLACK smoke from the exhaust. Whereas the stalling of the engine takes place only for an extra WEAK mixture.

Right option is (d) Pressure relief

Easy explanation: The carburetor is a device that PROVIDES air-fuel MIXTURE to the ENGINE in all the working OPERATION of an engine like the idling, crushing and accelerating period but WHEREAS the pressure relief system has no connection to the carburetor.

The correct option is (b) 2.5

To ELABORATE: The carburetor is screwed in completely and then opening BACK by two and a half turns. This screwing in the same decreases the idle PORT area and hence decreases the engine SPEED. The screw is adjusted until the engine RUNS smoothly at the required speed.

Correct answer is (b) 2

Best explanation: There are 2 JETS present in a SIMPLE carburetor they are the main jet and the pilot jet. These jets are very important and should never be CLEANED with wire WHEREAS they should be cleaned with petrol and then with a blast of air.

Correct choice is (a) Remove the THROTTLE and choke linkage

The EXPLANATION is: To remove the carburetor, first of all, remove the air cleaner and disconnect the throttle and choke LINKAGES. Next disconnect the VACUUM advance unit and any other connection that many be there.

Right answer is (a) To know the play of the acceleration PEDAL

The BEST I can explain: The ACCELERATOR pedal throttle valve should be completely closed, while on PRESSING pedal fully, it should be in the full OPEN position. This should be checked and in case of some action, the linkage must be adjusted, as provided for in the manufacturer’s manual.

The correct option is (b) LOSS of power

To elaborate: The EXTRA rich mixture when burnt has the colour of the EXHAUST in black which is caused due to unburnt CARBON particles in the exhaust. WHEREAS the stalling of the engine, unburnt carbon particle and overheating of the engine happens for an extra weak mixture.

Correct CHOICE is (d) SURGING while idling

The best I can explain: The extra WEAK mixture is RECOGNIZED by flat spot while accelerating, stalling of the engine, LOUD popping in the carburetor, overheating of the engine and loss of the power. Whereas the surging while idling is due to extra rich mixture.

Correct choice is (c) ENGINE speed

To ELABORATE: Screwing the idle screw in the same DIRECTION decreases the idle port area and HENCE decreases the engine speed. Generally, this is done by screwing -in completely and then opening back by one or two TURNS.

The CORRECT choice is (c) PETROL and blast of air

Explanation: The carburetor jets should first be cleaned with petrol and then with a blast of air and it should be NEVER cleaned with wire because the screw adjustment helps in the smooth run of the engine at the REQUIRED SPEED.

Correct choice is (a) Main

The best explanation: The piston moves up and down, the needle also moves up and down .the lower END of the needle is inside the main jet. The up and down movement of the tapering needle causes the ANNULAR AREA for FUEL flow to INCREASE or decrease.

The correct option is (a) High volumetric EFFICIENCY

For explanation I WOULD say: The drought type is most widely used as it has high volumetric efficiency, GRAVITY assist for the flow,etc. Whereas the leakage, defective float, and jet overflowing are the SIGN of a bad CARBURETOR which is not desired.

Correct choice is (c) At high altitude

To EXPLAIN I would say: At high altitudes, the MIXTURE tends to become richer in a single jet CARBURETOR as there is no supply of air at higher altitudes DUE to which the engine will have more FUEL consumption when compared to an engine at sea level.

Correct option is (a) One

For explanation I would say: The damper plunger has a one-way VALVE in it. It REGULATES the rate of LIFT of piston but ALLOWS the same to fall freely when the throttle valve is closed. However the throttle valve is opened suddenly for acceleration, the lifting speed of the piston is retarded by the damper plunger.

Right answer is (c) MIXTURE strength

Easiest explanation: The jet adjusting nut is meant to adjust mixture strength. Tightening the nut will raise the jet, thereby reducing the ANNULAR area for fuel FLOW. SIMILARLY loosening the nut powers the jet and THUS increases the fuel supply which is getting delivered to the engine.

The correct answer is (b) Metering ROD

To elaborate: The metering rod consists of several steps of DIAMETER SIZES at its bottom and is CONNECTED with the accelerator pedal through linkage. When the accelerator pedal is pressed, the throttle is HELD wide open and simultaneously the metering rod is lifted.

The correct choice is (c) Idle PORT

Explanation: For idling circuit, the throttle valve is almost CLOSED and the whole ENGINE suction is applied at the idle port, through which the air and the fuel are drawn GIVING rich mixture. This rich mixture requires more fuel for the proper COMBUSTION.

Correct option is (B) Membrane pump

To elaborate: To avoid flat spot during acceleration a separate membrane pump is provided which delivers spurts of EXTRA NEEDED fuel for acceleration. Pump lever is connected to the accelerator pedal so that when the same is PRESSED, the lever moves towards left, thus pressing the membrane towards the left and forcing petrol into the main jet.

Right choice is (c) Down- drought

For explanation I would SAY: Solex carburetor is a down drought type of carburetor, with special PROVISION for a progressive starter which SUPPLIES rich mixture for starting and then gradually weakens it TILL the ENGINE has reached its operating temperature.

Right option is (c) 3

To elaborate: There are three jets present In a zenith carburetor. The jets are the main jet, compensating jet and the idling jet. The main jet has an outer COVER, the ANNULAR PASSAGE between the main jet and outer cover FORMS a delivery tube for the compensating jet.

Correct CHOICE is (c) S U carburetor

Explanation: The S U carburetor is a TYPICAL example of variable venturi or constant vacuum type of carburetor. There is both a VERTICAL and HORIZONTAL model is being produced. The horizontal type has a spring-loaded PISTON to control the air passage.

The correct choice is (b) Accelerator

The BEST I can EXPLAIN: The throttle is directly connected to the accelerator pedal wherein depending on the accelerator pedal the AMOUNT of AIR and FUEL required is sent inside the combustion chamber.

Correct answer is (C) Cruising

For explanation I would say: During cruising the air-FUEL mixture is lean as the emission is controlled by using this RATIO. Where more air is burnt for the same value of the fuel when operating at sea level. These weaker mixtures provide a good ECONOMY when compared to the economy of the rich mixture.

Right CHOICE is (a) 14.7:1

The best explanation: The STOICHIOMETRIC ratio of air-fuel is 14.7:1. It MEANS that 14.6 parts of air and 1 part of gasoline or petrol (by mass) is the one which would give CHEMICALLY CORRECT combustion of petrol under ideal conditions.

The correct answer is (d) To delay the ignition timing depending in the exhaust gas

The explanation: The functions of a carburetor is to keep a small reserve of fuel at the constant head, VAPORIZE the fuel to prepare a homogeneous air-fuel mixture,supply correct amount of the air-fuel mixture at the correct strength and the ECU TAKES care of the ignition timing depending on the input from the oxygen SENSOR.

The correct choice is (b) FUEL jet

Explanation: The fuel supply from the float CHAMBER at any time is metered by a MEANS of the fuel jet from where the fuel flows to the VENTURI through the discharge nozzle. The venturi is simply a restriction in the air PASSAGE where the passage area is minimum.

The correct option is (b) 5

To explain: The fuel LEVEL in the FLOAT chamber is maintained about 5mm below the NOZZLE outlet. A small vent in the float chamber keeps the pressure inside atmospheric and in modern practice is preferred to vent the float chamber to the AIR INTAKE of the carburetor.

Correct option is (a) Three-piece valve with rubber seat TIP

Explanation: A three-piece valve with a rubber seat tip and a spring-loaded ball In the BODY of the STEM. WHEREAS the other components like the vent,nozzle and the throttle valve are the main parts of a CARBURETOR which helps in the air-fuel mixture ratio.

Correct option is (d) Ignition timing

The BEST I can EXPLAIN: The amount of fuel delivered depends upon the major factors like JET size, float level, and venturi vacuum. Whereas the ignition timing does not AFFECT the amount of fuel that is being delivered to the ENGINE via the carburetor.

Correct choice is (b) Air-fuel

To EXPLAIN: The purpose of a THROTTLE valve is to control the quantity of the air-fuel MIXTURE and it is attached to the accelerator pedal. Whereas there is no such GREAT effect of the throttle valve in the factors like temperature, ENTHALPY, and entropy.