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List the additives of Lubricant used in S.I. engine and state their advantages.

Role of following lubricant additives (one mark each) 1. Zinc ditinophosphate: - Zinc ditinophosphate serves as an anti – oxidant and anticorrosive additive.

2. Fatty acids: - This type of additives prevents rusting of ferrous engine parts during and form acidic moisture accumulation during cold engine operation.

3. Organic Acids: - This type of additives improves the detergent action of lubricating oil.

4. Ester: - To lower the pour point of lubricating oil.

5. Silicon polymers: - This additive serves as Antifoam Agent.

Draw and explain Battery ignition system.

Battery Ignition system : I t consists of six or twelve volt battery, ignition switch,induction coil, circuit breaker condenser and distributor. All the circuit parts are shown in figure. One terminal of battery is ground to engine frame and other is connected through the ignition switch to one primary terminal of induction coil. The other primary connection is connected to one end of contact point of circuit breaker and through closed points to ground. The ignition switchis made on and engine is crancked. When the contacts touch, the current flows the battery to the switch.

Define the following related I.C. engine

i) Indicated Power (ip) is defined as the power developed by combustion of fuel in the cylinder of engine. It is always more than brake power. ii Brake Power:-  The useful power which is available at the crank shaft is called as brake power.  It is denoted by “B.P.”  It has unit kW iii) B.S.F.C: It is the weight of fuel required to develop 1KW of the brake power for period of 1 hour. Unit of B.S.F.C is Kg/KWh. It is defined as the amount of fuel consumed per unit of break power developed per hour.

Explain different stages of combustion in C.I. engine with sketch.

1) Ignition delay period : During this fuel has already admitted but has not yer ignited. This is counted from start of injection to the point where P-O curve separates from pure air compression curve. 2) Rapid or uncontrolled combustion : In this stage pressure rise because of during the delay period the fuel droplet have time to spread over a wide area and fresh air around them.

Name the different sensors used in ECU of modern automobile with their application....

Crank angle sensor: A permanent magnet inductive signal generator is mounted in close proximity to the flywheel, where it radiates a magnetic field. As the flywheel spins and the pins are rotated in the magnetic field, an alternating (AC) waveform is delivered to the ECM to indicate speed of rotation.

Air Flow Sensor (AFS): The AFS is normally located between the air filter and the throttle body. As air flows through the sensor, it deflects a vane (flap) which wipes a potentiometer resistance track and so varies the resistance of the track and generates a variable voltage signal.

Draw and explain simple vapour absorption refrigeration system

A Simple Vapor absorption system consists of evaporator, absorber, generator, condenser, expansion valve, pump & reducing valve. In this system ammonia is used as refrigerant and solution is used is aqua ammonia. Strong solution of aqua ammonia contains as much as ammonia as it can and weak solution contains less ammonia. The compressor of vapor compressor system is replaced by an absorber, generator, reducing valve and pump. The heat flow in the system at generator, and work is supplied to pump. Ammonia vapors coming out of evaporator are drawn in absorber.


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