Description : In four stroke engine which of the following is also known as power stroke a. Suction stroke b. Compression stroke c. Expansion stroke d. Exhaust stroke (Ans:c) Measurements of fuel and air ... into IC engine,___________its efficiency A. increase B. decrease C. does not alter D. unpredictable on
Last Answer : ANSWER : B
Description : Fuel is injected into the cylinder at the end of ______________ stroke. a) suction b) compression c) expansion d) exhaust
Last Answer : Answer: b Explanation: Fuel is injected into the cylinder at the end of compression stroke and not at suction or expansion stroke.
Description : The _____________ sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature
Last Answer : Answer: c Explanation: The air flow sensor, monitors mass or volume of air flowing into the intake manifold for adjusting the quantity of fuel while exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.
Description : Scavenging air in diesel engine means a. air used for combustion under pressure b. forced air for cooling the cylinder c. burnt air containing products of combustion d. air used for forcing burnt gases out of the engines cylinder during the exhaust stroke
Last Answer : ANSWER d. air used for forcing burnt gases out of the engines cylinder during the exhaust stroke
Description : In four stroke engine there is one power stroke in _____ of crankshaft rotation. a. 180° b. 360° c. 540° d. 720° (Ans:d)
Last Answer : The ascending order of strokes in four stroke engine is a. Suction stroke - Expansion stroke - Compression stroke - Exhaust stroke b. Suction stroke - Compression stroke - Expansion stroke -Exhaust ... stroke d. Suction stroke - Compression stroke - Exhaust stroke - Expansion stroke (Ans:b)
Description : Which of the following engine can work on very lean mixture a. Spark ignition engine b. compression ignition engine c. two stroke engine d. Four stroke engine
Last Answer : ANSWER b. compression ignition engine
Description : In diesel engine, the compression ratio as compared with the expansion ratio is a. same b. less c. more d. variable
Last Answer : ANSWER c. more
Description : In compression ignition (CI) engine, the compression ratio is a. Cylinder volume / Clearance volume b. Swept Volume / Cylinder Volume c. Clearance volume / Cylinder volume d. Cylinder volume / Swept volume (Ans:a)
Last Answer : In two stroke engine there is one power stroke in _____ of crankshaft rotation. a. 90° b. 180° c. 270° d. 360° (Ans:d)
Description : The compression ratio in a Spark Ignition (SI) engine is generally in between a. 7 to 10 b. 10 to 14 c. 14 to 18 d. 18 to 22 (Ans:a)
Last Answer : Which of the following is not true for two stroke engine as compared to four stroke engine? a. Less cooling is required b. Greater lubrication is required c. More uniform torque on crankshaft d. Complete exhaust of products of combustion (Ans:a)
Description : For same power output and same r, as compared to 2- stroke engines, four stroke SI engines have (a) Higher fuel consumption (b) Lower thermal efficiency (c) Highest exhaust temperatures (d) Higher thermal efficiency
Last Answer : Ans :d
Description : In spark ignition engines, the knocking tendency can be decreased by a) decreasing compression ratio b) controlling intake throttle c) controlling ignition timing d) adding dopes like tetraethyl lead and ethylene dibromide
Last Answer : Answer: d Explanation: None.
Description : If the temperature of intake air in internal combustion engine is lowered, the efficiency will a. increase b. decrease c. remains same d. increases upto certain limit and then decrease
Last Answer : ANSWER a. increase
Description : If the intake air temperature of Internal combustion engine increases, its efficiency will a. increase b. decrease c.remains same d unpredictable
Last Answer : ANSWER b. decrease
Description : The size of inlet valve of an engine in comparison to exhaust valve is A. more B. less C. same D. varies from design to design
Description : In a single acting reciprocating compressor, the suction, compression and delivery of air takes place in A. One stroke B. Two stroke C. Three stroke D. Four stroke
Description : The ratio of work done per cycle to the stroke volume of the compressor is known as A. Compressor capacity B. Compression ratio C. Compressor efficiency D. Mean effective pressure
Last Answer : ANSWER : D
Description : A two stroke engine has a speed of 750 rpm. A four stroke engine having an identical cylinder size runs at 1500 rpm. The theoretical output of the two stroke engine will (a) Be twice that of the four stroke ... ) Be the same as that of the four stoke (d) Depend upon whether it is a CI or SI engine
Last Answer : Ans :c
Description : State the functions of following elements: i) Diesel engine system ii) Air intake system iii) Engine exhaust system iv) Engine starting system.
Last Answer : i) Diesel engine system:- Four strokes Two strokes ii) Air intake system:- Air intake system is provided to supply air to engine cylinder for fuel combustion. iii) Engine exhaust system ... provided to rotate the engine initially until the firing starts and engine run under its own power.
Description : The output of a diesel engine can be increased without increasing the engine speed or size in the following way A. feeding more fuel B. increasing the flywheel size C. heating intake air D. supercharging
Description : The ___________ sensor, monitors vacuum in the engine intake manifold so that the mixture strength can be adjusted with changes in engine load. a) throttle position b) manifold pressure c) camshaft position d) knock
Last Answer : Answer: b Explanation: The manifold pressure sensor, monitors vacuum in the engine intake manifold so that the mixture strength can be adjusted with changes in engine load and the camshaft position sensor, senses rotation of engine camshaft for speed and timing of injection.
Description : Keeping other parameters constant brake power of diesel engine can be increased by (a) Decreasing the density of intake air (b) Increasing the temperature of intake air (c) Increasing the pressure of intake air (d) Decreasing the pressure of intake air
Last Answer : Ans : c
Description : If one cylinder of a diesel engine receives more fuel than others , then for that cylinder the A. exhaust will be smoky B. scavenging occurs C. exhaust temperature will be high D. engine starts overheating
Description : The _____________ sensor, checks the temperature of the ambient air entering the engine for fine tuning the mixture strength. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature
Last Answer : Answer: d Explanation: The air inlet temperature sensor, checks the temperature of the ambient air entering the engine for fine tuning the mixture strength whereas the engine temperature sensor senses the ... gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.
Description : The _____________ sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature
Last Answer : Answer: a Explanation: The engine temperature sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting while the ... gas senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio.
Description : In _____________ sensor, output voltage changes in proportion to air-fuel ratio. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature
Last Answer : Answer: b Explanation: Only in exhaust gas sensor, output voltage changes in proportion to air-fuel ratio.
Description : _____________ senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio. a) Engine temperature b) Exhaust gas c) Air flow d) Air inlet temperature
Last Answer : Answer: b Explanation: Exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates airfuel ratio while engine temperature sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting.
Description : The mean effective pressure obtained from the engine indicator indicates the a. maximum pressure developed b. instantaneous pressure c. exhaust pressure d. average pressure
Last Answer : ANSWER d. average pressure
Description : Supercharging is the process of a. supplying the engine with air at a density greater than the density of the surrounding atmosphere b. providing forced cooling air c. injecting excess fuel d. raising the exhaust pressure
Last Answer : ANSWER a. supplying the engine with air at a density greater than the density of the surrounding atmosphere
Description : The condition of refrigerant before entering the expansion or throttle valve, in a vapour compression system (a) dry vapour (b) wet vapour (c)liquid-vapour mixture (d) high pressure saturated liquid
Last Answer : Ans: d
Description : Where does the lowest temperature occur in a vapour compression cycle ? (a) condenser (b) evaporator (c) compressor (d) expansion valve
Last Answer : Ans: b
Description : In vapour compression refrigeration system, refrigerant occurs as liquid between (a) condenser and expansion valve (b) compressor and evaporator (c) expansion valve and evaporator (d) compressor and condenser
Last Answer : Ans: c
Description : The higher temperature in vapour compression cycle occurs at (a) compressor discharge. (b) expansion valve (c) evaporator (d) condenser discharge
Last Answer : Ans: a
Description : In a vapour compression cycle, the refrigerant immediately after expansion valve is (a) liquid (b) sub-cooled liquid (c) saturated liquid (d) wet vapour
Description : Domestic refrigerator working on vapour compression cycle uses the following type of expansion device (a) electrically operated throttling valve (b) manually operated valve (c) thermostatic valve (d) capillary tube
Description : In vapour compression cycle the condition off refrigerant is dry saturated vapour (a) after passing through the condenser (b) before passing through the condenser (c)before entering the expansion valve (d) before entering the compressor
Last Answer : Ans: D
Description : In vapour compression cycle the condition of refrigerant is superheated vapour (a) after passing through the condenser (b) before passing through the condenser (c) after passing through the expansion or throttle valve (d) beforeentering the expansion valve
Description : In vapour compression cycle, the condition of refrigerant is high pressure saturated liquid (a) after passing through the condenser (b) before passing through the condenser (c) after passing through the expansion or throttle valve (d) before entering the expansion valve
Description : In vapour compression cycle, the condition of refrigerant is very wet vapour (a) after passing through the condenser (b) before passing through the condenser (c) after passing through the expansion or throttle valve (d) before entering the expansion valve
Description : In vapour compression cycle, the condition of refrigerant is saturated liquid (a) after passing through the condenser (b) before passing through the condenser (c) after passing through the expansion throttle valve (d) before entering the expansion valve
Description : Volumetric efficiency is affected by (A) Turbulence velocity and temperature of intake manifold (B) Efficiency of exhaust stroke (C) Valve timing overlap (D) All the above
Last Answer : (D) All the above
Description : In two stroke engine one power occurs in _______ of crank rotation A. 180° B. 360° C. 270° D. 720°
Description : Morse test is conducted on the engine to calculate the mechanical efficiency of A. single cylinder CI engine B. single cylinder SI engine C. only on two stroke engines D. multi cylinder engine
Description : For low load operation more economical engine is a. petrol engine b. diesel engine c. muticylinder engine d. two stroke engine
Last Answer : ANSWER b. diesel engine
Description : The actual volume of fresh charge admitted in 4-stroke petrol engine is A. equal to stroke volume B. equal stroke volume and clearance volume C. less than stroke volume D. more than stroke volume
Last Answer : ANSWER : C
Description : In a typical medium speed 4- stroke Diesel engine, the inlet valve A. opens 20°before top dead centre and closes at 35°afterthebottomdead centre. B. opens up at top dead centre and closes at bottomdead centre C. may open orcloseanywhere D. remains open for 200°
Last Answer : ANSWER : A
Description : A gas engine has a volume of 300 cc and clearance volume of 25 cc. Its volumetric efficiency is 0.8 and mech efficiency is 0.9. What is the volume of the mixture taken in per stroke? (a) 248 cc (b) 252 cc (c) 264 cc (d) 286 cc
Description : The term scavenging is generally associated with a. 2-stroke engine b. 4-stroke engine c. high efficiency engine d. diesel engine
Last Answer : ANSWER C. high efficiency engine
Description : An engine working on air standard Otto cycle has a cylinder diameter of 10 cm and stroke length of 15 cm. The ratio of specific heats for air is 1.4. If the clearance volume is 196.3 cc and the heat supplied per kg of air per ... kg of air is a. 879.1 kJ/ b. 890.2 kJ c. 895.3 kJ d. 973.5 kJ
Last Answer : ANSWER d. 973.5 kJ
Description : For the same capacity engines, the compression ratio of diesel engine a. is lower than the compression ratio of SI engine b. is higher than the compression ratio of SI engine c. is same as the compression ratio of SI engine d. cannot say
Last Answer : ANSWER b. is higher than the compression ratio of SI engine
Description : For same compression ratio a. Diesel cycle has lower efficiency than Otto cycle b. Diesel cycle has higher efficiency than Otto cycle c. Diesel cycle and Otto cycle have equal efficiencies d. Depends upon the load on engine
Last Answer : Answer a. Diesel cycle has lower efficiency than Otto cycle