Working of 4-Stroke Petrol Engine

      Four stroke petrol engine

                       Works on the principle of theoretical Otto or constant volume cycle consist of a cylinder with one end fitted with cover and other left open .cover is provided with inlet and outlet apertures (opened and closed by mechanically operated valves). Valve operating inlet is inlet valve and one operating exhaust is exhaust valve. Spark plug is at top of the cover which ignites the petrol a freely reciprocating piston inside cylinder, connecting rod and crank converts reciprocated motion of piston into rotational motion.

1.  1. .    Suction stroke

           Inlet valve opens, piston moves from T.D.C to B.D.C. energy required for this stroke is provided by cranking at time of storing and while running fly wheel provide mechanical energy. Pressure initially is atmospheric, but volume increases as piston moves and pressure decreases.

Pressure difference between atmospheric and in cylinder provides suction of petrol- air mixture.

2.     2. Compression stroke

                 Piston moves B.D.C to T.D.C initially energy provided by cranking at starting and then by flywheel at time of running.

At this stroke air-petrol mix is compressed at cylinder (to 1:7 to 1:11). This process is theoretically reversible adiabatic.

At the end of this stroke air-petrol mix ignited by spark provided by spark plug. Here, hot gases are released which increases pressure at constant volume

3.   3.   Working / Power stroke

                   Piston moves from T.D.C to B.D.C by force exerted by hot gases linear motion of piston causes it to produce the mechanical power during the strike which is transmitted to crank shaft by connecting rod and crank ,

As piston moves pressure gradually decreases, at or near the end of this stroke exhaust valve opens which causes lowering in pressure at constant volume.

4.    4.  Exhaust stroke

                  Piston moves from B.D.C to T.D.C. Energy required for this stroke is provided flywheel

As this stroke being performed burnt gases will be expelled out of cylinder at atmospheric pressure.

Basic Frech

    sentece            prononciation           meaning

1. je m'appele alok          jomepal alok                my name is alok.

2. jai dix-huit(18) ans        jay dixui aan            i've 18 years old.

3. je suis indien(for males)    jway sui aandian        i'm indian
           indenne(for girls)  

4. je suis celibataire        jway sui celibate        i'm senior

5. je suis marie(for mens)    jway sui marrry            i'm married
           mariee(for womens)   

6. jai un freres et non soeurs  jway Uu frrekhkhs et        i've one brother and no sister
                                nun sueres

7. tu as            two aas                 you have

8. nous avons            nou-swaons            we have



french-words                meaning
dix-huit                        18
vinght-trans                 23
vinght-huit                  28
trente-huit                   38
qui                               yes
non                             no
madame                    madam
tre`sben                    very good
freres                        brother
soeurs                      sister
un                            one
suivant                    next one
il                               he
elle                           she
on                             we
ils ont    (il-sont)                they(boy's group)
elles ont(elle-sont)            they(girls group)
merci                                 thank you
ademain                            see you tommorow

Question Tags

QUESTION TAG [FOR POSITIVE SCENTENCES]

·      POSITIVE SENTENCE IS CONVERTED TO NEGATIVE

·      NEGATIVE SENTENCE IS CONVERTED TO POSITIVE.

SIMPLE CLAUSE :-

·      SUB+[HELPING VERB + MAIN VERB +OBJ] SUB MAY BE NOUN OR PRONOUN

TAG CLAUSE:- [HELPING VERB + NOT + SUB] SUBJECT IS ALWAYS PRONOUN.

HELPING VERB REMAINS SAME

EXAMPLE:-

RAM IS EATING FOOD.[SIMPLE SENTENCE]

IS NOT HE? [QUESTION TAG]

HE EATS A LOT [SIMPLE SENTENCE]

DOES NOT HE? [QUESTION TAG]

IN THIS SENTENCE DOES IS USED BECAUSE THIS IS A PRESENT IN DEFINITE SENTENCE AND IN IT DO AND DOES IS USED TO MAKE NEGATIVE AND INTERROGATIVE SENTENCES

QUESTION TAG [FOR NEGATIVE SCENTENCES]

sub + HV + not + MV+obj {simple sentence}

helping verb + subject { question tag}

EXAMPLE:-

THEY DO NOT HAVE FIVE CARS {SIMPLE SENTENCES}

do they? {QUESTION TAG}

IMPORTANT:- [has,have,had] these can be used as main as well as helping verb [if there is another main verb present then these are used as helping verbs otherwise they are used as main verb in the sentence].

EXAMPLES OF SCENTENCES CONTAINING QUESTION TAGS

I am not helping him.

Applying all the rules our ans will be

Am i ? [question tag]

Harry was not washing pot .

was he ?

IMPORTANT :-

IN CASE OF WORD {LET} SHALL IS USED.

EXAMPLE:= LET US HAVE FUN .

OUR ANS IS = shall we ?

lets have a cup of tea .

shall we ?

IN CASE OF IMPERATIVE SENTENCES [WILL] IS USED

PLEASE DO NOT DISTURB US

ANS IS := WILL YOU ?

imperative scentences are those scentences in which we give order or we request for something .

Parts of I.C. Engine

Basic Path Of REIKI

1. Face
Palms of your hands are placed against your hands over your eyes lightly and fingers upon your forehead. No pressure needed, touch lightly.

2. Crown and Top of head
Place hands on both side of head, heels of your hands resting near your ears, fingertips touching at the crown.

3. Back of the head
Crossing your arms behind your head, Place one hand over your head and other directly above rope of your neck.

4. Chin and Jawline
Rest chin inside palms of your cupped hands. Allow hands to wrap themselves along your jawline.

5. Neck Collarbone and Heart
Grab your neck inside the v formed by your thumbs and fingers. Lower your other hand and rest it between your collarbone and heart center.

6. Ribs and Rib-Cage
Place your hand on your upper ribcage between chest. Relax your bent elbows.

7.Abdomen
Place hands on tummy (solar plexus area) above navel, allowing your fingertips to touch.

8. Pelvic bones
Place one hand over each pelvic bone, again allowing your fingertips to touch.

9. Shoulder blades
Reach your arms over your head, bending your elbows and placing your hands over shoulder blades or on top of your shoulder.

10. Mid-back

reach behind your back with elbows bent and place your hands on center of your back

Inter Combustion engine (I.C.Engine)

             Internal combustion engine

It is an engine which converts heat energy into mechanical energy. Heat is produced due to process of combustion

Classification

·       Type of fuel used

a.     Petrol engine

b.    Diesel engine

c.      Bio-fuel engine

·       No of strokes

a.      2 stroke engine

b.      4 stroke engine

Stroke: - linear momentum of piston inside cylinder.

Four strokes are: - ignition, compression, expansion, exhaustion.

·        Method of ignition

a.      Spark ignition engine (also known petrol engine)

--eternal medium like spark from spark plug is given to ignite charge (charge is mixture of petrol and gas.)

b.      Compression ignition engine

--gas is compressed to that much extent so it burst to ignite fuel.

è Petrol ignition engine has more temperature than diesel.

·        According to thermodynamic cycles

a.      Otto cycle (principle for petrol engine.)

Otto cycle: Otto cycle is the typical cycle for most of the cars internal combustion engines that work using gasoline as a fuel

b.      Diesel cycle

·        On method of cooling

a.      Air cooled engine

b.      Water cooled engine

          Petrol engine               

                     

       Working

·        Ignition

                 Petrol engines use spark ignition and high voltage current for the spark may be provided by a magneto or an ignition coil. In modern car engines the ignition timing is managed by an electronic Engine Control Unit.

·       Cooling

                      Petrol engines may be air-cooled, with fins (to increase the surface area on the cylinders and cylinder head); or liquid-cooled, by a water jacket and radiator. The coolant was formerly water, but is now usually a mixture of water and either ethylene glycol or propylene glycol. The cooling system is usually slightly pressurized to further raise the boiling point of the coolant.

·        Power measurement

The most common way of engine rating is what is known as the brake power, measured at the flywheel, and given in kilowatts (metric) or horsepower (USA). The term "brake" comes from the use of a brake in a dynamometer test to load the engine

·       

      Different parts of Internal Combustion Engine

1.      Inlet valve: it is moved with help of rocker arm to lift up and pass the charge or gas.

2.      Piston: it moves up and down between TDC (top dead centre) & BDC (bottom dead centre) to produce a stroke.

7. Crank Shaft: it rotates with every stroke (half with one stroke) and provides power for exhaust, expansion.

9. Outlet valve: it’s also moved with rocker arm to pass the exhaust gas.

10: Piston Ring: it provides sealing action for piston to restrict passage of fuels and gas to crank shaft.

è Bore: it is the internal diameter of cylinder

è Spark plug is used in case of petrol engine and fuel injector is used in case of diesel engine.