Rocket Fuel in our cars

8/9/2019 Rocket Fuel in our cars

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TO OBTAIN THE MAXIMUM

ENERGY FROM THE

GASOLINE, THE COMPRESSED

FUEL/AIR MIXTURE INSIDE

THE COMBUSTION CHAMBER

NEEDS TO BURN EVENLY,

PROPAGATING OUT FROM THE

SPARK PLUG UNTIL ALL THE

FUEL IS CONSUMED. THISWOULD DELIVER AN OPTIMUM

POWER STROKE. IN REAL LIFE,

A SERIES OF PRE-FLAME

REACTIONS WILL OCCUR IN

THE UNBURNT "END GASES"

IN THE COMBUSTION

CHAMBER BEFORE THE FLAME

FRONT ARRIVES. IF THESE

REACTIONS FORM

MOLECULES OR SPECIES

THAT CAN AUTOIGNITE

BEFORE THE FLAME FRONT

ARRIVES, KNOCK WILL OCCUR





THESE CYCLIC VARIATIONS CAN EVENLEAD TO FAILURE OF CRANKSHAFT ,SURFACE PITTING OF THE PISTON & EVENBREAKDOWN OF ENGINE

THE COMBINATION OF INTENSE

PRESSURE WAVES & OVERHEATING CANINDUCE PISTON FAILURE IN A FEWMINUTES SINCE KNOCK & IGNITION BOTHARE FAVOURED AT HIGH TEMPERATURESSO ONE MAY LEAD TO THE OTHER UNDERHIGH SPEED KNOCK MAY EVEN LEAD TOPRE IGNITION WHICH THEN ACCELERATES

ENGINE DESTRUCTION

DURING KNOCKING SHOCK WAVES ATPRESSURES MORE THAN 150-200 BAR AREPRODUCED AT TEMPERATURES GREATER

THAN 2000° C. WHICH PRODUCESIMMENSE VIBRATIONS WITHIN THE ENGINE.

WHAT IS KNOCKING



IN RACING CARS SUCH AS FORMULA 1 , AUDI , BMW , MERCEDES, THE ENGINE IS

DESIGNED SUCH AS TO RUN ON A HIGHER C.R. THE REQUIREMENTS OF SUCH ANENGINE INVOLVE FUELS WITH OCTANE NUMBER GREATER THAN 95 TO 105. SUCH AFUEL WITH HIGN OCTANE RATING IS NOT FOUND ON OUR LOCAL PETROL PUMPINGSTATIONS. HENCE SUCH ENGINES WHEN RUN AT LOW SPEEDS HAVE TO CONSUMELEAN FUEL MICTURE WHICH ARE RESPONSIBLE FOR AUTOIGNITION OF FUELS i.e.KNOCKING OCCURS i.e. DETONATION

FOR THE MASSIVE ENGINES RUNNING AT HIGHER LOADS AS IN THE CASE OFSPORTS CARS AT FULLY OPENED THROTTLE OR AT RPM GREATER THAN 2000 -3000KNOCKING BECOMES A MAJOR PROBLEM AT HIGH SPEEDS.

HENCE DOPING OF FUELS BECOMES NECESSARY TO ACHIEVE REQUIRED RON i.e.“ OCTANE NUMBER RATING “ TO SOVE THIS PROBLEM

AS A RESULT OF WHICH THE RATIO OF FUEL (HYDROCARBON) TO THE AIR BECOMES SUFFICIENT FOR COMPLETE COMBUSTION.



USING TOLUENE AS AN ADDITIVE

WHY TOLUENE ?

THE FOLLOWING FACTORS HAVE AN IMPACT ONKNOCKING

1)↑LENGTH OF ‘C’ CHAIN ⇒ ↑KNOCKING

2)PRESENCE OF ALDEHYDES & PEROXIDES ↑ KNOCKING

3)NAPTHENES HAVE A GREATER KNOCKING TENDENCY

HOWEVER THE SAME CAN BE ↓ BY

1)CENTRALIZING ‘C’ ATOMS IN HYDROCARBONMOLECULE

2)↑ DOUBLE BONDS

3)↑ BRANCHING IN HYDROCARBON CHAIN

4)ADDING –CH3 TO THE CENTRAL ‘C’ ATOM INHYDROCARBON CHAIN

CONCLUSION

A MORE COMPACT MOLECULAR STRUCTURE ⇒

↓ TENDENCY TO KNOCK



WHY TOLUENE ?

TOLUENE

IS DENSER THAN ORDINARY GASOLINE (0.87 G/Ml VS. 0.72-0.74) AND CONTAINS MORE ENERGY PER

UNIT VOLUME. THUS COMBUSTION OF TOLUENE LEADS TO MORE ENERGY BEING LIBERATED AND

THUS MORE POWER GENERATED. THUS IT TAKES SMALLER QUANTITIES OF TOLUENE TO ACHIEVE

THE SAME OCTANE BOOST COMPARED TO 100 OCTANE RACING GAS.

THIS IS

IN CONTRAST TO OXYGENATED OCTANE BOOSTERS LIKE ETHANOL OR MTBE WHICH CONTAIN LESS

ENERGY PER UNIT VOLUME COMPARED TO GASOLINE. THE HIGHER HEATING VALUE OF TOLUENE

ALSO MEANS THAT THE EXHAUST GASES CONTAIN MORE KINETIC ENERGY, WHICH IN TURN MEANS

THAT THERE IS MORE ENERGY TO DRIVE TURBOCHARGER VANES. IN PRACTICAL TERMS THIS IS

EXPERIENCED AS A FASTER ONSET OF TURBO BOOST.



EFFECT OF TOLUENE

CONTENT THE OCTANE NUMBER OF FUEL FOR FORMULA 1 RACING IS LIMITED

TO A MAXIMUM NUMBER OF RON 102. ADOPTING A HIGHER

COMPRESSION RATIO IS EXPECTED TO IMPROVE BOTH POWER &

B.S.F.C . HOWEVER AT THE SAME TIME THE POSSIBILITY OF KNOCKING

BECOMES HIGHER. THEREFORE THE KNOCKING PROPERTIES OF FUELS

DETERMINE MAXIMUM COMPRESSION RATIO. IT SOMETIMES APPEARS

THAT DIFFERENCES IN FUEL INGREDIENTS EFFECT KNOCKING

PROPERTIES EVEN THOUGH THE RON OF THE FUELS IS SAME. THE

DEVELOPMENT OF A FUEL WITH GOOD KNOCKING PROPERTIES

UNDER HIGH SPEED & BOOST CONDITIONS IS ESSENTIAL FOR

ADOPTING A HIGH COMPRESSION RATIO.

THE TANK CAPACITY REGULATION LIMITS FUEL AMOUNT TO 150

LITERS. & REFUELING DURING A RACE EVENT IS FORBIDDEN. IN

ORDER TO OBTAIN A LARGELY CALORIFIC IN CAPACITY IS NEEDED I.E.

A DENSE FUEL. COMPARATIVE EVALUATION OF VARIOUS FUELS

REVEALED THAT A FUEL WITH TOLUENE CONTENT IS MOST

FAVORABLE TO MEET THE REQUIREMENTS.



OCTANE VALUES OF VARIOUS FUELS





THANX FOR

UR KIND

ATTENTION

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Rocket Fuel in our cars