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If you did your homework, this will make more sense!. If you didn’t, get it turned late tomorrow. COOLING SYSTEMS. AUTO 1. We will take notes in a little bit. HEAT. WHAT MAKES AN ENGINE RUN?. NO! WHAT REALLY MAKES AN ENGINE RUN?. WHERE DOES THE HEAT COME FROM?. THAT’S RIGHT, BURNING FUEL.
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If you did your homework, this will make more sense! If you didn’t, get it turned late tomorrow. COOLING SYSTEMS AUTO 1 We will take notes in a little bit.
HEAT WHAT MAKES AN ENGINE RUN? NO! WHAT REALLY MAKES AN ENGINE RUN?
WHERE DOES THE HEAT COME FROM? THAT’S RIGHT, BURNING FUEL • HEAT CAUSES EXPANSION WHICH CAUSES? • PRESSURE! • PRESSURE PUSHES PISTON DOWN WHICH MAKES THE WHEELS GO ROUND AND ROUND ENERGY……….
ELECTRICAL CHEMICAL NUCLEAR THERMAL RADIANT MECHANICAL TYPES OF ENERGY
FUEL IS CHEMICAL ENERGY WHEN BURNED COVERTS TO... THERMAL ENERGY (HEAT) WHICH CAUSES EXPANSION (PRESSURE) WHICH COVERTS TO… MECHANICAL ENERGY WHICH WE USE TO MOVE THINGS THIS IS ENERGY CONVERSION
REMEMBER, YOU CAN’T CREATE OR DESTROY ENERGY YOU CAN ONLY CHANGE ITS FORM THIS IS ENERGY CONVERSION IN OTHER WORDS, THERE IS ONLY SO MUCH ENERGY HERE ON EARTH AND WE CAN’T ADD TO IT OR RUN OUT OF IT. NEVER USE IT UP! WOW ENERGY CONVERSION?
FUEL IS CHEMICAL ENERGY WHEN BURNED COVERTS TO... THERMAL ENERGY (HEAT) WHICH CAUSES EXPANSION (PRESSURE) WHICH COVERTS TO… MECHANICAL ENERGY WHICH WE USE TO MOVE THINGS WE HAD BETTER WRITE THIS DOWN IN OUR FUEL NOTES.
YOU CAN’T CREATE OR DESTROY ENERGY, YOU CAN ONLY CHANGE ITS FORM! ITS FORM IS CHANGED BY A CHEMICAL REACTION. THE MOST COMMON TYPE OF CHEMICAL REACTION IS COMBUSTION LETS MOVE ON
HEAT IS THE RAPID MOVEMENT OF ATOMS OR MOLECULES IN A SUBSTANCE ABSOLUTE 0 IS-460F (-273C) HEAT IS A FORM OF ENERGY HEAT IS MEASURED BY………. TEMPERATURE DEGREES IN FAHRENHEIT OR CELSIUS BTU’s VOLUME OF HEAT HEAT LETS CONCENTRATE ONWE HAD BETTER WRITE THESE DOWN IF WE DON’T ALREADY KNOW THEM
BRITISH THERMAL UNIT ONE (1) BTU WILL RAISE THE TEMPERATURE OF ONE (1) POUND OF WATER ONE (1) DEGREE FAHRENHEIT (F) BTU,s ????
TEMPERATURE IS THE DEGREE OF HEAT OR HOW HOT. FOR EXAMPLE, A MATCH MIGHT BURN AT 400 DEGREES F. BTU IS THE VOLUME OF HEAT OR HOW MUCH, BUT NOT TEMPERATURE. EXAMPLE, THE AMOUNT HEAT IT TAKES TO HEAT THIS ROOM, OR RAISE THE TEMPERATURE OF THIS ROOM WHAT IS THE DIFFERENCE BETWEEN TEMPERATURE AND BTU,s ?
COMBUSTION TEMPERATURES CAN REACH UP TO __________ DURNING THE COMBUSTION PROCESS. THINK ABOUT THIS QUESTION BEFORE YOU FORM AN ANSWER. WOULD YOU WANT THE VOLUME OF HEAT FROM ONE 6000 DEGREE F POWER STROKE TO HEAT THIS ROOM? NOT IN THE WINTER TIME
DO WE HAVE THE IDEA OF THE DIFFERENCES BETWEEN TEMPERATURE OF HEAT AND VOLUME OF HEAT?
ONE GALLON OF GASOLINE HAS APPROXIMATELY 115,000 BTU,s. THAT MEANS THE AVERAGE GALLON OF GASOLINE HAS THE ENERGY TO RAISE THE TEMPERATURE OF ONE POUND OF WATER 115,000 DEGREES F. (IMPOSSIBLE) OR… RAISE 115,000 LBS OF WATER ONE DEGREE F. OR RASIE 1,150 LBS OF WATER (ABOUT 150 GALS.) 100 DEGREES F. GALLON OF GASOLINE
OTHER FUELS HAVE DIFFERENT BTU,s DIESEL HAS APPROXIMAELY 135,000 BTU,s PER GALLON ALCOHOL HAS APPROXIMATELY 85,000 BTU,s PER GALLON
ONE GALLON115,000 BTU COST $1.30 - $1.60
LOST TO EXHAUST 35% LOST OUT EXHAUST
LOST TO COOLING LOST TO EXHAUST 35% LOST TO COOLING SYSTEM
FRICTIONAL LOSSES 15% LOST TO FRICTIONAL LOSSES LOST TO COOLING LOST TO EXHAUST
WOW FRICTIONAL LOSES LOST TO COOLING APPROXIMATELY 15% LEFT TO MOVE THE CAR. LOST TO EXHAUST
IF TODAYS VEHICLES CAN AVERAGE 20 MILES PER GALLON NOW USING JUST 15% OF THE ENERGY IN A GALLON OF FUEL... WHAT KIND OF MILAGE COULD THEY GET IF WE COULD IMPROVE IT TO 50% OF THE ENERGY IN A GALLON OF FUEL???
TODAY 20 MPG USING 15% OF ENERGY TOMMOROW?? 70 MPG USING 50% OF ENERGY MILES PER GALLON AVERAGES
SO WHY DO WE HAVE TO REMOVE 35% OF THE HEAT WITH A COOLING SYSTEM? WE JUST PAID BIG MONEY TO BUY FUEL TO CREATE HEAT! LIMITED BY CURRENT MATERIAL TECHNOLOGY LIMITED BY CURRENT LUBRICATION TECHNOLOGY
CYLINDER WALL TEMPERATURE MUST BE KEPT BELOW 500 DEGREES F.WHY? OIL BREAKS DOWN (BURNS) CAN YOU SAY DRY FRICTION?
HEAT TRANSFERMAKE SURE YOU GET THIS IN YOUR NOTES THE MOVEMENT OF HEAT FROM ONE PLACE TO ANOTHER
THREE TYPES OF HEAT TRANSFER CONDUCTION CONVECTION RADIATION
CONDUCTION TRANSFER OF HEAT THRU SOLIDS
CONVECTION TRANSFER OF HEAT THRU LIQUIDS OR VAPORS
RADIATION TRANSFER OF HEAT THRU LIGHT RAYS
EXPERIMENT TIME
CAN’T DESTROY OR CREATE ENERGY ENERGY CONVERSION SIX TYPES OF ENERGY IN AUTOMOBILES WE USE, ELECTRICAL, THERMAL, CHEMICAL, RADIANT, AND MECHANICAL. DON’T USE NUCLEAR HEAT WHAT IT IS AND HOW IT IS MEASURED DIFFERENCES BETWEEN TEMP AND BTU LETS REVIEW
DIFFERENT FUELS HAVE DIFFERENT ENERGY CONTENT (BTU) TODAYS ENGINES ARE NOT VERY EFFICIENT
APPROXIMATELY 15% OF THE ENERGY IN GASOLINE IS USED TO MOVE THE CAR. FRICTIONAL LOSES LOST TO COOLING LOST TO EXHAUST
DURING COMBUSTION EXPLOSION WOULD HAVE TRANSFER THRU RADIATION TO HEAD, CYLINDER WALL, AND TOP OF PISTON ALSO TRANSFER THRU CONVECTION TO HEAD, CYLINDER WALL AND TOP OF PISTON and…. WHICH TYPE OF HEAT TRANSFER DO WE USE IN AN ENGINE?
FROM INSIDE OF CYLINDER WALL AND HEAD… HEAT TRANSFER THRU CONDUCTION TO OUTSIDE OF CYLINDER WALL AND HEAD FROM OUTSIDE OF CYLINDER WALL AND HEAD… HEAT TRANSFER THRU CONVECTION TO SURROUNDING AIR ON AIR COOLED TO SURROUNDING LIQUID IN WATER JACKET ON LIQUID COOLED
TYPES OF COOLING SYSTEMS AIR COOLED LIQUID COOLED
AIR COOLING LETS TAKE THE SIMPLE SYSTEM FIRST
TYPES OF AIR COOLING WE WILL NEED THIS IN OUR NOTES FORCED DRAFT OPEN DRAFT
FORCED DRAFT HAS A FAN TO FORCE AIR ACROSS ENGINE USUALLY USED ON ENGINES THAT ARE STATIONARY OR THAT AREN’T MOVED VERY FAST USES SHROUDS TO DIRECT AIR TO PROPER PLACES ALL YOUR ENGINES ARE FORCED DRAFT YOUR FLYWHEEL ACTS AS THE FAN
LETS ADD THAT TO OUR ENGINE PARTS LIST PURPOSES FOR THE FLYWHEEL A.TO KEEP ENGINE MOVING THRU NON POWER STROKES B. ACTS AS A FAN FOR THE COOLING SYSTEM C. WE WILL GET D. C. AND D. LATER
SHROUDS FOR FORCED DRAFT WHAT WOULD HAPPEN IF WE LEFT ONE OFF?
NOTICE THE FINS. THESE ARE CALLED HEAT DISAPATING FINS. THEY ADD SURFACE AREA SO MORE HEAT CAN BE REMOVED. WHAT WOULD HAPPEN IF WE BROKE ONE OFF?
TYPCIAL AIR COOLED MOTORCYCLE ENGINE LETS LOOK AT AN OPEN DRAFT AIR COOLED ENGINE HAS NO FAN ENGINE MUST MOVE THROUGH AIR FOR AIR MOVEMENT MAY OR MAY NOT HAVE SHROUDS
MUST HAVE HEAT DISAPATING FINS AS WELL REMEMBER ENGINE MUST MOVE THROUGH AIR TO GET PROPER COOLING ON THE OPEN DRAFT DESIGN! WITHOUT AIR MOVEMENT, ENGINE CAN OVERHEAT. ESPECIALLY ON HOT DAYS.