COMPOUND VORTEX CONTROLLED COMBUSTION (CVCC)

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A presentation about the Honda's Compound Vortex Controlled Combustion (CVCC).

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COMPOUND VORTEX CONTROLLED COMBUSTION (CVCC)

  1. 1. COMPOUND VORTEX CONTROLLEDCOMBUSTION
  2. 2. CONTENTS• INTRODUCTION• CONSTRUCTION & OPERATION• EARLY DESIGN FLAW• ADVANTAGES• CVCC EQUIPED ENGINES• CONCLUSION2
  3. 3. INTRODUCTION3• CVCC - Compound Vortex Controlled Combustion• CVCC is a trademark by the Honda MotorCompany for an engine with reduced automotiveemissions• The first mention of Honda developed CVCCtechnology was done by Mr. Soichiro HondaFebruary 12, 1971
  4. 4. CVCC engine for Honda Civic4• The CVCC engine debuted in 1975 and had ahead design that allowed for more efficientcombustion.• CVCC system did not require a catalytic converteror unleaded fuel.
  5. 5. Construction and operation• Honda CVCC engines have normal inlet andexhaust valves, plus a small auxiliary inlet valvewhich provides a relatively rich air–fuel mixtureto a volume near the spark plug.• The remaining air–fuel charge, drawn into thecylinder through the main inlet valve, is leanerthan normal.• Upon ignition flame fronts emerge from theperforations and ignite the remainder of the air–fuel charge.5
  6. 6. Construction & Operation Contd…• The remaining engine cycle is as per a standardfour stroke engine.• The volume near the spark plug is contained by asmall perforated metal plate.• Rich mixture (near spark plug)+ lean mixture (inthe cylinder) = Stable running• Yet complete combustion of fuel, thus reducingCO (carbon monoxide) and hydrocarbonemissions.6
  7. 7. 7Fig: Schematic diagram of CVCC engine
  8. 8. Suction Stroke• A large amount of very leanmixture is drawn through themain intake valve into the maincombustion chamber.• A very small amount of richmixture is drawn through theauxiliary intake valve into the pre-chamber8
  9. 9. CompressionStroke• A rich mixture is present in thepre-chamber• A moderate mixture is formedin the main combustionchamber near the pre-chamber outlet• A very lean mixture is presentin the remainder of the maincombustion chamber.9
  10. 10. Ignition• When the spark plug fires, the rich mixture in thepre-chamber is easily ignited.10
  11. 11. Expansion Stroke• The flame from the pre-chamberignites the moderate mixture• This, in turn, ignites the leanmixture in the main combustionchamber.• The formation of carbon monoxideis minimized because of this lean mixture.11
  12. 12. Bottom Dead Center• The stable and slow burning inthe main combustion chamberhas two desired effects.• The peak temperature stays lowenough to minimize theformation of oxides of nitrogen.• The mean temperature is maintained highenough and long enough to substantiallyreduce hydrocarbon emissions.12
  13. 13. Exhaust Stroke• The hot gases exit throughthe exhaust valve, andoxidation continues in themanifold.13
  14. 14. Early design flaw• Early CVCC engines had a problem with theauxiliary valves retaining collars vibrating loose.• Once unscrewed, engine oil would leak from thevalve train into the pre-combustion chamber,causing a sudden loss of power and massiveamounts of smoke to emanate from the exhaustpipe.14
  15. 15. Early design flaw contd…• The condition simulated a blown engine, eventhough the needed repair was quite simple.• Honda eventually came up with a fix involvingmetal retaining rings that slipped over thecollars and prevented them from backing outof their threads15
  16. 16. Advantages• Able to use carburettors.• Did not rely on intake swirl• Previous versions of stratified charge enginesneeded costly fuel injection systems• Previous engines tried to increase the velocityand swirl of the intake charge in keeping therich and lean mixtures separated.• Able to keep the charges adequately separatedby combustion chamber shape.16
  17. 17. CVCC EQUIPED ENGINES• The ED series introduced the CVCCtechnology.• This group displaced 1,487 cc.• Uses a SOHC 8-valve design.• Output with a 3 barrel carburetor was 52 hp(39 kW) @ 5000 rpm17
  18. 18. CVCC EQUIPED ENGINES cntd…• ED1– 1975- Honda Civic CVCC• ED2– 1975- Honda Civic Wagon• ED3– 1976-1979 Honda Civic CVCC• ED4– 1976-1979 Honda Civic Wagon18
  19. 19. CONCLUSIONThe CVCC reduce carbon monoxide andhydrocarbon emissions by the creation of anadditional auxiliary inlet valve that allowed anengine to run smoothly with a lean air/fuelmixture in the cylinder area and a rich air/fuelmixture at the spark plug.19
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