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

1. COMPOUND VORTEX CONTROLLED
COMBUSTION

2. CONTENTS
• INTRODUCTION
• CONSTRUCTION & OPERATION
• EARLY DESIGN FLAW
• ADVANTAGES
• CVCC EQUIPED ENGINES
• CONCLUSION
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3. INTRODUCTION
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• CVCC - Compound Vortex Controlled Combustion
• CVCC is a trademark by the Honda Motor
Company for an engine with reduced automotive
emissions
• The first mention of Honda developed CVCC
technology was done by Mr. Soichiro Honda
February 12, 1971

4. CVCC engine for Honda Civic
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• The CVCC engine debuted in 1975 and had a
head design that allowed for more efficient
combustion.
• CVCC system did not require a catalytic converter
or unleaded fuel.

5. Construction and operation
• Honda CVCC engines have normal inlet and
exhaust valves, plus a small auxiliary inlet valve
which provides a relatively rich air–fuel mixture
to a volume near the spark plug.
• The remaining air–fuel charge, drawn into the
cylinder through the main inlet valve, is leaner
than normal.
• Upon ignition flame fronts emerge from the
perforations and ignite the remainder of the air–
fuel charge.
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6. Construction & Operation Contd…
• The remaining engine cycle is as per a standard
four stroke engine.
• The volume near the spark plug is contained by a
small perforated metal plate.
• Rich mixture (near spark plug)+ lean mixture (in
the cylinder) = Stable running
• Yet complete combustion of fuel, thus reducing
CO (carbon monoxide) and hydrocarbon
emissions.
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Fig: Schematic diagram of CVCC engine

8. Suction Stroke
• A large amount of very lean
mixture is drawn through the
main intake valve into the main
combustion chamber.
• A very small amount of rich
mixture is drawn through the
auxiliary intake valve into the pre-chamber
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9. Compression
Stroke
• A rich mixture is present in the
pre-chamber
• A moderate mixture is formed
in the main combustion
chamber near the pre-chamber outlet
• A very lean mixture is present
in the remainder of the main
combustion chamber.
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10. Ignition
• When the spark plug fires, the rich mixture in the
pre-chamber is easily ignited.
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11. Expansion Stroke
• The flame from the pre-chamber
ignites the moderate mixture
• This, in turn, ignites the lean
mixture in the main combustion
chamber.
• The formation of carbon monoxide
is minimized because of this lean mixture.
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12. Bottom Dead Center
• The stable and slow burning in
the main combustion chamber
has two desired effects.
• The peak temperature stays low
enough to minimize the
formation of oxides of nitrogen.
• The mean temperature is maintained high
enough and long enough to substantially
reduce hydrocarbon emissions.
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13. Exhaust Stroke
• The hot gases exit through
the exhaust valve, and
oxidation continues in the
manifold.
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14. Early design flaw
• Early CVCC engines had a problem with the
auxiliary valves retaining collars vibrating loose.
• Once unscrewed, engine oil would leak from the
valve train into the pre-combustion chamber,
causing a sudden loss of power and massive
amounts of smoke to emanate from the exhaust
pipe.
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15. Early design flaw contd…
• The condition simulated a blown engine, even
though the needed repair was quite simple.
• Honda eventually came up with a fix involving
metal retaining rings that slipped over the
collars and prevented them from backing out
of their threads
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16. Advantages
• Able to use carburettors.
• Did not rely on intake swirl
• Previous versions of stratified charge engines
needed costly fuel injection systems
• Previous engines tried to increase the velocity
and swirl of the intake charge in keeping the
rich and lean mixtures separated.
• Able to keep the charges adequately separated
by combustion chamber shape.
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17. CVCC EQUIPED ENGINES
• The ED series introduced the CVCC
technology.
• This group displaced 1,487 cc.
• Uses a SOHC 8-valve design.
• Output with a 3 barrel carburetor was 52 hp
(39 kW) @ 5000 rpm
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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 Wagon
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19. CONCLUSION
The CVCC reduce carbon monoxide and
hydrocarbon emissions by the creation of an
additional auxiliary inlet valve that allowed an
engine to run smoothly with a lean air/fuel
mixture in the cylinder area and a rich air/fuel
mixture at the spark plug.
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