Emission
Control
Systems-California
Crankcase
The engine crankcase breather outlet incorporates an oil separator flame-trap
emission
(arrester) in the top of the valve rocker cover which is connected by hoses to
control
the controlled depression chamber between the piston
and
the throttle disc of
the carburetter. Piston blowby fumes are drawn into the depression chamber
of the carburetter from the rocker cover, and are joined by purged air from the
primary charcoal canister of the fuel evaporative loss system. These fumes
combine with the inlet charge for combustion in the normal way.
Exhaust
The exhaust emission control system is designed to give the required degree of
emission
control of the carbon monoxide, unburnt hydrocarbons and oxides of nitrogen
control
content of exhau st gases.
The emission control system is a combination of engine components and air
injection techniques and consists of a special carburetter, air injection into the
exhaust
man
ifold and exhaust gas recirculation.
THE
EMISSION CONTROL COMPONENTS
1. Primary charcoal adsorption canister
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The catalytic converter is fitted into the exhaust system in order to reduce carbon
monoxide
and
hydrocarbon emissions.
The carburetter
is manufactured t pecial exhaust emission specification and
is tuned to give the maximum erni i n control consistent with retai ning vehicle
performance and drivability. The metering needle is
arra
nged in such a manner
that
it is always lightly spring loaded against the side of the jet to ensure con-
sistency of fuel metering.
A throttle by-pass valve limits the inlet manifold
depression and ensures that durin g conditions of engine overrun the air/fuel
mixture enters the engine cylinders in a burnable condition consistent with low
emission levels.
The carburetter
is manufactured t pecial exha ust emission specification and
is tuned to give the maximum emi i n control consistent with retaining vehicle
performance and drivability. The m tering needle is
arra
nged in such a manner
that
it is always lightly spring loaded against the side of the jet to ensure con-
comoustlon In rne
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The exhaust gas recirculation valve mounted on the exhaust manifold will
re-circulate a controlled quantity of the exhaust gases to reduce comb ustion
chamber temperature.
When the gulp valve opens, a small
q ianti ty f air is admitted directly into the
inlet manifold to lean off the rich air/f
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"I n i ture which is present in the manifold
under cond itions immediately
f
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win 1 thr ttle closure. This mixture, having
been reduced to a burnable c n lition, ' n bines with engine inlet charge for
combustion in the engine cylind rs in the normal way.
An air pump mounted on the front of the engine, and belt driven from the
crankshaft pulley, supplies air under pressure through a hose, a check valve,
and distribution pipe to the exhau t manifold. The check valve prevents high
pressure exhaust gases from blowing back into the pump due to, for example,
pump
drive failure.
The quantity of air-polluting elements in the gases leaving the exhaust pipe is
reduced by adding air to the
hot
gases immediately they leave the combustion
chambers of the engine. The injection of air into the exhaust gases promotes a
continued conversion of the undesirable hydrocarbon and carbon monox ide
components of the exhaust gases to relatively harmless carbon dioxide
and
water.
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15
15. Air injection pipe
16. Air pump
17. Check valve
18. Air temperature control valve
19.
Hot
air pipe
20. Exhaust gas recirculation valve
21. E.G.R. valve pipe
22.
E.G
.R. valve flame
trap
23. E.G .R. valve flame
trap
line to carburetter
24. Flame
trap
line to E.G.R. valve
25. Distributor flame
trap
26. Distributor flame
trap
line to carburetter
27. Flame
trap
line to distributor vacuum unit
28. Air vent pipe
15. Air injection pipe
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29
/ 8
18
12
·5
1. Primary charcoal adsorption canister
2. Vapour lines
3. Purge line
4. Connecting pipe
5. Secondary charcoal adso
rpt
ion canister
6. Restricted connection
7. Restrictor
8. Sealed oil filler cap
9. Oil separator/flame trap (arrester)
10. Fuel pipe
11. Fuel
pump
12. Running-on control valve
13. Sensing pipe
14. Running-on control hose
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