During recent years the laws which regulate exhaust gas emissions have become increasingly strict. The constant volume sampling or CVS test is used deformine allowable limits of hydrocarbons, carbon-monoxide and oxides of nitrogen. It is possible to meet the present emission limits with secondary air injection, catalytic converter and E.G.R. (exhaust gas recirculation).
This emission control system has a number of disadvantages:
o The E.G.R. system increases fuel consumption considerably and decreases overall driveability and performance.
o The power required to drive the air pump lowers performance and increases fuel consumption, o The additional emission components which are required result in increased manufacturing costs. The additional number of parts increases the probability of something failing.
The oxygen sensor system consist of:
An oxygen sensor (C) which measures the oxygen in the exhaust; an electronic control unit (A); and a frequency valve (F) operated by the control unit which adjusts the air/fuel mixture.
A pair of micro-switches change the control unit signal at idle (D) and provide full load enrichment at full throttle (E). A relay (B) also provides full load enrichment when the engine speed exceeds 3.500 ± 150 R.P.M.
A new 3-way catalytic converter is used which replaces the standard catalytic converter, air-pump and E.G.R. system.
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