Carbon Monoxide CO Emission

Carbon monoxide (CO) is a byproduct of incomplete combustion and is essentially partially burned fuel. If the air/fuel mixture does not have enough oxygen present during combustion, it will not bum completely. When combustion takes place in an oxygen starved environment, there is insufficient oxygen present to fully oxidize the carbon atoms into carbon dioxide (CO2). When carbon atoms bond with only one oxygen atom carbon monoxide (CO) forms.

Oxygen Starved Combustion

During combustion with rich A/F mixtures, the carbon from HC only partially oxidizes, resulting in carbon monoxide (CO) rather than carbon dioxide (CO2).

An oxygen starved combustion environment occurs as a result of air/fuel ratios which are richer than stoichiometry (14.7 to 1). There are several engine operating conditions when this occurs normally. For example, during cold operation, warm-up, and power enrichment. It is, therefore, normal for higher concentrations of carbon monoxide to be produced under these operating conditions. Causes of excessive carbon monoxide includes leaky injectors, high fuel pressure, improper closed loop control, etc.

Effects of A/F Ratio

on Exhaust CO

o s-

O

iS

O

Exhaust CO is lowest when

1 \

~K O

A/F ratio is leaner than

1 \

"ideal"; however, CO

150l \ i V

U

5

increases dramatically with

'w t

richer mixtures.

1 \ l_ \

E .2

HC

1

1 c

4

1

\ S

1

\ w

100,-

1 1 1

3

f 1

2

50,-

i

1

25'-

\

1

.5

1

-

CO

0

n.

«

. HE

10

12

14

16

18

20

22

Richer

<-

Leaner

When the engine is at warm idle or cruise, very little carbon monoxide is produced because there is sufficient oxygen available during combustion to fully oxidize the carbon atoms. This results in higher levels of carbon dioxide (CO2) the principal by-product of efficient combustion.

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Responses

  • togo
    Does 2011 toyota camry produce carbon monoxide?
    2 years ago
  • brhane
    What toyota vehicles produce the most carbon monoxide?
    1 month ago
  • Timo
    Is there danger of carbon dioxide in toyota 4x4 suvs?
    25 days ago

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