Explanation about Emission Control System

1. Emission Control System
Purpose
● The emission control systems are installed to
reduce the amount of CO, HC and Nox exhausted
from the engine.
● To prevent the atmospheric release of blow by
gas HC and evaporated fuel containing HC being
released from the tank.

2. Function of each system
 1. PCV – Reduce HC
 2. EVAP – Reduce evaporative HC
 3. EGR – Reduce NOx
 4. TWC – Reduce CO, HC, NOx

3. Type of Exhaust Emission
Pollutants
 Carbon Monoxide (CO)
 ● Carbon monoxide is a colorless, odorless,
tasteless and toxic gas produced as a by-
product of combustion.

 ● A product of incomplete combustion.
 ● The main source of CO in our air is vehicles
emission.

4.  Health Effects
 ● CO reduce the blood’s ability to carry
oxygen to body tissue including vital organs
such as the heart and brain.
 ● It is most harmful to those who suffer
from heart and respiratory disease.

5. Symptoms Associated With a Given
Concentration of CO Over Time

6. Nitrogen Oxide (Nox)
 ● Generated when nitrogen in the air reacts with oxygen at
the high temperature and pressure in side the engine.
 ● Nox gases are formed everywhere where there is
combustion – like in an engine.

 ● In areas of high motor vehicle traffic, such as in large cities,
the amount of nitrogen oxides emitted into the atmosphere as
air pollution can be significant.

 ● Nox react to form smog and acid rain.
 ● Fuel NOx can contribute as much as 50% of total emissions
when combusting oil and as much as 80% when combusting
coal.

7. Health effects
 ● NOx reacts with ammonia, moisture, and
other compounds to form nitric acid vapor
and related particles.
 ● Small particles can penetrate deeply into
sensitive lung tissue and damage it, causing
premature death in extreme cases.
 ● Inhalation of such particles may cause or
worsen respiratory diseases

8. Sulfur Oxide (Sox)
 ●A general term for oxide of
sulphur, which are emitted from
motor vehicle burning fuel
containing sulphur.

9. Health effects
 ●Emissions harm human health
depends primarily on ground-level
ambient concentrations, the
number of people exposed and
duration of exposure.

10. hydrocarbon
 In chemistry, a hydrocarbon is any
chemical compound that consists
only of the elements carbon (C)
and hydrogen (H).

11. Health effect
High levels of hydrocarbons in the
atmosphere can reduce the amount
of available oxygen. Carcinogenic
(cancer causing) forms of
hydrocarbons are considered
hazardous air pollutants, or air
toxins and can lead to the
development of cancer.

13. CATALYTIC CONVERTER DESIGN

14. EGR VALVE

15. EGR VALVE

16. Basic operation of EGR valve
 When a strong intake manifold
vacuum was pulled (the less the
throttle was opened ie. You took you
foot off the pedal) the EGR valve
opens to let exhaust gases into the
intake manifold. As more throttle is
applied, vacuum drops and the EGR
valve closes.

17. EGR SYSTEM

18. INSIDE CATALYTIC CONVERTER

19. Meaning of oxidation
Oxidation is the loss of electrons
from an atom, molecule or ion,
whereas reduction is the gain of
electrons.

24. PCV VALVE

25. LOCATION OF EXHAUST GAS EMISSION
CONTROL COMPONENTS