A Presentation on

Engine emissions

and

its control

PREPARED BY :-

APPU KUMAR

1214340039

ME-1

IMS ENGG . COLLEGE

PREPARED BY :-

APPU KUMAR

1214340039

ME-1

IMS ENGG . COLLEGE

Engine emissions :- 1. exhaust emissions

2.non-exhaust emission

Exhaust emissions :-

Unburnt hydrocarbon( HC)

Oxides of carbon (CO2,CO)

NO,NO2

SO2,SO3

Particulates, soot ,smoke

First four are common to both SI and CI engines and last are mainly from CI engines

Emissions as a function of equivalence ratio

for a SI engine

Emissions as a function of

equivalence ratio for a CI engine

Hydrocarbon emission :-

causes :-

Incomplete combustion

Crevice volumes and flow in crevices

Leakage past the exhaust valves

Valve overlap

Deposits on walls

CARBON MONOXIDE (CO) EMISSION

Created when engine is operated with

a fuel rich equivalence ratio

CO+1/2O2=CO2+heat

Oxides of nitrogen :-

Created mostly from nitrogen in the air Found in fuel blends Fuel may contain trace amounts of

NH3,NC,HCNPrimarily causes for photochemical smog.NO2 +energy from sunlight

=NO+O+smogMINOR EMISSIONS :-Aldehyde, sulphur,lead, phosphorus

Emission control methods :-

1.Thermal converters• means of lowering emissions

• Are high temperatures chamber

through which the exhaust gas flows

• Promotes oxidation of the CO and HC

which remain in the exhaust.

2. CATALYTIC CONVERTERS :-

Catalytic converters :-

• Automotive catalytic converter are made of platinum, palladium and rhodium or a combination of these materials.

• Platinum and palladium are used to change HC and CO into CO2 and Water.

• Rhodium acts to reduce NOx emissions

• Due to enhance emissions standard later model catalytic converters now use cerium to attract and release oxygen inside the converter to aid in the process of changing HC and CO to CO2 and H2o

Catalytic converter :-

The catalyst agent inside a catalytic converter is either ceramic beads or a honeycomb-shaped blocks.

All catalytic converters are encased in a stainless steal housing.

NOTE: stainless steal is used on newer vehicle with catalytic converters because the production of water will rust traditional exhaust system medals in only a few years

Problems related to catalytic

converters

Cold starts ups :-

Not efficient when engines are cold

After engine started it takes several

minutes to become efficient

Temperature at which becomes 50 %

efficient is called light off temperature

in the range of 250-300 c

Non exhaust emissions :- Sources in an automobile which emit

emissions

Fuel tank

Carburetor

Crankcase

MODERN EVAPORATIVE EMISSION

CONTROL SYSTEM

Crankcase blow by :-