Technology to control Emissions:
Computerization of the automobile is needed to control the emissions from automobiles. The number of gases produces during combustion such as Hydrocarbons, carbon monoxide and oxides of nitrogen which are emitted into the atmosphere from the tail pipe.
The clean air act of 1977 set a limithow much amount of each of the pollutants that could be emitted from an automobile. The manufacturers design car having self adjusting engine which control the pollution. In 1981 saw the first of these self adjusting engines in the motor vehicle. They were also called feedback fuel control systems.
The sensor(oxygen sensor) was installed in the system that would measure the fuel content of the exhaust stream and then would send a signal to a microprocessor, which check the value and operate to create the proper ratio of air/fuel. A computer system is design as they were able to adjust ignition spark timing as well as operate the other emission controls that were installed on the motor vehicle.
If a fault is seen then computer will alert the vehicle operator by illuminating a malfunction indicator light. The computer will record the fault in its memory, so that a technician can at a later date retrieve that fault in the form of a code which will help to determine during the time of repairing.
Few are the most popular emission control devices which are installed on the automobile now a day: EGR VALVE, CATALYTIC CONVERTER, AIR PUMP, PCV VALVE, CHARCOAL CANISTER.
How emission control work?
Automotive emissions are controlled in three ways:
1. It promotes more complete combustion so that there is less by products.
2. To reintroduce excessive hydrocarbons back into the engine for combustion
3. Which provide an additional area for oxidation or combustion to occur? This additional area is called a catalytic converter.
1. CATALYTIC CONVERTER
The catalytic converter looks like a muffler. It is located in the exhaust system. Inside the converter are pellets or a honeycomb which is made of platinum or palladium. The platinum or palladium isact as a catalyst.As hydrocarbons or carbon monoxide in the exhaust are passed over the catalystthen it is chemically oxidized converted into carbon dioxide and water. During this, it develops heat and the converter can be seen to glow from excessive heat.
2. PCV VALVE
The take of vapors produced in the crankcase during the normal combustion process is done by positive crankcase ventilation (PCV)system which is redirecting them into the air/fuel intake systemwhich to be burned during combustion.
3. EGR VALVE
The function of the exhaust gas recirculation valve (EGR) valve is to collect a small amount of exhaust gas into the intake system; this dilutes the air/fuel mixture so as to lower the combustion chamber temperature.
4. EVAPORATIVE CONTROLS
An evaporative control system was developed to eliminate the source of pollution. The fuel evaporative control (EVAP System) system plays a role to trap and store evaporative emissions from the gas tank and carburetor.
5. AIR INJECTION
To eliminate the source of emissions an air injection system was created. This is one of emission control that has no effect on engine performance. The only one thing is required a careful inspection of the air pump drive belt.