Treating The Exhaust Gas In IC Engine- Catalytic Converter

The Catalytic converter converts the pollutants like HC, CO and No2 into harmless gases. It is placed between exhaust manifold and silencer. It contains the plastic pallets coated with the catalyst.

All exhaust gas must flow through it. The catalyst causes a chemical change without being a part of the chemical reaction. The catalytic converter may have two different catalysts. One catalyst treats the HC and CO. The other treats No2. The catalyst encourages the HC and CO to unit with oxygen to become H2O and Co2. This type of converter is known as oxidizing converter because it oxidizes the HC and CO. The metal platinum and palladium are used as oxidizing catalysts.

The Catalyst for NO2 splits the oxygen from the NO2. The No2 becomes harmless nitrogen and oxygen. This type of converter is known as reducing converter. The metal rhodium is used as reducing catalyst Vehicles with catalyst and makes it ineffective. For the catalytic converter to the most effective, the air fuel mixture must have stoichiometric ratio 14 : 7 :1

To achieve the described air fuel ratio at all operating conditions, a feed back system is used. It determines the correct air fuel ratio of the intake charge by measuring the amount of oxygen remaining in the exhaust. The diesel engine catalytic converter is a pure oxidation catalytic converter. It oxidizes HC and CO into water and CO2. It can not reduce NO2.

Comments

ELECTRICAL COMPARATORS AND ITS WORKING

Electrical Comparators are used as a means of detecting and amplifying small movements of a work contacting elements. An electrical comparator consists essentially of a pick-up head or transducer for converting a displacement into a corresponding change in current and a meter or recorder connected in the circuit to indicate the electrical change, calibrated to show in terms of displacement. Generally, an amplifier is needed to provide the requisite sensitivity and to match the characteristics of different parts of the circuit. Electrical comparators can be classified according to the electrical principle used in the pick-up head. Most of the comparators use either a differential transformer, an inductance bridge, a strain gauge or a capacitor as a means of detecting movement of the gauging element. There are different types of electrical comparators. One kind called an electrolimit gauge is used to check or measure the outside diameter of a roll. The object to be checked is place

THROTTLE GOVERNING OF STEAM TURBINES

Steam Pressure at inlet to a steam turbine is reduced by throttling process to maintain the speed of the turbine constant at part load and hence this method of governing is called "Throttle Governing". Construction : Throttle governing system consists of a centrifugal governor, a lever , an oil pump , a pilot piston , control valve , a relay piston and a throttle valve. The throttle valve is moved by a relay piston. The relay piston is actuated by pilot piston control valve. There are two piston valves covering ports in the pilot piston control valve without any overlap. These piston valves are operated by lubricating oil supplied by a gear pump at 2 to 4 bar. The oil returns to the drain from this chamber. Working : When the turbine works on full rated load, the throttle valve will remain open. When the load is decreased, the energy output of the turbine becomes in excess and the turbine shaft speed increases. Hence, governor sleeve will lift. The upward movement of the

Advantages And Disadvantages Of Air Refrigeration System :

Advantages Of Air Refrigeration : 1. The refrigerant used namely air is cheap and easily available. 2. There is no danger of fire or toxic effects due to leakages. 3. The weight to ton of refrigeration ratio is less as compared to other systems. Disadvantages Of Air Refrigeration : 1. The quantity of Refrigerant used per ton of refrigeration is high as compared to other systems. 2. The COP of the system is very low. Therefore running cost is high. 3. The danger of frosting at the expander valves is more as the air contains moisture content.

Mechinopedia For Mechanical Engineers

Search This Blog