Category: Performance of Internal Combustion Engines

It is desirable that a catalytic converter has an effective life time equal to half to the car life or at least 2 lakh km. Converters lose their efficiency with age due to thermal degradation and poisoning of the active catalyst material. Just a small amount of lead on a catalyst site reduces HC emission…

The emissions exhausted into the surroundings pollute the atmosphere and cause the following problems: Pollutant Health hazards (a) Carbon monoxide, CO Interferes with transfer of oxygen through the body, causes headache, nausea, dizziness, permanent visionary damage, coma, and even death. (b) Nitrogen oxides (NOx) Tissue changes in lungs, heart, liver, and kidney. (c) Hydrocarbons (HC)…

A catalyst is a substance that accelerates a chemical reaction by lowering the energy needed for it to proceed. It is not consumed in the reaction. A three-way catalytic converter reduces the concentration of CO, HC, and NOx in the exhaust. A catalytic converter is usually a stainless steel container mounted along the exhaust pipe of…

The concentration NOx in the exhaust is closely related to the peak cycle temperature. There are different methods by which peak cycle temperature can be reduced and NOx emission can be controlled. There are mainly three methods which are commonly used as follows: catalyst (which is already discussed), water injection (rarely used), and exhaust gas recirculation (EGR)…

It is claimed by many manufacturers that odour additive compounds can reduce odour intensity. However, it is observed that by using additives, there is hardly any effect on odour formation and is carried by exhaust gases. The control of odours by using catalysts are under development and experiments have revealed that a few oxidation catalysts…

Formation of smoke is basically a process of conversion of molecules of hydrocarbon fuels into particles of soot. It should be noted that soot is not carbon but simply an agglomeration of very large polybenzenoid free radicals. It is also observed that soot formation during the early part of the actual combustion process is common…

The increase in the levels of SO2, SO3, NOx, and suspended particulate matter creates havoc with the surrounding atmosphere. Out of these, SO2 is the most potent as it causes bronchitis spasms. O3 causes inflammations of the inner lining of air passages. A cocktail of these lethal substances narrows and inflames the air passages leads to smelling…

Among the gaseous pollutants emitted by the diesel engine, NOx are the most significant. In this respect, the diesel engine is not very much behind the gasoline engine. NOx being most hazardous, the limit is set to 350 ppm in many countries. In many diesel engines, NOx varies from a few hundreds to 1000 ppm. The mechanism of…

CO is formed when there is insufficient O2 to completely oxidise the fuel during combustion of fuel. The amount of CO formed in a diesel engine is considerably lower than a petrol engine because of supply of continuous excess air to the engine. Theoretically, diesel engine should not emit CO at all as it always operates…

The concentration of hydrocarbons in diesel exhaust varies from a few ppm to a several thousand ppm, depending on the load on the engine and its speed. The hydrocarbons in diesel exhaust are composed of a mixture of many individual hydrocarbons in the fuel supplied to the engine as well as partly burned hydrocarbons produced…