Category: Performance of Internal Combustion Engines

It has been observed from the experiments that the products of partial oxidation are the main cause of odour in diesel exhaust. This partial oxidation may due to a very lean mixture during idling or due to wall-quenching effect. The effect of fuel-air ratio and odour is shown in Fig. 11.25. The members of the aldehyde…

Engine exhaust smoke is the result of incomplete combustion. Smoke from exhaust is a visible indicator of the combustion process within the engine. It is generated at any volume in the engine where the mixture is rich. The fuel-air ratio greater than 1.5 and at pressures developed in diesel engine produces soot. Once soot is formed,…

The diesel engine is used more than any other type of engine for transportation, thermal power generation, and many other industrial and agricultural applications. The exhaust emissions from combustion in diesel engine are no different from those of combustion processes in petrol engine, the difference being only in the level of concentration of individual pollutants.…

The basic principle of a crank case blow-by control system is the recirculation of vapours back to the inlet manifold. Figure 11.24 shows a typical closed type known as a positive crank case ventilation (PCV) system. The gases escaping past the piston and entering into the crankcase are returned to the inlet manifold and then to the…

An emission control programme aims at reducing the concentration of CO, HC, and NO. The main approaches adopted are as follows: To reduce atmospheric pollution, two different approaches are followed: In petrol engines, the main pollutants which are objectionable and are to be reduced are HC, CO, and NOx. The methods used are as follows:

Spark ignition engine emissions are divided into three categories as exhaust emission, evaporative emission, and crank case emission. Figure 11.19 Emissions from SI engines The major constituents which contribute to air pollution are CO, NOx, and hydrocarbons (HC) coming from SI engine exhaust. The percentages of different constituents coming out from the above three mentioed sources…

A four-stroke diesel engine of 3000 cc capacity develops 14 kW per m3 of free air induced per minute. When running at 3500 rev/min, it has a volumetric efficiency of 85% referred to free air-conditions of 1.013 bar and 27°C. It is proposed to boost the power of the engine by supercharging by a blower (driven…

The power output of an engine depends on the amount of air inducted into the cylinder per unit time, the degree of utilisation of this air, and the thermal efficiency of the engine. The amount of air inducted per unit time can be increased by increasing the engine speed or by increasing the density of…

Brake power is measured with the following ways: where W = load on load carrier, N L = distances from centre of shaft to load, m. Example 11.5 A four-cylinder engine running at 1200 rpm gave 18.6 kW brake power. The average torque when one cylinder was cut off was 105 N.m. Determine the indicated thermal efficiency…

The arrangement to measure the consumption of air by air-box method is shown in Fig. 11.12. It consists of an air-tight box fitted with a sharp-edged orifice of known coefficient of discharge. Due to the suction of engine, there is a pressure depression in the box which causes the flow through orifice for obtaining a steady…