21 Internal Combustion Engine Design Overview

As shown in Figure 2.3, internal combustion (IC) engines convert heat from combustion of a fuel into rotary motion of a crankshaft which, in turn, drives a generator in a distributed generation (DG) system. IC engines consist of:

• Air filter to filter wear particles from incoming air

• Cylinder block, cylinder liners, and cylinder heads to contain combustion and moving components

• Intake manifold to direct the air to the combustion chamber

• Pistons with sealing rings; the piston fits in and rides up and down in a cylinder liner

• Connecting rods which connect the pistons to the crankshaft; pistons undergo a reciprocating motion within a combustion chamber (the volume is confined by the piston, cylinder liner, and cylinder head)

• Valves or ports through which the air or air/fuel mixture enters the combustion chamber; exhaust valves allow the products of combustion to leave the combustion chamber

• Exhaust manifold to direct the products of combustion from the combustion chamber

• Lubrication system to produce a lubricating oil film between all moving parts

• Cooling system for heat rejection; this may be a system of ducting and fins for air-cooling or an internal system of passages for liquid cooling

• Turbocharger(s) or rotary compressors which may be used to increase the charge and power density (amount of power per cubic centimeter or cubic inch of piston displacement) of the engine

Figure 2.4 shows some of the components of the top end of a compression ignition engine.

Engines are classified as spark ignited or compression ignited. When the piston is farthest from the cylinder head, it is at bottom dead center (BDC). When the piston is at the top of its stroke, it is at top dead center (TDC). The compression ratio is the ratio of the volume confined by the combustion chamber at BDC divided by the volume at TDC. At a compression ratio of about 16:1, the gas is hot enough to self-ignite without a spark plug. A diesel engine operates at around 16:1 and is a compression-ignition engine.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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