All about Exhaust Manifold

Introduction

Automobiles today are highly equipped with all technological advancements to get most out of while putting the minimum input.

Automobiles use the air-fuel mixture to generate power, and this air finds its way into the engine through the intake manifold, which we have discussed earlier and on the other hand, these burnt gases are released into the atmosphere after passing from the exhaust system, starting off with exhaust manifold.

Today we shall be discussing Exhaust Manifold and its advantages and working.

Working

Intake Manifold and Exhaust Manifold forms the respiratory system of any automobile.

Exhaust Manifold is a tubular structure having single tubes each for 1 cylinder attached to the exhaust side of the engine.

The gases after completing the combustion process exits from the exhaust port into the exhaust manifold, that are then passed through catalytic converted into the muffler and finally into the tailpipe that leads the exhaust air into the atmosphere.

The design of the Exhaust Manifold is really very important for efficient engine performance as the fast exhaust gases are moved from the combustion chamber the more fresh air can be sucked, hence more oxygen and more power are produced.

The gases after combusting in the combustion chamber are already at very high pressure. When the exhaust valve opens, the pressure difference between the chamber and the entry of exhaust manifold allows the exhaust gases to move into the exhaust manifold creating a Vaccum inside the chamber to allow new fresh charges to fill up the chamber for power production is called Scavenging.

Exhaust Manifold plays a very important role as the optimized design of exhaust manifold allows the minimum back pressure to be experienced while the exhaust port is opened for effective scavenging, thus effective Volumetric Efficiency

Design

The Exhaust Manifolds are typically made of stainless steel, cast-iron or heavy-gauge steel, and directs exhaust gases from multiple cylinders to a single exhaust pipe. The exhaust manifold also helps to minimize leakage of heat, air, and gases.

Copper gaskets connecting the manifold to the cylinder head

can be used to create a more airtight system, though these are not necessary.

By minimizing the loss of heat, the exhaust manifold reduces the temperature under the hood.

This helps to prevent damage and overheating to heat-sensitive parts, increasing power by reducing the temperature of the intake manifold.

As gases move more quickly in higher temperatures, the exhaust manifold helps to increase the speed at which exhaust leaves the system.

Limitation

As each cylinders fire at different times, so an ideal exhaust manifold would contain pipes of different lengths to ensure that exhaust gases from one cylinder have been cleared from the system before another fire, to prevent back pressure
.
Due to space constraints, exhaust manifolds typically contain short pipes of uniform length. Though compact, this design increases back pressure, subsequently increasing heat loss under the hood and reducing engine performance.

Originally published at https://www.carengineered.com on June 1, 2020.