Intake & Exhaust : Intake system procedure

Checking & changing an air filter

Part 1. Preparation and safety

Objective

• Check, remove, and replace an engine air filter — throttle body and plenum types.

Personal safety
Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:

• Work clothing - such as coveralls and steel-capped footwear
• Eye protection - such as safety glasses and face masks
• Ear protection - such as earmuffs and earplugs
• Hand protection – such as rubber gloves and barrier cream
• Respiratory equipment – such as face masks and valved respirators

Intake & Exhaust : Exhaust system components II

• Exhaust manifold
• Exhaust pipe
• Extractors
• Mufflers
• Catalytic converters
• Flexible connections
• Ceramic coatings
• Electronic mufflers
• Thermal expansion
• Superchargers
• Intercoolers
• Frequency
• Back-pressure

Exhaust manifold

The exhaust manifold is bolted to the cylinder head or onto the exhaust ports.
On passenger vehicles the exhaust manifold is usually made of cast iron.
Sometimes there is a separate passage for each exhaust port.
The length of the passages in the exhaust manifold should be designed so that pulses of exhaust gases from one cylinder assist the flow of gases from another.
It has large tubular sections, to improve gas flow, And no sharp bends to slow the gases down.
As well, the exhaust manifold must be shaped to allow for the location of the engine, and the bodywork of the vehicle. Some vehicles use heat shields to protect nearby components and the passenger compartment from the heat radiated from the exhaust components.

Intake & Exhaust : Exhaust system components I

• Exhaust manifold
• Engine pipe
• Catalytic converter
• Exhaust brackets
• Muffler & components

Exhaust system components

The primary components of the automotive exhaust system are:

Exhaust manifold

The exhaust manifold is bolted to the engine's cylinder head. It can be of a one-piece or two-piece construction. In performance type vehicles, the exhaust manifold is often replaced with extractors.
A normal exhaust manifold is usually made from cast iron.
Due to the extreme temperatures generated at the exhaust manifold, heat shields can be installed to protect other vehicle components from heat damage.

Engine pipe

Intake & Exhaust : Intake system components

• Air cleaners
• Carburetor air cleaners
• EFI air cleaners
• Intake manifolds
• Intake air heating
• Volumetric efficiency
• Forced induction

Air cleaners

An air cleaner filters air that passes through it to stop harmful particles reaching the engine.
The air cleaner on a carbureted engine can be on top of the carburetor, or beside the engine, connected to the carburetor by a hose or duct.
Position is usually decided by how much space there is, or bonnet profile.
On some electronically fuel injected engines, the air cleaner is on top of the throttle body, similar to a carburetor.
Other air cleaners are connected by ducts.
Diesel engines often have more than one air cleaner. This may be due to their severe working conditions.
They’re usually mounted away from the engine to obtain cleaner, cooler air.
A lot of air passes through the intake system into the engine. In a gasoline engine, it’s about 15 times the amount of fuel by weight.
By volume that’s 10,000 times more air than fuel.
The air-fuel mixture enters the engine so the air needs to be clean.
Any abrasives that enter the engine can cause wear and damage.
It also has a silencing effect, muffling noise produced by the air entering the engine.
It can act as a flame trap. So if a gasoline engine backfires, the air cleaner can contain the flame within the intake manifold or carburetor.

Intake & Exhaust : Intake system components

• Intake manifold
• Throttle body/carburetor
• Air induction components

Intake system components

The primary components of the automotive intake system are:

Intake manifold

The intake manifold is attached to the cylinder head. Its construction and design depends on its application. It is normally made of an aluminum alloy.
On carbureted engines, the intake manifold supports or houses the carburetor. While on EFI engines it can house or support a throttle body.

Throttle body/carburetor

Intake & Exhaust : System

• Carbureted systems
• Electronic fuel injection systems
• Diesel induction systems
• Exhaust systems

Carbureted systems

On a carbureted engine, the intake system is part of the fuel system.
The main function of the intake system on a gasoline engine is the delivery of the required amount of the mixture of air and fuel.
In a basic system, air enters the air cleaner for filtering, then passes into the carburettor, where it mixes with the required amount of fuel. This air-fuel mixture then enters the intake manifold, and finally the cylinder.
The same basic principle applies on the rotary engine.
On all carbureted systems, the intake system can be crucial in increasing engine output. This can be done by increasing volumetric efficiency, that is, by increasing the amount of air-fuel mixture burned in the cylinders.
This can be achieved by using a larger inlet valve to admit more charge into the combustion chamber; by using large, free-flowing intake manifolds; or by using extra carburetors.
Carbureted intake systems were once standard for gasoline engines, but increasingly they are being displaced by electronic fuel injected systems.