Inlet And Exhaust System; The Structure And Working Principle Of Air Cleaner - ZONGSHEN ZS250GY-3(EFI) Maintenance Manual

The inlet system of engine mainly consists of air cleaner and inlet pipe.The main function of which
is to guide and filtrate air,reduce inlet noise and control the volume of mixed gas which is going to engine.
The exhaust system mainly consists of exhaust pipe and muffler.The main function of which is to
transfer the exhaust gas to atmosphere,reduce the noise when exhausting and the temperature of exhaust
gas and eliminate the spark in exhaust gas.A good exhaust system can advance the inlet and exhaust
system,increase engine power and reduce the fuel consumption,so it is also called exhaust muffler.
1 The Structure of Inlet System

[1]The Structure and Working Principle of Air Cleaner

Air cleaner is the important component of inlet system.The function of which is to filtrate,purify the
air entering into cylinder,avoid dust,sand entering into cylinder so that it will reduce the abrasion of
cylinder,piston and piston ring.Its performance has a big effect on the motivity of engine,noise of inlet and
service lifetime.Experiences indicate the abrasion of cylinder will increase 8 times ,the abrasion of piston
will increase 3 times and the abrasion of piston ring will increase 9 times if air cleaner is not installed.In
this way,the reliability of engine will reduce and the service lifetime will be shortened.Therefore,motor-
cycle must be installed with air cleaner. The requirement of air cleaner is not only to filtrate the air,but also
the resistance of air flowing must be small so that the volume of engine inlet will enhance.More require-
ments are reliable working performance,simple structure,small dimension of appearance,light body and
easy to maintain.The air cleaner mainly consists of element and sealed box.When engine runs,air will
enter into the front cavity of air cleaner through air pipe,then flow into the rear cavity after filtration.and
finally enter the throttle.
[2]The Structure and Working Principle of Inlet Pipe
Inlet pipe is the important component to con-
nect throttle and engine inlet.Meanwhile,it has a
function of supporting throttle and has a simple
structure.Its bending shape depends on the posi-
tion which the throttle should be corresponding to the
engine inlet,but you should think about the influ-
ence of inlet resistance.If the pipe is long,it has an
advantage of fuel pulverization,but air resistance is
big.If the pipe is short,which is not good for fuel
pulverization,but air resistance is small.
The mixed gas after pulverization of throttle
flows into cylinder through inlet pipe and engine
inlet.The inlet pipe reduces the heat which engine
has transferred to throttle and separates the shake of
engine from throttle.
2 The Structure and Working Principle of Exhaust
System
The exhaust pipe in exhaust muffler is made of
bending steel pipe.It locates between exhaust vent of
engine and muffler.Its funtion is to guide the exhaust
gas from engine to the muffler.
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Section 3

Inlet and Exhaust System