Page 464 of 1336
1130-33
Functions
Piston transfers the combustion energy from engine to connecting rod.
C. Snap ring
Locks the piston pin. - A. Piston ring
#1 ring (Top ring) : Prevents the high pressurized combustion gas from leaking into crank chamber,
and prevents the engine oil getting into combustion chamber.
#2 ring: Scrapes the engine oil on the cylinder bore, and prevents the leaked combustion gas from #1
ring from leaking into the crank chamber.
Oil ring: Scrapes the engine oil on the cylinder bore. -
-
-
B. Piston pin
Connects the piston the connecting rod, and transfers the linear movement of piston to connecting rod
to convert it to rotating energy. -
Piston ring
Piston ring end gap (mm)
#1 end gap: 0.170 ~ 0.320
#2 end gap: 0.300 ~ 0.450Piston ring side clearance (mm)
#1 groove: 0.040 ~ 0.080
#2 groove: 0.040 ~ 0.080
Page 470 of 1336
1128-01
Front view
Rear view
Spring pin (cylinder head mounting)
Expansion plug (exhaust: 6)
Screw plug (water jacket plug) (30Nm)
Screw plug (oil gallery plug)
Spring pin (T.G.C.C) A.
B.
C.
D.
E.
Overview
The cylinder block is made of special cast iron, and contains the major components such as cylinder
head, crankshaft and piston assembly. There are oil and coolant galleries to lubricate and cool the
engine.
Components
Plug screw (water jacket plug) (70Nm)
Expansion plug (intake: 4)
Spring pin (A/C mounting)
Oil gallery (oil filter assembly)
Ctankshaft position sensor mounting
Plug screw (oil gallery plug)
Spring pin (RR seal mounting) A.
B.
C.
D.
E.
F.
G.
Page 471 of 1336
Engine oil
Coolant
Coolant and oil flows
Cylinder head
Cylinder block water
jacket
Coolant pumpCoolant pipe
Thermostat
Supply line to cylinder head
Oil pumpSupply line to PCJ
Main bearing
Oil filter assembly
Page 493 of 1336

1745-01
1. OVERVIEW
This system purifies the exhaust gas generated by the combustion in the engine to reduce the pollutants
and noise during that arise during combustion.
Harmful materials produced in the combustion process is treated and reduced in the exhaust system.
Harmful materials discharged from the crankcase and fuel tank is drawn into the intake system again to
reduce discharge amount of harmful materials.
Emission aftertreatment system
Catalytic Converter & O2 Sensor
The catalytic converter is a monolith type purification system composed of cordierite which purifies
exhaust gas through the small holes of active monolith catalyst from the exhaust manifold. As exhaus
t
gas passes through the small holes in the layer in the middle, its CO and HC are reduced by
oxidization reaction and its NOx is reduced by reduction reaction to Pt, Ph and Pd. The oxygen
sensor sends signals for feedback and determination of catalyst condition. For detailed description,
see the corresponding section. -
The fuel evaporative gas is a gas evaporated to the atmosphere in the section between the fuel tank and
fuel line, and its main component is hydrocarbon (HC). The fuel evaporative gas is temporarily stored in
the canister, and it is drawn to the engine through the throttle body when the purge control solenoid valve
is open according to the engine operating condition.
Gas in the combustion chamber is sealed by the piston. However, gas is leaked through the gap
between the cylinder and piston and drawn into the crankcase during the compression and explosion
strokes. This gas is blow-by gas and its main components are hydrocarbon and carbon monoxide. If this
gas is drawn into the crankcase, the system can be corroded and oil can be deteriorated. Also, if this
gas is discharged into the air, it can pollute the environment. To prevent these, the blow-by gas
reduction system (also called as crankcase ventilation system) draws the blow-by gas from the
crankcase to the combustion chamber for combustion.
Purge Canister Control
Blow-by gas control system (crankcase ventilation system)
Page 498 of 1336
1443-01
1. SPECIFICATION
Description Specification
Spark plugInternal resistance
Center electrode Iridium alloy
Ground electrode Platinum alloy
Electrode clearance 1.1 mm
Change interval 160,000 km
Ignition coilPrimary operating current
Generated voltage
(primary/secondary)Max. 400 V / 5~20 kV
Ignition type Independent ignition type
Ignition sequence 1-3-4-2
Page 499 of 1336
2. LAYOUT
Ignition Coil
Bolt
Spark Plug 1.
2.
3.
Page 500 of 1336
1443-01
1. OVERVIEW
The ignition system is to supply high voltage generated from the ignition coil to the spark plug. The
G20DF engine is equipped with the independent type direct ignition system that the ignition coil is
installed in each cylinder.
The basic ignition timing in each cylinder is determined by the signals from camshaft position sensor and
crankshaft position sensor.
This ignition system controls the electronic ignition timing received from the engine ECU. To control the
ignition timing precisely, the ECU use the information below:
Engine load
Coolant temperature
Intake air temperature
Engine rpm
Camshaft position sensor (CPS)
Crankshaft position sensor (CKS) -
-
-
-
-
-
If the signal from the camshaft position sensor is not delivered to the engine ECU, the ignition coil and
fuel system cannot be operated.
Page 501 of 1336
2. COMPONENTS
Ignition coil
Camshaft position
sensorKnock sensorInjector
Spark plug