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2) ECU Control
(1) Function
a. ECU Function
ECU receives and analyzes signals from various sensors and then modifies those signals into
permissible voltage levels and analyzes to control respective actuators.
ECU microprocessor calculates injection period and injection timing proper for engine piston speed and
crankshaft angle based on input data and stored specific map to control the engine power and emission
gas.
Output signal of the ECU microprocessor drives pressure control valve to control the rail pressure and
activates injector solenoid valve to control the fuel injection period and injection timing; so controls
various actuators in response to engine changes. Auxiliary function of ECU has adopted to reduce
emission gas, improve fuel economy and enhance safety, comforts and conveniences. For example,
there are EGR, booster pressure control, autocruise (export only) and immobilizer and adopted CAN
communication to exchange data among electrical systems (automatic T/M and brake system) in the
vehicle fluently. And Scanner can be used to diagnose vehicle status and defectives.
<00760097008c00990088009b00900095008e0047009b008c00940097008c00990088009b009c0099008c0047009900880095008e008c00470096008d0047006c006a007c00470090009a0047009500960099009400880093009300a000470054005b005700
47009b009600470052005f005c00b6006a004700880095008b> protected from factors like oil,
water and electromagnetism and there should be no mechanical shocks.
To control the fuel volume precisely under repeated injections, high current should be applied instantly
so there is injector drive circuit in the ECU to generate necessary current during injector drive stages.
Current control circuit divides current applying time (injection time) into full-in-current-phase and hold-
current-phase and then the injectors should work very correctly under every working condition.
b. Control Function
Controls by operating stages
To make optimum combustion under every operating stage, ECU should calculate proper injection
volume in each stage by considering various factors.
Starting injection volume control
During initial starting, injecting fuel volume will be calculated by function of temperature and engine
cranking speed. Starting injection continues from when the ignition switch is turned to ignition
position to till the engine reaches to allowable minimum speed.
Driving mode control
If the vehicle runs normally, fuel injection volume will be calculated by accelerator pedal travel and
engine rpm and the drive map will be used to match the drivers inputs with optimum engine power. -
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5) Guidelines on Engine Service
(1) Cautions before service works
Make sure to disconnect the negative (-) cable from the battery to prevent any damage to electric
systems.
Make sure to clean the working area and to prepare the necessary tools before service works.
Always place the ignition switch to OFF position if not required. Otherwise, there could be unexpected
damage to electric devices or personal injuries due to short-circuit.
To prevent the foreign material from entering into the fuel injection system, completely seal the inlets o
f
HP pump, fuel hoses and high pressure pipes.
To remoev the engine, use the dedicated equipments such as engine jack, transmission jack, engine
stand and engine crane. -
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(2) Engine and accessories
When disassembling the engine, related parts (bolts, gaskets, etc.) should be stored as a set.
Clean the components completely with engine oil before assembling if needed.
Fully drain the engine oil, coolant and fuel from the vehicle and seal the inlets with the plugs before
removing the engine.
All the interference should be eliminated before removing the engine. -
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- To prevent the personal injuries and vehicle damages that can be caused by mistakes during service
and to provide the optimized performance and safety after service works, the service technicials must
keep the basic cautions and service guidelines below. These could be easily forgotten during service
works.
Engine has a lot of precise components. The specified tightening torque and correct procedures should
be kept during service works. And, the working area is always clean and well prepared.
To prevent any damage to electric systems, make sure to disconnect the negative (-) cable from the
battery and place the ignition switch to OFF position before servicing.
Use only the specified parts with same ratings when replacing the electric devices. Check the
grounds and connections for looseness. -
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(3) Electric devices
Extraordinary care should be taken when servicing the electric systems. Currently, the engine uses a lot
of electric devices. Short circuit and poor contact may cause the low engine performance, incomplete
combustion and other abnormalities.
When working with the fuel or oil systems in enclosed area, always keep the working area well-
ventilated and never allow anybody to smoke.
Gaskets and seals on the fuel and oil systems should be replaced with new ones. All bolts and nuts
should be tightened as specified.
Make sure to check the connections for leak after installation. -
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(4) Fuel and lubrication system
02-6
3. GUIDELINES ON ENGINE SERVICE
G20DF engine is for FF (Front Engine Front Drive) type vehicle. Therefore, there are some deferent
maintenance and repair works compared to the engine for FR (Front Engine Rear Drive) type vehicle.
For safe and correct works, you must observe the working procedures and instructions in this manual.
And, use the designated tools as follow:
: Power train mounting stand / Engine hanger / Engine stand / Heavy duty engine jack.
Cautions before service works ▶
G20DF engine is FF (Front Engine Front Drive) type engine, and the engine and transmission are
integrated in a same module. Remember that there are many differences compared to
conventional engine in FR (Front Engine Rear Drive) type SUV vehicle.
To remove the engine, use the dedicated equipments such as engine jack, transmission jack,
engine stand and engine crane (1 ton).
To prevent the engine from abruptly starting during service in engine compartment, never allow
anybody to stay in the vehicle.
Make sure to disconnect the negative (-) cable from the battery to prevent any damage to electric
systems.
Make sure to clean the working area and to prepare the necessary tools before service works.
Always place the ignition switch to OFF position if not required. Otherwise, there could be
unexpected damage to electric devices or personal injuries due to short-circuit..
To prevent the foreign material from entering into the fuel injection system, completely seal the
inlets of HP pump, fuel hoses and high pressure pipes.
Do not remove the engine while supporting the oil pan with a jack. -
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Lifting up the vehicle ▶
Before lifting up the vehicle with a lift, correctly support the lifting points.
To prevent the vehicle from rolling down, put the chocks under the tires (when using a 4-post lift).
Make sure to support the correct lifting points (when using a 2-post lift). -
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02-71116-01
Engine and accessories ▶
Engine has a lot of precise components. The specified tightening torque and correct procedures should
be kept during service works. And, the working area is always clean and well prepared.
When disassembling the engine, related parts (bolts, gaskets, etc.) should be stored as a set.
Carefully read the disassembly and reassembly procedures in this manual before starting the
works.
Clean the components completely with engine oil before assembling if needed.
Fully drain the engine oil, coolant and fuel from the vehicle and seal the inlets with the plugs before
removing the engine.
All the interference should be eliminated before removing the engine. -
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Tightening the fastener ▶
When reassembling the parts to G20DF, use the angle tightening as a final step.
1. Clean the mating surfaces before tightening.
2. Place the marks with paint to tighten by angle if the angle wrench is not available.Exhaust system ▶
Wear the protective gloves before removing the exhaust pipe.
The exhaust pipe is very hot immediately after stopping th engine. Check if the exhaust pipe is fully
cooled down before servicing the exhaust system. -
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Cooling system ▶
Scalding hot coolant and steam could be blown out under pressure, which could cause serious
injury. Never remove the coolant reservoir cap when the engine and the radiator are hot. -
The position and direction of the componets is based on the rear view.
Do not tighten the fasteners with excessive force. Especially, the threads of cylinder block could be
damaged.
The self screw bolt makes the thread itself when tightening it. Do not apply excessive force.
Do not reuse the bolt that has been tightened with angle tightening method.
02-8
Fuel and engine oil system ▶
The engine oil and fuel damages the painted surfaces and rubber material of the vehicle.
Disconnect the negative cable from the battery before servicing the fuel system, and prepare the
service plug grip.
When working with the fuel or oil systems in enclosed area, always keep the working area well-
ventilated and never allow anybody to smoke.
Do not allow the gasoline to contact to rubber or leather parts.
Carefully separate the pipe between high pressure fuel pump and fuel injector so that any fuel can
be spilled out.
Fully release the pressure from the fuel system before removing any parts of fuel system.
To release the fuel pressure in high pressure line, let the engine fully cool down.
Gaskets and seals on the fuel and oil systems should be replaced with new ones. All bolts and nuts
should be tightened as specified.
Prolonged exposure to the engine oil make cause a skin cancer or an irritation.
Used engine cotains the hazardous material that may cause the skin cancer. Do not allow the used
engine to make contact with your skin.
Make sure to wear the protection gloves and goggle when handling the engine oil. If contact
happens, rinse affected areas immediately with plenty of water. Do not wash it with gasoline or
solvent. If irritation persists, consult a doctor.
Improperly disposed engine oil can pollute the environment. Dispose the used engine oil and oil
filter in accordance with local environmental regulations.
Make sure to check the connections for leak after installation. -
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Electric devices ▶
To prevent any damage to electric systems, make sure to disconnect the negative (-) cable from the
battery and place the ignition switch to OFF position before servicing.
Use only the specified parts with same ratings when replacing the electric devices. Check the
grounds and connections for looseness. -
- Extraordinary care should be taken when servicing the electric systems. Currently, the engine uses a lot
of electric devices. Short circuit and poor contact may cause the low engine performance, incomplete
combustion and other abnormalities.
02-211311-01
The drive chain is single chain drive system with simple design and variable performance, and it utilizes
the hydraulic tensioner to reduce the wave impact generated by the chain. The silent chain provides the
silence during the operation. To improve NVH, the shoulder bolt has been introduced. Overview ▶
Layout and Components ▶
Hydraulic tensioner
Consists of tensioner housing
plug, spring, check valve, and
operated by hydraulic
pressure and spring in
tensioner
Chain bush upper
Chain type: Single bush
type
Chains: 146 ea
Tensioner rail
Installed between exjaust
camshaft sprocket and
crankshaft sprocket
Crankshaft sprocket
Teeth: 21 ea
Oil pump sprocket
Teeth: 28 ea
Exhaust camshaft
sprocket
Teeth:42 eaIntake camshaft
sprocket
CVVT
Teeth: 42 ea
OCV
Controls the hydraulic circuit
to control the intake cam
sprocket variably
Clamping rail
Installed between intake
camshaft sprocket and
crankshaft sprocket
Mechanical tensioner
Operated by spring in
tensioner
Chain lower bush
Chain type: Single bush type
Chains: 58 ea
07-8
1) Operation Flow
3. OPERATING PROCESS
CVVT
Cam journal
bearing
Main oil gallery
in cylinder block
Oil pressure
switch
Oil filter assembly
Oil supply Oil pump Main journal bearingChain
tensioner
Oil jet
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Rear oxygen
sensor
2) Components for ECU Input
Coolant temperature
sensorCamshaft position
sensorCrankshaft position
sensor
Front oxygen sensor
Knock sensor
G20DF Engine ECUElectronic throttle
body
Refrigerant pressure sensor
Clutch pedal signal
Blower switch signal
Brake pedal signal
CAN
ABS & ESP
Instrument cluster
TCU -
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Oil pressure
switchOil pressure warning lamp
T-MAP sensor