SsangYong Actyon Sports II. Manual - part 53

15-9

0000-00

Fuel rail pressure 

sensor

(2) Components for ECU Input

CAN

- ABS & ESP
- GCU
- Instrument 
  cluster
- TCU

Swirl valve 

position sensor

Differential 

pressure sensor

E-EGR valve 

position sensor

Camshaft position 

sensor

Coolant 

temperature 

sensor

Exhaust gas 

temperature 

sensor

HFM sensor

Oxygen sensor

T-MAP sensor

Crankshaft 

position sensor

Accelerator pedal 

sensor

Throttle position 

sensor

Knock sensor

-Auto cruise switch
- Rear right wheel 
  speed (without ABS)
- Refrigerant pressure 
  sensor
- Clutch pedal signal
- Blower switch signal
- Brake pedal signal

Water sensor

15-10

(3) Components for ECU Output

CAN

E-EGR cooler 

bypass valve

- Instrument cluster

- TCU

- Self diagnosis

PTC heater

Cooling fan

E-EGR valve

Variable swirl 

valve

E-VGT actuator

IMV valve

A/C compressor

Injector

Throttle position 

sensor

- Glow plug unit

- ABS & ESP unit

- GCU

15-11

0000-00

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.
Operating temperature range of ECU is normally -40 to +85°C and 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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15-12

(2) Fuel injection control

a. Multi injection

Fuel injection process consists of 3 steps: Main Injection, Pilot Injection, Post Injection

Injection

Function

Main

Produces engine power

Pilot 1

Reduces PM by injecting   before 
main injection.

After

PM control

Pilot 2

Reduces NOx and noise by 
shortening main injection delay 
due to flammability 

Post 1

Reduces PM by enabling fuel 
activation.

Pre

Controls NOx emission level, 
Combustion noise and
Stable idle 

Post 2

Activates CDPF by increasing 
exhaust gas temperature and 
supplying reduction material

Pilot injection

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Multi injection

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