SSANGYONG RODIUS 2004.09 Manual page 53

(3) CIRCUIT DESCRIPTION
A. INPUT SIGNAL OF ECU
According to input signals from various sensors, engine ECU calculates driver's
demand (position of the acceleratorpedal) and then controls overall operating performance
of engine and vehicle on that time. ECU receives signals from sensors through data line
and then performs effective engine air-fuel ratio controls based onthose signals. Engine
speed is measured by crankshaft speed (position) sensor and camshaft speed (position)
sensor determinesinjection order and ECU detects driver's
demand) through electrical signal that generated byvariable resistance changes in
accelerator pedal sensor.
Air flow (hot film) sensor detects intake air volume and then transmits to ECU. Especially,
the engine ECU controls theair-fuel ratio by recognizing instant air volume changes
through air flow sensor to pursue low emission gases (EGR valvecontrol). Furthermore, the
ECU uses signals from coolant temperature and air temperature sensor, booster
pressuresensor and atmospheric pressure sensor as compensation signal to respond to
injection start and pilot injection setvalues and to various operations and variables.
B. CONTROL FUNCTION OF ECU
- Controls by operating stages:
To make optimum combustion under every operating stage, ECU should calculate
proper injection volume ineach stage by considering various factors.
- Starting injection volume control:
During initial starting, injecting fuel volume will be calculated by function of temperature
and engine crankingspeed.
Starting injection continues from when the ignition switch is turned to ignition position to
till the engine reachesto allowable minimum speed.
- Driving mode control:
If the vehicle runs normally, fuel injection volume will be calculated by accelerator pedal
travel and engine rpmand the drive map will be used to match the drivers inputs with
optimum engine power.
C. ECU INPUTS·OUTPUTS
pedal position (driver's
D. STRUCTURE AND FUNCTION OF ECU
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 ~ +85°C
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.
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and protected from
CIRCUIT
RODIUS 2004.09