Electronic Fuel Injection System; Fuel Injection Control System - Suzuki DF200 Service Manual

3-20 ENGINE CONTROL SYSTEM

ELECTRONIC FUEL INJECTION SYSTEM

The fuel injection system used by the DF200/DF225/DF250 is a speed-density, multi-point, sequential, elec-
tronic fuel injection type.
The fuel injection system is composed of the fuel line components, air intake components, and components
for system control (ECM, sensors, switches, etc.).

FUEL INJECTION CONTROL SYSTEM

OUTLINE
Sensors are mounted at precise locations on the motor to monitor the current conditions of engine operation
and send signals to the ECM. Based on these signals, the ECM determines the optimum fuel injection time
duration (fuel amount), fuel injection timing (multi-point sequential timing) and controls the injector operating
signals accordingly.
Fuel injection start timing is set at a constant of ATDC 280° (640° of crankshaft rotation) on the exhaust stroke.
Basic sensors
MAP sensor:
Informs ECM of collector assembly (surge tank) pressure.
CKP sensor:
Informs ECM of engine speed and crankshaft angle.
Compensating sensors
Cylinder temperature sensor:
Informs ECM of cylinder temperature.
Exhaust manifold temperature sensor:
Informs ECM of exhaust manifold temperature.
IAT sensor:
Informs ECM of intake air temperature.
TPS (Throttle position sensor):
Informs ECM of throttle opening angle.
MAP sensor:
Informs ECM of barometric pressure at time of engine start.
Battery voltage:
Constantly monitored by the ECM.
Others
CMP sensor:
Informs ECM of camshaft angle.
Shift position sensor:
Informs ECM of shift position (neutral or in-gear).
Battery
charge
coil
Rectifier &
regulator
30A fuse
60A fuse
15A fuse
Battery
ECM
main
relay
A A
Ignition
switch
Fuel injection time duration
(amount) is determined by
a digital map designed in
relation to collector assembly
(surge tank) pressure and
engine speed.
Fuel amount compensation
Multi-point sequential timing
Signal Signal
ECM
CPU
A A A A
Injector
ECM
Signal Signal Signal Signal
Injector
Sensor/switch
signal input