High Pressure Fuel Pump Control System Description - Suzuki DF70A Service Manual

1G-7 Fuel System:

High Pressure Fuel Pump Control System Description

To supply the optimum fuel amount, the ECM controls the fuel pump drive duty cycle, a repeated "ON" / "OFF" signal,
at a specified rate (1 000 times a second).
Based on engine speed and battery voltage, the ECM determines the optimum duty cycle (repeating "ON" time rate
within a cycle) and sends this signal to the fuel pump.
CKP sensor:
Informs ECM of engine speed.
Battery voltage
Ignition switch:
Informs ECM of "START" signal.
Cylinder temp. sensor:
Informs ECM of cylinder temperature.
7
3
8
4
6
5
BATT
9
1. Sensor/switch signal input
2. Fuel pump
3. ECM main relay
4. 30 A fuse
5. 15 A fuse
Duty cycle signal for fuel pump (example: 80% duty)
"ON" time
× 100 = duty (%)
1 cycle time
OFF
ON
ECM
ECM
CPU
1
FP
2
I9J011170007-01
6. 40 A fuse
7. Battery charge coil
8. Rectifier/Regulator
9. Ignition switch
0.8 ms
Time
1 ms (1cycle)
I9J011170008-01
Z9J0111701003
Signal FP
Fuel pump
I9J011170006-01