Fi System - Yamaha Vmax VMX17C 2009 Service Manual

EAS2S31083

FI SYSTEM

The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regulator maintains the
fuel pressure that is applied to the fuel injector at only 324 kPa (3.24 kgf/cm², 47.0 psi). Accordingly,
when the energizing signal from the ECU energizes the fuel injector, the fuel passage opens, causing
the fuel to be injected into the intake manifold only during the time the passage remains open. There-
fore, the longer the length of time the fuel injector is energized (injection duration), the greater the vol-
ume of fuel that is supplied. Conversely, the shorter the length of time the fuel injector is energized
(injection duration), the lesser the volume of fuel that is supplied.
The injection duration and the injection timing are controlled by the ECU. Signals that are input from the
throttle position sensor, accelerator position sensor, coolant temperature sensor, cylinder identification
sensor, atmospheric pressure sensor, lean angle sensor, crankshaft position sensor, intake air pres-
sure sensor, intake air temperature sensor, rear wheel sensor and O
mine the injection duration. The injection timing is determined through the signals from the crankshaft
position sensor. As a result, the volume of fuel that is required by the engine can be supplied at all times
in accordance with the driving conditions.
16
#1 #2
18
17
1. Fuel pump
2. Injector
3. Cylinder identification sensor
4. ECU (engine control unit)
5. Throttle position sensor
6. Accelerator position sensor
7. Rear wheel sensor
8. Lean angle sensor
9. Atmospheric pressure sensor
10. O sensor
2
11. Catalytic converter
12. Coolant temperature sensor
20
1
A
#3 #4
2
19
B
15
14
sensor enable the ECU to deter-
2
5 6
C
4
12
3
13
13. Crankshaft position sensor
14. Intake air pressure sensor
15. Throttle body
16. Intake air temperature sensor
17. Air filter case
18. Intake funnel servo motor
19. Throttle servo motor
20. Atmospheric pressure sensor
A. Fuel system
B. Air system
C. Control system
1-3
FEATURES
7
8
9
10
11