Yamaha ROADLINER XV19SW, Service Manual

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FEATURES
1-3
ET1D71018
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 392 kPa (3.92 kg/cm², 55.7 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, crankshaft position sensor, intake air pressure sensor, air temperature sensor,
engine temperature sensor, speed sensor and O
2
sensor enable the ECU to determine 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.
Illustration is for reference only.
15
A
1
2
3
4
C
5
8
7
6
10
11
12
13
14
B
#1 #2
9
1. Pressure regulator
2. Fuel pump
3. Fuel injector
4. Ignition coil
5. ECU (electronic control unit)
6. Air temperature sensor
7. ISC (idle speed control) unit
8. Throttle position sensor
9. O
2
sensor
10. Catalytic converter
11. Engine temperature sensor
12. Crankshaft position sensor
13. Intake air pressure sensor
14. Throttle body
15. Air filter case
A. Fuel system
B. Air system
C. Control system