Fi System - Yamaha TMAX XP500F 2015 Service Manual

EAS30617

FI SYSTEM

The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regulator (in the fuel pump)
maintains the fuel pressure that is applied to the fuel injector at a certain level. Accordingly, when the
energizing signal from the ECU (engine control unit) 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.
Therefore, the longer the length of time the fuel injector is energized (injection duration), the greater the
volume 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 (engine control unit). Signals
that are input from the throttle position sensor, crankshaft position sensor, intake air pressure sensor,
intake air temperature sensor, coolant temperature sensor, and O
control unit) 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.
1. Fuel pump
2. Fuel injector
3. Ignition coil
4. ECU (engine control unit)
5. Catalyst
6. O sensor
2
7. Coolant temperature sensor
8. Crankshaft position sensor
9. Intake air pressure sensor
10. Throttle body
11. Intake air temperature sensor
12. Air filter case
sensor enable the ECU (engine
2
13. Throttle position sensor
A. Fuel system
B. Air system
C. Control system
1-3
FEATURES