Yamaha YZF-R1 2012, Service Manual

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FEATURES
1-3
EAS14B1017
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 a certain level. 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. 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. Signals that are input from
the throttle position sensor, accelerator position sensor, coolant temperature sensor, atmospheric
pressure sensor, cylinder identification sensor, lean angle sensor, crankshaft position sensor, intake
air pressure sensor, air temperature sensor, rear 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 and cylinder identification 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.
1. Secondary injector
2. Fuel pump
3. Primary injector
4. Cylinder identification sensor
5. ECU (engine control unit)
6. Throttle position sensor
7. Accelerator position sensor
8. Rear speed sensor
9. Intake air temperature sensor
10.Lean angle sensor
11.O
2
sensor
12.Catalytic converter
13.Coolant temperature sensor
14.Crankshaft position sensor
15.Intake air pressure sensor
16.Throttle servo motor
17.Throttle body
18.Atmospheric pressure sensor
19.Air filter case
20.Intake funnel servo motor
A. Fuel system
B. Air system
C. Control system