General information and features of the F.I. System and sensors as presented in Chapter 1
The crankshaft position sensor uses the signals of the crankshaft position sensor that is mounted on the left side of the crankshaft. When the rotation of the pickup rotor that is attached to the crankshaft causes the projections on the rotor to pass by the crankshaft position sensor, an electromotive force is generated in the coil. The voltage of this force is then input into the ECU, which calculates the position of the crankshaft and the speed of the engine. The ignition timing is then determined in accordance with the calculated data, in order to determine the corresponding injection timing. Based on the changes in the time intervals of the signals generated by the crankshaft position sensor, the ECU calculates the ignition timing advance to suit the operating conditions. The injection timing is also advanced in accordance with the ignition timing in order to supply fuel to the engine at an optimal timing.
The cylinder identification sensor is installed on the camshaft drive gear cover. When the cam of cylinder #1 rotates, the pickup rotor installed on the cam also rotates. When the pickup rotor passes by the sensor, trigger poles on the rotor generate a signal and send it to the ECU. Based on this signal and the signal from the crankshaft position sensor, the ECU then actuates the injectors to supply fuel.
When the crank angle is 110 degrees or higher, no signals are transmitted from the crankshaft position sensor to the ECU. Once the crank angle is less than 110 degrees, the first signal that the ECU receives from the sensor identifies cylinder #1 at 82.... BTDC. When the ECU receives a signal from the cylinder identification sensor, cylinder #1 is at 82.... BTDC on the exhaust stroke. When the ECU does not receive a signal from the cylinder identification sensor, cylinder #1 is at 82.... BTDC on the compression stroke.
The throttle position sensor measures the intake air volume by detecting the position of the throttle valve. It detects the mechanical angle of the throttle valve through the positional relationship between the moving contact that moves in unison with the throttle shaft and the resistor board. In actual operation, the ECU supplies 5 V power to both ends of the resistor board and the voltage that is output by the throttle position sensor is used to determine the angle of the throttle valve.
The lean angle cut-off switch stops the supply of fuel to the engine in case the motorcycle overturns. When the motorcycle is in the normal state, the cut-off switch outputs a constant voltage of approximately 1.0 V (low level). When the motorcycle tilts, the float in the switch tilts in proportion to the tilt of the motorcycle. However, the voltage output to the ECU remains unchanged at the low level.
When the tilt of the motorcycle exceeds 70 degrees (according to the tilt of the float), the signal from the sensor increases to approximately 4.0 V (high level). When the ECU receives the high-level volt-age, it determines that the motorcycle has overturned, and stops the delivery of fuel to the engine by turning OFF the fuel injection system relay that powers the fuel pump and the injectors. Once the cut-off switch is tripped, the ECU maintains this state; therefore, even if the motorcycle has recovered its upright position, this state will not be canceled unless the main switch is turned OFF, and then turned back ON.General information and features of the F.I. System and sensors