Ycc-T (Yamaha Chip Controlled Throttle) - Yamaha FZ09E Service Manual

EA$1AC1 l t»
YCC-T (Yamaha Chip Controlled Throttle)
Mechanism characteristics
FEATURES
Yamaha developed the YCC-T system employing the most advanced electronic control technologies.
Electronic control throttle systems have been used on automobiles, but Yamaha has developed a fast-
er, more compact system specifically for the needs of a sports motorcycle. The Yamaha-developed
system has a high-speed calculating capacity that produces computations of running conditions every
1
/ 1 OOOth of a second.
The YCC-T system is designed to respond to the throttle action of the rider by having the ECU instan-
taneously calculate the ideal throttle valve opening and generate signals to operate the motor-driven
throttle valves and thus actively control the intake air volume.
The ECU contains two CPUs with a capacity about five times that of conventional units, making it pos·
sible for the system to respond extremely quickly to the slightest adjustments made by the rider. In par-
ticular, optimized control of the throttle valve opening provides the optimum volume of intake air for
easy-to-use torque, even in a high-revving engine.
Aims and advantages of usin g YCC·T
• Increased engine power
By shortening the air intake path, higher engine speed is possible
~
Increased engine power.
• Improved driveability
Air intake volume is controlled according to the operating
conditions ~
Improved throttle response to
meet engine requirement.
Driving force is controlled at the optimal level according to the transmission gear position and engine
speed ~ Improved throttle control.
• Engine braking control
Due to the throttle control, optimal engine braking is made possible.
• Simplified idle speed control (ISC) mechanism
The bypass mechanism and ISC actuator are eliminated
~
A simple mechanism is used to maintain
a steady idle speed.
• Reduced weight
Compared to using a sub-throttle mechanism, weight is reduced.
4
1. Accelerator position sensor
2. Throttle servo motor
3. Throttle position sensor
4. Throttle valves
1-9