Honda Worldwide | Technology Close-up



	Stops the engine automatically, starts the engine by only opening the throttle. Incorporating an ECU (Electronic Control Unit) that centrally controls engine operations on the basis of inputs from various sensors, the “idling stop system” automatically stops idling when the vehicle stops for a traffic signal or traffic jam, and restarts the vehicle when the throttle is opened.

Key points of development

In the “idling stop system”, the ECU centrally controls engine operations on the basis of inputs from various sensors. By precisely controlling revolutions of the ACG starter, which is directly mounted on the end of the crankshaft and serves as an ACG (alternator), as well as a starter motor, the system permits jolt-free restarting. The speed sensor, thermo-sensor, throttle sensor, pulse generator, and seat sensor detect conditions such as stopping of the vehicle, engine temperature, throttle opening, engine revolutions, seating of the rider, etc. During cold starts, the ECU automatically stops the engine when warm, and restarts the engine when the throttle is opened. It also controls the stand-by indicator lamp that notifies the rider of the condition of the “idling stop system”.

”Idling stop system” configuration

Operations of “idling stop system”

Additional functions when “idling stop” occurs/When the vehicle is in the “idling-stop” condition, the stand-by indicator blinks to inform the rider that the vehicle is ready to be started by opening the throttle. A seat switch, which detects presence of a rider, is used to prevent unexpected engine starting when no rider is on the vehicle. The headlamp voltage is also regulated to reduce electric power consumption. The meter for Crea Scoopy-i	1.When starting the engine (initial starting)
	Initially, the rider starts the engine by pushing the starter button in the same manner as an ordinary scooter because it sometimes takes several seconds to start a cold engine after long-term storage or when the ambient temperature is low. Under these conditions, the engine continues to idle eventhough the vehicle is not moving for more than 3 seconds.
	2.When engine is warm and/or during vehicle movement (shifts to the “idling stop” mode)
	After initial engine start, vehicle speed has exceeded 10km/h, and the water temperature sensor detects a temperature above 50?, by which the ECU judges that the engine has been warmed up, the system shifts to the “idling stop” mode from the next stop of the vehicle.
	3.When the vehicle stops moving (“idling stop” ready)
	As the vehicle stops with the throttle fully closed and the rider seated, the ignition is turned off to stop the engine. The ignition turns off 3 seconds after the vehicle stops moving. The delayed engine shut-off allows the rider the ability to make a U turn or a momentary stop at a stop sign.
	4.When restarting ( engine restart and vehicle movement )
	When restarting, the throttle sensor attached to the carburetor detects an opening of the throttle, and the system turns on the starter motor as well as allowing ignition. As the engine starts and the engine speed increases, the centrifugal clutch engages, thus starting the vehicle movement.

0.9 second from the opening of throttle to the start of vehicle

The time period from the opening of throttle to the start of vehicle is 0.5sec when the engine is idling, and it is 0.9sec when not idling. Although there is a delay of 0.4sec, practically the delay in the starting of vehicle is almost unnoticeable.

Time from opening throttle to vehicle movement

This graph compares the time period from opening throttle to vehicle movement with and without the engine idling. The time duration from opening throttle is shown on the horizontal axis, engine revolutions shown on the left vertical axis, and the distance of vehicle travel shown on the right vertical axis.