Honda Develops Idling Stop System

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The automotive industry is hoping to popularize multiple technologies to reduce fuel consumption and exhaust emissions. One such technology recently proposed for cars is called an “idling stop system,” something that stops the engine from running while the vehicle is stopped due to a traffic signal, traffic jam, etc. It’s a system Honda engineers first placed on a two-wheeler in 2001.

The “Crea Scoopy-i” – a 50cc scooter equipped with a water-cooled 4-stroke engine – was the first vehicle to be developed with the “idling stop system.” Honda says the Crea Scoopy-i’s fuel economy, compared to models without the “idling stop system”, improved by 5.5% while reducing CO2 emissions by 5.2%, CO by 8%, and HC by 2%.

Here’s how the system works:

1.When Starting the Engine
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 though the vehicle is not moving for more than 3 seconds.

2.When Engine is Warm and/or During Vehicle Movement
After initial engine start, vehicle speed has exceeded 6mph, and the water temperature sensor detects a temperature above 50 degrees, 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
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
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. 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.

In the “idling stop system”, it is important to have a quiet starting charging system that keeps the battery adequately charged to assure starter motor operations. Also, it is important to have a fuel supply system that ensures restarting of the engine even after the throttle has been opened. The key component for engine starting and battery charging is the brushless ACG starter having a combination of alternator and starter functions.

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