Tuesday, February 24, 2009

Brainy new gizmos improve Royal Enfield

Sensors will help manage the new unit constructed engine (UCE) on 2009 Royal Enfield motorcycles. They are designed to be trouble free, so most riders won't even notice them, but the clever ways they improve performance and fuel economy are worthy of notice.

The sensors monitor engine speed, temperature, throttle position, manifold air pressure and oxygen in the exhaust. Another notices if the bike has fallen over, and cuts the engine. Still another sensor warns the rider that fuel is low: when the Low Fuel warning lights up on the gauge, you're "on reserve" (less than 1.7 gallons) and need to find a gas station.

Also in that gauge in the headlight housing is the Malfunction Indicator Lamp (MIL), shaped like a little motor. It warns the rider that a sensor has notified the black box under the seat of a problem. That electronic control unit (ECU) will remember the problem and pinpoint it later for a mechanic.

It's all part of an Engine Management System that employs electronic fuel injection, electronic ignition and catalytic converter to make the Bullet faster, more reliable, more fuel efficient and cleaner.

Most of the sensors are tucked out of sight but one, the oxygen sensor on the exhaust head pipe, could not be completely hidden. To work, explained Royal Enfield's Hari Kumar, the sensor must be an exact distance down the head pipe from the motor.

To continue working, it must stick into the head pipe from above, so moisture and carbon fall off instead of falling inside it. To be replaceable, should it ever stop working, the senor must stick out of the head pipe, which could make it a wart on an otherwise handsome part of the motorcycle.

Hari smiled as he used his hands to describe how Royal Enfield engineers were required to angle the sensor so that it worked and was safe but enters the pipe from just around the left side of the bike, where the frame down tube partly hides it and distracts the eye.

It's just an example of the surprising care that Royal Enfield put into the new product. The UCE engine will power the G5 and retro-look C5 motorcycles when they go on sale in the U.S.


  1. Anonymous2/24/2009

    PREDICTION; The most common "modification" on the new C5 will be to keep it running in open-loop. In this mode, the engine runs somewhat richer and consequently with a bit more power. EFI equiped engines are typically kept in open loop by buggering the temperature sensor.

    Al (k3eax@yahoo.com)

  2. In some circles, this is what we call "Breaking it" ;)


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