Yamaha TP-7023 User Manual download pdf (Page 99)

NTK LAMBDA SENSORS FOR MOTORCYCLES

TECHNICAL INFORMATION

Reducing the pollution created by the internal combustion engine is a great concern for us all. To ensure that

manufacturers build cleaner engines the allowable limits for certain polluting gases are set by various

government bodies. These limits are getting ever tighter and engine designers are under great pressure to find

ways of meeting the targets. A vital part of the pollution control used on many engines is the exhaust gas oxygen

sensor - more commonly known as the Lambda sensor. Commonplace on cars since the 1990’s, Lambda sensors

have been used on motorcycles since 1999 and are now fitted to an increasing number of machines over 125cc.

WHAT DOES THE LAMBDA SENSOR DO?

The most popular method used by vehicle manufacturers to reduce engine emissions is the three-way catalyst

(catalytic converter). This device has the ability to take the three main toxic gases produced by an engine which

are carbon monoxide (CO), oxides of nitrogen (NO

)

and hydrocarbons (HC) and convert them to considerably

less harmful, non-poisonous gases: carbon dioxide (CO

), water (H

O) and nitrogen (N

To carry out this conversion of gases efficiently the catalyst must operate within a specified temperature range but

also be provided with exhaust gases that are within certain very tight tolerances dependant predominantly on

air/fuel ratio. The precise control required to operate this system is provided by the use of an exhaust gas

oxygen (Lambda) sensor installed upstream of the catalyst. A Lambda sensor has the ability to precisely

measure the residual oxygen present in exhaust gases. By sending a signal to the control unit it can initiate a

change to keep the fuelling system operating within the very tight tolerances required. This is known as a

closed-loop control system.

TORQUE FIGURES

Torque figures and thread form information:

M18 x 1.5mm - 35 ~ 45Nm M12 x 1.5mm - 18 ~ 23Nm

A worn or damaged sensor may affect the bike’s general performance, increase fuel consumption, increase

unwanted emissions and even damage the catalyst.

1 2 ... 94 95 96 97 98 99 100 101 102 103 104 ... 107 108

No comments

Yamaha TP-7023 User Manual Page 99