Saturn S series Twin Cam cylinder head had now featured a new roller-rocker setup with hydraulic tappets and roller cams replacing the conventional bucket lifter setup of the previous engine in the S series. Also introduced for the 1999 model year S-series vehicles that were sold in California was a different type of an exhaust manifold that housed an upstream catalytic converter (this converter had heated up much faster than the conventional unit, and it had also decreased exhaust emissions faster as well), and it also had provisions for an air-injection reaction system (This had injected fresh air into the exhaust to reduce
Flame supervision device supply of oxygen for efficient combustion, thus avoiding the production of poisonous carbon monoxide. As well as detecting a blocked supply of oxygen, these must also detect a blocked exhaust or reversed flow in the exhaust flue owing to wind conditions. Two methods are used to provide these, an Oxygen Depletion System (ODS) that measures the availability of oxygen for combustion or an Atmospheric Sensing Device (ASD) measures excess heat rise in the exhaust. Flame supervision device For gas appliances, a flame supervision device (FSD) – alternative name: flame failure device (FFD) – is a general term for any device