Direct-injection gasoline engines, motorsport applications, and even motorcycles place very specific demands on the technology used for exhaust gas measurement and its aftertreatment, but as you will learn, the engine brings engineers what it takes to “keep it clean” major challenge. Environmental protection In the popularization of automobiles, nitrogen and oxygen sensor technology is particularly important.
Nitric oxide and nitrogen dioxide
To make gasoline engines more economical and environmentally friendly, automakers are increasingly relying on direct gasoline injection engines, which under certain conditions, mainly part load (cruising) conditions, can operate on fairly lean air/fuel mixtures run. The result of this could be a 12-20% reduction in fuel consumption, but as with most things in life, there is a price to pay for this gain.
One of the gaseous compounds produced as a result of the combustion process within an engine during spark ignition is a compound collectively referred to as NOx. For the automotive industry, the term is used to describe nitric oxide and nitrogen dioxide contained in exhaust gas. NOx compounds are environmentally harmful by-products of the combustion process, which are effectively addressed in most vehicles through the function of the three-way catalytic converter.
Spark ignition engines tend to produce more of these compounds when operating on very lean fuel conditions, while direct injection engines operate in this region in stratified mode. Three-way catalysts cannot cope with this problem due to the excess oxygen in the exhaust gas, which reforms NOx and requires additional treatment of the exhaust gas.Read More →