Published on May 12th, 2015 | by Daniel Sherman Fernandez0
Continental to lower NOx emissions in diesel engines
Continental is developing a number of technologies to lower NOx emissions in diesel engines. The advanced systems are designed to assist OEMs in meeting the stricter standards on exhaust emissions outlined in Euro 6, as well as the super ultra-low emission vehicle limits for California and the forthcoming real driving emissions test conditions.
The Tier One supplier has developed a compact catalytic converter that can be installed close to the engine, meaning it heats up faster and so begins converting untreated emissions earlier, while an electrically heated version performs a similar function in hybrid vehicles.
It is not always practical for the catalytic converter to be so closely-coupled to the engine and, to cater for such situations, Continental has constructed one with a bi-valve so that the inlet and outlet for exhaust gases are on the same side.
Continental’s head of fuel and exhaust management, Markus Distelhoff said: “The component is very short, and the external circulation keeps the catalyst hot inside for a long period, with the heat evenly distributed.”
For the converter to be effective, it is important to inject urea as a reducing agent into the exhaust gas, but standard systems are difficult to achieve with a close-coupled design so Continental has developed one that injects the solution in the opposite direction of the exhaust flow. The urea is subsequently sprayed on a structure with a hydrolytic coating on the back of the catalytic converter.
Distelhoff said: “The counter-flow injection system prevents urea sedimentation and ammonia slip, as well as a lack of reducing agents in the exhaust flow, even in highly compact designs.”