Dr Markus Distelhoff, head of fuel and exhaust management in Continental’s Powertrain Division, says that the new approach for the first time enables positioning the DOC (diesel oxidation catalytic converter) near the engine – in turn, resulting in DOC volumes reduced by 30%.
Equally, using the recently developed Crossversal catalyst substrate, the DOC weight can be cut by around 20%. Furthermore, thanks to the new DOC’s higher working temperature, urea injection can begin earlier.
And he adds that low heat loss and high conversion efficiency rates of this new substrate will also help meet future NOx emission limits such as CARB 2023 (California Air Resources Board) in the US.
Meanwhile, in addition to the DOC technology, Continental’s new system now includes a urea dosing unit integrated in the tank, the SCR (selective catalytic reduction) control unit, and the catalyst substrate.
“Until now, positioning a DOC close-coupled to the engine in HGVs was impossible, due to the installation space available,” states Dr Distelhoff.
“But incorporating a lightweight and efficient catalyst substrate, our solution now makes it possible to achieve compact, square geometries that can be positioned close to the engine, thereby opening up a number of advantages,” he adds.
Dr Distelhoff explains that heavy-duty engines achieve lowest fuel efficiency at highest loads. However, in other operating situations, engines hardly release any heat.
That’s fine for fuel efficiency, but it presents challenges for aftertreatment systems where they are located downstream on the cab chassis – simply because lower-temperature exhaust gases make for inefficient aftertreatment.
Installing the DOC close to the engine changes this: as the efficiency of the DOC increases with operating temperature, so the volume of the DOC can be reduced. And hence Conti’s claims for the new system.