Vitesco Technologies: Hybrids are also becoming cleaner thanks to E-Cat

The spun-off Regensburg-based Conti drive subsidiary Vitesco Technologies has introduced an electric catalyst heating system for high-voltage hybrid vehicles, which is expected to make these vehicles significantly lower in emissions during real-world operation. This is made possible by a new DC/DC converter for the heating plates of the electrically heated catalyst EMICAT. In vehicles with pure combustion engines and in mild hybrids, the system is already in use. The E-catalyst enables lower pollutant emissions during real-world operation, which is becoming increasingly important in light of future regulations such as Euro7.

“The combination of a heating catalyst and a new DC/DC converter reduces real emissions in critical situations, namely when the combustion engine restarts,” explains Klaus Hau, Head of the Sensing & Actuation Business Unit at Vitesco Technologies.

With the converter for electric catalyst heating in plug-in hybrids, an additional option for electrification is being presented to the market. The challenge with PHEVs lies in the conflict between CO2 efficiency and low cold-start emissions. Hybrid vehicles exploit their CO2 savings potential by shutting off the combustion engine as often as possible and instead driving electrically. However, this results in longer operating pauses for the combustion engine, during which the vehicle emits no CO2. During these phases, the engine cools down. When restarted, the exhaust stream is initially cold – potentially too cold to convert pollutants in the catalyst, the supplier outlines the problem.

“Especially in efficiently driven hybrids, cold starts are actually the norm,” says Rolf Brück, Head of Catalysts and Filters at Vitesco Technologies.

From an emissions reduction perspective, this is a challenge because most cycle emissions can occur during cold starts. If the goal is to optimally utilize electrification in a vehicle to save CO2, a solution is needed for all cold start situations, according to Vitesco specialists. For high-voltage hybrids like the increasingly popular plug-in hybrid, this form of exhaust aftertreatment has not been available so far, as the heating plate cannot be supplied directly from the high voltage system of 200 to 450 volts. The newly developed DC/DC converter now generates the low voltage and power for the heating plate from the high voltage of the drive system. The compact unit is based on modern printed circuit board technology and is expected to achieve a high efficiency of 95 percent.