Published on July 11th, 2017 | by Steve Hanley
Electric Tech From Continental Slashes NOx Diesel Emissions
Continental is one of the largest OEM suppliers to the auto industry. Over the years, it has been heavily involved in making diesel engines more efficient and less polluting. Diesel has become a dirty word in the past two years in the world of transportation, thanks in large part to the machinations of Volkswagen and its diesel emissions cheating software.
Diesel Emissions And NOx
Internal combustion engines all create unsavory byproducts that pollute the atmosphere. They fall into three main categories — carbon dioxide, nitrous oxides, and particulates. Today’s emissions regulations mean what exits the tailpipe of a modern car is much less harmful than it was a few decades ago, but you still shouldn’t put your lips around one and breathe deeply.
Diesel engines tend to create more nitrous oxide pollutants — commonly referred to as NOx — than gasoline engines, due mostly to higher combustion temperatures and pressures. Many manufacturers use a urea injection system to control NOx emissions, but that adds complicated hardware to the engine and costs more money.
Former Volkswagen CEO Ferdinand Piech once bragged that his engineers could control NOx emissions without using urea injection. Then he fired all of them who couldn’t make his boast a reality. Eventually, the engineers decided to shut Piech up and get him off their backs by simply installing software that made it look like they had solved the problem. It was cheating, but Volkswagen was simply the company that did it best. Diesel emissions cheating is alleged to have occurred at Mercedes, Audi, Peugeot, Citroen, and Fiat.
Continental’s 48 Volt Catalytic Converter
Now Continental says it has found a way to slash NOx emissions by 60% in real world testing. The secret? Using a 48 volt electrical system to promote rapid heating of the catalytic converter. Getting the cat up to temperature more quickly allows it to get to work converting NOx emissions sooner after a cold start.
Johannes Drechsel, development engineer at Continental, explained the new system to Auto Express this way. “Instead of a normal catalytic converter that relies on the engine to bring it up to temperature, our catalyst relies on electricity from the 48 volt system to heat up,” he said. “Because it uses electricity rather than the engine, the catalyst heats up much quicker, which allows for high efficiency NOx reductions.”
The system still uses a urea injection component, but simplifies it by injecting it directly into the exhaust system immediately, which eliminates the need for a separate mixer. Fitted to an existing Volkswagen Golf TDI, the Continental system reduced NOx emissions by 60% in real world driving. There were other benefits as well. Carbon dioxide emissions were 3% lower and fuel economy was up 4%.
Now the next question is whether the system would provide a similar benefit to heavy trucks. Diesel powered trucks are vital to the world economy, but they spew more pollutants into the atmosphere than automobiles. Controlling emissions from trucks would be a huge step forward for the environment.
48 volt electrical systems are being used more frequently by car makers for such duties as powering stop/start engine technology. They also can be used for the electric steering, braking, and air conditioning systems that are becoming more common on today’s cars.
Source and photo credit: Auto Express