French automaker PSA/Peugeot-Citroen SA is an industry leader in diesel technology. Its engineers have developed some of the cleanest running diesel cars on the market, and its partnership with Ford Motor Co. in developing diesel engines is starting to gain worldwide acclaim. Patrice Marez, department manager for powertrain system design at PSA/Peugeot-Citroen, is one of the company's top diesel engine experts. He spoke with Staff Reporter Richard Truett at Peugeot's Paris headquarters.
Can you describe the working relationship on diesels with Ford Motor Co.? Do Ford and Peugeot engineers work side by side on projects?
Ford in the United States has two groups, advanced research in Dearborn, Mich., and also in Germany. It is the same team in fact. In the advanced research group we are working very closely with Ford every day in the U.S. and in Germany.
Peugeot has the expertise in aftertreatment and in diesel engine technology. What does Ford bring to the partnership?
With Ford we can go faster and enlarge all the possibilities of the technologies. It's a very wide field for post-treatment emissions. Consider you have oxidation catalysts and DPFS (Diesel Particulate Filter System) technology and you have maybe an NOx (nitrous oxide) trap. There are a lot of items that have to be improved.
With the new Diesel Particulate Filter System, Peugeot is leading the way in diesel emissions aftertreatment technology. But the trap has to be taken off the car and cleaned. How does this work?
You find some additives and ashes inside the filter and some other materials in small parts. The idea is to wash it with water in a special apparatus. We keep all the residue and compact it. It's every 120,000 kilometers that it has to be cleaned.
How will Peugeot meet proposed tougher European emissions rules?
We think that particulate emissions could be more stringent. We will have no problem with that due to the fact that with the filter system we have already reduced particulate emissions to zero. As for greenhouse emissions there are some discussions about NOx levels. It is the key issue. It is clear our main policy is to reduce NOx at the source. Diesel technology has not completely finished improvements.
Why has Peugeot been so aggressive in improving diesel technology?
We want to not only improve emissions and reduce fuel consumption but improve the image of diesels. You can see on many PSA cars that we have completely removed the black smoke. It was important to us to focus on that because it was not acceptable to be in the city or in the landscape with black smoke.
What parts of the diesel engine offer the best potential for improvements in performance and emissions?
It is clear there has been a tremendous amount of progress to be made in the injection system. And I can say that it is not finished, in fact. What we are thinking now for Euro V is something such as six, seven or even nine injection events per cycle, such as three pilot injection, one main injection and one or two post injections. With that we could reduce the injector nozzle diameter.
Mercedes-Benz is going to use a urea injection system for cars in the United States. Is that is a good way to go?
Theoretically, it is a solution. The main problem is to install it in high volume in cars. It's too soon to say if it is a good way to go.
Why is biodiesel good for diesel emissions?
Biofuel is oxygenated, so during the combustion reaction you find oxygen, which is important because it reduces particulates and NOx and improves exhaust gas recirculation.