EuroAuto: Hybrids, Diesel, Gas?

Columns From: 11/1/2008 Automotive Design & Production, , Editor from Automotive Engineer

As Delphi's Manager of Global Powertrain Marketing, Vishy Seetharaman's job is to peer into the future and predict trends so that the company is able to respond in a timely manner to the demands from its OEM customers.

As Delphi's Manager of Global Powertrain Marketing, Vishy Seetharaman's job is to peer into the future and predict trends so that the company is able to respond in a timely manner to the demands from its OEM customers. Nowadays, when he sees a blip in hybrid sales, he and his colleagues have to determine whether it is a one-off or the start of something more permanent. But this hasn't always been so. "People were initially a little skeptical about the penetration of hybrid and electric hybrid technology, but that has significantly changed over the years," he says. "Even without tax incentives for hybrids in North America, there is still the expectation that there will be an increase in hybrid electric propulsion systems with one of the constraints being the very rapidly changing and evolving battery technology. I think that is going to be either an enabler or a constraint due to the costs involved."

This is a view shared by Dr Ernst Scheid, Executive Vice President of FEV, who has gone on record as saying: "Development of electric cars over the next few years will change from being a niche item into a standard production vehicle. This trend will be accelerated by politically determined boundary conditions. This does not mean the end of the internal combustion engine but it is an indication that alternatives are gaining ground in some areas of application."

Seetharaman agrees that the internal combustion engine still has a healthy future, with the diesel in Europe likely to remain the favoured powertrain. "I think the bigger question in Europe is at what level will diesel penetration peak. Will it be around 50 to 55% or will it remain on a slightly upward trend? However, with the emissions requirements becoming more stringent, together with gasoline technology improving, I do see spark ignition engines making a comeback in terms of market share." Seetharaman's oblique reference to requirements is to the Environment Committee of the European Parliament which voted by a substantial margin in late September to hold to an average target of 120 g of carbon dioxide per kilometer from new passenger cars by 2012. It also voted for a new long-term target of 95 g CO2/km for 2020. The current level is around 160 g/km. Of the 120 g/km target, 130 g/km is to be reached by improvements in vehicle engine technology with a further 10 g/km reduction being obtained by using other technical improvements such as better tires or the use of biofuels.

"I also think the differences between Europe and North America are going to narrow in the future. This is despite the fact that fuel prices are so much lower in North America while people travel longer distances on highways than they do in other parts of the world, nor is there anything like the stop-and-go traffic conditions you see elsewhere. However, one of the things that the OEMs and suppliers like Delphi have realized is that some technologies really are applicable around the globe because they deliver the same value no matter the size of the vehicle. In order for diesels to meet the same emissions levels as gasoline in North America, it means making them more complex and so detracting from some of the fuel economy benefits, so that impacts the choice as well. However, we do expect diesel penetration in North America to increase, but on a limited basis with a small number of passenger cars and work application-type SUVs or trucks becoming diesel where the aftertreatment costs are paid for by the decrease in fuel consumption. For a large number of passenger car applications, though, because of the stringent emissions standards in the kinds of vehicles that people like to drive, the emissions regulations are a constraint on significant penetration."

eetharaman therefore still sees a bright future for the gasoline engine and that it may make some sort of comeback. "To start with, one could argue that gasoline hybrids are a little more viable than diesel ones. If you think about electric hybrids, they tend to line up with spark ignition engines quite well. This is partly due to the fact that small diesel engines are now as fuel efficient to start out with—they have this thing about being unthrottled and therefore don't have the pumping losses associated with gasoline engines and that means the benefits of hybrid technology that allows stop/start and idling are not as great on a diesel as they are on a gasoline, so I personally see more gasoline engines tied up with strong hybrids than I see diesels."

Then there are the advances being made in gasoline engine technology. In Delphi's case it is the Multec 20, its spray stratified gasoline direct injection (GDi) injector. With solenoid technology that delivers outstanding spray performance, the spray stratified GDi system, which is also known as "lean" burn, improves fuel economy while reducing engine noise and harmful emissions. Spray-stratified GDi uses less fuel by creating a stratified charge with a stoichiometric air-fuel ratio near the spark plug with no fuel outside the mixture plume in the remainder of the chamber. "Delphi's spray stratified GDi will deliver all the performance OEMs need at significantly lower cost than piezo injectors," says Delphi's Dr. Walter Piock, Chief Engineer for advanced powertrains. "As a cost-effective and robust solution, Delphi's Multec 20 is fuel-injection technology's next big advancement."

However, it will not be a universal solution as different conditions prevail in different parts of the world. "Due to the stringent NOx emissions standards in the U.S., it's going to be hard for the stratified or lean-burn direct-injection engine to come on-stream very quickly," says Seetharaman. "However, in Europe, because the conditions are different it's coming on fairly quickly. It doesn't mean that there is a different technology between the U.S. and Europe, it's the timing that is different. So in the U.S. we expect to see far more homogeneous gasoline direct injection while in Europe, which has a lot of homogeneous gasoline direct injection, we expect them to move to a stratified version much sooner than you will see in North America."