Automotive Engineer

What are the key criteria for the next generation of range-extender powertrains?

“It’s really a balance between where else might we want to take it from a vehicle application perspective, and how we reduce the cost.

How do you see range-extender technology developing in the next 10 years?

“I think you’ll see more of them. I think you’ll still see an integration of electrified vehicle technology with combustion engines. I don’t think the combustion engine will be a foreigner in the industry and I’ll go so far as to say even in 40 years from now you’ll still see a number of combustion engines.

There are other companies developing range-extender powertrains – how do you stay ahead?

“I think we have the advantage of being first, and we’re working very actively to find ways to take cost out of the system. We think we’ve got some learning to do around how we would do that, what we need to do with scale and applicability. So we’re working on that. One of the things we also think is very important is, when the Ampera transitions between being in pure electric mode to being in charge sustaining mode, there’s absolutely no real difference that’s discernible to the driver. We think that’s a pretty key attribute and that does impose some constraints around the engine sizing. Could it be a three-cylinder? It could in principle but you can’t go extremely small without really deteriorating the driving experience. 

What place will combustion engine technologies such as boosting and direct injection have on future range-extender engines?

“It’s hard to say. Boosting is a little harder to see because of the cost and how you run the engine in a range extender environment versus in a traditional car, but others certainly apply – things like direct fuel injection and variable valve timing.

GM has invested a lot of money in range-extender technology, so why not license it to other companies?

“Interesting thought. The short answer is we investigate different partnerships and opportunities all the time but there are no plans right now. 

How will powertrain technologies differ between North America and Europe?

“There will be some convergence. A good example of it even today is where we have a 1.4-litre turbo in the Chevy Cruise in North America. That engine was engineered in Europe. It’s a good example of convergence. At the higher end it will look different because the market for utility vehicles – pick-up trucks in North America – will probably get smaller but it’s not going to go away. Those are going to have V8s, maybe hybrid V8s to help with the CO2 and the fuel economy. But we’re certainly not going to see those kinds of powertrains in Europe. I think we will see the leading edge of CO2 will really be here in Europe.

What transmission technologies can we expect to see in future vehicles?

“We’re just at the start of electrified transmissions so we’ll have to see how those develop from a market acceptance point of view. There’s huge pressure on cost, taking money out of the motors and how they’re integrated into the transmission. The power electronics are a big part of that, converting power from the battery into high-voltage AC to run the motors. In terms of other transmission technologies, as we look through Europe, we still see manual transmissions as being the dominant technology. It’s about an 80/20 mix now. I think you might see that become more like a 70/30 mix, but still predominantly manual. We’re working on having unparalleled shift comfort – we think we’re quite good at efficiency already. Then on non-manual transmissions I think you’ll see a mix of technologies. There’ll still be conventional planetary automatics but you’ll see some increase in automated manuals because there’s really been quite good progress there in terms of getting over the torque interruption.