INTERVIEW: GKN's eAxle all-wheel-drive technology with Rob Rickell
Porsche 918 Spyder
Interview with Rob Rickell, Senior Vice President Global Engineering, Principal Engineer, GKN plc. GKN has just publicised its involvement with the Porsche 918 programme, Calum MacRae caught up with him to discuss this and other developments.
j-a: The Porsche 918 Spyder entered production in November 2013, and is due to end production this year, why are you only letting the world know your involvement with the programme now?
RR: Quite simple really, particularly with Porsche as they want to talk about their cars before any of their suppliers and they've got a brand to protect. We have to apply for permission to communicate anything about the innovations we're supplying on their programmes. In fact, it's quite rare that their suppliers are allowed to talk about the technology they are supplying. With them building only 918 cars it's clearly a flagship and will lead to many more applications.
j-a: By way of comparison what was the lead-time with Peugeot or Citroen with the eAxles you supply? Were you able to announce that simultaneously with PSA?
RR: No, there was a bit of a lag but it was quicker with PSA. Again, we had to apply for permission - we always do.
j-a: Practically for GKN, what does being selected as a Porsche Technology Partner mean? How is it different to being nominated as a supplier?
RR: We're really proud of it. We're the only supplier named as a technology partner on that vehicle. Being a Technology Partner means that you're working together with their engineering team right at the beginning of the programme - we were such an essential part of getting that vehicle right in terms of its hybrid and AWD performance. There were incredibly tough targets on the programme - the toughest specification we've ever had on an eAxle or on a hybrid vehicle - with a clear goal to build the best performing hybrid sports car, including a lap time of under 7 minutes on the Nurburgring and low emissions on the European cycle of 3L/100km.
j-a: Has GKN been a Technology Partner with Porsche before on any other programme?
RR: No - it was the first time for GKN. We do the other AWD systems for them - the 911 4S for example is our system - and we've been their supplier for CVJs, half-shafts and propshafts for many, many years but nothing compares to the technology required for the 918.
j-a: The eAxle for the 918 Spyder is described as an evolution of your eAxle? What's different to the Axle for the PSA version or the i8's two-speed eAxle?
RR: It is an evolution and clearly we want some synergy between all the systems we are supplying. What we were looking at here though was an incredible power density for the size and weight, being able to handle a lot of torque, a very, very enclosed space making cooling difficult. It was a flagship for us: achieving the 918's requirements means we're confident we take the eAxle anywhere else in the market.
j-a: Is it correct to surmise that if you had a two-speed eAxle for an electric car with just FWD or RWD you'd be able to get rid of the EV's transmission?
RR: One of the projects we're working on is a pure EV with an eAxle on both the front and rear, but yes we can do it for just FWD or RWD. What we're seeing at the moment though is that the market wants AWD and hybridisation. Although the two-speed eAxle can extends a pure EV's range or make the battery pack requirements smaller, depending on design needs, what we're seeing is that the market prefers hybridisation at the moment. And, in any case, the eAxle does facilitate a pure EV mode of about 50km, which is useful as we approach more and more restrictions on emissions in big cities.
j-a: How significant is the eAxle business set to become to GKN in the future? How many eAxle contracts do you have presently and in the pipeline?
RR: The first one was with PSA, the second one was the BMW i8 - similar to the Porsche, but with a two-speed it can stay in operation all the way up to top speed rather than disconnecting at a certain speed. We actually see the future being more about two-speed eAxles than the one-speed. But it's a scalable design that we can offer right across the spectrum. This year we'll two more coming on to the market - both derived from European B-/C-platform FWD based vehicles, so both FWD but with hybrid AWD and an eAxle on the rear - and then four more coming in the next couple of years.
j-a: What are the fuel economy benefits of the eAxle versus conventional AWD/4WD?
RR: On the standard European cycle there's at least a 30% saving compared with standard AWD. With WLTP we see that the savings derived from the eAxle get better - our technology is configured with one eye on future regulations - which when compared with a technology like stop-start where the benefits decrease under WLTP is a good thing for our business.
j-a: What about on-cost for the eAxle versus conventional AWD systems? Is it a system we are likely to see in more sectors?
RR: Clearly it has an on-cost when compared with conventional AWD but that's a price for a 30% improvement and avoiding the penalties that not meeting CO2 targets will bring. We have other technologies where the on-cost is less, such as driveline disconnect, but there you're getting single figure CO2 savings.
j-a: At the moment we haven't seen any eAxle applications for more conventional AWD vehicles in the SUV segments. Will this change in the future?
RR: Yes, we're working on two, neither of them this year but in the next couple of years. The market segment is a significant opportunity.
j-a: What sort of volume do you see for AWD globally and by region currently and in five years' time? What share does GKN have of the business? Looking to the future what percentage of the AWD systems you supply are likely to be eAxle versus conventional systems?
RR: It's a growing market and we've grown with the overall market. It's been a big success globally. If there's an AWD or FWD/RWD option take up of the AWD option has been very, very good. Most of the growth has been on the modern crossover type AWD based on passenger car platforms, the market for traditional AWD on truck platforms has been flat or declining. What we find is that once customers have driven the AWD they don't want to go back - they see how well it performs in all conditions not just snow and ice. It's in all segments too - we recently announced our involvement in the Fiat 500X and Jeep Renegade programmes, both using our AWD with disconnect technology, and the driveability of the AWD versions compared with their FWD siblings is much higher.
If you look at modern AWD systems with hybridisation and disconnect we are number one. If you take all the AWD market, including all the trucks in the US, we're certainly in the top three.
Global All-Wheel-Drive market estimates
|Global AWD production (million units)||1.8||3.5||4.7||8.2||9.5|
|% share of global vehicle production||3.1||5.5||6.4||9.1||9.2|
|Source: just-auto; industry sources|