In this interview, Matthew Beecham talked with Alexander Gädke, director, advanced engineering, ZF Lenksysteme about the company’s steering innovations.
just-auto: Could we start by asking if you could talk us through ZF Lenksysteme’s roadmap for its steering systems? I guess fuel efficiency, packaging, complexity, quality and, of course, cost considerations must all be taken into account?
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In the past years fuel efficiency was the main driving force to introduce EPS into all passenger vehicles. While all cars will be equipped in future with EPS, there is the possibility to introduce new functionalities into all cars. These can be safety functions as well as comfort functions.
To fulfil the cost, quality and packaging requirements of our customers, ZF Lenksysteme GmbH (ZFLS) developed a modular kit for the EPS. This modular kit consists of the most important parts of an EPS, e.g. ECU, motor, sensor, gear.
just-auto: In the early days of EPS, customers and reviewers criticised the poor steering feel, especially vagueness around the centre position. I guess these issues have now been cleared-up?
Based on new control algorithms that have been developed for the EPS, it is now possible to create a first class steering feel. The EPS systems (EPSdp, EPSapa) of ZFLS are [a] benchmark regarding performance and steering feel in the market.
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By GlobalDatajust-auto: As I understand it, Ford is increasingly using electric steering in its models not just to enhance driving comfort and improve fuel economy but open the door to driver-friendly features such as parallel parking assist. Could electric steering technology act as catalyst for a number of other driver-enhanced features?
There will be a lot of new driver assistance functionalities available for end-customers in the future. It has already started with parallel parking assistance (for example in VW Golf, Passat since 2005) and will go further on to functionalities like lane keeping assistance.
It will also be possible to have functions for autonomous congestion steering and probably we will drive in future completely autonomously, at least on highways. [However,] the sensors to detect the surrounding area (camera, radar, etc.) have to be improved.
just-auto: I guess EPS systems are pushing hydraulic steering-assist systems off the road. How do you see the hydraulic steering sector evolving over the next few years?
We think that the hydraulic steering will not disappear as fast from the market as often said. Especially in the emerging markets, hydraulic power steering will still be an issue in the low price segment.
just-auto: If EHPS systems are a bridging technology, the question is how long do you define that transition period? Will that period reach into 2015 or 2020 or will it end in two years time? I guess it depends on the platform that you have been introducing that technology?
EHPS systems will disappear from the market within the next years. These systems have disadvantages especially regarding cost and functionality compared to EPS. For example, it is not possible to provide functionalities like parallel parking assist by an EHPS system. Also the fuel efficiency is not as good as an EPS. The saving of an EPS compared to an HPS System is about 99%. An EHPS system saves about 80% compared to HPS.
just-auto: What is the interest in EPHS systems for hybrid vehicles?
Most of the hybrid vehicles today are heavy vehicles like SUVs. In the past, EHPS was needed because EPS was not powerful enough to steer these heavy vehicles. But today our EPS systems are improved [to the point] that we are able to provide EPS systems to all vehicle classes, including heavy SUVs.
just-auto: Is there an appetite for expensive EPS in some emerging markets such as eastern Europe, India and China? How do you see this application being used in emerging markets?
We also see a request for EPS systems in the emerging markets, especially for small vehicles. But these EPS systems will come with lower requirements regarding functionalities and steering performance compared to Europe or the US. By reducing these requirements, the costs for these systems can be reduced.
just-auto: Some analysts estimate that by 2015, we could expect the European steering market to see fitment rates of 25-30% HPS 55-65% EPS and 5-10% EHPS. How do you see the market growing over the next five years?
These values are fitting pretty well to our forecasts.
just-auto: As we see it, steer by wire is still an advanced technology with limited application potential. Sure, you can prove and realise all sorts of advanced features with it but to bring it into the vehicle will cost the OEM an immense amount of money. So I guess the question here is: will the end customer be willing to pay for it if he / she could get nearly the same functionality with an AFS and EPAS combined?
We think that steer-by-wire is still [the] future. At the moment, there is not a real benefit in such a system. On the other hand, the cost for such a system will be much higher compared to an EPS.
just-auto: What is next for steering systems? We’ve seen how your EPS system has become very popular among automakers. Technically speaking though, what’s in the pipeline, i.e. next generation?
The EPS is a very young system. Probably there won’t be a very new generation within the next ten years. Most technical improvements will be done on the component site. One keyword when we are talking about component improvement is light weight construction. By reducing the weight of an EPS it will be possible to save even more fuel in the future. Therefore, new materials are investigated at the moment.
just-auto: Are there other approaches being developed that use advanced electronic techniques? What about rear wheel steering perhaps supplemented by ultra-capacitors coupled with improvements in sensors, power and control?
We think that rear wheel steering will be a niche market in the future. But ZF is working on this system as well.
