How were you able to obtain the resources and gain support for this project?
Getting all of that in place was anything but easy. For a long time, my search for supporters and financial backers for this project was fruitless. In actual fact, Continental Engineering Services is the right place to try things out as an engineer and initiate new developments, especially for niche projects. Nevertheless, I did not get the go-ahead until I had personally convinced our managing director, Bernd Neitzel, with a detailed business plan. Besides the technology, what made the difference was analysis of the focal sales markets in the U.S.A., Australia and Europe. In the U.S.A., around 11 million trailers are registered (of which around 6 million could potentially use the new brake system). In Australia, the number of registrations is approximately 500,000, of which around 200,000 would be suitable for our Trailer ABS. In Europe, the booming caravan market in particular promises good business (likewise around 150,000–200,000 vehicles per year).
Did the particular circumstances at Continental Engineering Services also help you to develop the project further as you wanted?
Yes, the special “CES mindset” that manifests itself primarily in the openness that people show in their dealings with one another and in the pragmatic approach to development work certainly helps. That also gives you the freedom to challenge conventional thinking once in a while and, due to the flat hierarchy, we are sometimes able to bring about decisions more quickly than others.
What types of brake systems are currently available in these markets?
Around the world, we have completely different brake systems for trailers. In Europe, we have drum brakes that are operated with Bowden cables. That is an overrun brake with a spring-loaded drawbar (attachment on the trailer). If you apply the front brakes, the trailer is pushed into the towing vehicle by centrifugal force, i.e. the trailer “overruns”. As a result, a Bowden cable for the brake is operated via a lever system. The harder you brake, the more forcefully the trailer is pushed into the towing vehicle. The main problem here is the poor reaction time of the Bowden cables, especially when they get old and are not well lubricated. Moreover, the system does not work when the vehicle is reversing, which is a real problem with heavy loads of more than two metric tons. The technology behind our European system comes from the 1950s!
In the U.S.A. and Australia, there are two brake systems that are not permitted in the EU, but both are better than the outdated European system. There, towing vehicles have a brake controller for acceleration in the X, Y and Z directions that measures the pedal travel and generates an equivalent signal that is transmitted to the trailer via the trailer socket. Unlike in systems with overrun couplings, the trailer hitch in this case is rigid. In the cheaper systems, there is a purely electric brake, i.e. a drum brake with an electromagnet. Depending on the current that is transmitted from the front via the controller, the brake shoes are then electromagnetically drawn onto the drums. As a result, the towing vehicle at the front and the trailer at the rear both brake at the same time. With these systems, it is possible to vary the braking intensity manually. In Germany, that is not allowed for the sole reason of preventing incorrect operation by the user.
Another system uses electrohydraulic brakes (electric over hydraulic) that are actuated in exactly the same way. Here, an electrical signal regulates the brake pressure built up by a hydraulic pump and delivers it hydraulically to a drum or disk brake.
And how does your design work?
When the brake pedal is depressed in the towing vehicle, the trailer is slowed down by an equivalent amount, just like with the electrohydraulic system in the U.S.A. In order to cover large trailer volumes as well, we have integrated the MK 100 XT brake component with two (single-axle) or four (tandem-axle) wheel speed sensors as the centerpiece of the system. A remote-capable sensor cluster always records acceleration values at the most suitable point depending on the size of the trailer.
The MK 100 XT is controlled by the signals detected there, in order to build up the necessary brake pressure for the given situation. If a wheel comes into contact with slippery ground, for example, the brake pressure generated by the pump motor of the MK 100 XT can be reduced for this wheel, thus preventing individual wheels from locking. Like the systems predominant in the U.S.A. and Australia, our system works when the vehicle and trailer are driving forwards and reversing as well as on hills ascents and descents. As prescribed for the trailer systems in Australia and Europe, a mechanical handbrake is also envisaged for our solution.
The current European legal framework does not allow for a brake controller to be used in the EU system. As a result, there is no option to transmit signals for braking operations and other functions from the towing vehicle to the trailer in these countries. In this case, that has to take place via a CAN connection. However, this is very time-consuming because it is necessary to ensure, that the trailer is able to read every possible CAN signal for every possible tow vehicle.
Instead, the system that I have developed allows for a plug & play solution for all towing vehicles and trailers with a standardized interface. By using the MK 100, we then even have an opportunity to realize a sort of ESP. That means that you can apply the brakes to the wheels on both sides individually, thus preventing the combination from swaying. As a result, a trailer ESP in the towing vehicle is not necessary because the trailer is kept stable and in lane by its own hydraulic brake system.
In order to maintain the functionality of the system at all times, we have also incorporated a fallback mode that uses a brake light signal, i.e. if the sensor signals fail, the brake light signal can be used as a trigger. And if, in the worst-case scenario, the trailer breaks away from the tow vehicle, the break-away switch initiates emergency braking with ABS and ESP.
When developing a trailer braking system, you also have to consider the various standards for trailer sockets around the world. While in Europe this means having to factor in a 13-pin socket connection (ECE standard), 7-pin socket connections with different designs are used in the U.S.A. and Australia (they are flat in Australia but round in America). In addition, thanks to the new SAE J 3008 standard, there is a second 12-pin socket in the U.S.A. that was developed by the German company Erich Jaeger. This allows the transmission of CAN, video and other sensor data, e.g. for a reversing camera on the trailer or for coverage of the blind spot etc.
For which types of trailers is Trailer ABS suitable? What kinds of loads can safely be towed with it?
Our system can be used for normal trailers and the fifth-wheel trailers that are very popular in the U.S.A. (often used with pickup trucks), sometimes referred to as goose neck trailers. They are more comfortable to drive, because the load rests directly on the axle and not one and a half meters behind it. That is better in terms of weight distribution.
The brake system integrated in our innovative project covers trailer loads of up to seven metric tons, which means that we are covering the usual requirements both in Europe and in Australia completely; in the U.S.A. it is still a solution for around 60% of the trailers that are in use. (Average trailer towing loads in Europe: up to 3.5 metric tons; in Australia: up to 4.5 metric tons; in the U.S.A.: up to 15 metric tons)
Do you already have any customers for Trailer ABS?
We have already had a very large number of inquiries. Of course, it helps in that respect that we can already point to a fully functional solution in the form of our Trailer ABS innovation project. We are in contact with two manufacturers in the U.S.A. and Australia who offer axle brakes that are prepared for wheel speed sensors. European trailer manufacturers, on the other hand, are currently installing only mechanical drum brakes. For them, we would have to adapt our system for hydraulic disk brakes. However, the European trailer manufacturers are yet to see any need for assistance functions such as ABS, ESP, blind spot monitoring or a reversing camera on trailers. For that reason, we are expecting developments in that respect only after legislation tightens safety requirements for trailer systems. We are prepared for that and will then be able to respond immediately. In Australia and the U.S.A., by contrast, we are expecting that some manufacturers will take action themselves in advance. Even though the topic has, of course, become a personal matter over the years, I am 100% convinced that the project will be a commercial success.
Advantages of Trailer ABS
- Greater braking force
- Shorter braking distances due to shorter system response times
- Works when the vehicle and trailer are driving forward and reversing as well as on hill ascents and descents
- Improved safety due to ABS and ESC
- Optimized sway control as the system is positioned right inside the trailer
- Enables higher towing speeds (up to 120 km/h instead of 100 km/h)
- Available as an OEM solution or as a retrofit solution for the aftermarket
||Ralf Hiller, 37, gained qualifications in Germany and the US. Hiller studied mechanical engineering with a focus on vehicle technology in Bingen and Rüsselsheim in Germany and at MIT in the U.S.A. He worked in the combustion engine laboratory at MIT with the aim of settling in the U.S.A. However, after missing out on a new work visa, he moved back to Germany and came to Continental TEVES as an external employee. After that, he worked in valve development for ABS valves (hydraulics) for two years and in the area of ABS pump motors for a further two years. For some three and a half years now, he has been working for Continental Engineering Services (CES), where he is primarily concerned with system engineering and E/E architecture, but also attends to test management or special projects that require him to look at the bigger picture.