Q&A with TRW: Review of electronic braking systems
Continuing just-auto’s series of interviews with the world’s leading brake manufacturers, Matthew Beecham talked with Vince Austin, Director of Product Planning for TRW’s Braking Systems business.
The path towards brake-by-wire in the automotive industry has not been all that smooth. Could we start by asking for your opinion of where we are now?
By wire systems have had a challenging history – a few systems have come into production but the costs have been high and the associated issues have prompted suppliers and manufacturers to take a step back and explore a modification of hydraulic systems to suit a variety of powertrains. TRW has recently introduced its Future Brake System which combines brake actuation with a slip control modulator in one compact unit. It is 100% electrically powered but has a hydraulic back up capability.
However, we expect that conventional systems will stay around for at least the next ten years – they’re very cost effective, robust, and reliable, and the hydraulics gives you the advantage of automatic brake balancing. It’s unfortunate that it will take this long, as from an engineering perspective, it’s very interesting! But as the industry is commercially driven, it will be some time before we see true by-wire systems in large numbers.
How does TRW minimise the impacts of brake system diversity between ICE, HEV and EV vehicles?
TRW offers a modular ESC product family (EBC 460) which is compatible with a range powertrains including hybrids and electric vehicles. EBC460 features everything from standard versions – some even developed to remove the pressure sensor to lower cost without compromising performance – through to premium versions with six-piston pumps that can rapidly build and apply brake pressure for driver assist functionality, such as emergency braking.
The aim of our ESC family is to share the maximum number of components across the different system architectures. We offer three main product architectures – ABS, ESC and ESC Premium – each with slightly different packaging sizes, but sharing components for standardization purposes. Within the architecture, the product can be configured to suit the vehicle manufacturer’s braking, vehicle sizing and functionality requirements. Many functional upgrades are achieved via software that can be scaled up with different microprocessor sizes. TRW’s systems for HEV and EV vehicles utilize many components that are common within EBC 460 product family – this results in a more competitive and robust product.
I guess a challenge of regenerative brake systems is its capability to be applied on all platforms, not just the premium segment. In what ways can cost be reduced to achieve this?
For suppliers, one of the important strategies to keep costs down is to maintain common bills of material, manufacturing equipment, and processes, etc. These efficiencies of scale allow for the units to be produced at lower cost.
In addition, the Future Brake System architecture brings together previously separate components including the electronic brake control, hydraulic actuation and motor pump unit for brake pressure accumulation into a single multi-plexing unit which can work across various powertrain configurations in a cost-competitive package. Large-scale fitment of Future Brake Systems will also have a positive effect on their competitiveness.
In terms of tomorrow’s electronic braking systems, to what extent do you see a trend of integration?
The increase in vehicle safety requirements has led to the development of several braking innovations which offer advanced intergration of several control systems. We see this trend continuing and TRW has developed a number of technologies which can be integrated with other control systems to enhance driver safety.
For example, TRW’s integrated electric park brake system (EPB) is composed of two electro mechanical actuators integrated into the rear disc brake calipers, an electronic control unit with the park brake control software, and an EPB switch actuated by the driver. The system interfaces with other control units (ESC, Powertrain, etc) helping to enable a number of advanced functions such as dynamic braking and emergency braking. The trend is to integrate the control function within the Slip Control Electronic Control Unit (ECU), thereby eliminating the discrete ECU. TRW can and does offer complete EPBi systems to the market today.
A further example is TRW’s Automatic Emergency Braking (AEB) system which fuses sensory information from radar and video to help protect drivers and pedestrians. Such systems will start to be mandated on trucks from 2013, and this legislation alongside other industry drivers such as changes to NCAP ratings to include more active safety features, will accelerate the fitment of integrated systems even further. These systems typically utilize a Premium ESC with six-piston pumps that can rapidly build and apply brake pressure for driver assist functionality, such as emergency braking.
How do you see this new braking technology being rolled out in some emerging markets?
The example of the Brazil ABS legislation shows that governments can and will take action to introduce important technologies to the marketplace.
TRW’s stance is that all drivers, passengers and other road users deserve to be safe. In emerging markets like China where road safety is a significant and growing issue, it is critical that drivers have advanced technologies and learn how to use or interact with them. A big challenge ahead is not just equipping vehicles properly but changing the mindset of vehicle drivers and other road users in understanding that the rules of the road are very important. TRW has launched and is continuing an effort to teach Chinese children basic safety precepts such as buckling seat belts and how to cross the road safely. The acceptance of technologies and the safe driving mindset will take time but ultimately should prevail. We are witnessing significant increases in Slip Control fitment in China, Brazil, and India which is an indication that these emerging markets are interest in increased safety.
A decade ago, EPB systems were treated as independent technologies. Nowadays, it appears the theme is very much centered on integrated, combined electronic braking systems. As we understand it, electric park brakes are being fitted on more and more cars, permeating down the car segments. Is this correct?
EPB technology has experienced considerable growth since its market introduction in 2001. TRW was first to market with the technology and has since produced over 15 million units. At TRW, we are constantly evolving our products to make them more efficient and more accessible to all vehicle segments and regions – something we have been able to achieve through the success of our EPB technology within the mass vehicle market segment. For example, we offer integrated solutions (EPBi) and front axle configurations (EPB front) as a cost effective solution in order to address requirements for the A and B segment vehicle market.
EPB is forecasted to be standard on one in five of all European-built vehicles by 20151. Projections also show that approximately half of the mid to larger sized European passenger cars will have EPB in this timeframe, while the technology will continue to penetrate other regions and countries including China where EPB will see significant growth over the next five years. In addition to Europe, TRW has industrialized EPB in North America and China as well in order to meet increased demand from its customers.
Could you explain TRW’s EPB, i.e. technology used, its special characteristics and on which vehicles it is currently fitted?
The remainder of this interview is available on just-auto's QUBE research service