Further integration of functions and components as a key driver in electric brake systems

Gasgoo.com: China has no vehicle safety regulations to require the use of Electronic Stability Control (ESC), and what's more it is still not available in most cars sold in the country. How do you see its future application in China? Is there any difference between different kinds of ESC products?

Hu: Generally speaking, a new legislation is often firstly introduced in North America and the European Union before it is adopted by China. The US government has legislated that all the new cars sold in NA market must be equipped with ESC from September, 2011 and the European Union is also requiring Electronic Stability Control systems to be equipped as standard equipment in all new passenger vehicle models starting November, 2011 and in all newly registered passenger vehicles from November, 2014.

Even though ESC equipment rate is low in China, due to the significant improvement of vehicle safety, it will soon become popular in China as well, along with the legislation and/or corresponding standards, where the mutual cooperation and efforts of the government, OEMs and suppliers will be vital.

ESC products from different suppliers have slight differences. As an example, under critical driving situation, the ESC programs will control not only the engine torque output but also the intervention of hydraulic brake of each individual wheel. Suppliers will use brake intervention as well as engine torque intervention, but due to the different control strategy, one may tend to intervene more with engine torque control while the other prefer to intervene with brakes a little bit more. There are a lot of such kind of differences in details, which could possibly contribute to either more consideration of the comfort during driving or more consideration of performance and safety.

Gasgoo.com: Which kind of vehicles do Continental's Electric Parking Brakes (EPB) and Regenerative Brake System (RBS) apply to? Will these technologies be used in mass-market vehicle segments?

Hu: Electric Parking Brakes (EPB) and Regenerative Brake Systems (RBS) are really different concepts and applied for different purposes.

EPB is used for vehicles with normal hydraulic brakes. The EPB could be applied in order to improve the comfort of the parking brake, or could be applied in case the cockpit is too compact so as it is very difficult to put in a handbrake lever. As for pure parking brake performance, EPB does not bring significant advantage over conventional systems, but in addition EPB helps to realize the features like Automatic Vehicle Hold. And in the meantime, stand alone EPB will add to the new ECU and actuator to the system, therefore EPB is not the final solution.

As a next step, we have designed electrically operated combined caliper (FNec) and Intelligent Parking Brake (IPB), where we integrated the EPB ECU into the ESC, and the actuator of EPB is integrated into caliper and turned it into FNec caliper. Furthermore, future development trend for brake system would be a transaction from hydraulic brake to dry brake system , as an intermediate step, we are developing an electro-hydraulic hybrid braking system consisting of hydraulic brake at front axle and dry brake on rear axle.

As for RBS (Regenerative Brake Systems), Continental's RBS is developed for hybrid and electric vehicles and fuel cell vehicles. It could support the recuperation process, where we could re-capture and store part of the kinetic energy that would otherwise be lost during braking. The captured energy is used to recharge the electric batteries reducing the fuel consumption in the hybrid architecture and support during the vehicle acceleration afterwards, especially under the city driving condition, where the car starts/stops frequently.

Continental's RBS system is a complex system, specifically failsafe and comfort lead to high complexity of components and development work. As an example, without the pedal simulator, the driver for hybrid vehicle/EV will not be able to “feel the deceleration”. When the driver presses the brake pedal, the simulator provides optimum pedal feeling similar to hydraulic brakes, while the expected deceleration is achieved by applying braking torque with the hybrid drive. The braking energy is converted into electric power, which is used to charge the vehicle battery. If the driver requires greater deceleration than the generator function can provide, the hydraulic brake generates the additional brake force based on the driving input, with the fine-tuned hydraulic brake & electric generator brake blending, RBS system could achieve the driver expected deceleration while keeping similar pedal feeling like conventional system. Just because of this, both RBS product complexity and the needed development effort will be increased.

Understandably popularizing this technology will be R&D consuming effort, but it will inevitably become a long term trend and standard considering the development trend of hybrid vehicles and new energies.

Gasgoo.com: We know Continental has upgraded its active and passive safety integration concept - ContiGuard®, and Bosch has also developed Combined Active and Passive Safety (CAPS). Both of them incorporate elements such as ESC, ACC, airbag control units. Do you think further integration of functions and components as a major development trend in electronic brake systems? What are the future prospects for these technologies?

Hu: Yes, we see further integration of functions and components as one of the key drivers in electronic brake systems. Continental introduced in the early stage ABS hydraulic control unit, and then to meet market requirements we developed the ESC, which integrated hydraulic brake control and engine management system. Later on we expanded the functionality and performance of ESC by integrating steering control and adaptive damper control. And all these technologies formed the base of the so called “Global Chassis Control (GCC)” concept.

Even though the active safety technology can make the car safer with less risk to run into accident, we still could not avoid all accidents. Even if the technology is good enough, fatality rate still would not be zero. Considering that sometimes accident happens anyhow, we integrate the passive system functions into our system to minimize the injury which could happen during the accident by coordination between active safety and passive safety systems. Continental's ContiGuard® interlinks the brake and driver assistance systems, that are all vehicle's active and passive safety components, and integrates environmental sensors and telematics functions. The heart of the system is a risk calculator in the vehicle which determines the probability of an accident in any given traffic situation and, based on this information, initiates the necessary action to avoid an accident completely. If this is not possible, the system attempts to at least keep the consequences of the accident to a minimum. The brakes, for example, are pre-filled, the brake assist is prepared for maximum deceleration, the safety belts are tensioned, windows and sliding roof closed and even the airbags "forewarned" for optimum control if initiated. And after crash the system could even automatically call the medical center for rescue.

Today new possibilities for exploiting the system arise through the development of vehicle networking and system integration capacities, with ESC as the core of the system. To develop such system, one need to really master the system core know-how or core interface of all related sub-systems, there are not so many suppliers who can do this. And meanwhile, in China the automotive networking and communication technology are not widely used, the communication and network management between the high speed CAN Bus system like ESC, EMS and the low speed LIN bus system like body control/door control etc. are not so popular yet. So we really hope in the near future, the current vehicle network technology will be widely spread in China.

Gasgoo.com: In April Continental opened a R&D centre in Jiading Industrial Zone, Shanghai and four months later it held the groundbreaking ceremony of a new production plant to mainly produce its electronic control units & hydraulic electronic control units, body electronic modules and instrumentation components as well as thick film substrates in the same district. Will Continental extend its investment in China or does it have any plan to develop new technologies in its R&D centre in Shanghai?

Hu: Continental entered China by jointly founding Shanghai Automotive Brake Systems Co., Ltd. in 1994 in Jiading with Shanghai Automotive Industry Corporation (SAIC). Since 1997 we began to develop ABS for Chinese market and in 2000 we completed construction of China's first winter test center in Heihe of Heilongjiang province, the northern part of China. In the beginning of 2006 we commenced development of ESC in China.

Thus as we always did, we will continue our investment and technology innovations and intensify our R&D localization strategy to develop tailor-made products for the Chinese market, while providing excellent support and global expertise to our local customers. Furthermore, Continental is in the process of building its new Asia Headquarters in Yangpu district of Shanghai that will also host an R&D centre. The Jiading technical center is to conduct vehicle application development and system tests of Continental's electronic brake, hydraulic brake and engine management systems. Our new Asia Headquarters and R&D in Yangpu which will focus on vehicle electronics development will be officially opened in Q4 this year.

About the interviewee:

Guoliang Hu started his career and joined Continental joint venture Shanghai Automotive Brake Systems Co., Ltd. (SABS) in 2000, where he worked in Product Engineering Department, Electronic Brake Systems (EBS) and later R&D. Then he was appointed to Head of Electronic Control Units (ECU) Software/Hardware application and later complete EBS application development.

In 2005, Guoliang Hu took the position as R&D Director Engineering for SABS, with overall responsibility of Hydraulic Brake Systems / Electronic Brake systems / Actuation and Brake Hose products. One year later, he took over the position of Chief Engineer/R&D Director EBS and founded EBS development in new Technical Center in Jiading. Since July 2008, Guoliang Hu was assigned to Customer Center Chinese OEM, in charge of business with Chinese OEMs from EBS side.