Continental Corporation has successfully adapted some of the safety and comfort features it has developed for cars and sports utility vehicles into heavy vehicles including trucks and buses. Though a few of these safety-related features have already been adapted in trucks plying in Europe and elsewhere, it is very likely that in the not- to-distant future these technologies would be in demand in countries like India.
This was stated by Amrei Drechsler, vice-president, Advanced Driver Assistance Systems, Continental in a conversation with newspersons from various Asian countries recently in Cologne. Drechsler noted that leading carmakers have already put in place several safety features like lane departure warning, blind spot detection and adaptive cruise control. Now with an electric steering, various such comfort functions can be used with this system. It permits direct access in order to assist and support the driver more than has ever before been possible. Driver assistance systems are possible only with electric steering, including the lane keeping system, which warns drivers when they are about to depart from the lane.
According to Ms Drechsler, Continental’s latest development is an electrically enhanced steering for heavy vehicles. The company’s Chassis and Safety division has developed a modular power pack, comprising of control electronics and an electric motor, which makes it possible to install electrically enhanced steering in large saloons or SUVs with existing 12-volt onboard power systems. To date, this feature was predominantly installed in the midsize and small car segments. Electrically enhanced steering systems provide the driver with additional comfort and driving enjoyment while at the same time improving vehicle dynamics. Electrically enhanced steering systems save a tangible amount of fuel.
Continental now meets even the tough requirements that these heavy vehicles impose on electrically enhanced steering systems. Alongside the strong and yet highly compact electric motor, the short-term peaks in power output also call for a robust electronic control structure that can withstand heavy strain. The hardware components of the steering enhanced system developed by Continental are scalable, meaning that they can be adjusted flexibly to the vehicle class; the same also applies to the electric motor, which can supply up to 16 kilograms Newton metres of supporting force in the overall steering system.
Alongside its benefits in everyday operation, electrically enhanced steering also offers advantages for automotive manufacturers. Component warranty periods can be extended because electrically enhanced steering systems do not require refills of hydraulic oil and thus there are no service intervals. Electrically enhanced steering is also easier to integrate into individual models than hydraulic servo steering systems because it requires significantly less space.
Enhanced comfort and vehicle dynamics
The further benefits of electric steering include various comfort functions that can be used only with this system. It permits direct access in order to assist and support the driver more than has ever before been possible. Driver assistance systems are possible only with electric steering, including the lane keeping system, which warns drivers when they are about to depart from the lane. In this feature, the control electronics can put the vehicle back on course within the lane by means of a planned, supporting intervention in the vehicle’s steering. In addition, the complex control electronics make it possible to adjust the steering to the current driving circumstances.
When the vehicle is traveling slowly, such as in the city, the steering system provides more assistance than on fast curves on the highway. For SUVs, the steering characteristics can also be adjusted to the particularities of off-road driving. Whether on the road or off: The driver receives optimum feedback on the current driving situation from the steering system at all times.
Active support
The electric steering system supports the driver’s steering motions, by an electric motor connected to the steering column increasing the steering wheel torque in accordance with the driving speed and the automotive manufacturer’s individual settings. In contrast to conventional servo steering, in which a hydraulic system handles this task, the electrical system has a number of advantages: The electric motor only has to be activated when steering assistance is actually required, and that takes place in just fractions of a millisecond. In a hydraulic system, however, the buildup of pressure always has to be maintained within the system so that the steering assistance system can support the driver anytime.
To accomplish this, the hydraulic pump has to receive a constant supply of drive energy from the engine. What’s more, the electric steering system requires that fewer
components be installed into the vehicle, plus hydraulic oil is not needed. This combination of savings on weight and substantially lower demand for energy to drive the steering assistance system yields fuel economy gains of 0.4 litres for every 100 kilometres. For that reason, and because of the legal requirements concerning reduced
CO2 emissions, systems of this type will increasingly take hold on the vehicle market in the years to come, largely displacing conventional hydraulic servo steering.
“That means that this technology developed by Continental is another building block toward achieving our ambitious CO2 emissions reduction goals in the next few years. The possible scalability the technology offers means that we will be able to use it in all vehicle segments,” emphasises Dr Peter Laier, executive vice-president of the Chassis Components Business Unit within the Chassis & Safety division at Continental.
Electrically enhanced steering will noticeably replace conventional hydraulic systems over the next few years. “For 2015, we expect that electric steering systems will hold a market share of 75 to 80 percent in new cars worldwide,” says Laier. In the United States, two vehicle manufacturers plan to produce all passenger cars in the future exclusively with electrically enhanced steering systems.