BERU launches the next generation of PTC auxiliary heaters

BERU has undertaken a critical step in the development of a new generation of electric PTC auxiliary heaters. This innovative concept offers automakers greater benefits: The new systems are smaller, lighter and more flexible in application, as well as offer more safety and reliability during operation.

(Ludwigsburg, 07 may 2008) Today’s fuel-efficient engines have increased efficiency and therefore dissipate less heat to the cooling system. As a consequence, at low outside temperatures these engines take a long time to provide the desired amount of heat in the passenger compartment. PTC auxiliary heaters from BERU make up for this shortfall by providing supplementary heating. The PTC heater installed in the air duct behind the coolant heat exchanger, heats the air, which in turn heats up the passenger compartment and clears the windscreen in seconds.

BERU PTC auxiliary heaters: compact, flexible, and cost-efficient

With the latest generation of electric PTC auxiliary heaters, the Ludwigsburg specialist for Ignition Technology, Diesel Cold-Start Technology, Electronics and Sensors has made a further decisive step in the development of its products. The innovative concept offers automakers with compelling benefits during development and manufacturing. The new models have considerably fewer components and retain the well-established rugged heating rod concept. It was possible to achieve this design through use of extruded aluminium profiles that are optimised from a thermal standpoint. This design achievement has lowered the number of components in the heater from an average of 150 down to fewer than 25 per system.

Further benefits of the new PTC auxiliary heater models:

• They are about one-third lighter than their predecessors with fins.
• They are smaller than their predecessors. The new design principle, for instance, permits construction of compact, three-stage heaters with a profile width of about only 70 millimetres.
• They can be manufactured with any number of heating stages. This means that single-stage mini-heaters for decentralised heating can be produced just as readily as powerful, four or five stage heaters with electronic control.
• They offer twice the thermal safety, an additional benefit when it comes to the service life of the product: In all high-output models, the switching elements and PC board are thermally isolated from each other by a bus bar; in addition, an excess temperature cut-out is incorporated into the PTC’s electronics.
• The tooling costs are lower than that for earlier models with fins. Moreover, the shorter manufacturing time for tooling has made possible for BERU to considerably reduced the development time needed for customer specific applications.

BERU PTC auxiliary heaters: the right solution

From the compact mechanical model to the electronically controlled comfort system: BERU offers flexible product solutions for both, the climate control system manufacturers as well as its customers in the international automotive industry.

Currently, BERU has five PTC product lines in its range:

• Plain Line: Single or multi-stage auxiliary heaters for classic standard applications. The controls employ relays mounted externally in a control box in the vehicle.
• M-Relay Line: Compact, multi-stage auxiliary heaters with integrated mechanical relays. The benefit of this system is that the integration of the auxiliary heater into the electrical system of a vehicle requires no additional development effort. Furthermore, the secondary costs associated with wiring, relays, applications and installation are reduced.
• E-Relay Line: Especially compact PTC auxiliary heater with integrated, wear-free Smart-Power switches instead of mechanical relays. There is no mechanical switching noise, longer service life and optimal safety due to built-in temperature monitoring.
• Basic Line: Easy-to-install, microprocessor-controlled PTC auxiliary heater as a plug & play solution requiring noticeably less wiring in the vehicle. In this compact design, the heater rods are supplied individually via PWM-controlled power transistors instead of stepwise or incremental control. It utilises a closed-loop control concept, the heat output is continually adjusted to satisfy actual requirements. Internal diagnostics monitor, among other items, the temperature, voltage and current of the power transistors.
• Comfort Line: The high-tech PTC solution from BERU with maximum functionality, performance and convenience. Microprocessor-based, with variable control of heat output. Output power adjustment, functioning and diagnosis are based on one of the common bus systems such as CAN or LIN. The intelligent control behaviour of the BERU Comfort Line minimises power fluctuations in the on-board electrical system. Battery voltage, current levels, power transistors and heater rods are monitored to initiate appropriate countermeasures in the event of a sudden voltage drop, short circuit or similar fault condition.

BERU currently supplies PTC auxiliary heaters to automotive manufacturers such as Audi, Ford, Hyundai, Jaguar, Kia, Mazda, Nissan, Seat, Skoda, Volvo and VW. The electronics of the PTC systems are manufactured on fully automated production lines at BERU Electronics in Bretten. The heating elements are manufactured at the joint venture BERU Eichenauer GmbH in Kandel.

BERU subjects the PTC auxiliary heater components and systems to extensive testing to ensure that the PTC auxiliary heater functions reliably for many years under rigorous everyday use. BERU also conducts all qualification tests – in its own test laboratory – from development to production-ready status. The facilities in Bretten, Ludwigsburg and Kandel have a variety of special testing equipment to accomplish performance tests, including climate chambers and airflow measurement set-ups as well as EMC laboratory, to ensure informative results with real-world relevance. Upon request, BERU can also carry out tests related directly to user applications. This eliminates the need for our customers to install and maintain their own testing and measurement equipment, albeit the time and effort associated with testing.