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Heat for every drive concept: Eberspaecher supplies efficient systems for electric and hybrid cars

The electrification of the powertrain makes it imperative for the heating system to be decoupled from the waste heat of the engine. This requires tailor-made solutions for the various drive technologies. As a system supplier, the Eberspaecher Group covers the entire spectrum – from the high-voltage application through to the heater suitable for 100 percent bioethanol. The spread of alternative drive concepts is enormous, ranging from the fuel-efficient combustion engine via full and plug-in hybrids and via electric vehicles with range extenders through to purely electric vehicles. The range of demands on climate comfort is equally wide, because the correct temperature in the vehicle is not solely of importance for the vehicle occupants but also for the battery.

Since the VW Beetle was first equipped, the name of Eberspaecher has been synonymous with heat in the vehicle. The group of companies supplies vehicle manufacturers with fuel-operated heaters as standard or special equipment ex works as well as for retrofitting. Via its subsidiary Eberspaecher catem, the Group is a leading supplier of electrical vehicle heaters. Electrical PTC heaters manage without fuel and with no additional tank. They can thus be integrated simply into different vehicle concepts, thereby saving space. PTC stands for Positive Temperature Coefficient and is a temperature-dependent semiconductor resistor. Its resistance level rises almost abruptly with increasing temperature.

High-voltage PTC heaters from Eberspaecher catem are designed for voltage ranges of up to 500 volts and are available in various power settings. The heating systems are already being used, among others, in the first electric production vehicles in the USA, Japan as well as in parts of Europe and have already been fitted into the respective vehicle concept in the development phase in line with customer-specific requirements.

PTC coolant heaters – the solution for vehicles with range extenders
PTC coolant heaters from Eberspaecher catem – continuous-flow heaters with integrated high-voltage control – can be integrated simply into the water circuit of the engine, for instance in vehicles with range extenders or hybrid drives. The selectable operating voltage of the units extends up to 500 volts, an order of magnitude required in such drive concepts. The electrical heater and the waste heat of the combustion engine together produce an efficient solution: taking into account a coolant circuit with a volume of four liters and the relevant heat losses, efficiency is around 90 percent. The integrated power control communicates via a selectable PWM, LIN or CAN signal. The series production launch of the first generation of the coolant heater was in 2010, the second coolant heater generation goes into series production in 2013.

Bioethanol fuel heater – full heat and range
Another approach is the fuel-operated water heater, independent of the engine, which also utilizes the already existing infrastructure of the water circuit and the climate system to heat the interior. In 2011, Eberspaecher brought a bioethanol fuel heater for electric vehicles to the stage of market readiness in the shape of the Hydronic 2 E-Mobility E4S. It generates heat in an environmentally friendly way and barely drains the battery. Since consumption, at 0.4 to 0.5 liters of bioethanol per hour, is extremely economical, the required tank volume is correspondingly low.

Direct and rapid: PTC air heaters for electric vehicles
Eberspaecher catem’s high-voltage PTC air heaters offer comfortable interior heating for electrically powered vehicles. For this task, depending on the size of the vehicle, a heat output of between 4 kW and 5 kW is necessary. Due to the direct heating of the air, rapid and comfortable heating (efficiency around 99 percent) of the passenger compartment is possible. In less than 60 seconds an air outlet temperature of approximately 60°C is already available at the vents – more quickly than with any other system. The definable rated voltage is within the 500-volt range. Electrical air heaters can replace conventional water heat exchangers in the interior and convert electrical energy directly into heat – without taking up extra available space. The integrated, infinitely variable power control can communicate via the selectable PWM, LIN or CAN signal.

PTC battery heater – safeguards the operating range
The temperature level of a lithium-ion battery is of great importance for its performance – and thus also for the range of all vehicles with electrified drives. Ideally, the battery temperature should be between 15 and 30 degrees. Outside this range, the performance of the rechargeable battery decreases significantly. In Eberspaecher catem’s PTC battery heater, which is also already in use in an initial electric production vehicle, the heater, designed as a flow-through system, is used for battery heating. Depending on the size of the rechargeable battery, between 500 and 1,000 watts are needed for this. If required, the battery heater is switched on or off on the vehicle side. Both the low-voltage range up to 60 V and the high-voltage range may be selected as the operating voltage.

48-volt PTC air heater – auxiliary heater for an alternative on-board electrical system
The energy requirement in the vehicle is rising continuously due to the steadily growing number of consumer loads. Interior heating plays a significant role here. However, due to the current load of the vehicle electrical system and the electrical interfaces, today’s 12-volt auxiliary heaters can only be used up to a maximum of 2 kW. 48-volt PTC air heaters are an attractive alternative which, however, require the insertion of a 48-volt vehicle electrical system. Using this, current consumption (amperes) at the same output could be reduced by 75 percent in comparison with the conventional 12-volt electrical system. Especially in electric and hybrid vehicles, the 48-volt electrical system opens up attractive horizons in terms of the required auxiliary heating. The 48-volt auxiliary heater – which Eberspaecher catem has already developed to the stage of production readiness – requires little installation space and can, like a 12-volt auxiliary heater, be fitted in parallel with a heat exchanger. The intelligent electronic control, which allows for performance-optimized and fuel-efficient energy and heat management and, as an option, communicates using a PWM, LIN or CAN signal, guarantees a highly efficient heating system.

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