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ixetic Shows R744-based Thermal Management Concept for Li-ion Packs; Other Pumps for Lower Energy Consumption

At the Frankfurt Motor Show (IAA), ixetic GmbH presented a concept R744-based thermal management system for lithium-ion battery packs in electric cars. (R744 refrigerant is chemically nothing more than pure CO2.)

The system uses a special compressor that works according to the principle of a heat pump—i.e., it can both cool and heat to an equal extent. The system constantly maintains the pack temperature at between 15 to 35 °C (59 to 95 °F), even when the vehicle is parked. If the vehicle is not running, the compressor takes the electricity it requires for cooling or heating directly from the battery.

The company notes that another advantage to its concept is the use of ixetic’s compressor as a vehicle heating system during the cold seasons. In contrast to vehicles with combustion engines, electric cars require an additional electric heating system.

A conventional additional heating system uses electricity from the vehicle battery, thereby limiting the possible driving radius by around 40%. The high efficiency of ixetic’s compressor, however, means that the amount by which driving distance is limited is significantly lower, at just 10 to 15%.

Development work by what is now ixetic on an R744 compressor targeted at mobile air conditioning systems began in 1996. As of 2011, European vehicle manufacturers will no longer be allowed to use the R134a cooling agent in air conditioning systems. The leading alternative to R134a is now R-1234yf (earlier post).

ixetic has been an independent company since March 2006. Before that, ixetic was part of the company LuK Fahrzeug-Hydraulik and LuK Automobiltechnik, which in turn belonged to INA Holding Schaeffler KG. Today, ixetic is owned by the holding company cognetas. The ixetic product range covers hydraulic pumps for steering, chassis and transmission applications, vacuum pumps for brake systems and lubricating oil pumps.

Other systems for reducing CO2 emissions. ixetic also presented a range of products featuring lower energy consumption at the IAA:

  • EV2 steering pump. The pump precisely matches pump capacity to need using a proportional valve in the steering system. This leads to lower circulating pressures, reducing fuel consumption. In testing (NEFZ), the pump saved 0.2 liters of fuel per 100 kilometers.

  • Mechanical vacuum pumps. These pumps generate the negative pressure required for brake pressure boosting in both diesel and gasoline vehicles that the intake system—unlike in the past—can no longer provide. Compared to its competitors, ixetic has reduced the entire speed range by approximately 50%, according to the company.

  • Gear pumps. The latest double-stroke vane-type vacuum pump for supplying oil to the gears is characterized by very good volumetric effectiveness at low speeds. Another fuel-saving feature is demand-dependent control, based on switchable displacements. This saves around 0.1 liter of fuel per 100 km compared to other pumps on the market.

  • Electrified vacuum pumps. Hybrid vehicles and vehicles fitted with start-stop automatic transmission use a new generation of electrically-driven vacuum and gear pumps. They require—regardless of the combustion engine—an independent electric drive. At the IAA ixetic exhibited electrified vacuum pumps now ready to go into production. These will be introduced onto the market in 2011. The electrified vacuum pumps save around 1.7 g of CO2 per kilometer compared to conventional vacuum pumps. In contrast to conventional pumps that continuously generate power via the combustion engine, the electrically-driven pumps only generate power according to need and thereby avoid energy-consuming idle running.

  • Electrically driven gear pump. An electrically driven gear pump supplies lubricating and cooling oil to the gears when the combustion engine is switched off. ixetic’s new gear pump generation reduces consumption by 1.9 percent, while CO2 emissions are reduced by 3.7 g/km.

    Whether for automatic transmission, dual clutch transmission or continuously variable transmission, the pump supplies the amount of oil that corresponds with the desired rotation speed. This applies in all electrically-driven driving situations or—in the case of an existing mechanically driven oil pump&mash;to meet demand peaks in a combustion engine driving cycle.

    — Dr. Reinhard Plietsch, Development Manager at ixetic


Henry Gibson

Pure propane can be used, but ir will not make any chemical company rich. Dupont did not object to the phase out of R12, because there was no money in producing it. Now R134a is being eliminated for something newer and more expensive. R600a is already used in millions of refrigerators.

ZEBRA batteries hold as much or more energy for size and weight as Lithium ones and they need no cooling except for air. Their operational heat can be used for heating.

There are fuel powered vehicle heaters that may be cheaper to operate for heating than electric heating. But a tiny fuel powered generator can charge the battery and heat the vehicle at the same time.

All cars should have electric replacements for braking and steering and fans et cetera. Frame mounted compressors can eliminate leakage, so no change in standard coolants is really necessary. ..HG..

Jeremy Koudelka

The most unreliable vehicle systems in my experience are refridgeration systems (a/c) - the most unreliable system should not be responsible to provide a primary function to what is generally engineered as the most robust system - drivetrain/powertrain. Actively cooling batteries usually results in a system that cannot cool itself in absence of the active component - batteries can be and should be designed for air cooling with cabin air or filtered external air only. In the case of the escape - if you lose a/c - which I'm sure happens alot more than say a transmission failure - you don't have a real long time before the battery overtemps and the system is in superduper limp mode.


Most of the frequent problems with vehicle AC is with the mechanically belt driven compressor + a few but rare refrigerant leaks.

A variable speed, higher efficiency, electric compressor unit, in a heatpump arrangement, could run for 25+ years and keep the cabin in high comfort even when the car ICE is not running.

Most HEVs, PHEVs and all BEVs will have such a unit.

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