Automotive air conditionning

The history of the automobile has led to standardization of "platforms" and mass production to lower manufacturing costs. This standardization is being called into question by the evolution of automobile pollution standards and the appearance of new propulsion systems. Some automakers have chosen to offer their customers a dedicated platform without the traditional gasoline or diesel engines. Toyota has begun with its Prius hybrid, and Hyundia with its Ioniq offers a hybrid, plug-hybrid and electric version.

To obtain clean cars, i.e. cars that do not emit pollutants into the atmosphere, carmakers are working in two areas:

• reduce the fuel consumption of their internal combustion engines and consequently pollutants ;

• stop or suppress combustion engine operation and therefore the release of pollutants.

These two axes have a direct impact on automotive air conditioning because :

• optimizing an internal combustion engine means minimizing its thermal losses or rejects, and the cabin heating function suffers as a result;

• eliminating combustion engine operation means eliminating pulley/belt drive for engine auxiliaries: mechanical air-conditioning compressor, engine cooling circuit water pump, and totally eliminating cabin heating and cooling.

The target in Europe for 2021 in terms of greenhouse gas emissions linked to fossil fuel consumption is 95 g of CO ₂ per kilometer driven, i.e. consumption of 4.1 L/100 km of gasoline or 3.6 L/100 km of diesel on a standardized cycle. This consumption can be achieved by various types of small-displacement (3-cylinder.)... hybrid and electric vehicles, but the "Diesel Gate" affair raised the problem of obtaining these standardized consumptions and the discrepancy found with actual vehicle consumptions. To give an idea, the extra consumption of air conditioning in summer at 30°C is of the order of 20 to 25 g of CO ₂ per km, and in the case of the use of an electric vehicle, range in winter is reduced by 30 to 50% by the use of heating. This air-conditioning consumption is not currently quantified in vehicle homologation cycles.

What's more, these hybrid and electric propulsion systems involve new components: batteries, electric motors and power electronics, all of which require cooling or heating to ensure reliability and optimum operation. Energy optimization during the various phases of a vehicle's life (seasons, road travel) requires the interweaving of different fluidic circuits and their thermal management....