Mercedes-Benz EQC EV soaking up summer heat of up to 50˚C in trials in Spain
19 June 2018
Mercedes-Benz will run the Mercedes-Benz EQC electric vehicle through hot weather trials in Spain. Following successful winter trials, the EQC is required to endure an extensive test program in the summer heat with temperatures of up to 50° C (122 ˚F).
Particular attention is being given to aspects which are very demanding for electric cars—air conditioning and charging, as well as cooling the battery, drive system and control units in extreme heat. Criteria such as driving dynamics and ride comfort are also subjected to further, stringent tests.
With the finishing straight in sight, we are now able to absolve another extremely demanding test program with our pre-series vehicles. But after successfully completed endurance tests in winter at minus 35 degrees C, we are confident that the heat trials will confirm that we are well on schedule for the start of series production.—Michael Kelz, Chief Engineer for the EQC
While the battery of an electric car “merely” loses power in the cold, exposure to great heat carries the risk of battery damage. Optimum management of these physical characteristics is the aim of the extreme tests in Spain. One main focus is on the battery’s cooling circuit: how does it cope with high power requirements? How does an almost fully charged battery respond to further charging? What influence does the heat have on operating range? Battery draining tests, i.e. test drives in which the battery is completely drained of power, are also part of the test program.
Another aspect is air conditioning of the interior—both during a journey and beforehand, as pre-climatization is an important comfort factor. This is when questions such as “Is the indicated time sufficient for pre-climatization?” and “Is the calculated range correct when the temperature is taken into consideration?” are answered. Furthermore, the noise characteristics of individual components such as the air conditioning compressor in the heat are specifically examined.
Fine dust is also a particular challenge during the trials in Spain, as the test technicians want to know where this dust might be deposited in the components, and whether the sealing concept works in practice.
Systematic complete-vehicle validation is among the extensive measures in the development process of every Mercedes-Benz model series. This serves to verify and to maintain the high quality standards.
Before a new product goes into production, the complete vehicle must reach a maturity level set by Mercedes-Benz. This takes place in several stages: step one is digital preliminary design and simulation. It is followed by validation—either of individual components on dynamometers or in test vehicles. This tests and validates, for example, the durability of a powertrain connection or of individual axle parts.
Digital testing covers all key areas of vehicle development: from the simulation and verification of buildability to crash, aerodynamic, ride & handling), NVH (Noise, Vibration, Harshness) and weight tests plus fuel consumption and operating range.
Despite all the advantages of digital testing in terms of speed, data availability and efficiency, no vehicle goes into series production without extensive real-world testing. The focus is on the long-term durability of components such as major assemblies on the dynamometer, and functional testing of the complete vehicle under different climatic conditions on the roads. In the case of the EQC, of course, special attention is paid to the electric powertrain and the battery.
A special role is also played by the acoustics of an electric car. Unlike in a combustion-engined car, there is hardly a sound from the powertrain. This makes sounds such as the rolling of the tires or wind noise more prominent.
Before being released for production, the vehicle must be tested and validated by numerous individuals from many different development departments. A total of several hundred experts are involved in testing. From the specialist departments, which approve their components and modules, through to testing/endurance testing of the complete vehicle.
In the case of the EQC, the overall development time is around four years. Before coming to market in many countries around the world, the EQC will have undergone extensive testing in Germany, Finland, Sweden, Spain, Italy, Dubai, South Africa, the USA and China.