The last time we checked in on the Ford Focus engineering team, they were flogging the next-generation Focus on the Grossglockner High Alpine Road in the Austrian Alps. They have since moved on from the high-altitude locale to do hot-weather testing in southern Spain.

While many of the engineering tests focus on how climate extremes affect the performance of the vehicle, the comfort of the driver and passengers in these tough conditions is equally important. Ford’s climate control test team travels the world to ensure that the car’s electronic automatic temperature control system can handle anything a customer can throw at it. Additionally, the team must fine-tune this system to ensure that it is as comfortable, effective and efficient as possible.

One of the team’s regular testing locations is Antequera in Southern Spain. Known as the crossroads of Andalucia, the medieval town is set on a plain some 2,000 feet above sea level. Outside of summer, it is a rich, fertile area popular with history buffs who flock to the town to see some of Europe’s oldest and most important dolmens, or burial sites.  But in the height of summer, the area around Antequera is one of the hottest places in continental Western Europe, with temperatures regularly rising above 100 degrees Fahrenheit. It is a parched, barren landscape, perfect for putting the next-generation Focus to the test.

Ford systems engineer Klaus Schuermanns was there for two weeks this summer, driving up to 300 miles a day, six days a week.

On this trip, the team was testing two camouflaged vehicles – a four-door version for the North American market and a five-door European-spec Focus. Klaus was at the wheel of the European model, while his colleagues sat in the passenger seat, studying a laptop displaying the findings of more than 200 sensors placed around the car. These sensors record a myriad of data, including ambient temperature, air-conditioning pressures, engine speed and sunlight. Chrome-nickel thermo couples are attached to the windows, the seats, the radio, and all around the drivers and passengers, monitoring the temperature throughout the cabin.

One of the main challenges for the team is that customers in North America have different preferences to their European counterparts, so the two test vehicles have different calibrations. North American customers generally like to feel a strong cooling effect while the European customer preference is for the cabin to be cooled slightly less and to not actually feel the chilled air. This is where the team’s experience in subjectively evaluating the system comes in. The sensors can monitor actual data, but the more subjective, human experience of how the cabin feels as it cools is just as important.

While other test teams have to push the car hard on mountain roads, testing the vehicle to its limits, Klaus and his colleagues have a rather more sedate challenge.

“Highway driving is the best way to test the climate system,” says Klaus. “It is not the most interesting road, and after driving several hundred miles on the same road for days at a time, it can get a bit boring, but we are not testing the driving dynamics of the car; we need a straight road and a constant speed, so we can concentrate on how the climate system is performing.”

After 150 miles of highway driving, the two cars pull over outside a small, deserted roadside café. At this time of year, few locals venture outside in the middle of the day, while tourists wisely flock to the beaches and the cooling sea breezes of the Costa del Sol, 60 miles to the south. Bypassing the shade offered by two large olive trees, the engineers park the vehicles side-by-side in direct sunlight.

“This is the pull down test,” explains Klaus.” It’s very important. The vehicles are soaked in the sun for about an hour, until the temperature in the cabin reaches about 140 degrees Fahrenheit. Then we get inside and we drive 20 miles or so and we see how long it takes to get back down to the chosen comfort point, and we monitor how this process feels inside the car. The first few minutes are really quite uncomfortable, but it’s a great AC system so after just a few minutes it is much more bearable.”

Other tests carried out by the engineers include an altitude test and a control curve, where the team changes the temperature settings in the car and then monitors how it feels as the system copes with the changes. As they drive, Klaus and his colleagues are able to directly make changes to the calibration. They have a debrief every evening to discuss their findings and plan the next day’s testing.