What does extreme cold testing involve ?
Renault Sport’s extreme cold tests are all about ensuring cars are able to start and the powertrain is able to operate at temperatures as low as -30°C. This involves testing a number of fuels and simulating low-traction conditions.
A significant portion of the work is carried out during development of the ABS/ESP steering systems, the aim being to ensure safe, comfortable and enjoyable driving on all surfaces.
Everything is tested, inspected and analysed, from the anti-lock braking system and traction control to acceleration and vehicle stability control, which prevents understeer and oversteer.
Inside, the passenger compartment’s overall ability to keep freezing weather at bay is tested. Driver controls, the heating system, the de-icing system and heated seats are checked and optimised for very low temperatures.
The various teams involved in the process thus take every step to ensure car performance is transparent for customers in all conditions.
How many extreme cold tests are conducted every year ?
The suspension system in each Renault Sport car is tested over a four-to-six-week period at test centres in Sweden.
Powertrain tests are pre-validated at the technical centre in Lardy and then conducted in real conditions for 15 days : extreme cold testing in Sweden and altitude and cold testing in Switzerland.
The project overview team attend testing once the specialists have completed their tasks and conduct general tests to check the consistency of their development work and approve it.
How do you go about selecting the test bases ?
Frédéric Laurent, head of the powertrain development service
“We use a Renault base in Kiruna, northern Sweden, where temperatures can reach -30°C. The base has tracks on frozen lakes and we can use all types of fuels there.
The site in Switzerland is also shared with Renault, which makes things easier in terms of fuel. We can drive in cold weather, at altitude and on steep gradients. With Italy being so close, we only have to go a few kilometres to check settings at a lower altitude and at less extreme temperatures.”
Philippe Mérimée, head of the suspension development service
“We use test tracks in Lapland in the north of Sweden, at Arvdsjaur and Arjeplog. They’re respectively run by Continental and Bosch, who make our driver-assistance systems, and they’re used by all the European car manufacturers. These test centres comprise tracks that are tailored to the settings of each system : icy slopes, straights designed to test braking on snow, ice and tarmac (heated) and handling tracks. The tracks are situated on land and on frozen lakes, and we also use local roads to check customer settings. As you might expect, all our tests are conducted with snow tyres.”
Laurent Dore, head of the synthesis/performance department
“We carry out most of our missions at Renault bases. The benchmark drives are completed beforehand, and it makes more sense for us to ensure product consistency through repeatable tests.”
Are all the cars in the range tested ?
The requirements are the same for an R.S., a GT or a GT Line. It is important that every Renault Sport customer receives a car that can be used on a daily basis anywhere in the world.
How many people are involved in the tests ?
We have small powertrain, suspension and project overview teams and they all take part in the extreme cold testing programme.
The powertrain team is made up of a minimum of five people, including the project leader, an engine-tuning specialist (SME) responsible for basic settings, a climate control SME and a powertrain-approval SME.
Our partner suspension-system suppliers (Bosch and Continental Teves) are also present at the tests, as well as an engineer, a test driver, a test technician and specialists in each system (two to three people).
Every project also features an overview team comprising at least two people : a function performance specialist (SMP) and an overview performance specialist, who heads up the project.
How is data analysed ?
Cars are fully instrumented for powertrain tests, which means data can be directly analysed on site. This helps us be more responsive and allows us to meet product expectations more quickly.
As regards suspension systems, development resources are fitted with ESP units with wheel-speed sensors and a series of other sensors that measure system performance. Renault Sport’s engineers, drivers and technicians also share their own personal opinions.
Subjective tests are also central to the work carried out by the overview team. The idea is to be able to test the latest settings made by the function specialists in extreme conditions, on cars closely resembling their definitive versions. The aim is to offer customers performance that best reflects their everyday expectations.
What is the minimum temperature at which a car will start ?
Specifications vary from region to region. It’s -30°C in Russia and -20°C in the rest of Europe.
How do the cars behave ?
Frédéric Laurent : “We always pre-validate on an artificial test bed, and the first laps on an actual track are usually good. It’s then a case of managing performance, as air temperatures are lower than on test beds in France. The problem lies in ensuring the same level of performance with a single setting and different fuels. That’s because there’s a significant difference in terms of volatility.”
Philippe Mérimée : “By the end of the development phase, our cars are usually very well set up and suppliers often ask to borrow them for demonstrations for our competitors.”
Laurent Dore : “As far as the teams are concerned, the main aim is to come up with a car that performs just as well in normal conditions as it does in extreme cold. A product that is unable to deliver the performance required by the customers, regardless of the weather and driving conditions, is a scenario that we just can’t contemplate.”