Driving on ice and snow puts the car’s abilities to the test. However, safe and comfortable winter driving also imposes demands on an effective climate unit that keeps the windows and door mirrors free from mist and ice.
The Volvo XC90 and all the other new cars emerging from the large Volvo Cars platform have a number of features that make winter driving as trouble-free as possible. Features that have a greater impact on safe and comfortable progress than might first meet the eye.
Be cool – with the help of the heating system
A snowy winter morning, all the cars are shrouded in white – and they are all icy cold. Without a heater, you have to scrape away snow and ice from the windscreen, side windows and rear-view mirrors before you can settle behind the wheel. Once you have started the engine (all Volvo cars are designed to start at temperatures down to –30°C), a number of functions are activated, either automatically or when you press a switch:
the rear screen and the door mirrors are electrically heated.
the driver’s and front passenger seats are heated, with a choice of two heating outputs.
the climate unit starts blowing air into the cabin. When the engine’s coolant has reached 35°C, the ventilation system gradually starts increasing the temperature and flow of the air blown into the cabin.
Computerised heating system
The most advanced Volvo climate unit, ECC (Electronic Climate Control), has two temperature sensors and a solar sensor.
The information that the sensors provide is used by the climate system’s processor to calculate how the air should be warmed up and where it should be delivered into the cabin so as to remove mist from the windscreen and side windows and to provide a pleasant interior climate in the shortest possible time.
At temperatures above 3°C, the air conditioning system serves as a dehumidifier to help remove mist even faster. In the Automatic setting, it is designed to deliver most of its warm air to the floor and windows since this is where moisture usually gathers – on shoes and on windows.
In order to be able to remove mist from the windscreen and side windows as quickly as possible, the Volvo XC90 has a number of highly effective air vents, including some strategically positioned in the B-pillars between the front and rear seats. In the summer, these vents help enhance comfort in the rear rows of seats. In addition, the panel vents in the front of the car have been optimised to provide draft-free ventilation.
Uniform temperature important for safe driving
A constant, pleasant temperature inside the cabin is an important safety factor when driving.
The most common mistake many drivers make is to select too high a temperature while the car is still cold, in an attempt to heat up the interior quickly. As a result, the temperature gets too high once the engine warms up.
Volvo Cars has undertaken surveys that clearly reveal that too high an interior temperature jeopardises driving safety.
Two groups of test drivers covered exactly the same stretch of road at two different cabin temperatures, 21ºC and 27°C.
The number of errors and cases of slow reaction while driving was far higher in the group where the cabin temperature was higher. This clearly shows that a driver who is too warm is a poorer driver.
It is also important to point out that this is not just a problem in the summer. The risks associated with excessive interior temperature are equally high in a car that has been warmed up too much in the winter.
Volvo’s climate units are designed to be straightforward and convenient to use, with clear and logical symbols and controls that are sufficiently large to be able to be operated by gloved hands in the winter.
With the advanced ECC unit, the driver just needs to select the required temperature. In Automatic mode, the unit adjusts fan speed and air distribution automatically to suit current conditions. However, you can naturally override the system and make individual manual adjustments.
Clean inside and out
The quality of the air inside the car has an important effect on comfort and health too. Since cold temperature has a negative effect on combustion, the surrounding air contains more unburned particles in the winter than in the summer.
That is why the climate system in the Volvo XC90, just like the other cars based on Volvo’s large platform, has been designed so it prioritises clean cabin air.
Dangerous particles are trapped
Among its many features, the Volvo XC90 is equipped with effective filters that make the air inside the cabin cleaner than the air outside.
Medical studies have shown that the main health hazard in the context of air pollution comes from the quantity of small particles (approximately 0.3 µm and smaller) present in the air. Volvo therefore imposes extremely rigorous demands on the choice of particle filter for its cars.
In cars equipped with ECC, you can even specify the optional Interior Air Quality System (IAQS).
Cars with this system feature a gas filter that contains active carbon, which cleans both recirculated air and the air entering the cabin from outside. The system also includes a sensor that monitors the level of gaseous pollutants in the outside air.
Whenever necessary, the sensor blocks outside air from entering the cabin and activates a timer to admit fresh air if it detects any tendency towards misting-up of the windows.
IAQS effectively blocks gases such as nitrogen oxides, ground-level ozone and hydrocarbons. The driver and passengers are protected from virtually all types of unpleasant odour, such as petrol and diesel vapours and whiffs of washer fluid and oil.
The system also monitors the level of carbon monoxide in the incoming air. In addition, it shuts off the air valves before the carbon monoxide level reaches unhealthy levels when you are driving behind a truck, in congested traffic or inside a tunnel.
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