ŠKODA vehicles are sold everywhere from the sweltering heat of Africa to the freezing Arctic Circle. They need to cope with temperatures from minus 35 to more than 50C, so it’s vital they have state-of-the-art systems and even heat exchangers the size of tennis courts.
Getting up to the ideal operating temperature fast and then maintaining that to get optimum performance, without affecting fuel efficiency, is vital for manufacturers. And according to Aleš Vrána, Chief Designer in ŠKODA’s engine mount department, it’s not just restricted to internal combustion engines.
“The need to discharge redundant heat from the engine is relevant for all vehicles, from those with combustion engines and hybrids to fully electric vehicles and cars with progressive fuel cell technologies,” says Aleš. “Cooling will therefore remain one of the most important areas for development.”
Making use of waste heat
In modern petrol and diesel engines, about a third of the fuel-supplied chemical energy is used by the drive system to turn the wheels. The rest is discharged from the engine as waste heat, in combustion gases and through a sophisticated multi-circuit cooling system. So how can we make efficient use of this waste heat?
One way of using it is now included in ŠKODA’s EA211 petrol engines: the exhaust manifold is integrated into the cylinder head and connected to the engine cooling circuit. In cold starts, hot combustion gases warm up the coolant right after being blown out of the cylinder, and the coolant then distributes heat throughout the engine to warm the oil.
But getting the engine up to its optimum operating temperature, to reduce friction and wear on moving parts, is just the first part of the story. Exhaust gases can heat up to almost 1,000C in extreme conditions; reducing that extends the life of the catalytic converter and improves fuel efficiency.
Air is a valuable resource
The cooling system can have a major influence on the design of the front of a car. Fresh air needs to flow through heat exchangers – including the main radiator – and the engine compartment, all of which is dictated by the shape, size and position of the many inlets at the front of the car. The layout and design influences how efficiently heat is carried away, but a highly efficient cooling system can adversely affect fuel economy.
“Air is a valuable resource that we need to use with a high degree of accuracy,” says Jan Burič, who is responsible for developing cooling systems at ŠKODA Auto. “The air flows in the engine compartment cause passive resistance, which creates as much as 10 per cent of the total frontal aerodynamic resistance. But the aerodynamic resistance coefficient has a major impact on fuel consumption. The goal in developing cooling systems is to minimise the consumption of air while maximising its use.”
Responding to this challenge, engineers in the engine mount department developed a system several years ago that limited the flow of air into the engine compartment when a car was being used in ‘partial-load’ mode. This has been used in some series production models in European markets, including the Octavia GreenLine and the new Superb.
Developing more systems for the future remains a high priority, and Petr Mikšovský, also from the engine mount department, says new calculation methods and ever-more sophisticated technologies are helping ŠKODA to make considerable advances: “We’re like F1 race mechanics, and could never succeed if we weren’t a well-tuned team.”
Did you know?
• Heat is exchanged between coolant and air by up to four main and five auxiliary exchangers, and their total surface area can be the same as a tennis court
• Up to 120 litres of coolant flow through the main exchanger (the radiator) every minute when a vehicle is being driven at maximum speed
• The cooling system components are connected by as much as 50m of hoses and tubes
• The people developing cooling systems at the factory divide the world into four maximum-air-temperature groups; in ‘super-hot’ countries the cooling system has to work reliably with maximum engine load in temperatures of 50C in the shade
• The engine mount department is responsible for integrating engines into vehicles and for developing all peripheral systems (highlighted in green), including cooling, exhaust system, air intake system and engine mount.
To find out more about SKODA Models and to book test drive with any SKODA car, visit our website, or visit our showroom:
Unit 4E,
Abbey Road Retail and Business Park,
Durham,
County Durham,
(0191) 383 7500
wwww.pulmanskoda.co.uk
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