Capital Equipment News December 2018

PROFILE

The diesel combustion engine remains a cost-efficient solution for creating mechanical energy.

Will diesel engines be a thing of the past?

The diesel engine has become a highly efficient power source – but how much further can it be developed. In this article, Dr. Staffan Lundgren, senior technology advisor for Powertrain at the Volvo Group, discusses whether the humble engine has a future, and if so what it looks like.

Q: Why has the diesel engine remained such a popular power source? Staffan Lundgren [SL]: Diffusion combustion – where the combustion is concentrated around the ignition and oxygen is diffused around the combustion area – is very efficient. It has minimal energy losses to the walls of the engine through radiation or convection – much lower than a gasolene engine. The basic diesel engine is very strong and can withstand very high pressures. Q: How efficient is it? SL: There have been big improvements – jumping from around 35% efficiency in the 1980s to today’s 50% efficiency. That means half of the fuel is now being put into useful mechanical work. For reference – a gasoline engine is around 35% efficient. These gains have come from high pressure common rail fuel injection systems, turbo-charging and the

introduction of computing power to control precisely the combustion and the after- treatment management systems. Q: Is increasing fuel efficiency customers’ No.1 demand? SL: Yes, good fuel efficiency is the most important element, but customers also require good engine performance and durability. Then it has to be durable and meet emissions requirements – and these are sometimes in competition with one another. SL: There is an upside trend – customers are moving larger loads and that requires greater power. The Volvo Group’s largest output is now 1 000 hp. But compared to passenger cars, all heavy duty applications are still (relatively) underpowered. Q: Are engines also becoming more powerful?

CAPITAL EQUIPMENT NEWS DECEMBER 2018 28