Compliance with the magic figure of 130 gr/km valid until 2020 has got the engine development departments working flat out. This figure is the only one that has led to a radical rethink of the modern engine, as the Euro 4 to Euro 6 standards do not significantly differ as regards the polluting gases measured for approval (CO, HC and NOx).
The Lambda 1 petrol engine is a high generator of CO2, in fact in the catalytic converter two oxidations and a reduction occur, CO2 being a large part of the results.
Today, the only way to reduce CO2 emissions lies in reducing consumption. At the moment there is no system or device that assists the engine in lowering this emission.
To reduce consumption and consequently CO2 emissions, there are peripheral engine systems, for example:
• Start-Stop, stopping of the engine at traffic lights or when the vehicle is stationary for short periods of time.
• Variable pressure oil pumps, electric water pumps to prevent unnecessary friction in the engine depending on what phase it is in.
• Aerodynamic systems to reduce vehicle drag, such as front radiator flaps.
• Designed weight of the body and mechanical components.
All these examples only have one purpose, which is to be able to move the vehicle with as little friction as possible, or in other words, move the vehicle using the least amount of fuel possible.
As regards the new generation engines, vehicle manufacturers are considering two new engine concepts:
• Downsizing: Smaller cylinder capacity.
• Downspeeding: Delivery of the maximum torque over a very wide range of engine rpm.
• Downsizing or small cylinder capacity is the new generation of engines up to 1.4 litres that can be two, three or four low consumption cylinders, and most are turbocharged. The aim is to have a small engine that is light and turbocharged, which achieves the powers of higher cylinder capacity and heavier engines, the majority of these being naturally aspirated.
|Ecoboost Ford - 3 cylinders - 1.0L turbocharged|
|PSA 1.0L - 1.2L - Pure Tech - 3 cylinders|
|Opel SIDI 1.0 L - 3 cylinders|
|V.A.G. 1.2L TFSI - Four cylinders|
Downspeeding or torque delivery at low rpm. This concept is based on the rpm window where the engine is most often used. They can have a torque that can be moved between 1400 rpm and 4000 rpm depending on the manufacturer. This torque curve is completely flat between these two speeds, and the torque immediately available. This avoids sharp movements of the accelerator to request torque, which reduces consumption. This characteristic is achieved with the new generation direct injection systems and the small turbochargers currently fitted.
Downsped engines may also be downsized.
To end, it should also be mentioned that from 2016, the third-generation stratified charge or lean burn engines will appear, a system which considerably reduces CO2, but this is another concept which we will talk about later.