Of all the false myths that persist about the diesel, perhaps the most well-known have to do with a supposed increased pollution and level of noise than gasoline engines. But they are not the only ones: that if you are slower, if will end up disappearing, that if in brief will not have access to the center of the cities... And, however, the advances in recent years mean that modern diesel does not look at all to those manufactured 15 years ago. According to ANFAC, the Spanish Association of Manufacturers of Cars and Trucks, “the new diesel engines, as any internal combustion engine in general, comply with the regulations on pollutant emissions most demanding in the world (RDE), and are an important technology for CO2 reductions". Discover here some of the truths of the diesel.
The reason why the ancient engines of diesel oil were slower and more noisy than the petrol has to do with the difference in the combustion process in the diesel is auto-ignition. “This system causes a time delay, which is the one that goes from the injected fuel to self-ignition. For years, this delay was very large and was that the engines were slower,” explains José María López Martínez, director of the University Institute of Research of the Car (INSIA) of the Universidad Politécnica of Madrid. However, the technological advances brought new combustion chambers, increased injection pressures and the incorporation of groups of boost (turbo), “what made that time delay is lower and it could achieve the same regimes of turning on the petrol engines (and therefore, speed)”.
The diesel engine Ingenium four-cylinder Land Rover, for example, offers high levels of torque from low revs to achieve an excellent response and acceleration increased. Thus, the Discovery Sport goes from 0 to 100 km/h in 7.5 seconds, thanks to its 240 HP and 500 Nm of torque, while achieving a consumption of 6.4 l per 100 km and CO2 emissions of 169 g/km in the combined cycle european, while the version of 150 HP with manual transmission achieves emissions of only 123 g/km The system of Exhaust gas Recirculation (EGR) has for its part a circuit of low pressure, refrigerated to reduce the losses of pumping and thus improving the efficiency.
And what happens with the noise?
In the diesel engine, the noise comes from a phenomenon that takes place during the combustion process, and is known as the stiff, “as a result of the auto-ignition of a large amount of fuel during that time delay. This causes a pressure spike very high and fast, and a mechanical vibration, which is causing the noise in these engines,” says Lopez. The same advances that have helped to reduce this delay and they got a higher speed did the noise decrease considerably, something that they have also contributed to improvements in the design, to improve the engine mounts and come these panelling with the absorbent material of the noise, so that this does not pass to the interior of the passenger compartment.
as for the exhaust noise, what is certain is that it is very similar in both types of engine (diesel and gasoline). The catalysts, the turbo and the muffler all contribute to that noise, limited by european regulations, is almost imperceptible in the modern engines. It is the case of, for example, the versions of 150 and 180 HP for the Range Rover Evoque, with 68 dB in motion. And is that the engines Ingenium turbodiesel of the English brand are notable for low emissions and for behavior, especially soft, characteristics that, at least, to place them at the same level as the petrol versions.
A constant evolution
If there is something that seems certain is that the environmental regulations eu will continue to hardening the maximum levels of emissions permitted in all vehicles driven by combustion engines. And precisely for this reason, the manufacturers will continue to adapt its versions and optimizing their performance. “Today, a diesel vehicle new emits 85 % less NOx than those of more than 15 years, and 99% fewer particles. In addition, since they reduce emissions of CO2 by 25 % compared to their gasoline counterparts”, say sources of ANFAC. According to forecasts, in five years, sales of vehicles with diesel engines will provide between 22 and 28% of the market share in Europe.
For Lopez Martinez, the diesel will have taken a giant step in recent years: “right Now, it is an engine that takes in the exhaust pipe a series of devices for treatment of gases to remove carbon monoxide (CO) and unburned hydrocarbons (HC). Also they have a built particulate filter, and SCR catalyst with urea (AdBlue) contributes to NOx reduction”: by injecting this liquid in the gas exit, these react with the NOx and convert it into nitrogen and water, harmless. In consequence, the emission levels are very low and comply with the regulations EU6D. “You now move your finger over the exhaust pipe and it comes out clean. The stigma of diesel as a dirty engine has completely gone”.
so Much so that, to the director of INSIA, it is without a doubt the engine of higher performance of those who exist in the present (whether gasoline, natural gas or LPG). Land Rover, for its part, has a world-advanced facilities in which we work with the new diesel engines so that they meet all the requirements EU6, subjecting their vehicles to more than three million miles of road testing, exposing them to real-world conditions and testing their emissions to ensure that the driving experience is not only enjoyable but, above all, environmentally responsible.Updated Date: 23 January 2020, 13:00