In times of extensive discussion about e-mobility and zero emissions, internal combustion engines are under fire. Christoph Rofka, Head of Technology at ABB Turbocharging, is nonetheless convinced: Anyone writing off the internal combustion engine has failed to recognize its potential.
charge!: The internal combustion engine has fallen into disrepute. Many are prophesying its demise.
Christoph Rofka: But the internal combustion (IC) engine is, and will be, a success story. It is the principal prime mover that transforms the fuel energy into useful mechanical power. It does it very efficiently and consistently, is very robust and requires very little upkeep. You can install an IC engine practically anywhere. Its scope of application is enormous, from emergency generator-sets in hospitals to 200 MW baseload power stations, and for the propulsion of a small boat up to a 400 m container ship. In addition, they are enormously flexible in terms of fuel and fuel quality. These are all points in favor of IC engines. The challenges are its emissions, e. g. nitrogen oxides, particulates and CO2.
So, a success with snags. What can be done?
I cannot follow the logic of simply saying that IC engines must be replaced. They must be developed further in a sensible way. There is still great potential in a technology that might appear to have reached its limits. But we need commitment, imagination and money for innovation, which legislation must also be prepared to support. Otherwise, not much will happen. Unfortunately, in recent years the development steps have been on average rather small.
The IMO wants a reduction in the total emissions from shipping of 50 percent by 2050 and a reduction in the average carbon intensity of 40 percent by 2030 and 70 percent by 2050, compared to 2008. These are ambitious targets.
We are actively supporting these goals. The industry is now challenged to come up with the relevant measures. But there are different aspects to be taken into account such as ship design, equipment, and operation. If we want IC engines to be a convincing factor in the future, we have to press on with technological advances. In the short to medium term, significant increases in efficiency and reductions in raw emissions are still possible: Via new designs and internal changes, via further attenuation of emissions by means of cleaner fuels and by optimizing exhaust aftertreatment. Long-term, and above all with regard to the year 2050 targets, IC engines must re-establish themselves as the source of power, by burning alternative fuels and synthetic fuels.
What can ABB Turbocharging’s contribution be?
A very decisive one, thanks to clever air management by means of optimized turbocharging and variable valve timing, because both are key technologies for engine performance. Looking to the future, they will gain importance in terms of the new synthetic fuels and a potential deterioration or greater variation in fuel characteristics. But even short-term, with fossil fuels, turbocharging and variable valve timing possess huge possibilities for reducing raw emissions and raising engine efficiency.
How exactly?
ABB’s Power2 two-stage turbocharging system is not merely a proven way of multiplying power, but Power2 also contributes to as much as a 60 percent reduction in NOx emissions. The system has been successfully introduced to the market (more on Power2 in the sidebar). At the same time, we are further developing this technology and making the system lighter and compacter and, as such, more attractive for engine builders.
In what direction is variable valve timing being developed and what can it do?
We have already tested our Valve Control Management (VCM) system intensively on gas engines and been able to extract considerable improvements in engine power density, controllability, efficiency and robustness, while at the same time proving VCM’s durability. All tests show clearly the positive effect of VCM on stable combustion during fluctuations in fuel quality and thus on maintaining high engine performance. More recent studies have also revealed interesting potentials for VCM on diesel engines. As well as increasing the width of their operating range, power density and efficiency, VCM can also be utilized to control the temperature of exhaust gases reaching aftertreatment (more on VCM in the box). With the potentials described here and its contribution to ever more popular modular engine concepts, going forward VCM is set to gain and gain in importance.
So-called next generation fuels are going to replace fossil fuels. What are the alternative fuels and what influence will they have on turbocharging?
Long-term, the vision is to replace fossil fuels as far as possible with alternative and synthetic fuels. Biomass and excess electricity from wind and solar energy production can be converted into intermediate energy reserves (Power-to-Fuel or E-Fuel) – for example to gases like hydrogen, methane or into liquid fuels, which is a somewhat more elaborate procedure. With the fuel from the intermediate reserve, electrical or mechanical power can be produced. Again, IC engines come into their own. In terms of turbocharging, according to the combustion characteristics of the fuel and the combustion process, it might be necessary to rematch the turbocharger’s turbine and the compressor and apply other materials. Variable valve timing systems like VCM will play a central role in all this.
« Even short-term, with fossil fuels, turbocharging and variable valve timing possess huge possibilities for reducing raw emissions and raising engine efficiency. »
