Jan Macek to welcome all to the 38th FISITA World Congress tomorrow – Tuesday 13 September 2021. In this Spotlight, Macek looks at the current challenges of improving mobility while reducing emissions
I will mention the current complicated situation for decisions on the way to the best future mobility system in my welcome address to the Congress. The societal requirements are based on real or imaginary challenges of the future world. The new technology possibilities and the increasing needs for affordability of mobility of persons and goods for the whole world with a rapidly increasing population have caused many positive and negative expectations, corrected by evident aftermaths already found.
The searching to find completely new solutions is typical for every new generation of engineers, often assuming the infinite possibilities of new technologies. Nevertheless, revolution with the best intentions causes many surprising results, as we know from personal experience in this part of Europe. The evolution does not offer attractive disrupting innovations, but it offers a knowledge base for finding the real limits of engineering and experience from the past revolutions. Therefore, the combination of disruptive technologies and the current know-how should show the direction for R&D for engineers.
What to do? Just in an ideal case – try to repeat, and repeat, and repeat optimization of any design and compare it to competitive designs using above mentioned holistic criteria. Never lose other solutions from our portfolio of expertise.
As an example, powertrains have been based on internal combustion engines (ICE’s) for many years, but not exclusively on them. During the last 50 years there were many evolutionary changes in this field of engineering activities. The reasons as described previously were both rationalistic and radically activist ones, especially the pressure of society to reduce the environmental and health impacts of increasing transport, from which a major part is created by road transport with ICE’s as prime generator. Today it seems this type of powertrain is old fashioned and without prospects. Is it really true?
Image of a Czech-manufactured Tatra 400 electric trolley bus that was produced 1948-1955 stopping opposite the Czech Technical University in Prague main building. Macek commented that this was based on the TATRA off-road T 111 chassis, which was not very good for paved streets. Image provided by Jan Macek.
The power demand of a vehicle is very unsteady, calling for fast release and accumulation of energy. The basic mechanical energy accumulator is inertia and gravitation mass of a vehicle, which is currently forgotten time-to-time. The potential of using flexible, adjustable mechatronic systems has provided wide possibilities for optimization of a vehicle control in operation during last decades. All those factors call for a deep understanding of interactions between physical hardware, limited by laws of nature, and both control and informatics engineering. In the future, the link between individual vehicle and traffic control will occur, as well, although using features different form today’s predictions.
The evolutionary development of ICE’s has been perhaps medially not very attractive, but the progress done is huge. Not only diesels but also spark ignition engines have increased efficiency using these before inapplicable engine power increasing and operation-adapting changes due to massive use of turbo- and supercharging with boost pressure control, reducing relative level of engine losses. Mechatronic tools for fuel injection and ignition control, connected with variable valve actuation, have made available combustion control and adapting to different fuel quality. The effective compression ratio may be changed without deterioration of expansion ratio. In-cylinder turbulence can be controlled to some extent. The size and positions of injector orifices, piston accelerations (even in alternative cranktrains) and shape of vanes at turbocharger rotors have remained unchanged, although some progress has been achieved even here. The problem of heat loss to cooled cylinder walls and throttling during blow-down exhaust period has yet not been solved. And, still, high speed two-stroke engine poses more problems than advantages.
The introduction of direct injection to all types of engine ignition systems caused particulate formation in concentration traces of droplets, which has required particle filter use
Increased brake efficiency and reduction of green-house gas emissions were achieved respecting strict regulations for pollutants. Especially nitrogen oxides, linked logically to high indicated efficiency, can be removed by complicated reduction systems, suitable for oxidation burnt gas environment, but also by low temperature combustion, which seems to be applicable with amplified ignition energy sources. The introduction of direct injection to all types of engine ignition systems caused particulate formation in concentration traces of droplets, which has required particle filter use. Both catalytic and filtration treatments increase exhaust backpressure, which has to be compensated by other efficiency gains.
The mechatronic systems can be applied if suitable communication between components and serial-production engine self-calibration takes place. In this way, silent Industry 4.0 implementation occurred in vehicles much earlier before it was claimed in other industrial fields.
The overall analysis of the complex energy production and distribution costs including investment issues has not been carried out with sufficient details up to now
As mentioned above, ICE’s have proven high fuel flexibility, considering the change from standard fossil fuels to renewable energy vectors in liquid or gaseous phases. Synthetic fuels (power-to-gas starting with hydrogen, power-to-fuel, etc.) may spare infrastructure re-building costs in the future, enabling the continuous transition to new fuel distribution systems. The overall analysis of the complex energy production and distribution costs including investment issues has not been carried out with sufficient details up to now. It cannot be performed by simple linear accumulation of non-linear system with internal feed-backs of effects.
The electrification of vehicles poses huge challenges today. There is no doubt the hybridization of vehicle powertrains reduces energy consumption, avoiding part load, low efficiency operation of an ICE, and making additional recuperation of energy possible. The increase of vehicle price is the black side of this achievement. Without sophisticated, physics-based and predictive powertrain and vehicle control, the increased price cannot be compensated.
There are physics reasons for limits of energy density in an accumulator cell
Although in Europe exclusively preferred by European Commission, the storage of large amount of electric energy onboard of battery electric vehicle should be carefully assessed, since the weight is decisive for tractive energy consumption. There are physics reasons for limits of energy density in an accumulator cell. The necessity of carrying both reduction and oxidization agents inside a battery is the basic one. Moreover, the compounds of highly reactive elements in recent batteries are not stable at higher temperatures, which adds another significant weight of cooling system. The limit of 250 Wh/kg seems to be valid at least for the next 10 years, and it is by more than an order of magnitude distant from the energy density of liquid fuel, even if reduced by rather better efficiency of completely electric powertrain. This is a result of critical assessment of real-life results, not taking the medial and grant application noise into account. Nevertheless, operation at short distances, e.g., in cities, offers a very good domain for battery vehicle use. The life cycle assessment shows the change to carbon-less sources of electricity is necessary, before battery vehicles can improve global green-house gas emissions. Since renewable sources of electric energy have to be duplicated by weather-independent power-stations to provide for uninterrupted power supply emitting significant amount of carbon dioxide, the only carbon-less source is nuclear energy.
Even the Germany-based emission factors for electricity avoid any contribution to green-house impacts of road transport in comparison to other powertrains with the exception of small gasoline cars, since the durability of batteries is limited and the energy demand for manufacturing them too high.
The operational TTW (tank-to-wheel) efficiency of electric cars is close to 60% only due to losses during charging and discharging, and WTT (well-to-tank) greenhouse gas production is significant for electric energy mix today, except for nuclear-based countries, as France, or biomass and hydro-power based ones, as Brasil. The real situation of the main competitive battery manufacturer, China, is even worse due to its coal-based power supply and the intentions to extend this type of power generation. This is not criticism, only a statement of facts.
the way to cost competitive design of fuel cell vehicles is still long
The combination of renewable fuel and hybrid is promising for hydrogen fuel cell cars. Hydrogen PEM fuel cell works at low temperature and its poor dynamics is compensated by battery boosting. Hydrogen may provide a way to stable and comparatively efficient electricity accumulation, but the way to cost competitive design of fuel cell vehicles is still long, many decades.
The future powertrain concept may contribute to green-house gas emissions more significantly, if completely optimized, taking the whole life-cycle and the use of rare and scarce materials in them. The location of material resources calls for another optimization, which – together with necessary and costly infrastructure changes – cannot be done by physics itself but in combination with economy, especially that of capital investment profitability.
The current black-and-white decisions, carrying some populistic features and being based on low level of information non-expert public majority, do not offer any long-term solution for the Earth
Humankind will find, hopefully, the way to such a holistic approach. The current black-and-white decisions, carrying some populistic features and being based on low level of information non-expert public majority, do not offer any long-term solution for the Earth.
Concluding objective strong and weak sides of an ICE, its future in road transport is ensured for many decades and not only for long-haul freight transport, if the optimizing compromise is sought for. The issue might occur after Europe stops the further ICE development, seeking for “zero tail-pipe emission vehicles”, and other industrial countries then build their competitiveness on the base of European know-how, selling their products to the territory of their origin.
In any case, a multiple powertrain port-folio, not excluding new, but keeping well-optimized old solutions and combining them into hybrids with really predictive control of performance is perhaps a more expensive but rationalistic tool to support future competitiveness. All the innovations reducing the weight of car bodies, developed for electric cars, have to be applied in all vehicle designs, not only for electric cars – an example of positive feed-backs in the system.
The best compromise between old and new will help in solving the user and environment friendly future mobility device
I would like express my hope the current congress will put a substantial stone in the knowledge house of optimized vehicles and mobility systems associated with them. The best compromise between old and new will help in solving the user and environment friendly future mobility device.
Jan Macek, 22 August 2021
About the FISITA World Congress
Since 1947, the FISITA World Congress has been the leading international meeting place for industry experts, engineers and executives to exchange ideas and discuss the trends that drive the automotive industry forward. The theme for the 38th FISITA World Congress is 'From automobile to mobility. New roles. New challenges' and it will take place 14-16 September 2021, with the opportunity for the global audience to join virtually available for the first time. Registration is now open, with the Early Bird and special registration rates available until 31 August 2021.
Content from the 2020 FISITA Web Congress is available within the FISITA Technical Library, while material from previous Congress events back to 1998 is available in the FISITA Store. By the time of this year’s Congress, all the content will be available within the FISITA Technical Library, with free access provided to FISITA members.