The automotive industry is a strategic branch of industry within the EU and international framework.
It is permanently facing to the durable challenges that are presented in the form of requirements concerning efficient exploitation of the fuel energy, reduction of the emissions and application of the new technologies.
Nowadays there is valid within the European countries the emission standard Euro 6, which should help to eliminate most of the harmful substances that are occurring in the air.
The upcoming new emission standard Euro 7 will be even more strict and demanding.
In the 2015 year occurred information about a fact that in some of the motorcars was installed a software, which enabled to hide the over-limit values of the nitrogen oxides during the emission testing process.
This affair is called “dieselgate”.
Officially, all the motorcars fulfil limits defined for production of the nitrogen oxides (NOx).
The emission testing process is performed in the laboratory conditions and the above-mentioned “special” software was able to overreach the testing machine.
The collusive software cooperated with the engine control unit, identified the measuring process and switched the engine into the operational regime with the reduced emission values.
It is possible to say that the current emission limits are very demanding.
From this reason there are occurring serious problems for the automobile factories how to meet the emission standards (Puškár et al., 2015).
Technological development of the future and better engines, together with application of the anti-emission actions, requires expensive investments.
However, there is at disposal one possible solution, which consists in application of a new, special technology.
This innovative technology is called the “Homogeneous Charge Compression Ignition”, i.e. the HCCI technology, which is based on a specific combination of the gasoline engine (using the spark ignition principle) with the diesel engine (utilizing the compression ignition process).
Such combination of two quite different ignition methods in one combustion engine offers the best operational characteristics of both ignition systems.
There is applied in this case a gasoline as the engine fuel, but the indicated efficiency of such engine is higher, similarly to the diesel engine.
The process of the homogenous charge combustion is running at once within the piston combustion volume.
Thanks to this fact the whole charge is combusted almost completely.
Efficiency level of the gasoline exploitation is very high thanks to application of the progressive and perspective HCCI technology.
Another positive result consists in a substantial reduction of the engine fuel consumption, together with reduction of the exhaust gas emissions and what is important the NOx emission level is almost zero.
On the other hand, it is necessary to say that application of the HCCI technology induces some of fundamental problems, for instance a high level of the pressure values, high thermal loading during the compression process, complicated control of the self-ignition process etc..
The worldwide reputable automotive companies are dealing with a development of the HCCI technologies.
The contemporary problems concerning the diesel engines emphasize an importance of such development strategy, which is based on the HCCI-engines.
The innovative HCCI technology, which is integrated together with the modern motor-management components (e.g.
with the direct fuel injection, VVT etc), enables to save the fuel and to fulfil the future emission standards.
The global efficiency of the piston combustion engine, which is equipped with the HCCI technology, is close to the diesel engine efficiency; however, the HCCI-engine does not require application of an expensive system necessary for elimination of the NOx emissions.
Effectiveness of the HCCI system is based on the fuel combustion at lower temperature levels and on reduction of heat losses, together with the decreased CO2 emissions.
The piston combustion engine equipped with the HCCI technology is determined not only as a driving aggregate for the “classic” motorcars, but this kind of engine can be also used as a driving unit of the electric generators installed in the vehicles with the hybrid drives.
Conclusions
The research and development, which was performed, resulted in a significant reduction of the fuel consumption compared to the standard engine. Optimisation of the driving unit improved the combustion process in order to reach higher level of the fuel consumption efficiency with a positive influence on the environment due to reduction of the carbon oxide emissions.
The results of our research work are presented periodically at the international competition Shell Eco-marathon in London. The system, which is based on thermal control of the HCCI technology developed for reduction of the vehicle NOX emissions in order to fulfil the future standard Euro 7, is applied in the experimental vehicle designed for participation at the international competition shell eco marathon 2018.
Reference: M. Puškár, M. Kopas, System based on thermal control of the HCCI technology developed for reduction of the vehicle NOX emissions in order to fulfil the future standard Euro 7, Sci. Total Environ. 643 (2018) 674–680. doi:10.1016/j.scitotenv.2018.06.082.
