Lead partner: FEV
A set of three powertrains will demonstrate improved internal combustion engine efficiency; key target is improvements on reaching Peak Brake Thermal Efficiency (BTE) of around 50%.
Use case UCC2 focuses on demonstrating the potential for achieving 50% BTE in three HD demonstrator engines, by combustion control, friction reduction, air path optimization and heat loss reduction by:
- Identifying the split in total thermal efficiency improvement considering mechanical efficiency, combustion control, air pass handling and heat transfer;
- Experimental validation on engine test bench will be supported with thermodynamic and mechanical simulation work.
A broad suite of technologies is needed to enhance the thermal efficiency of the current state of the art internal combustion engines (ICE). The ICE thermal efficiency innovations to be implemented are presented below for Diesel based and for natural gas (NG) based (spark ignition) engines.
In terms of combustion process innovations, the following innovations are part of the project:
- Higher Compression Ratio, Peak combustion pressure, Bowl optimisation and optimised fuel injection strategy;
- Higher efficient turbo, optimal valve timing and valve lift system for Miller cycle, improved insulation of ducts and exhaust manifold;
- Stoichiometric NG combustion process improvement (increased in-cylinder turbulent kinetic energy, passive pre-chamber ignition system) and reduction of knock sensitivity (HP and LP EGR, water injection, non-conventional cam shaft profiles with late intake valve closing);
- Engine rightsizing;
- Innovations and adaptations needed to enable the usage of the most promising future renewable fuels.
Improved air handling: Miller cycle, optimised turbo, EATS optimisation, optimised EGR and cooling;
Heat transfer improvements: Shorter heat release, multi-pulse fuel injectors, use of alternative fuels, longer stroke enabling higher compression ratios, insulated combustion chamber.
Friction reduction & reduction of parasitic losses: Surface coating of bearings, improved lubricant oil, optimised piston/conrod geometry and use of power reduced variable/electric pumps for oil and water circuits and other smart auxiliaries. Secondly, the introduction of advanced thermal barrier coating concepts on piston, liner, cylinder head as well as exhaust manifold / duct. And novel low friction crank train specifically designed for mechanical loads found in spark-ignition engines.