The project looks at developing a new homogenous combustion process (HCCI) for passenger cars diesel engine. The innovative combination of several engine and injection technologies will be investigated and implemented on single-cylinder engine concepts up to final economic and technical assessment of the in-vehicle on the road potential. The main technical objectives are to meet EURO 4 emissions limits without fuel sensitive after treatment for NOx and/or particulates while maintaining low well to wheel CO2 emissions advantage of the best state of the art diesel engines.
The objectives of the SPACE LIGHT project were to research and develop a high efficient low CO2 emissions diesel engine for passenger car which could achieve robust ultra low NOx and particulates
emissions (Euro 4, with potential for Euro 5) during the whole vehicle life without depending on complex
and fuel sensitive aftertreatment technology.
The originality of the work proposed in "SPACE LIGHT" is based on a unique and appropriate innovative
combination of several adapted technologies recently available
under development within the partners
involved (such as dedicated "SPACE" spray pattern Common Rail DI, flexible Variable Valve Actuation -
WA and interna) fluid dynamic control of the air and EGR charge mixing process) in order to achieve diesel HIMCCI (Homogeneous Interna) Mixture Charged Compression Ignition) combustion.
The main tasks will start from research study of HCCI combustion specifications before to perform design analysis, manufacturing, development testing and final technical/economic assessment of the selected engine concepts. The undertaking of these tasks will rely on the combined multidisciplinary expertise of partners from 4 member states and one associated member state. During this European project, a well structured methodology and approach in 5 WorkPackages (WP) combining 1D and 3D Computational Fluid Dynamics (CFD), optical diagnostics (outside and inside the engine) and single cylinder engine development testing has been used and proven to be very effective.
The concept specifications work which
deals with Premixed Charge homogeneous diesel operation found that
premixed operation will not be the final choice for the "SPACE LIGHT" engine but more a
solution to undertake a parametric study. The first aim of such study - to increase the knowledge in HCCI
- was reached.
Then, it has been possible to undertake almost as planned the WP B (HIMCCI concepts design analysis)
and the WPC (HIMCCI engine concepts procurement). The hardware necessary to undertake the WPD has been developed and procured. It includes an innovative variable valve actuation system (WA), a new injection system with multiple injection strategy and appropriate "SPACE" spray pattern known under the narre of NADITM (Narrow Angle Direct Injection).
In the WPD (HIMCCI concepts development testing), the implementation of the innovative electro
hydraulic VVA on the single cylinder engines of the project was rather complex and took more time than
expected. To fit with the engine partners specifications, it was obliged to take the risk of improving the VVA hydraulic power pack design. However, the results obtained demonstrated the great potential of such innovative combustion process in terms of Wear zero NOx and PM reduction white keeping high efficiency and acceptable noise level.
Finally, the results of the WPE (HIMCCI concepts validation and assessment) show that the main project objectives have been successfully achieved. Nevertheless, they also show that a Diesel Particulate Filter (DPF) will probably become necessary for levels like Euro 5 and further. However, the low particulates (PM) emissions of the SPACE LIGHT engine will reduce the constraints on the DPF (ultra low PM in engine conditions where it is difficult to regenerate the DPF) and therefore will increase its robustness thanks to this advantage of less severe specifications.
At the completion of this project, some technical issues which have not been fully investigated during the
project, still remain to be solved before future practical application in production passenger car:
the level of HC & CO emissions will probably require specific aftertreatment device (active at tow
temperature) not available today,
the combustion noise can be higher than currently acceptable levels and further HCCI control and calibration work will be necessary,
the multicylinder engine configuration and the transient effects have not been considered in the frame and methodology of this project. To operate a multicylinder engine with a smooth transition between HIMCCI and conventional Cl operating points will need significant further development work.