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The Magma engine concept is characterised by a high compression ratio, central injector combustion system employed in a downsized direct-injection gasoline engine. An advanced boosting system and Miller cycle intake-valve closing strategies are used to control combustion knock while maintaining specific performance. A key feature of the Magma concept is the use of high CR without compromise to mainstream full-load performance levels. This paper focuses on development of the Magma combustion system using a single-cylinder engine, including valve event, air motion and injection strategies. Key findings are that Early Intake Valve Closing (EIVC) is effective both in mitigating knock and improving fuel consumption. A Net Indicated Mean Effective Pressure (NIMEP) equivalent to 23.6 bar Brake Mean Effective Pressure (BMEP) on a multi-cylinder engine has been achieved with a geometric compression ratio of 13:1.

This paper describes the design and development of a direct acting valve train for high speed operation in a racing motorcycle engine. At the outset of the project the engine speed limiter was set to 14000 rpm and this was eventually raised to 16000 rpm. The paper covers the evolution of the design and includes descriptions of the components including camshaft, tappet, shim, retainer, valve and valve springs. Valve train dynamic analysis software was used for the following tasks. Assessment of the influence of the changed parts on valve train dynamics and durability Design of new cam profiles Setting speed limit for each build level Investigation of failures These activities are covered in this paper.