Design of Compact Aluminum Cylinder Head 2015-26-0035
The cylinder head of a diesel engine is a multi-functional entity, decidingthe performance and emission parameters of the engine. It also acts as a structural and sealing member. It accommodates ports for gas exchange process; injectors for combustion process, cooling passages optimized for heat transfer, valve train mechanism, and lubrication circuits and in addition in our case integrated common rail fuel injection pump drive and systems. Aluminum is light weight with benefits. Combustion is direct injection subject to higher thermal and mechanical loads, it must be robust enough to withstand the high operating temperature and peak firing pressure. The design and development of effective Intake and Exhaust Ports remains critical to improve volumetric efficiency.
Compactness not only helps in packaging by having optimum LBH but also in making it light. To start with design considerations are Bore pitch of cylinder block which is centre of each cylinder position, Block-head positioning dowels, cylinder head bolt receiving locations etc. to be considered while laying-out. Next it is desirable to start with combustion layout which accommodates Valves, glow plug, injector, ports, head bolt locations etc. Considering modularity cylinder head height has been designed for accommodating camshaft and other necessities.
With shrinking emission limits, the management of Blow-by Gases and Intake port swirl provides priorities. However the diesel head design is primary, we can consider while designing to accommodate a spark plug which will make the engine multi-fuel capability. This paper discusses the options that were considered in designing a compact cylinder Head for penta-fuel application operating in a complex environment. The aluminum alloy selection plays a pivotal role in design and manufacturability of the intricate internal shape of the cylinder head with almost zero rejections after machining. With both linear and non-Linear Design variables, a frugal approach is used for engineering an efficient 2-Valve cylinder head for 1.5 liter engine used in LCV application.
In layout design, uniqueness is not only to get maximum valve sizes or to get package spark plug or injector in optimum position but also to make an effective valve bridge.