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The Swedish Biomimetics 3000's μMist® platform technology has been used to develop a radically new injection system. This prototype system, developed and characterized with support from Lotus, as part of Swedish Biomimetics 3000®'s V₂IO innovation accelerating model, delivers improved combustion efficiency through achieving exceptionally small droplets, at fuel rail pressures far less than conventional GDI systems and as low as PFI systems. The system gives the opportunity to prepare and deliver all of the fuel load for the engine while the intake valves are open and after the exhaust valves have closed, thereby offering the potential to use advanced charge scavenging techniques in PFI engines which have hitherto been restricted to direct-injection engines, and at a lower system cost than a GDI injection system.

There is a great deal of interest in new technologies to assist in reducing the CO2 output of passenger vehicles, as part of the drive to meet the limits agreed by the EU and the European Automobile Manufacturer's Association ACEA, itself a result of the Kyoto Protocol. For the internal combustion engine, the most promising of these include gasoline direct injection, downsizing and fully variable valve trains. While new types of spray-guided gasoline direct injection (GDI) combustion systems are finally set to yield the level of fuel consumption improvement which was originally promised for the so-called ‘first generation’ wall- and air-guided types of GDI, injectors for spray-guided combustion systems are not yet in production to help justify the added complication and cost of the NOx trap necessary with a stratified combustion concept.

The paper describes a combined experimental-theoretical investigation into the intake flow produced by a port commonly used for both DI diesel and gasoline engines, namely a helical. The study consists of two major parts. Firstly, 3 orthogonal velocity components were measured under steady flow conditions within the valve gap using LDA. Data was obtained around the valve periphery and in different planes between the valve and the cylinder head. This was repeated for a number of different valve lifts. Prior to the second stage, an unsteady gas-dynamics calculation was performed to determine the thermodynamic conditions immediately upstream of the valve and the mass flow rate through the valve opening throughout the intake stroke.

Three dimensional velocity measurements of the in-cylinder aerodynamics in the steady airflow rig for two different Diesel cylinder heads were obtained by laser anemometry. Complex recirculating flows with high mean velocity gradients were found while the fluctuating component of velocity was relatively constant. Vector addition of two components in turn allowed rapid comparison to be made of the airflow characteristics between cylinder heads and and comparison with earlier hot wire and vane anemometer measurements. The directed port cylinder head was found to produce two main vortices whereas a cast helical port produced a flow which approached simple solid body rotation.