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This paper describes the coupling of a 1D engine simulation code (Ricardo WAVE) to a 3D CFD code (STAR-CD) to study the flow behaviour inside a Close-Coupled Catalytic converter (CCC). A SI engine was modelled in WAVE and the CCC modelled in STAR-CD. The predictions of the stand-alone WAVE model were validated against engine bed tests before the coupled 1D/3D simulations were performed at 3000 RPM WOT for both motored and firing conditions. The predicted exhaust velocities downstream of the catalyst monolith in the coupled simulations matched fairly well with Laser Doppler Anemometry (LDA) measurements.

Performance improvements of automotive catalytic converters can be achieved by improving the flow distribution of exhaust gases within the substrate. The flow distribution is often assumed to be adequately described by measurements obtained from steady flow rigs. An experimental study was carried out to characterise the flow distribution through the substrate of a close-coupled catalytic converter for both steady and pulsating conditions on a flow rig and on a motored engine. Computational fluid dynamic (CFD) simulations were also performed. On the flow rig, the flow from each port was activated separately discharging air to different regions of the substrate. This resulted in a high degree of flow maldistribution. For steady flow maldistribution increased with Reynolds number. Pulsating the flow resulted in a reduction in flow maldistribution. Different flow distributions were observed on the motored engine when compared to composite maps derived from the rig.

Knock in a spark-ignition engine was characterized in terms of its occurrence and magnitude or intensity. Cylinder pressure data from 90 consecutive individual cycles were generated from a single-cylinder engine of disc chamber design at about 72kHz sampling rate over a range of operating conditions between no knock and 100% of the cycles knocking. Mean values and distribution of following parameters were analysed: knock occurrence crank angle, knock intensity, combustion rate and the end-gas thermodynamic state. The effects of fuel octane number and inlet air temperature on these parameters were studied. The thermal imaging technique has been applied to record two-dimensional surface temperatures of cylinder head and piston simultaneously. The change in surface temperatures during knocking and non-knocking cycles was thus studied. As expected, increase in the inlet air temperature or decrease in the fuel octane number caused the knock onset to occur at less advanced spark timing.

The warm-up characteristics of a spark-ignition engine significantly affect fuel consumption and emissions from cars. A thermal imaging technique has been applied to measure the cylinder head surface temperature and piston surface temperature of an internal combustion engine simultaneously. The two-dimensional thermal images of the cylinder head surface temperature were viewed through an infra-red transmitting window mounted in the piston. The piston surface temperature was measured by painting black two small areas of the window's top surface. The similar thermal characteristics of the window material (silicon) to those of a normal piston and good heat transfer between the window and the piston provided realistic operation conditions. The mean and extreme values of the inlet valve, exhaust valve, two other areas of the cylinder head surface and window surface temperatures were measured from the thermal images during the first two minutes of the engine start.

A thermal imaging system has been developed for viewing and recording the cylinder head surface temperatures of an internal combustion engine. The system consists of an I.R scanner, associated calibration and image processing equipment and an infra-red transmitting window mounted in the piston. The infrared window material used (silicon) has thermal characteristics close to those of a normal piston. The two dimensional temperature distribution of a cylinder head surface has been measured during start-up. The imaging results from the camera were checked against the readings from the thermocouples fitted into the cylinder head. The agreement was very good, and gives confidence in the system.