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Modern water injection systems typically deliver water separately from the primary fuel system using a discrete injector either through the intake port or directly to the cylinder. Recently, however, water dilution strategies using fully hydrous fuel systems have been receiving increased attention. Hydrous fuels are water and liquid fuel blends that are fully mixed prior to delivery to the combustion system. Removing water from naturally hydrous fuels such as ethanol requires large amounts of energy; consequently, it is possible to combine water injection with more economical production by leaving some amount of water in the fuel. This paper compares experimentally the water dilution effects on the combustion and emissions characteristics and overall engine performance when delivering the water through either a hydrous fuel blend or discrete port water injection. A 2.4L 4-cylinder NA GDI engine was used in experimental testing.

This paper compares bulk impulse-torque and 2D planar PIV steady flow-field measurements created by an engine cylinder head and intake system model using a steady-flow bench and evaluates operational aspects of the steady-flow test system. The model included a full-sized intake manifold and cylinder head section from a Chrysler 2.4L PFI four-valve per cylinder engine mounted to an optical cylinder. Two test system operational aspects were evaluated: (1) upstream versus downstream engine location relative to the flowbench (operational modes corresponding to flow bench pulling or pushing through the system), (2) PIV seeding particulate choice. Several dry and oil fog particulates were assessed however, of the options tested, only laboratory grade glass and consumer grade talc allowed long enough operation for practical data acquisition. Tests were performed over lift-over-diameter (L/D) ratios spanning from 0.1 to 0.3.

In the development of an Adaptive Cruise Control (ACC) system, a model-based design process uses a simulation environment with models for sensor data, sensor fusion, ACC, and vehicle dynamics. Previous work has sought to control the dynamics between two vehicles both in simulation and empirical testing environments. This paper outlines a new modular simulation framework for full model- based design integration to iteratively design ACC systems. The simulation framework uses physics-based vehicle models to test ACC systems in three ways. The first two are Model-in-the-Loop (MIL) testing, using scripted scenarios or Driver-in-the-Loop (DIL) control of a target vehicle. The third testing method uses collected test data replayed as inputs to the simulation to additionally test sensor fusion algorithms. The simulation framework uses 3D visualization of the vehicles and implements mathematical driver comfortability models to better understand the perspectives of the driver or passenger.

Hybrid vehicle engines modified for high exhaust gas recirculation (EGR) are a good choice for high efficiency and low NOx emissions. Such operation can result in an HEV when a downsized engine is used at high load for a large fraction of its run time to recharge the battery or provide acceleration assist. However, high EGR will dilute the engine charge and may cause serious performance problems such as incomplete combustion, torque fluctuation, and engine misfire. An efficient way to overcome these drawbacks is to intensify tumble leading to increased turbulent intensity at the time of ignition. The enhancement of turbulent intensity will increase flame velocity and improve combustion quality, therefore increasing engine tolerance to higher EGR. It is accepted that the detailed experimental characterization of flow field near top dead center (TDC) in an engine environment is no longer practical and cost effective.

Today's engine and combustion process development is closely related to the intake port layout. Combustion, performance and emissions are coupled to the intensity of turbulence, the quality of mixture formation and the distribution of residual gas, all of which depend on the in-cylinder charge motion, which is mainly determined by the intake port and cylinder head design. Additionally, an increasing level of volumetric efficiency is demanded for a high power output. Most optimization efforts on typical homogeneous charge spark ignition (HCSI) engines have been at low loads because that is all that is required for a vehicle to make it through the FTP cycle. However, due to pumping losses, this is where such engines are least efficient, so it would be good to find strategies to allow the engine to operate at higher loads.

An investigation into applying a tracer gas method for determining trapping efficiency to 4-stroke engines is carried out. The experimental errors are identified and analyzed. The errors include incomplete cylinder reaction, exhaust instability, and inconsistent exhaust sampling. Tracer gas global kinetic mechanisms are reviewed and used as a means for tracer gas selection. The tracer gases investigated are nitrous oxide (N2O) and monomethylamine (CH3NH2). As a benchmark the oxygen tracer technique is analyzed, where oxygen is used as the tracer. Test results from a GM 5.7 l, 8 cylinder, 4-stroke engine are presented that include measurement of the experimental errors and the trapping efficiency. Of the tracers considered, N2O is determined to be optimal for the engine tested.