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Autonomous vehicle operation is dependent upon accurate position estimation and thus a major concern of implementing the autonomous navigation is obtaining robust and accurate data from sensors. This is especially true, in case of Inertial Measurement Unit (IMU) sensor data. The IMU consists of a 3-axis gyro, 3-axis accelerometer, and 3-axis magnetometer. The IMU provides vehicle orientation in 3D space in terms of yaw, roll and pitch. Out of which, yaw is a major parameter to control the ground vehicle’s lateral position during navigation. The accelerometer is responsible for attitude (roll-pitch) estimates and magnetometer is responsible for yaw estimates. However, the magnetometer is prone to environmental magnetic disturbances which induce errors in the measurement.

Ambient gas density and fuel vaporization effects on the penetration and dispersion of diesel sprays were examined over a gas density range spanning nearly two orders of magnitude. This range included gas densities more than a factor of two higher than top-dead-center conditions in current technology heavy-duty diesel engines. The results show that ambient gas density has a significantly larger effect on spray penetration and a smaller effect on spray dispersion than has been previously reported. The increased dependence of penetration on gas density is shown to be the result of gas density effects on dispersion. In addition, the results show that vaporization decreases penetration and dispersion by as much as 20% relative to non-vaporizing sprays; however, the effects of vaporization decrease with increasing gas density.

The effects of ambient gas thermodynamic state and fuel composition on the autoignition of natural gas under direct-injection diesel conditions were studied experimentally in a constant-volume combustion vessel and computationally using a detailed chemical kinetic model. Natural gas compositions representative of variations observed across the U.S. were considered. These results extend previous observations to more realistic natural gas compositions and a wider range of thermodynamic states that include the top-dead-center conditions in the natural gas version of the 6V-92 engine being developed by Detroit Diesel Corporation. At temperatures less than 1200 K, the experiments demonstrated that the ignition delay of natural gas under diesel conditions has a dependence on temperature that is Arrhenius in character and a dependence on pressure that is close to first order.

The impingement of liquid fuels on surfaces in IC engines affects performance and emissions. To better understand liquid/solid interactions, the impact of single droplets on a healed surface was experimentally examined. The droplet impingement was photographed with a high speed cine camera to obtain a history of the hydrodynamics of the impingement process. Images obtained from the cine photography were inspected to determine hydrodynamic regimes: wetting, transition, and non-wetting, associated with the specific impingement conditions (droplet size, velocity, surface temperature, and ambient pressure). Images from selected impingement conditions were further analyzed to quantify the atomization resulting from the impingement.