Analysis of detailed electric vehicle data in electrical engineering education
There is a large quantity of data available on the CAN bus of the Chevrolet Volt that can be obtained through the OBD2 connectors on both the passenger and driver side of the vehicle. Although much of this is not available on the console of the vehicle to passengers, it can be logged and collected to analyse various vehicle performance measures and behaviours as well as charging characteristics. A set of pertinent data has been collected simultaneously for approximately 40 vehicle parameters for numerous trips and charging events for the 2012 Chevrolet Volt. Some of the key parameters are battery voltage, battery current, motor currents, state of charge, engine rpm, vehicle speed, longitude, latitude, altitude, battery power, motor power, etc. This data has been used as a learning tool in the electrical engineering classroom for senior students in both advanced machine courses and in sustainable energy courses. Through analysis the students develop a better understanding of general electric vehicle operation principles and energy useage and management. They also develop problem solving skills and experience with analysing large data sets (certain trips have over 15 million data points) and using appropriate tools to perform large but repetitive tasks.
Characterizing energy usage of Chevrolet Volt versus speed
There is a large quantity of data available on the CAN bus of the Chevrolet Volt that can be obtained through the OBD2 connectors on both the passenger and driver side of the vehicle. Although much of this is not available on the console of the vehicle to passengers, with additional equipment it can be logged and collected to analyze various vehicle performance measures and behaviors as well as charging characteristics. Average energy usage is determined for a constant speed portion of a trip over a range of speeds from 30 mph to 75 mph. The energy usage ranges from 170 Wh/mile at 30 mph to the high of 369 Wh/mile at 75 mph. The segment used for evaluation was selected to have the smallest practical elevation change to reduce the dependency of the energy usage on this factor. The optimum speed for energy efficiency over this range has been determined experimentally and is found to be the lowest speed of 30mph. The average energy usage for a variety of complete trips is also given as a comparison of the usage over a variety of speeds and elevations as well as potential driving behavior effects.
Thermal stability of reconstituted collagen fibrils. Shrinkage characteristics upon in vitro maturation
Thermal stability measured as area shrinkage without tension during heating was determined for membranes of collagen fibrils reconstituted from solutions of highly purified rat skin collagens. Shrinkage in per cent of area at 25 degrees C and shrinkage temperature were quantitated in a standardized way and determined as a function of in vitro maturation time for 11 to 104 days after aggregation for the collagen membranes. Similar to reports on intact rat skin, shrinkage temperature remained constant and shrinkage per cent declined with a rate decreasing with time during maturation. Solubility in water at 80 degrees C for 2 hours was 95-96% and remained unchanged for the maturation time (about 2 months) studied. The decreased shrinkage reflecting a lower degree of collapse is ascribed to an increasing thermal stability of the membranes during maturation. Development of heat-stable bonds in the reconstituted collagen fibrils is taken up to be amenable to this increased stability. Similarity in changes of shrinkage characteristics during in vivo and in vitro maturation indicates that maturation changes in reconstituted collagen fibrils reflect those occurring in intact collagen during in vivo aging.