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When a driver completes an aggressive drive cycle on a hybrid vehicle, the High Voltage (HV) battery system may be at risk of exceeding the power limit temperature, due to continuous absorption of radiative and convective heat from the environment, such as from exhaust and pavement, even after key-off. In such a case, in the absence of active cooling, the vehicle may not be keyed-on until battery temperatures are reduced below critical values. A transient thermal analysis is conducted on a HV battery system to simulate the key-off operation using an effective Computational Fluid Dynamics (CFD) methodology. Two stages are considered in this methodology to capture the complexity of the geometry and the multiple phenomena that need to be simulated in the model. The introduced modeling technique can be used for Full Hybrid Electric Vehicle (FHEV) and Plug-in Hybrid Electric Vehicle (PHEV) transient key-off situations.

This paper presents a review of the regulatory, environmental, and health issues surrounding the use of halons as a fire suppressant and a summary of the recently completed Racecar Fire Suppressant Exposure Study by ICF Consulting, Inc., under contract with the U.S. Environmental Protection Agency (EPA) (U.S. EPA, 2004a). In 2003 the EPA learned that the SFI Foundation Inc., the organization responsible for developing safety regulations and testing requirements for numerous Performance Racing Industry (PRI) sanctioning bodies, was revising its Quality Assurance Specification for On Board Fire Suppression Systems (SFI Specification 17.1). The previous Specification 17.1 required either halon 1211 or halon 1301 to be used in these systems. Halons are ozone-depleting substances (ODS) widely used in fire protection applications and whose production and use are controlled under the Montreal Protocol and the Clean Air Act (CAA).

Collection of diesel exhaust using the Tapered Element Oscillating Microbalance (TEOM) instrument was investigated as an alternative to the traditional method of filter weighing for particulate matter mass determination. Such an approach, if successful, would eliminate considerable manual labor involved in weighing, as well as the delay of hours or days before final results were known. To avoid known artifacts in the second-by-second mode of operation, the TEOM was used in a phase-by-phase mode and was equilibrated with air of constant temperature and humidity before each measurement. Electrically operated valves were used to automate the equilibration and measurement process. The study also included a comparison between two types of TEOM filter - an older type and a new one designed by the TEOM manufacturer for more uniform flow and less flexing. Best results were obtained with the TEOM using the new filter under no-flow conditions.