Search Results

The fuel filler tube check valve (FTCV) is an integral part of a vehicle’s refueling system. The primary function of this valve is to control the refueling characteristics in a manner that enables the vehicle to be refueled efficiently and under wide ranging conditions, while limiting the amount of fuel or fuel vapor emissions being released into the environment. These valves accomplish this function by allowing the flow of gasoline to pass through the valve and into the tank during the refueling process with minimal restriction while limiting the reverse flow as the fuel tank approaches full. The location of these valves varies from vehicle to vehicle but are generally located within the fuel filler or fuel tank system. They have been engineered and developed to ensure the vehicle will meet customer and industry refueling requirements as well as refueling emissions mandates from the Environmental Protection Agency (EPA) and the California Air Resources Board (CARB).

This paper summarizes hot surface ignition characteristics of R134a and R1234yf automotive air conditioning fluids on typical under-hood automotive surfaces that possess sufficient heat to ignite flammable or combustible fluids. It further investigates the effect, if any, that these two different fluids may have on the propagation of a fire in two identically equipped vehicles under similar test conditions. This testing, in part, is in response to the United States Environmental Protection Agency's proposal which seeks comments concerning the proposed replacement of the current R134a air conditioning refrigerant with R1234yf. R134a is currently regarded as the global choice for automotive air conditioning systems however the EPA classifies it as an ozone-depleting substance (ODS) and is tasked with proposing and reviewing alternatives that do not contribute to stratospheric ozone depletion.

With concerns over increasing worldwide demand for gasoline and greenhouse gases, many automotive companies are increasing their product lineup of vehicles to include flex-fuel vehicles that are capable of operating on fuel blends ranging from 100% gasoline up to a blend of 15% gasoline/85% ethanol (E85). For the purpose of this paper, data was obtained that will enable an evaluation relating to the effect the use of E85 fuel has on exhaust system surface temperatures compared to that of regular unleaded gasoline while the vehicle undergoes a typical drive cycle. Three vehicles from three different automotive manufacturers were tested. The surface of the exhaust systems was instrumented with thermocouples at specific locations to monitor temperatures from the manifold to the catalytic converter outlet. The exhaust system surface temperatures were recorded during an operation cycle that included steady vehicle speed operation; cold start and idle and wide open throttle conditions.