Abstract: Devices and techniques are generally described for implementing a vehicle voice user interface. In some examples, a first request may be received from a first computing system. In some further examples, natural language data comprising a semantic representation of the first request may be determined. In some further examples, first metadata corresponding to the first computing system may be determined. In some examples, a restriction on execution of the first action may be determined in accordance with the first metadata. In at least some further examples, output data indicative of the restriction on execution of the first action may be sent to the first computing system.

Abstract: A fuel cell system that employs one or more wax elements to provide passive control. In one embodiment, a wax element device is positioned within a coolant stream pipe. The wax element device includes a wax element positioned within a container. An electrically conductive rod is positioned within the wax element and extends out of the pipe. As the wax element expands and contracts in response to temperature changes in the cooling fluid, the rod moves up and down to make various electrical contacts and control the various devices, such a coolant pump and a coolant fan. In another embodiment, the rod extends into a cathode exhaust pipe of the fuel cell system, and is coupled to a back-pressure valve therein. As the temperature of the cooling fluid changes, the wax element expands and contracts to control the position of the back-pressure valve.

Abstract: A fuel cell system that employs a purge valve, an accumulator and a bleed valve for selectively purging and bleeding anode exhaust gas. When the purge valve is opened, the anode exhaust gas purges to the accumulator where it is collected. The bleed valve provides a controlled release of the anode exhaust gas from the accumulator that allows the concentration of hydrogen bled from the accumulator to remain below its combustible limit. In one embodiment, the purged anode exhaust gas is combined with the cathode exhaust gas and released to atmosphere. In another embodiment, the purged anode exhaust gas is combined with a cathode input gas. In another embodiment, the purged anode exhaust gas is combined with an anode input gas.

Abstract: A fuel cell system that employs one or more wax elements to provide passive control. In one embodiment, a wax element device is positioned within a coolant stream pipe. The wax element device includes a wax element positioned within a container. An electrically conductive rod is positioned within the wax element and extends out of the pipe. As the wax element expands and contracts in response to temperature changes in the cooling fluid, the rod moves up and down to make various electrical contacts and control the various devices, such a coolant pump and a coolant fan. In another embodiment, the rod extends into a cathode exhaust pipe of the fuel cell system, and is coupled to a back-pressure valve therein. As the temperature of the cooling fluid changes, the wax element expands and contracts to control the position of the back-pressure valve.

Abstract: A fuel cell system having first and second fuel cells that each receive anode reactant flows and cathode reactant flows. Each of the fuel cells uses the reactant flows to produce electricity. The electricity production by the fuel cells produces respective first and second anode and cathode effluents that are exhausted from the respective fuel cells. The second fuel cell is connected to and downstream from the first fuel cell so that the anode reactant flow to the second fuel cell is formed from a portion of the anode effluent exhausted from the first fuel cell.

Abstract: A fuel cell system that employs a purge valve, an accumulator and a bleed valve for selectively purging and bleeding anode exhaust gas. When the purge valve is opened, the anode exhaust gas purges to the accumulator where it is collected. The bleed valve provides a controlled release of the anode exhaust gas from the accumulator that allows the concentration of hydrogen bled from the accumulator to remain below its combustible limit. In one embodiment, the purged anode exhaust gas is combined with the cathode exhaust gas and released to atmosphere. In another embodiment, the purged anode exhaust gas is combined with a cathode input gas. In another embodiment, the purged anode exhaust gas is combined with an anode input gas.

Abstract: A fuel cell system having first and second fuel cells that each receive anode reactant flows and cathode reactant flows. Each of the fuel cells uses the reactant flows to produce electricity. The electricity production by the fuel cells produces respective first and second anode and cathode effluents that are exhausted from the respective fuel cells. The second fuel cell is connected to and downstream from the first fuel cell so that the anode reactant flow to the second fuel cell is formed from a portion of the anode effluent exhausted from the first fuel cell.