Abstract: A fuel cell/battery hybrid power system is disclosed which has a microprocessor based control system. The control system enables the fuel cell to be taken out of the system by a switch when its predetermined maximum desired energy output is about to be exceeded by load requirements. The battery is protected from overcharging by a switch which is activated responsive to the sensing of state of charge, load current and fuel cell current.

Abstract: A fuel cell system is comprised of a fuel cell module including sub-stacks of series-connected fuel cells, the sub-stacks being held together in a stacked arrangement with cold plates of a cooling means located between the sub-stacks to function as electrical terminals. The anode and cathode terminals of the sub-stacks are connected in parallel by means of the coolant manifolds which electrically connect selected cold plates. The system may comprise a plurality of the fuel cell modules connected in series.The sub-stacks are designed to provide a voltage output equivalent to the desired voltage demand of a low voltage, high current DC load such as an electrolytic cell to be driven by the fuel cell system. This arrangement in conjunction with switching means can be used to drive a DC electrical load with a total voltage output selected to match that of the load being driven. This arrangement eliminates the need for expensive voltage regulation equipment.

Abstract: An air-to-fuel ratio control mechanism in an internal combustion engine operates in partial response to the output of a control circuit, which circuit in turn is responsive to the output of an oxygen sensor mounted in the exhaust of the engine. The control circuit biases the control mechanism toward a predetermined desired air-to-fuel ratio, normally at or near stoichiometric. When the sensor output deviates above a first predetermined value or below a second predetermined value for longer than a predetermined time period, a comparator circuit provides a disabling signal which disconnects the control circuit from the air-to-fuel ratio control mechanism. At the same time, the disabling signal connects a predetermined signal to the air-to-fuel ratio control mechanism. This predetermined signal simulates a nominal control circuit output to maintain the air-to-fuel ratio close to stoichiometric or some other preferred setting such as a air/fuel ratio which is lean.