Abstract: The invention is a method for diagnosing operation of a nonthermal plasma discharge device and a lean NOx trap disposed in the exhaust of an internal combustion engine. The method further includes reducing power to the nonthermal plasma discharge device and determining that the nonthermal plasma discharge device is operating properly when a concentration of NOx of exhaust gases exiting the lean NOx trap increases in response to reducing power to the nonthermal plasma discharge device. Additionally, the nonthermal plasma discharge device is found not to be operating when the NOx concentration remains substantially constant in response to a decrease in power supplied to the nonthermal plasma discharge device.

Abstract: In an exhaust aftertreatment system, which includes a nonthermal plasma discharge device followed by a NOx storage device followed by a precious metal catalyst, a method is disclosed for operating the engine at a lean air-fuel ratio when the NOx storage device is not full and for operating the engine rich when the NOx storage device is substantially full. Electrical energy supplied to the nonthermal plasma discharge device during lean operation is discontinued during rich operation of the engine.

Abstract: A system and method of controlling J/L specific energy deposition in accordance with either measured or estimated values of engine or vehicle operational parameters in order to optimize emission reduction versus energy cost over a driving cycle. A typical strategy varies the J/L specific energy deposition in relation to a measured or estimated value of a relevant parameter such as engine-out NOx concentration to improve energy cost versus emission performance over a driving cycle.

Abstract: An exhaust system for a combustion system, comprising a storage device for collecting NO.sub.x, hydrocarbon, or particulate emissions, or mixture of these emissions, and a plasma reactor for destroying the collected emissions is described. After the emission is collected in by the storage device for a period of time, the emission is then destroyed in a non-thermal plasma generated by the plasma reactor. With respect to the direction of flow of the exhaust stream, the storage device must be located before the terminus of the plasma reactor, and it may be located wholly before, overlap with, or be contained within the plasma reactor.

Abstract: A method for improving fuel control in an internal combustion engine employs a pressure ratio to determine the engine's actual volumetric efficiency continuously as the engine is operating. The air/fuel ratio of the engine's combustible mixture is affected by the volumetric efficiency. The volumetric efficiency varies during engine operation. Determination of the actual volumetric efficiency on a real-time basis allows greater accuracy in fuel metering. The pressure ratio used in the determination of the volumetric efficiency is the ratio of the intake and exhaust pressures or the inverse of this ratio. The ratio of pressures is combined with a second factor representative of the forces acting upon the air or air/fuel mixture inducted into the engine. The pressure ratio may be obtained without actual measurement of the pressure in the engine's exhaust conduit.