Abstract: A method for monitoring operation of a solenoid valve having an armature and a poppet coupled to the armature includes the steps of energizing a coil in the valve to generate a current signature reflecting current vs. time, detecting a first inflection point in the current signature, wherein the first inflection point occurs when the armature starts to move from one of the open and closed positions toward the other of the open and closed positions, and detecting a second inflection point in the current signature. The second inflection point occurs when the armature moves completely to the other of the open and closed positions. In one embodiment, the first inflection point indicates when the valve begins to open, making it possible to accurately determine the elapsed opening time of the valve.

Abstract: An exhaust line fuel injection system and associated methods of operation and control are disclosed. The fuel passes through a regulating valve connected to a pressurized fuel source and an outlet connected to an exhaust system fuel supply line. The exhaust system fuel supply line is connected to a nozzle, which generally comprises a check-valve and is configured to inject the fuel into the exhaust line. Using a pressure measuring device, an indication of the exhaust system fuel supply line pressure is obtained. A controller provides control over the flow regulating valve using feedback from the pressure indication and a predetermined relationship between the flow rate through the nozzle and one of the exhaust system fuel supply line pressure and the pressure drop across the nozzle. The method can be implemented with a single pressure measuring device. The same pressure measurements, especially their frequency spectrum, can be used to detect system faults.

Abstract: A method of controlling a pulse width modulated fuel injector includes pumping fuel to the fuel injector with a variable-pressure fuel supply and commanding a mass flow. The method measures an actual fuel pressure of the variable-pressure fuel supply and adapts a duty cycle command for the fuel injector based upon an open loop calculation that utilizes both the commanded mass flow and the measured actual fuel pressure. The method may be characterized by an absence of controlling the actual fuel pressure of the variable-pressure fuel supply and may be further characterized by an absence of control by an electro-hydraulic regulator. The open loop calculation may use at least two coefficients.

Abstract: A method for detecting a leak in a dosing manifold system having a manifold body, first valve assembly, and a device capable of preventing fluid flow. The method including the steps of transporting a fluid into a control fluid circuit, trapping the fluid in the circuit with the first valve assembly and the device capable of preventing fluid flow, blocking the fluid outside the control fluid circuit, relieving pressure outside of the circuit via the first valve assembly, measuring pressure inside the circuit, and comparing the pressures with selected baseline values.

Abstract: An exhaust line fuel injection system and associated methods of operation and control are disclosed. The fuel passes through a regulating valve connected to a pressurized fuel source and an outlet connected to an exhaust system fuel supply line. The exhaust system fuel supply line is connected to a nozzle, which generally comprises a check-valve and is configured to inject the fuel into the exhaust line. Using a pressure measuring device, an indication of the exhaust system fuel supply line pressure is obtained. A controller provides control over the flow regulating valve using feedback from the pressure indication and a predetermined relationship between the flow rate through the nozzle and one of the exhaust system fuel supply line pressure and the pressure drop across the nozzle. The method can be implemented with a single pressure measuring device. The same pressure measurements, especially their frequency spectrum, can be used to detect system faults.

Abstract: A system for controlling pressure in a transmission comprises a transmission control unit, a valve controller that receives a desired pressure as input from the transmission control unit, a valve driver, a valve that regulates an amount of fluid in a transmission clutch, and a pressure transducer that reads a pressure in the transmission clutch and outputs a pressure reading to the valve controller, wherein the valve controller comprises logic for outputting to the valve driver an instruction for controlling the valve, the instruction being formulated using the desired pressure and the pressure reading.