Secondary air injection

About: Secondary air injection is a research topic. Over the lifetime, 11452 publications have been published within this topic receiving 112147 citations.

Experimental Investigation of Centrifugal Compressor Stabilization Techniques

Abstract: Results from a series of experiments to investigate techniques for extending the stable flow range of a centrifugal compressor are reported. The research was conducted in a high-speed centrifugal compressor at the NASA Glenn Research Center. The stabilizing effect of steadily flowing air-streams injected into the vaneless region of a vane-island diffuser through the shroud surface is described. Parametric variations of injection angle, injection flow rate, number of injectors, injector spacing, and injection versus bleed were investigated for a range of impeller speeds and tip clearances. Both the compressor discharge and an external source were used for the injection air supply. The stabilizing effect of flow obstructions created by tubes that were inserted into the diffuser vaneless space through the shroud was also investigated. Tube immersion into the vaneless space was varied in the flow obstruction experiments. Results from testing done at impeller design speed and tip clearance are presented. Surge margin improved by 1.7 points using injection air that was supplied from within the compressor. Externally supplied injection air was used to return the compressor to stable operation after being throttled into surge. The tubes, which were capped to prevent mass flux, provided 9.3 points of additional surge margin over the baseline surge margin of 11.7 points.

Turbocharged exhaust gas recirculation system

Abstract: An exhaust recirculation system includes a power source including at least one cylinder outputting exhaust gas and a particulate reducing device fluidly connected to at least one exhaust duct of the power source. The particulate reducing device is configured to reduce an amount of particulates in the exhaust gas. The exhaust recirculation system also includes a recirculation compressor configured to receive and compress at least a portion of the exhaust gas. An intake duct of the at least one cylinder of the power source is fluidly connected to the recirculation compressor to receive the compressed reduced-particulate exhaust gas.

Injection controller for internal combustion engine

Abstract: An injection controller for an internal combustion engine that suppresses the accumulation of deposits on a nozzle hole of a direct injection valve. The injection controller (50) includes the direct injection valve (21), which injects fuel into a cylinder, and an intake passage injection valve (22), which injects fuel into an intake passage. An ECU (31), which is connected to the direct injection and intake passage injection valves, executes a first fuel injection mode for injecting fuel with the direct injection valve and a second fuel injection mode for injecting fuel with the intake passage injection valve. The ECU switches fuel injection modes from the second fuel injection mode to the first fuel injection mode for a predetermined period when fuel is to be injected in the second fuel injection mode.

Emissions diagnostic system

Abstract: An emissions diagnostic system (10) is used with a compression ignition engine having an exhaust gas stream (36) directed into an SCR catalyst (60) capable of reducing NOx in the exhaust gas stream (36). The system (10) comprises a tank (12) for storing a solution of urea, a pump (24) in fluid communication with the tank (12) for drawing the solution of urea from the tank (12), a valve 30 in fluid communication with the pump (24) and the exhaust gas stream (36) for receiving the solution of urea from the pump (24), an air pump (32) connected to the valve (30) for providing air into the valve (30) for mixing with the solution of urea, the valve (30) for spraying the solution of urea into the exhaust gas stream (36), a sensor (56) for sensing the level of NOx emissions emitted by the SCR catalyst (60), and a control module (42) connected to the sensor (56) for determining whether the level of NOx emissions is at an acceptable level.