Smart actuator learn command process

Abstract

A variable geometry turbocharger (VGT) of an engine of a vehicle has a VGT mechanism and a VGT actuator connected to the VGT actuator. A controller is connected to the VGT actuator, and is configured to monitor at least one entry condition such as vehicle battery voltage, voltage at the VGT actuator, temperature of the engine, its oil, and its coolant, and exhaust gas temperature. If the entry conditions are met, the controller performs a learn procedure in which the VGT actuator cycles the VGT mechanism through its range of motion following a key-off shutdown command. The learn procedure may take place immediately preceding, during, or immediately following shutdown of the engine. The VGT actuator then reports to the controller an available range of motion of the VGT actuator and of the VGT mechanism.

Description

BACKGROUND[0001]This disclosure relates to an arrangement and method for reliably determining the available range of motion of a variable geometry turbocharger (VGT), such as the available range of vane motion in a VGT that varies the angle of the turbine vanes. Particularly, this disclosure relates to an arrangement and method for reliably determining the available range of motion of a VGT notwithstanding premature cranking of the engine by an operator or a cold state of the engine.RELATED ART[0002]VGT's are designed to allow the effective aspect ratio of a turbocharger to be varied as the operating conditions of an engine change. This is done by varying the geometry of the turbine housing, or by varying the angle of the turbine vanes, in order to maintain optimum aspect ratio of the turbine at varying engine speeds. With VGT's that vary the geometry of the turbine housing, the axial width of the inlet may be selectively blocked by an axially sliding wall, or the area of the nozzle...

AI Technical Summary

Benefits of technology

The patent text describes a process for a vehicle's engine that uses a variable geometry turbocharger (VGT) with a mechanism and an actuator. A controller monitors certain conditions and, if met, performs a learn procedure where the actuator cycles the mechanism through its range of motion. The actuator then reports the available range of motion to the controller. The technical effect is that this process ensures accurate control of the VGT mechanism for improved engine performance and efficiency.

Problems solved by technology

However, if the vehicle operator cranks the engine before the learn process is completed, the voltage and power available to the actuator may be insufficient to complete the learn cycle, among other potential failure modes.

This may result in a fault code being sent to the engine controller, the display of a malfunction indicator lamp (MIL), subsequent warranty costs, and lost vehicle uptime.

In addition, issuing the learn command with a cold engine may not accurately reflect the range or motion of the VGT mechanism and / or actuator, for example if the turbine vanes are fully or partially frozen, which may again drive unnecessary warranty costs.

However, this method has the potential to allow an actual problem to go unreported for an extended period, such as if the battery condition remains deficient through multiple learn processes while a failure condition develops within the VGT mechanism and / or actuator.

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