Fuel limiter for a uniflow-scavenged, two-stroke cycle, opposed-piston engine
AssigneeAchates Power, Inc.
InventorsNishit Nagar, Arunandan Sharma
Life of this patent
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Abstract
Control of fuel flow in a uniflow-scavenged, two-stroke cycle, opposed-piston engine includes limiting an amount of torque or fuel in response to a torque demand, based upon a comparison and a selection of fuel delivery options derived from a global airflow parameter and/or a trapped airflow parameter.
Claims2
A method for controlling operations of a uniflow-scavenged, two-stroke cycle, opposed-piston engine with a fuel source during demands for increased torque, comprising:
- receiving a torque demand for a desired torque level of the engine;
- determining a minimum value of a global air to fuel ratio (AFR) of the engine based on an engine speed and the desired torque level;
- determining a measured value of global mass airflow based on air flow conditions of the engine;
- determining a first maximum fuel quantity limit based on the minimum value of global AFR and the measured value of global mass airflow;
- determining a minimum value of a trapped AFR of the engine based on the engine speed and the desired torque level;
- determining a measured value of trapped mass airflow based on air flow conditions of the engine;
- determining a second maximum fuel quantity limit based on the minimum value of trapped AFR and the measured value of trapped mass airflow;
- and,
- limiting a quantity of fuel provided to the engine by:
- selecting the minimum of the first maximum fuel quantity limit, the second fuel quantity limit, and a desired fuel quantity derived from the torque demand, followed by providing a limited fuel command to the fuel source according to the selection;
- or,
- selecting the minimum of a torque based on the first maximum fuel quantity limit, a torque based on the second fuel quantity limit, and a desired torque derived from the torque demand, followed by providing a limited torque command to the fuel source according to the selection.
A method for limiting emissions of smoke by a uniflow-scavenged, two-stroke cycle, opposed-piston engine with a fuel source during demands for increased torque, comprising:
- receiving a torque demand for a desired torque level of the engine;
- determining a minimum value of a global smoke-limited air to fuel ratio (AFR) of the engine based on an engine speed and the desired torque level;
- determining a measured value of global mass airflow based on air flow conditions of the engine;
- determining a first maximum fuel quantity limit based on the minimum value of global smoke-limited AFR and the measured value of global mass airflow;
- determining a minimum value of a trapped smoke-limited AFR of the engine based on the engine speed and the desired torque level;
- determining a measured value of trapped mass airflow based on air flow conditions of the engine;
- determining a second maximum fuel quantity limit based on the minimum value of trapped smoke-limited AFR and the measured value of trapped mass airflow;
- and,
- limiting a quantity of fuel provided to the engine according to one of:
- selecting the minimum of the first maximum fuel quantity limit, the second fuel quantity limit, and a desired fuel quantity derived from the torque demand, followed by providing a limited fuel command to the fuel source according to the selection;
- and
- selecting the minimum of a torque based on the first maximum fuel quantity limit, a torque based on the second fuel quantity limit, and a desired torque derived from the torque demand, followed by providing a limited torque command to the fuel source according to the selection.
Dependencies are inferred from the claim text.