Engine speed control
AssigneeGeneral Motors Corporation
InventorsMichael Livshiz, Scott Joseph Chynoweth, Sharanjit Singh
Life of this patent
Estimating the term…
Abstract
An idle control system for internal combustion engines providing load rejection and/or load compensation for a given engine. speed reference and barometric pressure wherein the present invention accommodates for varying engine speed references and for varying barometric pressures, such as at different altitudes. The control system incorporates a load compensator, and a control structure including a multitude of sub-control blocks. The load compensator generates the needed airflow to compensate for the torque of engine loads and works with a feed-forward controller to reject anticipated loads. The calibration procedure is fully automated.
Claims12
A load compensator for an internal combustion engine speed control system including a predetermined torque model, said load compensator comprising:
- pressure ratio model means for defining pressure ratios for compensating altitude effects on a predetermined torque model of an internal combustion engine;
- a torque estimator connected with said pressure ratio model means for determining needed torque of the internal combustion engine responsive to a selected manifold air pressure, a selected spark advance, a selected pressure ratio, and a selected engine speed;
- and
- a mass air flow estimator connected with said torque estimator for determining mass airflow needed by the internal combustion engine responsive to a selected reference engine speed, a required torque value and a selected barometric pressure.
A speed control system for an internal combustion engine including a predetermined torque model, said speed control system comprising:
- a load compensator comprising:
- pressure ratio model means for defining pressure ratios for compensating altitude effects on a predetermined torque model of an internal combustion engine;
- a torque estimator connected with said pressure ratio model means for determining needed torque of the internal combustion engine responsive to a selected manifold air pressure, a selected spark advance, a selected pressure ratio, and a selected engine speed;
- and
- a mass air flow estimator connected with said torque estimator for determining mass airflow needed by the internal combustion engine responsive to a selected reference engine speed, a required torque value and a selected barometric pressure, wherein said mass air flow estimator generates a first airflow signal;
- and
- a control structure comprising:
- an engine speed controller for generating a second airflow signal;
- and
- a mass airflow controller for generating a commanded mass airflow signal responsive to at least said first and second airflow signals.
A method for providing load compensated speed control of an internal combustion engine, said method comprising the steps of:
- providing a predetermined torque model for the internal combustion engine via dynamometer based calibrations;
- generating pressure ratios for compensating altitude effects on the predetermined torque model;
- determining needed torque of the internal combustion engine within predetermined high and low torque limits responsive to a selected manifold air pressure, a selected spark advance, a selected pressure ratio, and a selected engine speed;
- determining mass airflow needed by the internal combustion engine within predetermined high and low mass airflow limits responsive to a selected reference engine speed, a required torque value and a selected barometric pressure;
- generating a first airflow signal responsive to said step of determining mass air flow;
- generating a second airflow signal responsive to predetermined engine speed data;
- and
- generating a commanded mass airflow signal responsive to at least said first and second airflow signals.
Dependencies are inferred from the claim text.