Engine Control for Generator Load Variations
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Solution Overview
Problem
Existing methods for controlling the operating parameters of an internal combustion engine in a motor vehicle are not robust against sudden changes in electrical load, leading to delayed adjustments and potential speed oscillations due to the complexity of generator models used for power calculation.
Innovation Solution
The method involves continuously monitoring operating variables like the DF signal and excitation current to determine the relative change in load, allowing for immediate adjustment of the control setpoint for the engine, thereby adapting to load changes without delay and ensuring precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex generator model is used to determine the mechanical drive power required by the generator, then the power calculation precision is improved, but the response time to load changes deteriorates due to signal and computing runtime delays
Solution Approach 1:
The control method is segmented into two independent parts: a fast response component using a simplified generator model for immediate load change detection, and a precise control component using a complex generator model for accurate power determination. This segmentation allows each part to optimize for its specific function without compromising the other.
Solution Approach 2:
The simplified generator model performs preliminary action by quickly detecting load changes and generating initial control signals before the complex generator model completes its detailed power calculation. This preliminary detection and actuation ensures rapid response to load changes while maintaining precision through subsequent precise control.
2Manufacturing precision
If the engine control adjusts the operating parameter based on the power value from the complex generator model, then the control precision is improved, but the engine speed stability deteriorates during sudden load changes due to delayed response
Solution Approach 1:
The control system is segmented into a simplified model for stability maintenance and a complex model for precision control. The simplified model handles rapid load change detection and initial engine response to maintain speed stability, while the complex model provides precise power determination for accurate control after the transient period.
Solution Approach 2:
The simplified generator model performs preliminary detection and control action during sudden load changes before the complex model completes its calculation. This preliminary action prevents engine speed instability by responding immediately to load changes, while the complex model subsequently provides precise control for steady-state operation.
3Speed
If a simplified generator model is used for fast response to load changes, then the response time is improved, but the power determination accuracy deteriorates
Solution Approach 1:
The control method is segmented into two stages: a fast response stage using a simplified generator model for immediate load change detection, and a precise control stage using a complex generator model for accurate power determination. This segmentation allows the system to optimize response speed when needed while maintaining accuracy for steady-state control.
Solution Approach 2:
The simplified generator model performs preliminary detection and generates initial control signals quickly in response to load changes. This preliminary action ensures fast response time, while the complex generator model subsequently provides accurate power determination for precise control, combining the advantages of both approaches.
Data Source
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AI summary
The invention relates to a method for adjusting an operating parameter of an internal combustion engine (18) in a motor vehicle (10), wherein an electric generator (16) of the motor vehicle (10) is driven by the internal combustion engine (18) and a current output value (P_gen_mech) of a mechanical driving power required by the generator (16) is repeatedly determined from at least one current parameter value of the generator (16) by an energy management unit (24). On the basis of the output value (P_gen_mech), an engine control unit (20) determines a control setpoint (R) for adjusting the operating parameter (Pm). According to the invention sudden load variations at the generator (16) shall be compensated during adjustment. For that purpose an operating variable (DF, le) of the generator (16) is monitored, and after a sudden load variation of the electrical load (Pel) a relative change of the operating variable (DF, le) caused by the sudden load variation is determined and a control setpoint (R') adapted to the sudden load variation is determined independently of the output value (P_gen_mech) of the energy management unit (24) and dependent on the relative change in the monitored operating variable (DF, le).