Engine Observer Model for Transient EGR Control

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Solution Overview

Problem

Traditional engine control systems face challenges in achieving the optimum combination of air and burnt gases within the engine cylinder due to the dynamics of the air system, leading to errors under transient conditions, particularly with open loop tables and PID controllers that rely on sensor feedback with inherent lag.

Innovation Solution

A physics-based feed forward control method using an engine observer model to monitor parameters, generate state estimates, and adjust actuator commands for the air throttle and EGR valve, improving response and calibration by prioritizing control objectives and accounting for system constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If open loop tables and PID controllers are used for EGR and intake manifold pressure control, then the system is simple to implement, but control accuracy deteriorates under transient conditions due to calibration limitations and sensor feedback lag

Engineering Contradiction:

Improveease of control system implementationVSAvoidcontrol accuracy under transient conditions

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces traditional mechanical control approaches (open loop tables and PID controllers) with a physics-based feed forward calculation system that uses an engine observer model to predict optimal EGR and intake manifold pressure settings in real-time, eliminating the need for complex calibration tables and reducing sensor feedback lag

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The engine observer model performs preliminary calculations of optimal control settings based on current engine state and physics-based equations before actual actuator adjustment, allowing the system to anticipate transient conditions and prepare appropriate control commands in advance rather than reacting after deviations occur

Inventive Principle:

Principle #10Preliminary action

2Reliability

If sensor feedback control is used for EGR and intake manifold pressure regulation, then the system can correct for deviations, but response speed deteriorates due to inherent sensor lag

Engineering Contradiction:

Improveability to correct control deviationsVSAvoidcontrol response speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The physics-based feed forward calculation uses the engine observer model to predict optimal control settings before deviations occur, allowing the system to proactively adjust EGR and intake manifold pressure rather than reacting after sensor feedback detects deviations, thereby eliminating the time lag inherent in feedback-based correction

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system incorporates model corrections that continuously refine the engine observer model based on actual sensor measurements, creating a feedback loop that improves the accuracy of feed forward predictions over time while maintaining fast response through real-time physics-based calculations

Inventive Principle:

Principle #23Feedback

3Device complexity

If traditional control strategies are used for air system regulation, then the control logic is simple, but the ability to prioritize control objectives and account for system constraints deteriorates

Engineering Contradiction:

Improvecontrol logic complexityVSAvoidability to prioritize control objectives

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent changes the fundamental parameters of control calculation by using physics-based equations that directly compute optimal EGR and intake manifold pressure settings based on real-time engine state, rather than relying on pre-calibrated lookup tables or simple PID proportional responses, enabling sophisticated prioritization of control objectives

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10830164B2Fresh air flow and exhaust gas recirculation control system and method

Publication Date: 2020.11.10 DEERE & CO

AI summary

A fresh air and exhaust gas control method for an engine includes monitoring parameters of an engine in an operational state using a plurality of sensors and generating engine state estimates using an engine observer model. The engine observer model represents an intake manifold volume, an exhaust manifold volume, and a charge air cooler volume. The method also includes generating a turbocharger rotational speed estimate using a turbocharger model and calculating a fresh air flow correction factor. The method further includes determining a desired air throttle position and a desired EGR valve position based on setpoint commands, the monitored engine parameters, the fresh air flow correction factor, the engine state estimates, and the turbocharger rotational speed estimate. The method additionally includes adjusting the air throttle based on the desired air throttle position and adjusting the EGR valve based on the desired EGR valve position.