Gasoline Engine Torque Control via Inverse Model

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Solution Overview

Problem

Current engine control systems induce significant time delays in translating accelerator pedal travel to desired engine torque, leading to inaccurate and oscillatory responses, as they rely on iterative solutions that do not account for transient spark changes.

Innovation Solution

A method that uses an inverse torque model to determine reference actuator positions by iteratively calculating air per cylinder values, incorporating spark advance, CAM position, and EGR valve position, with data from lookup tables and filters to quickly converge on accurate actuator settings, minimizing computational resources and response time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional iterative control systems are used to translate accelerator pedal travel to desired engine torque, then the system can achieve torque control functionality, but significant time delays and oscillatory responses occur

Engineering Contradiction:

Improvetorque control accuracyVSAvoidresponse time delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system pre-calculates and stores torque lookup tables that map accelerator pedal positions directly to desired torque values and corresponding actuator positions. This preliminary preparation eliminates the need for iterative calculations during transient operations, providing immediate torque response without time delays or oscillations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the traditional iterative mechanical control approach with a direct lookup table-based electronic control system. By substituting iterative mathematical solutions with pre-computed lookup tables, the system achieves instantaneous torque translation from accelerator pedal input without computational delays.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If iterative solutions are used to solve for desired air per cylinder during transients, then the system can adapt to changing conditions, but the system becomes slow and oscillatory

Engineering Contradiction:

Improvetransient adaptation capabilityVSAvoidsystem response speed

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

The system pre-calculates torque lookup tables that incorporate anticipated transient conditions and spark timing changes. By preparing these lookup tables in advance, the system can immediately respond to transient operations without performing iterative calculations during the transient event, maintaining both adaptability and speed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent creates simplified lookup table representations of the complex torque-control relationships. These lookup tables copy the essential control information in a condensed format that can be quickly accessed and applied during transient operations, eliminating the need for real-time iterative solving while preserving adaptive behavior.

Inventive Principle:

Principle #26Copying

3Ease of operation

If current spark timing is used during transients to calculate desired air per cylinder, then calculations can be performed, but the desired APC will be incorrect until the system settles down

Engineering Contradiction:

Improvecalculation simplicityVSAvoidair per cylinder accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system pre-calculates torque lookup tables that account for anticipated spark timing changes during transients. By incorporating future spark timing information into the pre-computed lookup tables, the system eliminates the error that occurs when using current (outdated) spark timing during transient operations, achieving accurate air per cylinder values immediately.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of using current spark timing to calculate desired APC and then iteratively adjusting it, the patent inverts the approach by pre-calculating the correct APC values in the lookup tables that account for the spark timing that will exist at the end of the transient. This reversal eliminates the fundamental error in the traditional approach.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10273900B2Method to determine reference airflow actuator positions for a gasoline engine

Publication Date: 2019.04.30 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A method to determine reference actuator positions for a gasoline engine, includes entering a base torque request, a known spark advance, a known CAM position and a known exhaust gas recirculation (EGR) valve position into an inverse torque model to generate a first iteration desired air per cylinder (APC) value. The first iteration desired APC value is passed through a deadband filter to produce a filtered first iteration desired APC signal. A Predicted As Cal (PAC) spark advance is calculated for the filtered first iteration desired APC value. The PAC spark advance and the base torque request are modified, and data from a first lookup table is entered to generate a second iteration desired APC value.