Engine Torque Monitoring via Dual Calculation Selection

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Solution Overview

Problem

Existing engine torque monitoring technologies fail to accurately detect torque deviations due to inaccuracies in injection pressure detection and calculation, leading to potential undetected engine torque exceeding allowable limits.

Innovation Solution

An engine control system that calculates actual torque using multiple operating state parameters, such as intake air amount and throttle opening, and selects the largest value between two calculated torques to ensure accurate detection and limit engine actuation when the actual torque exceeds allowable limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If actual torque is calculated based on injection pressure detection, then torque monitoring capability is provided, but measurement precision deteriorates due to detection inaccuracies and calculation troubles

Engineering Contradiction:
Improvetorque monitoring capabilityVSAvoidactual torque calculation accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent divides the actual torque calculation into two separate calculation methods: one based on injection pressure detection and another based on engine operating parameters (intake air amount, engine speed, throttle opening). Each method is independently executed and then compared to select the more reliable result, thereby segmenting the calculation process to avoid the weaknesses of any single method.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements a feedback mechanism where the results from both calculation methods are continuously compared. When the difference between the two calculated torque values exceeds a predetermined threshold, the system identifies this as an abnormal state and uses the larger value for monitoring, providing feedback that improves the overall measurement precision and reliability.

Inventive Principle:
Principle #23Feedback

2Device complexity

If single calculation method is used for actual torque, then device complexity is reduced, but reliability deteriorates due to undetected calculation troubles

Engineering Contradiction:
Improvecalculation system simplicityVSAvoidtorque detection accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges two different torque calculation approaches into a unified monitoring system. By combining the injection pressure-based calculation with the engine parameter-based calculation, the system achieves higher reliability without significantly increasing complexity, as both calculations use existing sensor data and the selection logic is straightforward.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3486470B1Engine control method and control device
Publication Date: 2021.08.18 NISSAN MOTOR CO LTD
  • EP3486470B1 patent drawingFigure 1
  • EP3486470B1 patent drawingFigure 2
  • EP3486470B1 patent drawingFigure 3

AI summary

An engine control device sets a target torque of an engine, and controls an engine torque based on the set target torque. An allowable torque greater than the target torque is set, and a plurality of different operating state parameters is detected as indicators indicating an actual operating state of the engine. Actual torques, which are the actual engine torques, are individually calculated based on the plurality of detected operating state parameters, and the largest value among the calculated actual torques is selected as a final actual torque. The selected actual torque is compared to the allowable torque to generate a control signal according to the result of comparison between the actual torque and the allowable torque.