Engine Torque Estimation Using Crank Angle Amplitude

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Solution Overview

Problem

Existing engine torque estimation methods face challenges in accurately calculating crank angular acceleration due to measurement resolution limitations and disturbances at high rotation ranges, leading to inaccuracies in estimated torque values.

Innovation Solution

An engine torque estimating system that includes a crank angle sensor, an acquiring circuit for chronological waveform data, a generating circuit for input data to a mathematical model, a calculating circuit for estimating engine torque, and a control circuit for engine control, which uses amplitude information from the crank angle signal to improve torque estimation accuracy without directly relying on crank angular acceleration calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If crank angular acceleration is calculated from crank angle signal, then engine torque can be estimated, but measurement resolution limitations and disturbances at high rotation ranges cause calculation inaccuracies

Engineering Contradiction:

Improvetorque estimation accuracyVSAvoidcalculation reliability at high rotation ranges

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the parameter used for torque estimation from crank angular acceleration to amplitude information of the crank angle signal. By using amplitude variations instead of angular acceleration calculations, the system avoids the measurement resolution and sampling cycle limitations that affect high-speed accuracy, thereby improving both torque estimation accuracy and reliability at high rotation ranges

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical calculation method (crank angular acceleration derivation) with an alternative approach based on amplitude information extraction from the crank angle signal. This substitution eliminates the need for complex differentiation operations that amplify measurement errors at high speeds, improving calculation reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If sampling cycles are increased to improve measurement resolution, then torque estimation accuracy improves, but system complexity and processing load increase

Engineering Contradiction:

Improvecrank angular acceleration measurement precisionVSAvoidsampling system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the measured parameter from crank angular acceleration to amplitude information of the crank angle signal. This parameter change allows accurate torque estimation without requiring high sampling rates, thereby reducing system complexity and processing load while maintaining measurement precision

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10969285B2Engine torque estimating device, engine control system, and engine torque estimation method

Publication Date: 2021.04.06 FUJITSU LTD

AI summary

An engine torque estimating system includes: an engine; a crank angle sensor installed for a crankshaft of an engine; an acquiring circuit for acquiring, from the crank angle sensor, a chronological waveform in which amplitude changes based on a rotational speed of the crankshaft; a generating circuit for generating input data to a mathematical model based on information of the amplitude of the chronological waveform; a calculating circuit for calculating an estimated value of engine torque by giving the generated input data to the mathematical model; and a control circuit for controlling the engine based on the estimated value of engine torque.