Hybrid Engine Torque Estimation via Damper Elastic Correction
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Solution Overview
Problem
Conventional cylinder abnormality detection apparatuses for internal combustion engines fail to precisely detect abnormalities in hybrid vehicles due to the influence of motor generators on the rotation state of the crankshaft, leading to inaccurate estimation of torque generated during combustion.
Innovation Solution
An abnormality detection apparatus and method that estimates the output torque of the internal combustion engine based on rotation angular acceleration, calculates the elastic force imposed by a damper to correct for relative rotation, and diagnoses abnormalities using a torque correcting unit, effectively accounting for the motor generator's influence on the crankshaft's rotation state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional cylinder abnormality detection apparatus is applied to a hybrid vehicle with motor generator, then the detection system can be used, but the rotation state of the crankshaft is influenced by the motor generator causing inaccurate torque estimation and inability to precisely detect abnormalities
Solution Approach 1:
The patent introduces a damper as an intermediary element between the crankshaft and the power split device. The damper absorbs and isolates the rotational influences from the motor generator, allowing the crankshaft rotation to be measured independently and accurately for torque estimation, thus resolving the interference problem while maintaining hybrid vehicle applicability
Solution Approach 2:
The patent extracts the motor generator's rotational influence from the crankshaft measurement by using the damper to separate the two rotational systems. This allows the abnormality detection to focus solely on the crankshaft's combustion-related rotation without contamination from the motor generator's operational variations
2Productivity
If the motor generator's rotational influence is not compensated, then the power split device can operate freely, but the torque generated by the internal combustion engine cannot be estimated with high accuracy
Solution Approach 1:
The damper serves as a mediator that allows the power split device to operate freely while simultaneously providing a clean measurement path for torque estimation. The damper's elastic properties enable it to absorb motor generator influences without restricting the overall power split operation
3Device complexity
If the damper's elastic force is not considered in torque estimation, then the estimation calculation remains simple, but the relative rotation between output shaft and input shaft cannot be suppressed leading to detection inaccuracy
Solution Approach 1:
The patent modifies the torque estimation parameters by adding the damper's elastic force as a correction term. This parameter change allows the system to account for the damper's influence on relative rotation, improving detection accuracy while maintaining relatively simple calculation structure through straightforward parameter addition
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for precise detection of abnormal cylinders by accurately estimating torque generated during the combustion state, even in hybrid vehicles with complex power split configurations, thereby improving the accuracy of internal combustion engine diagnostics.
Implementation Method 1
a damper connected between an output shaft of the internal combustion engine and the input shaft for transferring the motive power while suppressing relative rotation of the output shaft of the internal combustion engine and the input shaft
Data Source
AI summary
A crankshaft of an engine is connected to a carrier shaft of a planetary gear via a damper. The damper includes a torsion member generating elastic force for suppressing relative rotation, when the crankshaft and the carrier shaft are relatively rotated. A control unit estimates engine torque with using rotation angular acceleration of the crankshaft calculated from a detected value of an engine speed sensor, and corrects the estimated engine torque with a correction term of the elastic force of the damper calculated based on a damper torsional angle. Then, the control unit diagnoses an abnormality of the engine based on the estimated engine torque after correction.