Engine Combustion Diagnosis via Motor Current in Transient States
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Solution Overview
Problem
Existing internal combustion engines without in-cylinder pressure sensors or with failed sensors face challenges in accurately detecting combustion abnormalities, particularly in transient states, due to the high cost and installation complexity of in-cylinder pressure sensors, and misfire detection errors in vibration damping systems.
Innovation Solution
A diagnosis device that estimates combustion states using current information from an electric motor and fuel injection data, employing a combustion abnormality detection unit to analyze torque components and fuel injection parameters to identify abnormal combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If in-cylinder pressure sensors are installed to accurately detect combustion abnormalities, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses current information from the electric motor as an intermediary to indirectly estimate combustion states. Instead of directly measuring in-cylinder pressure with complex sensors, the system mediates through the electric motor's current characteristics, which reflect torque variations caused by combustion abnormalities. This approach achieves accurate detection without requiring physical sensors inside the cylinders.
Solution Approach 2:
The patent replaces the mechanical sensor-based measurement system with an electrical measurement system. By substituting physical in-cylinder pressure sensors with electrical current measurements from the motor, the system eliminates the need for mechanical sensor installation while maintaining detection capability through the relationship between motor current and engine torque.
2Reliability
If in-cylinder pressure sensors are installed to detect combustion states, then reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent makes the electric motor serve a dual function: not only does it generate electric power, but it also acts as a sensor to provide current information for combustion state estimation. This self-service approach eliminates the need for additional dedicated sensors, maintaining reliable combustion monitoring while keeping the engine manufacturing process simple and unchanged.
Solution Approach 2:
The patent applies multi-functionality to the electric motor, which simultaneously performs power generation and combustion monitoring functions. By making the motor universal in its roles, the system achieves reliable combustion state detection without adding separate manufacturing steps or components, thus maintaining ease of manufacture.
3Productivity
If vibration damping control is used to detect misfires, then productivity is improved, but measurement precision deteriorates due to control interference
Solution Approach 1:
The patent performs preliminary analysis by extracting torque components from current information before combustion abnormality detection. By pre-processing the current data to isolate torque-related components, the system eliminates interference from vibration damping control and other variables, enabling accurate misfire detection without being affected by control actions.
Data Source
AI summary
Provided is a diagnosis device for an internal combustion engine that, even where an existing internal combustion engine in which an in-cylinder pressure sensor is not installed or an internal combustion engine in which an in-cylinder pressure sensor is broken down is put in a transient state, can estimate a combustion state of the internal combustion engine. The diagnosis device for an internal combustion engine that diagnoses an internal combustion engine causing an electric motor to generate electric power includes: a current information acquisition unit that acquires current information from the electric motor; a fuel injection information acquisition unit that acquires fuel injection information from a control unit controlling the internal combustion engine; and a combustion abnormality detection unit that estimates a combustion state of the internal combustion engine on the basis of the current information and the fuel injection information.