Hybrid Engine Control Unit Switching Operation Lines
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Solution Overview
Problem
Hybrid vehicles experience discomfort to operators due to changes in engine operating conditions when switching between different operation lines, particularly when the available reducing agent in the exhaust gas purification system decreases, affecting fuel economy and NOx emission.
Innovation Solution
A hybrid vehicle with a control unit that manages the internal combustion engine, electric generator, and electric motor, using engine temperature sensors to switch between two operating conditions (A and B) in a way that they coincide, minimizing noticeable changes in engine operation, with the first condition optimizing fuel economy and the second condition minimizing particulate matter emission when the engine is not warmed up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the operation line is changed to reduce NOx emission when reducing agent decreases, then NOx emission is reduced, but fuel economy deteriorates
Solution Approach 1:
The control unit changes operational parameters (rotational speed and torque) based on engine temperature conditions. When engine temperature is low, the system selects operating points that prioritize NOx reduction; when temperature is high, it selects operating points that optimize fuel economy. This dynamic parameter adjustment resolves the contradiction by adapting to thermal conditions.
Solution Approach 2:
The system dynamically switches between different operation lines based on real-time engine temperature feedback. The control unit continuously monitors temperature and adjusts the selected operation line accordingly, transforming a static emission/fuel economy trade-off into a dynamic adaptation process that resolves the contradiction under varying operating conditions.
2Object-generated harmful factors
If the operation line is changed during engine operation to optimize emission or fuel economy, then emission or fuel economy is improved, but engine operation characteristics change causing discomfort to operator
Solution Approach 1:
The control unit carefully selects operation lines that maintain similar engine characteristics (rotational speed and torque) despite different emission optimization goals. By choosing operating points with comparable parameters, the system achieves emission improvement while minimizing perceptible changes in engine behavior that would cause operator discomfort.
Solution Approach 2:
The system applies different operation line selection strategies based on local engine temperature conditions. In low-temperature regions, emission-reducing operation lines are selected; in high-temperature regions, fuel-economy-optimizing lines are selected. This localized adaptation ensures emission improvement without causing noticeable disruptions to engine operation characteristics.
Data Source
AI summary
An engine (2) of a hybrid vehicle (1) is configured to operate along a prescribed operation line in an operation property diagram of the engine. In addition to a first operation line (A) that optimizes fuel economy, a second operation line (B) that minimizes undesired emission of particulate matter is defined. The two operation lines substantially coincide with each other in a certain region of the diagram. A control unit (7) of the vehicle switches the operating condition between the first operation line and the second operation line when the first operation line and the second operation line substantially coincide with each other.