Plug-in Hybrid Vehicle ECU Catalyst Warm-up Control
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Solution Overview
Problem
In plug-in hybrid vehicles, transitioning from a charge depleting mode to a charge sustain mode without warming up the catalyst can lead to deterioration in emission properties, resulting in a shorter actual running distance than expected and a sense of incongruity for the user.
Innovation Solution
A control apparatus and method that performs intermittent engine operation based on the required discharge amount and engine temperature to ensure catalyst warm-up during the charge depleting mode, allowing for a seamless transition to the charge sustain mode while maintaining emission purification performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the engine is started without warming up the catalyst during the transition from CD mode to CS mode, then the vehicle can transition smoothly between modes, but emission properties deteriorate
Solution Approach 1:
The catalyst is warmed up in advance during the CD mode before the transition to CS mode. The control apparatus determines whether catalyst warm-up is necessary based on predicted catalyst temperature at transition time, and if needed, operates the engine during CD mode to warm the catalyst before mode switching occurs.
Solution Approach 2:
The control apparatus dynamically adjusts engine operation during CD mode based on real-time temperature conditions and predicted transition requirements. The engine is operated intermittently during CD mode to warm the catalyst when necessary, rather than following a fixed operation pattern.
2Reliability
If the engine is operated to warm up the catalyst during CD mode, then emission purification performance is ensured, but the discharge amount of the battery decreases
Solution Approach 1:
The engine is operated partially during CD mode only when necessary for catalyst warm-up, rather than continuously or never. The control apparatus calculates predicted catalyst temperature and determines the minimum necessary engine operation to achieve adequate warm-up without excessive fuel consumption.
Solution Approach 2:
The control apparatus changes operational parameters dynamically by adjusting engine operation timing and duration based on predicted catalyst temperature and battery state of charge. This optimizes the balance between catalyst warm-up effectiveness and battery energy conservation.
3Reliability
If the engine is operated intermittently during CD mode for catalyst warm-up, then the actual running distance becomes longer than expected, but the user feels a sense of incongruity
Solution Approach 1:
The control apparatus uses feedback from temperature sensors and battery state monitoring to determine when engine operation is necessary. It calculates predicted catalyst temperature at transition time and adjusts engine operation accordingly, ensuring warm-up effectiveness while minimizing unnecessary operation that would confuse the user.
Solution Approach 2:
The system performs preliminary assessment of catalyst temperature conditions during CD mode and proactively warms up the catalyst only when predicted to be necessary for the upcoming transition, avoiding both insufficient warm-up and excessive engine operation.
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
Ensures emission purification performance during the transition from charge depleting to charge sustain mode without causing a sense of incongruity to the user by effectively warming up the catalyst and optimizing engine operation.
Implementation Method 1
a catalyst for purifying an exhaust gas of the internal combustion engine
Implementation Method 2
the engine and the catalyst have already been warmed up when the engine is started
Data Source
AI summary
An ECU (Electronic Control Unit) that controls a plug-in hybrid vehicle starts an engine when a required power as a value obtained by subtracting a required discharge amount from a drive power is larger than a threshold during intermittent control in a CD (Charge Depletion) mode, and stops the engine when the required power is smaller than a threshold. When intermittent control is being performed in the CD mode, the ECU limits the required discharge amount Pout to a relatively small value in a range where an engine coolant temperature is low, and sets the required discharge amount relatively large instead of imposing a limit thereon in a range where the engine coolant temperature is high.