Hybrid Vehicle Controller Adaptive Switching Logic
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Solution Overview
Problem
In hybrid vehicles equipped with a variable valve actuating device, when the operation characteristic of the intake valve becomes unchangeable, the output of the internal combustion engine decreases, leading to a reduction in State of Charge (SOC) of the electrical storage device, which compromises traveling performance in Charge Sustaining (CS) mode.
Innovation Solution
A controller is implemented to adjust the switching condition from Charge Depleting (CD) mode to CS mode, switching at a higher SOC when the intake valve's operation characteristic is unchangeable, thereby suppressing SOC consumption and ensuring traveling performance by compensating with the rotary electric machine's driving force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the variable valve actuating device fails and the intake valve operation characteristic becomes unchangeable, then the device complexity is reduced, but the internal combustion engine output decreases and SOC consumption increases
Solution Approach 1:
The patent applies dynamics by making the switching SOC threshold adaptive rather than fixed. The controller dynamically adjusts the SOC threshold for switching from CD mode to CS mode based on the operational status of the variable valve actuating device. When the device is normal, switching occurs at a lower SOC threshold; when the device fails and valve characteristics become unchangeable, the threshold is raised to a higher SOC level. This dynamic adjustment ensures that sufficient electric power is available to compensate for reduced engine output, preventing excessive SOC consumption while accepting the simpler mechanical state.
2Productivity
If the switching SOC threshold is kept low to maximize CD mode operation, then productivity is improved, but traveling performance deteriorates when engine output decreases due to valve actuation failure
Solution Approach 1:
The patent implements dynamics by making the SOC switching threshold adaptive based on the operational status of the variable valve actuating device. The controller monitors the device status and dynamically adjusts the threshold: when the device is functioning normally, the threshold is set lower to maximize CD mode operation and productivity; when the device fails and can no longer adjust intake valve characteristics, the threshold is raised to ensure sufficient SOC is available to compensate for the reduced engine output, thereby maintaining traveling performance and reliability.
3Reliability
If the switching condition is changed to switch at a higher SOC when valve actuation fails, then SOC consumption is suppressed and traveling performance is maintained, but the loss of energy increases due to reduced engine efficiency
Solution Approach 1:
The patent applies preliminary action by proactively raising the SOC switching threshold before the actual need for compensation arises. When the controller detects that the variable valve actuating device has failed and can no longer adjust intake valve characteristics, it preemptively increases the SOC threshold for switching from CD to CS mode. This ensures that sufficient electric power is available in advance to compensate for the reduced engine output, preventing situations where the engine operates inefficiently and excessive SOC depletion occurs, thereby minimizing overall energy loss.
Data Source
AI summary
A hybrid vehicle includes an internal combustion engine, an electrical storage device, a rotary electric machine, and a controller. The hybrid vehicle travels in a selected one of a charge sustaining mode and a charge depleting mode. Switching from the charge depleting mode to the charge sustaining mode is controlled such that a first state of charge is higher than a second state of charge. In the first state of charge, the controller switches from the charge depleting mode to the charge sustaining mode at the time when operation characteristic of the intake valve is unchangeable to a desired operation characteristic. In the second state of charge there is switching from the charge depleting mode to the charge sustaining mode at the time when the operation characteristic of the intake valve is changeable to a desired operation characteristic.