Hybrid Engine Activation Threshold Control
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Solution Overview
Problem
In hybrid vehicles, drivers face difficulty in operating the vehicle exclusively with the electric motor as they lack information on when the torque specified via the accelerator pedal exceeds the electric motor's capability, leading to unintended activation of the internal combustion engine.
Innovation Solution
A method where the internal combustion engine is activated only when the target drive torque exceeds the sum of the electric motor's torque and an additional torque, allowing the driver to intuitively understand the electric motor's range and avoid hybrid mode by metered accelerator pedal application, with the additional torque varying based on vehicle speed and electric motor torque, and the accelerator pedal gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the internal combustion engine is started when the target drive torque exceeds the electric motor's torque capability, then the vehicle can maintain sufficient drive torque, but the driver loses the ability to operate the vehicle exclusively with the electric motor
Solution Approach 1:
The patent applies preliminary action by introducing an additional torque margin before the electric motor's torque limit is reached. The control system calculates a threshold based on electric motor torque capability plus an additional torque component, and only activates the combustion engine when target drive torque exceeds this pre-calculated threshold. This prevents unintended engine activation and allows drivers to operate in electric-only mode by keeping accelerator pedal input below the threshold, while still ensuring sufficient power availability when needed.
2Power
If the internal combustion engine is activated automatically when target drive torque exceeds electric motor torque, then drive torque availability is ensured, but unexpected acceleration occurs reducing driver controllability
Solution Approach 1:
The patent applies preliminary anti-action by preemptively preventing the harmful effect of unexpected acceleration through a buffer zone. The additional torque component creates a buffer between the electric motor's maximum capability and the engine activation threshold. This buffer prevents sudden torque transitions by ensuring the engine only activates when the driver intentionally requests torque beyond what the electric motor can provide, even under maximum acceleration conditions, thereby maintaining driver controllability while ensuring power availability.
3Adaptability or versatility
If the additional torque increases with vehicle speed and electric motor torque, then the engine activation threshold adapts to driving conditions, but the control logic becomes more complex
Solution Approach 1:
The patent applies dynamics by making the additional torque component variable rather than fixed. The additional torque is dynamically adjusted based on real-time vehicle speed and electric motor torque capability. At higher speeds and when the electric motor can provide more torque, the additional torque margin increases, raising the engine activation threshold. This dynamic adaptation allows the system to maintain electric-only operation across a wider range of driving conditions while automatically ensuring engine activation when truly necessary, all through relatively simple control logic that adjusts parameters based on sensor inputs.
Data Source
Figure 1~2
AI summary
An internal combustion engine (7) of a vehicle which, in addition to the internal combustion engine (7), comprises an electric motor (8), each for driving the vehicle (10), is automatically activated if a setpoint drive torque (2) is greater than a sum of a drive torque (4) which can be instantaneously made available by the electric motor (8) and an additional torque (5). In this context, the additional torque (5) is greater than zero.