Hybrid Vehicle Torque Control Suppressing Unnecessary Engine Starts
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Solution Overview
Problem
Existing hybrid motor vehicle control methods fail to efficiently manage the transition between electric and internal combustion engine power, leading to unnecessary engine starts, inefficient energy use, and discomfort due to lack of noticeable acceleration when torque requirements exceed the electric machine's capacity, especially in situations like inclines or temporary torque demands.
Innovation Solution
A method that determines a torque threshold to decide between electric and hybrid driving modes, suppressing internal combustion engine starts when torque requirements are temporarily exceeded by assessing the deviation between target and actual driving conditions, allowing the vehicle to operate in electric mode even when the torque threshold is briefly exceeded, thus avoiding frequent engine starts and maintaining comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal combustion engine is started whenever the torque requirement exceeds the torque threshold, then the vehicle can meet torque demands, but the engine starts unnecessarily during temporary excesses leading to increased fuel consumption and wear
Solution Approach 1:
The control system dynamically evaluates the duration and magnitude of torque threshold exceedance by comparing actual driving conditions against target driving conditions. The engine start decision is made dynamic rather than static, considering temporal characteristics of the torque demand excess to distinguish between temporary and sustained requirements.
Solution Approach 2:
The system performs preliminary assessment of the driving condition deviation before triggering engine start. By evaluating whether the torque threshold exceedance is temporary or sustained in advance, the system avoids premature engine starts and only activates the engine when genuinely necessary for sustained torque demands.
2Loss of energy
If the vehicle operates in electric mode during temporary torque excesses, then fuel consumption is reduced and engine wear is minimized, but driving comfort may be compromised if acceleration is not noticeable
Solution Approach 1:
The control system continuously monitors driving conditions and compares actual performance against target values. This feedback mechanism allows the system to assess whether maintaining electric mode during torque threshold exceedance is appropriate, ensuring that comfort requirements are met while optimizing fuel consumption based on real-time vehicle response.
3Reliability
If the engine is suppressed from starting during temporary torque excesses, then engine wear is reduced and energy efficiency is improved, but the vehicle may fail to meet sustained torque requirements
Solution Approach 1:
The system dynamically adjusts engine start strategy based on the temporal characteristics of torque demand. By evaluating the duration and persistence of torque threshold exceedance, the control system distinguishes between temporary fluctuations that can be managed in electric mode and sustained demands that require hybrid operation, thereby optimizing both energy efficiency and torque delivery capability.
Data Source
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AI summary
A method for controlling a motor vehicle with an internal combustion engine (2) and an electric machine (3), wherein the motor vehicle can be operated in an electric driving state and in a hybrid driving state, wherein in the electric driving state the electric machine (3) provides a drive torque, and in the hybrid driving state the internal combustion engine (2) provides drive torque, wherein the motor vehicle is operated in a hybrid driving state when a torque request exceeds a first torque threshold (MD), wherein the method comprises: operating the motor vehicle in the electric driving state when the torque request exceeds the first torque threshold (MD), on the basis of a deviation between a setpoint driving state and an actual driving state (42, 51, 62, 64) of the motor vehicle.