Hybrid Drive Engine Start Prediction via Unfiltered Torque
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Solution Overview
Problem
In hybrid drive vehicles, when only the electric drive unit is operating, there is a response loss due to the internal combustion engine not starting until the nominal drive torque exceeds the maximum possible drive torque of the electric drive unit, leading to a lack of accelerating torque.
Innovation Solution
A method is introduced to predict the nominal drive torque by evaluating the unfiltered driver request torque before filtering, allowing the internal combustion engine to start early, before reaching the maximum torque limit of the electric drive unit, thereby preventing unnecessary response losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the internal combustion engine is started only when the nominal drive torque exceeds the maximum possible drive torque of the electric drive unit, then the electric drive unit can operate independently for longer, but the response time and accelerating torque are reduced
Solution Approach 1:
The control unit initiates the starting process of the internal combustion engine in advance, before the nominal drive torque actually exceeds the maximum possible drive torque of the electric drive unit. This preliminary action ensures that the internal combustion engine is already running or nearly running when additional torque is needed, eliminating response delays and ensuring continuous accelerating torque availability.
2Speed
If the internal combustion engine is started early, then the response time and accelerating torque are improved, but the electric drive unit cannot operate independently for as long
Solution Approach 1:
The control unit continuously monitors the nominal drive torque and compares it with the maximum possible drive torque of the electric drive unit. Based on this feedback, the control unit intelligently determines the optimal timing to start the internal combustion engine, balancing the need for rapid response with the desire to maintain electric-only operation as long as possible.
3Ease of operation
If the driver request torque is filtered before evaluation, then driving comfort is improved, but the accuracy of predicting when the torque limit will be reached is reduced
Solution Approach 1:
The control unit evaluates the unfiltered driver request torque in advance to predict when the torque limit will be reached, initiating the engine start process beforehand. The filtered torque value is then used for actual torque coordination and control. This approach allows accurate prediction while maintaining driving comfort through filtering during actual operation.
Data Source
AI summary
A method is provided for the early induction of an additional start of an internal combustion engine in a vehicle with a hybrid drive including at least one electric drive unit and one internal combustion engine. When only the electric drive is in operation, then the internal combustion engine is additionally started no later than when the determined requested nominal drive torque exceeds the maximum possible drive torque of the electric drive unit. In order to initiate an additional startup of the internal combustion engine before reaching or exceeding the maximum possible drive torque of the electric drive unit by way of the requested nominal drive torque, the still unfiltered driver request torque or a limited driver request torque is evaluated.