Hybrid Drive Engine Start-Stop Threshold Control
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Solution Overview
Problem
Hybrid drive systems in motor vehicles face high soot particle emissions during warm-up operations due to low filtration capacity of particulate filters, especially when the internal combustion engine is intermittently stopped and restarted, leading to increased soot development and emissions.
Innovation Solution
The method involves variably selecting start and stop threshold values based on the operating temperature of the internal combustion engine to maintain the engine temperature within a range that minimizes soot development, ensuring the internal combustion engine is started only when necessary and stopped when sufficient electric motor torque can be provided, thereby reducing soot emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the internal combustion engine is intermittently stopped and restarted to reduce fuel consumption, then energy efficiency is improved, but soot emissions increase due to low filtration capacity during warm-up
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the start and stop threshold values based on engine temperature. When the engine is cold, the thresholds are set to prevent stopping, ensuring the engine remains running and maintains temperature. When the engine is warm, the thresholds allow for stopping to reduce fuel consumption. This temperature-dependent parameter adjustment resolves the contradiction by adapting the stop-start strategy to thermal conditions, preventing soot emissions during cold operation while enabling energy savings during warm operation.
2Object-generated harmful factors
If the engine is kept running to maintain temperature and reduce soot, then soot emissions are reduced, but fuel consumption increases
Solution Approach 1:
The patent implements dynamics by making the engine control strategy adaptive rather than static. The start and stop threshold values are not fixed but dynamically adjusted based on real-time engine temperature measurements. This allows the system to transition between different operational modes: maintaining continuous operation when cold to prevent soot, and allowing stop-start operation when warm to reduce fuel consumption. The dynamic adaptation resolves the contradiction by optimizing the trade-off between emissions and energy consumption based on thermal state.
3Speed
If the start threshold value is lowered to enable more frequent engine starts, then responsiveness to demand is improved, but soot development increases due to more warm-up cycles
Solution Approach 1:
The patent applies parameter changes by setting the start threshold value as a function of engine temperature. When the engine is cold, the start threshold is raised (or stop threshold lowered) to prevent stopping, reducing the frequency of starts and thereby reducing soot development from repeated warm-up cycles. When the engine is warm, the thresholds are adjusted to allow more frequent starts, improving responsiveness to demand without significantly increasing soot emissions. This temperature-dependent parameter adjustment resolves the contradiction between responsiveness and soot development.
Data Source
AI summary
A method for operating a hybrid drive apparatus for a motor vehicle, having an exhaust-gas-producing internal combustion engine and an electric motor. The internal combustion engine and the electric motor, respectively alone or at least sometimes jointly, provide a drive torque, wherein, when a start threshold value is exceeded by a demand variable. The internal combustion engine is started and the drive torque is at least partially generated by the internal combustion engine, and, when a stop threshold value is not met by the demand variable, the internal combustion engine is stopped and the drive torque is generated solely by means of the electric motor.