Hybrid Engine Start Torque Control Under Low Lubrication
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Solution Overview
Problem
In hybrid vehicles, the combustion engine can suffer from component damage due to high load requirements during starting processes, especially when lubrication is inadequate, leading to undesirable wear and reduced driving comfort.
Innovation Solution
A procedure and engine control system that assess the lubrication state of the combustion engine during starting processes and operate the engine within a maximum permissible torque limit, thereby reducing wear and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the internal combustion engine is operated immediately at high load during starting process, then the desired torque can be provided immediately, but component damage occurs due to lack of lubrication
Solution Approach 1:
The patent applies preliminary action by operating the internal combustion engine at reduced torque levels before reaching high load conditions. This preliminary phase allows the lubrication system to build up oil pressure and supply lubricant to critical components before high torque operation begins, preventing component damage while still enabling the engine to start and operate.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the torque output of the internal combustion engine based on the lubrication state. The engine control system continuously monitors lubrication conditions and adapts the torque profile accordingly, transitioning from reduced torque during the lubrication buildup phase to full torque capability once adequate lubrication is established.
2Reliability
If the internal combustion engine is operated at reduced torque to protect components, then component wear is reduced, but driving comfort deteriorates due to torque loss
Solution Approach 1:
The patent merges the torque contribution of the internal combustion engine with that of the electric motor to maintain total torque output. While the internal combustion engine operates at reduced torque during the lubrication phase, the electric motor compensates by providing additional torque, ensuring that the total torque available to the drivetrain meets driver demands and maintains driving comfort.
Solution Approach 2:
The electric motor acts as an intermediary that compensates for the torque limitation of the internal combustion engine during the lubrication buildup phase. By coordinating the torque output of both power sources, the system ensures that the vehicle maintains adequate acceleration and performance characteristics despite the restricted internal combustion engine torque.
3Duration of action of moving object
If lubrication is skipped during electrical operation, then driving continuity is maintained, but potential engine damage occurs
Solution Approach 1:
The system performs preliminary lubrication action during electrical operation by running the internal combustion engine at idle or low load conditions. This allows the lubrication system to be activated and build up oil pressure in advance, ensuring that when the internal combustion engine transitions to high torque operation, adequate lubrication is already in place, preventing engine damage while maintaining driving continuity.
Data Source
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AI summary
The present invention relates to a method for operating an internal combustion engine (20) of a motor vehicle during a starting process of the internal combustion engine (20). The method comprises: obtaining a lubrication state variable which represents a lubrication state of the internal combustion engine (20); determining (61) a maximum permissible torque (Mv,z) of the internal combustion engine (20) depending on the lubrication state variable; and operating (62) the internal combustion engine (20) at an operating torque which is equal to or less than the determined maximum permissible torque (Mv,z). The invention also relates to an engine controller for carrying out the method.