Starter-Generator Restart Control for Dual-Mass Flywheel Protection
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Solution Overview
Problem
Activating the starter generator at a speed just above the first speed limit can lead to start aborts and damage to the dual-mass flywheel in internal combustion engines during start/stop operations, particularly due to the mechanical decoupling and torque transmission delays in belt-driven systems.
Innovation Solution
A method that involves determining the operating range, activating the starter generator to reach a torque threshold before initiating the internal combustion engine, and controlling the engine in two distinct phases to prevent damage, with the starter generator's support being phased out after engine startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the starter generator is activated at a speed just above the first speed limit, then the internal combustion engine can be restarted, but start aborts and damage to the dual-mass flywheel occur due to torque transmission delays
Solution Approach 1:
The control unit determines the current speed and compares it with the first speed limit before activation. By performing this preliminary speed check, the system prevents activation in the critical speed range that causes flywheel damage, while still allowing restarts at safe speeds above the second speed limit.
Solution Approach 2:
The control unit acts as an intermediary between the starter generator activation request and the actual activation. It mediates by evaluating the current speed against speed limits and deciding whether to permit activation, thereby preventing direct activation that would cause damage.
2Adaptability or versatility
If the starter generator is used to support engine drive above the first speed limit, then engine restart is enabled, but mechanical decoupling causes torque transmission delays and oscillations
Solution Approach 1:
The system changes the operational parameters by establishing different speed limits (first and second speed limits) that define safe operating ranges. By monitoring and responding to speed parameter changes, the control unit adjusts starter generator activation status to maintain safe operation.
3Power
If the starter generator is activated in the speed window between first and second speed limits, then engine support is provided, but the dual-mass flywheel oscillates and becomes damaged
Solution Approach 1:
The control unit takes preliminary anti-action by preventing starter generator activation when the current speed falls within the critical range between the first and second speed limits. This preemptive measure avoids the harmful oscillations and potential damage before they can occur.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach prevents start aborts and reduces the risk of dual-mass flywheel damage by ensuring controlled engine startup and torque transmission, thereby protecting the drive train components.
Implementation Method 1
A starter-generator combines the functions of a starter motor and an alternator in a single electrical machine. It can thus both accelerate a motor vehicle's internal combustion engine (starting mode)
Implementation Method 2
certain boundary conditions can be considered in the following order, starting from a high speed and moving to a lower speed: Above a first speed limit, the internal combustion engine can be started and operated via speed control. A starter-generator can be used here to support the drive of the internal combustion engine.
Data Source
Figure 1~2
AI summary
The invention relates to a method for operating an internal combustion engine (1), which can be driven using a starter generator (2), in at least one operating range (3). In the operating range (3), a start/stop operation is provided, and the internal combustion engine (1) is deactivated (4), wherein a throttle valve (5) is closed, a current rotational speed (6) of the internal combustion engine (1) is greater than null and is decreasing, and the current rotational speed (6) is greater than a rotational speed window (7) in which driving the internal combustion engine (1) using the starter generator (2) is excluded in order to protect the internal combustion engine (1). The method at least has the following steps: a) ascertaining the presence of the operating range (3); b) ascertaining a request (8) to drive the internal combustion engine (1); c) initially carrying out a first actuation (10) of the starter generator (2) until the starter generator (2) has at least reached a torque threshold (11) for driving the internal combustion engine (1); and then d) carrying out a second actuation (12) of the internal combustion engine (1).