Engine Load Control for Gear Shift Quality
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Solution Overview
Problem
High-inertia flywheels in motor vehicles with combustion engines lead to slower gear changes and transmission jerk due to reduced engine speed response, as they hinder the rate at which the engine can slow down or speed up during gear changes.
Innovation Solution
A motor vehicle system with an electronically controlled, variable load mechanism, such as a variable displacement oil pump, engine coolant pump, air conditioner pump, fuel pump, or electrical generator, that adjusts load levels during gear changes to enhance the gear change quality by increasing load during upshifts and decreasing load during downshifts, thereby optimizing engine speed synchronization with the gearbox.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a flywheel of high inertia is used to reduce vibrations and improve refinement, then vibration reduction is improved, but the engine speed response during gear changes deteriorates
Solution Approach 1:
The electronic controller modifies the load on the combustion engine in advance of the gear change event based on predicted gear change type. By preliminarily adjusting the load before the gear change occurs, the system prepares the engine for the upcoming speed change, enabling faster response despite the high-inertia flywheel's natural resistance to speed changes.
Solution Approach 2:
The system applies a counteracting load modification before the gear change to offset the detrimental effect of high flywheel inertia. By increasing load before an upshift or decreasing load before a downshift, the system creates a preliminary counter-force that helps overcome the flywheel's resistance to speed change, enabling faster engine speed response during the gear change event.
2Object-affected harmful factors
If the engine speed response is slowed by high-inertia flywheel, then vibration refinement is improved, but the gear change quality deteriorates due to slower gear change rate and speed mismatch
Solution Approach 1:
The electronic controller predicts the gear change type and modifies the engine load in advance, preparing the engine for the upcoming speed transition. This preliminary load adjustment enables the engine to respond faster during the gear change, improving gear change quality without requiring a reduction in flywheel inertia.
Solution Approach 2:
The system dynamically changes the load parameter on the combustion engine during gear change events. By modifying the load parameter (increasing before upshifts, decreasing before downshifts), the system alters the engine's speed response characteristics temporarily, enabling faster gear changes while maintaining the benefits of high-inertia flywheel during normal operation.
3Object-affected harmful factors
If the engine speed response is reduced by high-inertia flywheel, then vibration refinement is improved, but transmission jerk increases due to speed mismatch at clutch re-engagement
Solution Approach 1:
The system applies a counteracting load modification before the gear change to offset the detrimental effect of high flywheel inertia. By increasing load before an upshift or decreasing load before a downshift, the system creates a preliminary counter-force that helps overcome the flywheel's resistance to speed change, reducing speed mismatch and transmission jerk at clutch re-engagement.
Solution Approach 2:
The electronic controller dynamically adjusts the load parameter during gear change events to optimize engine speed response. By temporarily changing the load parameter based on predicted gear change type, the system reduces speed mismatch between engine and gearbox, thereby minimizing transmission jerk when the clutch is re-engaged.
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 reduces transmission jerk and improves gear change quality by allowing faster engine speed adjustments and synchronization with the gearbox, minimizing energy dissipation during gear changes.
Implementation Method 1
The at least one electrically controllable load according to the invention is a variable displacement oil pump, increasing the load applied to the combustion engine may comprises increasing the displacement of the oil pump and decreasing the load applied to the combustion engine may comprise reducing the displacement of the oil pump
Implementation Method 2
a multi-speed gearbox driveably connectable to the combustion engine by a friction clutch
Implementation Method 3
There is an ongoing need to improve the refinement of motor vehicles having internal combustion engines and one way of improving refinement is to reduce vibrations generated by fluctuations in engine rotational speed by increasing the inertia of the flywheel of such an engine
Data Source
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AI summary
A motor vehicle 5 is disclosed having an engine 10 driving a multi-speed gearbox 15 via a friction clutch 12. The engine 10 is arranged to drive a number of electrically controllable loads 20 the level of load applied by each of which to the engine 10 is controlled by an electronic controller 50 in response to a number of inputs 30. When the inputs 30 indicate that an upshift of the gearbox 15 is to take place the electronic controller 50 is arranged to increase the loads applied by the electrically controllable loads 20 to the engine 10 and when the inputs 30 indicate that a downshift of the gearbox 15 is to take place the electronic controller 50 is arranged to decrease the loads applied by the electrically controllable loads 20 to the engine 10 thereby improving the quality of the gear change irrespective of whether it is an upshift or a downshift.