Auto Hold Control Thresholds for Idle NVH Refinement
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Solution Overview
Problem
D-range neutral control logic in automatic transmission vehicles interferes with auto hold control, leading to changes in idle NVH refinement, causing customer dissatisfaction due to varying NVH levels during idle states.
Innovation Solution
Implementing a method that applies threshold values for vehicle speed, engine coolant temperature, and brake pedal effort to determine entry and maintenance of D-range neutral control, thereby limiting auto hold control interventions and maintaining refined idle noise levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If auto hold control is implemented to maintain idle state and reduce driver fatigue, then driver convenience is improved, but idle NVH refinement deteriorates due to intervention in D-range neutral control
Solution Approach 1:
The patent applies different threshold values for brake pedal effort depending on the control mode. When D-range neutral control is active, a first (stricter) threshold value is applied to prevent auto hold from interrupting the neutral control state. When D-range neutral control is not active, a second (more lenient) threshold value is applied. This parameter change resolves the contradiction by dynamically adjusting the auto hold entry conditions based on the current control state, thereby maintaining both driver convenience and idle NVH refinement.
2Object-affected harmful factors
If D-range neutral control is applied to refine idle NVH, then idle noise refinement is improved, but control system complexity increases due to interaction with auto hold logic
Solution Approach 1:
The patent segments the control logic by creating distinct control modes (D-range neutral control mode and auto hold control mode) with clearly defined entry and exit conditions. The controller determines which mode is active based on specific conditions (gear position, brake pedal effort threshold, vehicle speed, engine coolant temperature) and applies corresponding threshold values accordingly. This segmentation reduces control system complexity by avoiding continuous complex interactions between the two control logics, while still achieving refined idle NVH performance.
3Object-affected harmful factors
If threshold values are applied to limit auto hold entry conditions in D-range neutral control, then idle NVH refinement is maintained, but ease of operation may be reduced due to stricter control conditions
Solution Approach 1:
The patent implements dynamic threshold adjustment where the brake pedal effort threshold value changes based on the active control mode. When D-range neutral control is active, a first threshold value is used; when it is not active, a second threshold value is used. This dynamic approach allows the system to maintain strict control conditions only when necessary for NVH refinement, while relaxing conditions otherwise, thereby balancing idle NVH refinement with ease of operation.
Data Source
AI summary
A method for maintaining idle noise refinement in a vehicle is provided. The method may include performing a D-range neutral control, wherein a controller is configured to apply auto hold threshold values to conditions for entering an auto hold control in a neutral control state, and wherein the auto hold threshold values are determinant of an entry into the D-range neutral control such that the auto hold threshold values limit the conditions for entering the auto hold control.