Engine Speed Buffering for Powertrain Noise Reduction
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Solution Overview
Problem
Existing vehicle powertrain systems experience noticeable engine speed fluctuations in response to varying electrical load demands from external power consumers, leading to inefficient fuel consumption and potential annoyance to nearby individuals.
Innovation Solution
A powertrain operating method that utilizes a memory buffer to store and process requested instantaneous engine rotational speed values, allowing for smooth adjustments to meet power demands without frequent engine speed changes, thereby maintaining efficiency and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If engine speed is increased and decreased responsive to load changes generated by external electric power consumers, then electrical power demands are met, but engine speed fluctuations become noticeable and objectionable to persons proximate to the vehicle
Solution Approach 1:
The system performs preliminary action by storing multiple instantaneous engine speed requests in a buffer before executing the final speed adjustment. This buffer allows the system to anticipate and smooth out rapid load changes from external power consumers, preventing frequent engine speed fluctuations that would cause noise and annoyance while still meeting electrical power demands.
2Use of energy by moving object
If engine operates at idle speed, then fuel consumption is reduced, but engine may not generate sufficient power to meet demands of external power consumers
Solution Approach 1:
The system applies dynamics by enabling the engine to operate at idle speed under normal conditions to minimize fuel consumption, while dynamically adjusting to higher speeds only when electrical load demands exceed idle capacity. The buffer system allows smooth transitions between operating states, maintaining fuel efficiency while ensuring sufficient power availability when needed.
3Adaptability or versatility
If engine speed is adjusted frequently to meet varying electrical loads, then power demands are met, but engine speed cycling increases and reduces operational efficiency
Solution Approach 1:
The buffer stores multiple instantaneous engine speed requests and processes them systematically, performing preliminary filtering of rapid load changes. This allows the engine to respond adaptively to genuine load variations while ignoring transient fluctuations, thereby maintaining operational efficiency by reducing unnecessary speed cycling.
4Object-affected harmful factors
If conventional first order low pass filters are used to smooth engine speed changes, then noise is reduced, but response time to new buffer inputs is delayed
Solution Approach 1:
Instead of using conventional low pass filters that delay response, the system performs preliminary action by storing requests in a buffer and systematically processing them to identify the maximum instantaneous speed requirement. This approach reduces noise from frequent small adjustments while maintaining fast response to genuine load changes, eliminating the trade-off between smoothing and responsiveness.
Data Source
AI summary
Systems and methods for operating a vehicle that includes an engine and an electric machine are described. In one example, a speed of the engine may be adjusted so that the engine provides power to drive the electric machine without generating numerous rapid engine speed changes in a short amount of time.