Hybrid Vehicle Control Device Engine Noise Suppression
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Solution Overview
Problem
Hybrid vehicles generate noise due to engine braking when the battery charging level exceeds a threshold, causing discomfort to drivers who expect quiet electric operation, and existing systems fail to inhibit engine braking effectively during battery charging restrictions.
Innovation Solution
A control device for hybrid vehicles that utilizes the first motor generator as an electric motor by regenerative power during braking, with the engine as a load, and restricts the mechanical brake's use when the battery charging state is above a predetermined level, ensuring no engine sound is generated until a predetermined time has elapsed or the integrated braking value exceeds a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If engine braking is performed when battery charging level is above threshold, then regenerative braking efficiency is improved, but driver comfort deteriorates due to engine noise
Solution Approach 1:
The control device applies preliminary anti-action by proactively suppressing engine braking when the battery charging level exceeds the threshold value. The control unit detects the charging level and preemptively inhibits engine brake activation, preventing the harmful engine noise from occurring in the first place, thereby protecting driver comfort before the noise can affect the driver.
Solution Approach 2:
The control device changes the operational parameters of the braking system based on battery charging level. When the charging level exceeds the threshold, the control unit modifies the braking control parameters to disable engine braking and rely solely on mechanical braking, thus changing the system's behavior to eliminate engine noise while maintaining effective braking capability.
2Object-affected harmful factors
If mechanical brake is restricted when battery charging level is above threshold, then engine noise is suppressed, but brake heat accumulation increases
Solution Approach 1:
The control device applies dynamics by making the mechanical brake restriction conditional and time-limited rather than absolute. The control unit dynamically adjusts the braking strategy based on elapsed time since vehicle start and integrated braking values, allowing mechanical brake restriction only within specific temporal and operational boundaries, thus balancing noise suppression with heat management.
Solution Approach 2:
The control device applies partial action by restricting mechanical brake usage only to the extent necessary to suppress engine noise during specific conditions (when charging level is above threshold and within predetermined time frames). The control unit partially limits mechanical brake activation rather than completely disabling it, allowing selective use of mechanical braking when needed while avoiding excessive heat accumulation.
3Loss of energy
If engine braking is inhibited during cold start charging, then battery charging efficiency is improved, but braking distance increases
Solution Approach 1:
The control device applies universality by making the second motor generator multi-functional. It serves both as a driving motor during normal operation and as a regenerative brake during braking events. When engine braking is inhibited, the second motor generator universally handles both propulsion and braking functions, enabling it to provide regenerative braking without relying on engine brake assistance, thus maintaining charging efficiency while managing braking performance.
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 solution improves driving comfort by suppressing engine noise during battery charging restrictions, maintaining quiet electric operation and preventing excessive heat generation in the mechanical brake.
Implementation Method 1
a second motor generator connected to driving wheels and configured to be driven by supplying electric power from at least one of the battery and the first motor generator
Implementation Method 2
the control device performs a control to drive the first motor generator as an electric motor by regenerative power obtained by operating the second motor generator as a generator
Data Source
AI summary
The control device for the hybrid vehicle including: an engine; a first motor generator which generates electric power by power of the engine; a battery; and a second motor generator connected to driving wheels and driven by supplying electric power from at least one of the battery and the first motor generator. In the control device, a braking control, which drives the first motor generator as an electric motor by regenerative power obtained by operating the second motor generator as a generator at the time of braking of the hybrid vehicle, and in which the engine is utilized as a load of the first motor generator, is executed when a variable representing a charging state of the battery by a level of a value is equal to or greater than a predetermined value and use of a mechanical brake of the hybrid vehicle is restricted.