Hybrid Vehicle Power Generation Control Threshold Equalization
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Solution Overview
Problem
Conventional power generation control devices for hybrid vehicles experience control hunting and discomfort due to repeated starting and stopping of the engine, leading to increased engine noise and discomfort for occupants, especially in scenarios with frequent stops and starts like heavy traffic.
Innovation Solution
A power generation control device for hybrid vehicles that sets the series power generation start threshold and idle power generation start threshold of the battery charge capacity to the same value, preventing repeated engine starts and stops by ensuring the battery charge capacity remains within a range that does not limit the output of the first electric motor during traveling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the battery SOC threshold for starting the engine is increased during traveling to reduce noise, then the noise level is reduced, but control hunting occurs when stopping and starting is repeated, causing the engine to repeat starting and stopping which increases engine sound changes and discomfort
Solution Approach 1:
The patent applies dynamics by making the power generation control mode switchable between series power generation and idle power generation based on vehicle state. The controller dynamically selects the appropriate control mode (series or idle) according to whether the vehicle is traveling or stopped, preventing control hunting while maintaining noise reduction benefits. This is achieved by setting the same battery SOC threshold for both modes and using vehicle speed as the switching criterion.
2Object-affected harmful factors
If two different battery SOC threshold values are used (one for stopped state and one for traveling state), then noise is reduced during traveling, but control hunting occurs causing repeated engine starting and stopping
Solution Approach 1:
The patent applies segmentation by dividing the power generation control into two distinct modes: series power generation mode for traveling states and idle power generation mode for stopped states. Each mode has its own control characteristics, but both use the same battery SOC threshold. This segmentation allows the system to optimize for noise reduction in traveling while preventing control hunting in stopped states, thereby eliminating the harmful effect of repeated engine starting and stopping.
3Quantity of substance
If the engine is started frequently to charge the battery, then the battery charge capacity is maintained, but the repeated starting and stopping increases engine noise and causes discomfort
Solution Approach 1:
The patent applies periodic action through idle power generation during stopped states, where the engine operates periodically at a stable rotation speed to generate electricity and charge the battery. This periodic operation maintains battery charge capacity while avoiding the noise and discomfort associated with frequent engine starting and stopping, as the engine runs continuously at a steady state rather than undergoing repeated transitions.
Data Source
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AI summary
To provide a power generation control device for a hybrid vehicle that prevents discomfort from being imparted to the occupant in a traveling scenario in which stops and starts are repeated. A hybrid vehicle comprises a first motor/generator (MG1) that is mechanically coupled to drive wheels (19), a second motor/generator (MG2) that is mechanically coupled to an internal combustion engine (ICE), and a high-power battery (3) that is electrically coupled to two motor/generators (MG1, MG2). In this hybrid vehicle is provided a power generation controller (21), which carries out series power generation, in which electric power is generated in the second motor/generator (MG2) by the internal combustion engine (ICE) while traveling by using the first motor/generator (MG1) as the drive source, and idle power generation in which electric power is generated in the second motor/generator (MG2) by internal combustion engine (ICE) while the vehicle is stopped. This module (21) sets a series power generation start threshold (SOC1) of the battery SOC at which series power generation is started, and an idle power generation start threshold (SOC3) of the battery SOC at which idle power generation is started, to the same first common power generation start threshold (SOC1).