Series Hybrid Engine Speed Control During Vehicle Deceleration
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Solution Overview
Problem
In series hybrid electric vehicles, the internal combustion engine's rotation speed remains high during deceleration, leading to a strange driver experience and decreased marketability, as existing technologies do not effectively link engine operation sound with vehicle speed during deceleration.
Innovation Solution
A vehicle control device that executes fuel cut control and adjusts the internal combustion engine's rotation speed based on a predetermined target speed, using fuel cut control during deceleration requests to manage the rotation speed difference between the engine and target speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the internal combustion engine is operated steadily at the highest efficiency operating point, then fuel efficiency is improved, but the operation sound does not change with vehicle speed, causing driver strangeness and reduced marketability
Solution Approach 1:
The patent applies dynamics by making the engine rotation speed adjustable and variable based on vehicle operating conditions. Instead of fixed steady-state operation, the engine speed dynamically changes with vehicle speed during series traveling, creating a natural correlation between engine sound and vehicle motion that drivers expect, while still maintaining fuel efficiency through optimized control strategies.
Solution Approach 2:
The patent changes the operating parameters of the internal combustion engine, specifically the rotation speed, to correlate with vehicle speed. By adjusting the engine rotation speed parameter according to vehicle speed during series traveling, the system maintains fuel efficiency while producing natural-sounding engine operation that matches driver expectations from conventional vehicles.
2Power
If the rotation speed of the internal combustion engine is kept high during deceleration, then power availability is maintained, but driver experience deteriorates due to strange feeling and marketability decreases
Solution Approach 1:
The patent applies dynamics by implementing dynamic adjustment of engine rotation speed during deceleration events. The engine speed is reduced when deceleration is detected, creating a natural correlation between vehicle deceleration and engine sound reduction. This dynamic response maintains driver comfort and natural feeling while power availability is managed through the series hybrid architecture and electric motor assistance.
Data Source
AI summary
A vehicle control device is configured to: execute fuel cut control for stopping fuel supply to an internal combustion engine; when a vehicle is in series traveling, perform control based on a traveling state of the vehicle such that a rotation speed of the internal combustion engine is a predetermined target rotation speed; and when the vehicle is in the series traveling and there is a deceleration request, execute the fuel cut control in accordance with a rotation speed difference between a rotation speed of the internal combustion engine and the target rotation speed.