Vehicle Coasting Control Device for Fuel Efficiency
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Solution Overview
Problem
Current vehicle coasting control systems either reduce deceleration but increase fuel consumption or reduce fuel consumption but shorten coasting distance, lacking a solution for maximizing fuel efficiency.
Innovation Solution
A control device that selectively switches between two coasting control modes: one disconnecting the engine from the wheels at high loads and speeds for reduced deceleration and another using regenerative braking at lower loads and speeds to minimize electric power generation, optimizing fuel efficiency based on vehicle conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the power transmission path is disconnected by releasing the engagement device during coasting control, then the deceleration of the vehicle is reduced and coasting distance is extended, but fuel consumption increases due to maintaining engine at idle rotation speed
Solution Approach 1:
The patent dynamically switches between two coasting control modes based on real-time vehicle conditions (auxiliary machine load and vehicle speed). When auxiliary machine load is high and vehicle speed is high, the system selects first coasting control (disconnecting power transmission path) to maximize coasting distance. When auxiliary machine load is low or vehicle speed is low, it selects second coasting control (maintaining connected power transmission path with fuel cut) to minimize fuel consumption. This dynamic adaptation resolves the contradiction by optimizing the trade-off between coasting distance and fuel consumption according to operating conditions.
2Use of energy by moving object
If the engine is brought into a stop state by fuel cut during coasting, then fuel consumption is reduced, but the deceleration of the vehicle increases and coasting distance is shortened
Solution Approach 1:
The system dynamically selects between first coasting control (engine in drive state with disconnected power transmission path) for extended coasting distance and second coasting control (engine in stop state with connected power transmission path) for reduced fuel consumption. The selection is based on auxiliary machine load and vehicle speed thresholds, allowing the system to adaptively resolve the contradiction between fuel consumption reduction and coasting distance maintenance.
3Loss of energy
If regenerative control is performed through electric power generation of the generator in the second coasting control, then additional energy is recovered, but the deceleration of the vehicle increases further
Solution Approach 1:
The patent incorporates regenerative control as an optional feature within the second coasting control mode. When selected, the generator performs electric power generation to recover energy that would otherwise be lost, but this increases deceleration due to the additional load on the engine. The system dynamically determines whether to activate regenerative control based on battery state of charge and vehicle conditions, balancing energy recovery benefits against the impact on coasting distance.
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
The system achieves a larger fuel efficiency improvement by adjusting coasting control strategies according to load and speed conditions, extending coasting distance while reducing fuel consumption.
Implementation Method 1
the coasting control portion is configured to provide a regenerative control through electric power generation of the generator in the second coasting control
Data Source
AI summary
A control device of a vehicle including an engine, an auxiliary machine driven by rotation of the engine, and an engagement device selectively connecting and disconnecting a power transmission path between the engine and drive wheels comprises: a coasting control portion for selectively providing a first coasting control for allowing the vehicle to coast with the engine brought into a drive state while the power transmission path is disconnected by release of the engagement device, and a second coasting control for allowing the vehicle to coast with the engine brought into a stop state while the power transmission path is connected. If a load of the auxiliary machine is equal to or greater than a predetermined load and a vehicle speed is equal to or greater than a predetermined vehicle speed when a predetermined coasting start condition is satisfied, the coasting control portion provides the first coasting control.