Gear Stage Selection Using Limited Range Evaluation
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Solution Overview
Problem
Existing gear stage selection methods for stepped transmissions in vehicles do not always provide optimal fuel efficiency due to fluctuating running loads, and current model predictive control techniques require excessive calculations, making real-time application unrealistic.
Innovation Solution
A gear stage choosing apparatus that evaluates fuel efficiency in a limited range of gear stages around the estimated vehicle speed, using a shift map to determine the optimal gear stage for changing, and a simulation apparatus generating realistic gradient and vehicle speed patterns for testing and evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If model predictive control (MPC) is used to calculate fuel efficiency for all gear stages, then fuel efficiency optimization is improved, but calculation complexity increases making real-time control unrealistic
Solution Approach 1:
The patent segments the gear stage evaluation into two parts: (1) a determined gear stage obtained from shift map based on estimated future vehicle speed, and (2) a limited range of gear stages surrounding the determined gear stage. This segmentation avoids calculating all possible gear stages while still identifying the optimal gear stage for fuel efficiency.
Solution Approach 2:
The patent applies partial action by evaluating only a subset of gear stages (those within a specific range around the determined gear stage) rather than all possible gear stages. This partial evaluation is sufficient to find the optimal gear stage while significantly reducing calculation complexity for real-time control.
2Productivity
If a shift map is used to determine gear stage based on vehicle speed, then real-time control is achieved, but fuel efficiency optimization deteriorates due to fluctuating running loads
Solution Approach 1:
The patent uses preliminary action by estimating the vehicle speed after a lapse of a first period of time (future vehicle speed) before determining the gear stage. This allows the system to anticipate future conditions and select a gear stage that will be optimal when the gear change actually occurs, improving fuel efficiency while maintaining real-time control capability.
Solution Approach 2:
The patent incorporates feedback by using the estimated future vehicle speed (which reflects anticipated running load conditions) to adjust the gear stage selection beyond what a standard shift map would provide. This feedback mechanism allows the system to adapt to fluctuating running loads while maintaining real-time control.
Data Source
AI summary
A simulation apparatus that generates a gradient pattern of a running road for a vehicle and a vehicle speed pattern for simulation. The apparatus includes a gradient pattern generation unit configured to generate a gradient pattern of a running road by sequentially deriving a gradient for each section, and a vehicle speed pattern generation unit configured to generate a vehicle speed pattern by, in a model including a lead vehicle that runs in accordance with a first vehicle speed pattern, a rearmost vehicle that runs in accordance with a first preceding vehicle following algorithm, and one or more intermediate vehicles that increase or reduce by one for each first period at an equal probability between the lead vehicle and the rearmost vehicle and that runs in accordance with the first preceding vehicle following algorithm, deriving a vehicle speed of the rearmost vehicle.