Vehicle Transmission Gear Selection Algorithm for Fuel Efficiency

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Solution Overview

Problem

Current automatic transmissions do not adequately consider fuel consumption when selecting gears, leading to suboptimal fuel efficiency.

Innovation Solution

A method implemented in the transmission's control unit that estimates the required driving power based on vehicle speed, accelerator pedal position, and brake pedal status to identify the optimal gear that balances fuel efficiency, comfort, and mechanical wear, using a selection logic that communicates with the engine control unit via a CAN bus to determine the gear with the highest efficiency within physical limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If gear selection is based on traditional selection logics focusing on drivability and comfort, then vehicle operation smoothness is improved, but fuel consumption increases

Engineering Contradiction:
Improvedrivability and comfortVSAvoidfuel consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The invention changes the selection criteria parameters from traditional drivability-focused metrics to include fuel consumption efficiency. The control unit evaluates multiple parameters including engine load, vehicle speed, acceleration requests, and fuel consumption maps to determine the optimal gear that minimizes fuel consumption while maintaining acceptable drivability standards.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system implements feedback by continuously monitoring actual fuel consumption, driver behavior patterns, and vehicle operating conditions. The control unit uses this feedback to adaptively adjust gear selection strategies, learning from past driving patterns to optimize fuel efficiency while maintaining drivability comfort.

Inventive Principle:
Principle #23Feedback

2Use of energy by moving object

If gear selection optimizes for fuel consumption minimization, then energy efficiency is improved, but drivability and comfort deteriorate

Engineering Contradiction:
Improvefuel consumptionVSAvoiddrivability and comfort
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The invention transforms the gear selection approach by introducing fuel consumption as a primary evaluation parameter alongside traditional drivability metrics. The control unit calculates a综合 score considering both fuel efficiency and drivability parameters, selecting gears that optimize the balance between these competing requirements rather than prioritizing fuel consumption alone.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system dynamically adjusts the weight given to fuel consumption versus drivability parameters based on current operating conditions. During normal cruising, fuel consumption weighting is increased, while during dynamic driving situations requiring quick responses, drivability weighting is prioritized, creating a dynamic balance that adapts to real-time needs.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If the control unit implements complex selection logics to optimize gear choice, then fuel consumption decreases, but device complexity increases

Engineering Contradiction:
Improvefuel consumptionVSAvoidcontrol unit complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The invention leverages the existing multi-functionality of the transmission control unit, which already handles gear selection, clutch control, and coordination with engine management. By adding fuel consumption optimization algorithms to this existing multi-functional controller, the system achieves fuel efficiency improvements without requiring separate dedicated hardware, thus limiting the increase in overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control unit utilizes data already available from other vehicle systems (engine load sensors, speed sensors, accelerator position sensors) to perform fuel consumption calculations. Rather than requiring additional specialized sensors or measurement systems, the control unit self-serves by processing existing data streams to determine optimal gear selection for fuel efficiency.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2218945B1Identification method of the optimal gear for a transmission of a vehicle
Publication Date: 2015.07.22 FAB ITAL MAGNETI MARELLI SPA
  • EP2218945B1 patent drawingFigure 1
  • EP2218945B1 patent drawingFigure 2
  • EP2218945B1 patent drawingFigure 3

AI summary

Identification method of the optimal gear (GTARGET) for a transmission (6) of a vehicle (1) provided with an engine (4); the identification method includes the steps of: measuring a proceeding speed (V) of the vehicle (1); measuring a current rotation speed (ωCURR) of the engine (4); determining a reference driving power (PREF); identifying the available gears (GAVA) which are able to make the engine (4) provide the reference driving power (PREF) at the proceeding speed (V) of the vehicle (1); calculating for each available gear (GAVA) the corresponding expected rotation speed (ωA), which would be imposed on the engine (4) according to the proceeding speed (V) of the vehicle (1) and to a transmission ratio of the gear; calculating for each available gear (GAVA) the corresponding expected torque (TA), which would be required to the engine (4) according to the reference driving power (PREF) and to the expected rotation speed (ωA); determining for each available gear (GAVA) the corresponding expected efficiency (EA) from the engine (4) according to the expected rotation speed (ωA) and to the expected torque (TA); and identifying the optimal gear (GTARGET) among the available gears (GAVA) according to the corresponding expected efficiencies (EA).