Engine Control Unit Adaptive Idling-Stop Road Grade Thresholds

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Solution Overview

Problem

Existing engine control systems for vehicles face challenges in balancing the avoidance of unexpected vehicle behaviors during idling stops with improved fuel efficiency, as they either prioritize fuel efficiency at the cost of behavior control or vice versa, and struggle with accurate road-grade estimation and device abnormality diagnosis.

Innovation Solution

An engine control unit that includes an idling-stop controller, idling-start controller, and road-grade acquirer to determine coasting-state and stationary-state idling-stop conditions based on accurate road-grade estimation and device diagnosis, allowing for safe and frequent idling stops across various road grades and states, while inhibiting stops during device abnormalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If idling-stop is performed during coasting at any speed condition, then fuel efficiency is improved, but unexpected vehicle behaviors may occur during idling-stop

Engineering Contradiction:
Improvefuel efficiencyVSAvoidvehicle behavior control
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies parameter changes by implementing different road-grade thresholds for coasting-state idling-stop conditions compared to stationary-state conditions. Specifically, the coasting-state idling-stop condition uses a first road-grade threshold that is lower than the second road-grade threshold used for stationary-state, allowing the system to adaptively adjust operation parameters based on vehicle state to improve fuel efficiency while maintaining safety

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the idling-stop control strategy adaptive to different vehicle states (coasting vs. stationary). The system dynamically selects different road-grade thresholds and speed conditions based on whether the vehicle is coasting or stationary, enabling flexible control that responds to real-time operating conditions rather than using fixed parameters

Inventive Principle:
Principle #15Dynamics

2Productivity

If road-grade threshold is lowered to allow more idling-stops, then fuel efficiency improves, but accuracy of road-grade estimation becomes more critical

Engineering Contradiction:
Improveidling-stop frequencyVSAvoidroad-grade estimation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies beforehand cushioning by incorporating device abnormality diagnosis functionality that proactively monitors the road-grade estimation system and other critical components. The diagnoser detects abnormalities in advance and prevents idling-stop operations when estimation accuracy may be compromised, providing a safety buffer that allows the system to operate at lower road-grade thresholds without risking unexpected behaviors

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent implements feedback through the diagnoser that continuously monitors device status and road-grade estimation quality. When abnormalities are detected in the estimation system or related devices, the feedback mechanism prevents idling-stop operations, creating a closed-loop control system that adapts to measurement quality and maintains reliability while maximizing fuel efficiency

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2808536B1Engine control unit
Publication Date: 2019.12.11 MITSUBISHI MOTORS CORP
  • EP2808536B1 patent drawingFigure 1
  • EP2808536B1 patent drawingFigure 2
  • EP2808536B1 patent drawing

AI summary

A coasting-state idling-stop condition includes a road-grade (θ) acquired by a road-grade acquirer (11) being not higher than a first coasting-state road-grade (θPC1), before an initial automatic stop of an engine (1) by an idling-stop controller (15). A coasting-state idling-stop condition includes the road-grade (θ) acquired by the road-grade acquirer (11) being not higher than a second coasting-state road-grade (θPC2) higher than the first coasting-state road-grade (θPC1), after the initial automatic stop of the engine (1) by the idling-stop controller (15).