Hybrid Vehicle Range Control Under Generator Power Shortage

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Solution Overview

Problem

In series hybrid vehicles, if the generating power output of the electric generator is lower than the required running power output, the vehicle cannot continue high-load drives, and the estimated total distance to empty is inaccurate, leading to driver discomfort due to unexpected power output drops.

Innovation Solution

A control method for hybrid vehicles that calculates an actual distance to empty by distinguishing between high-load and low-load running conditions, using different methods to estimate total distance to empty based on the remaining battery charge and fuel, and adjusting for the limitations of the fuel cell stack's power output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the generating power output of the electric generator is lower than the required running power output, then the vehicle cannot continue high-load drives, but the estimated total distance to empty becomes inaccurate

Engineering Contradiction:
Improvedistance to empty estimation accuracyVSAvoidvehicle running reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the distance to empty calculation into two distinct components: a first distance to empty based on battery charge availability and a second distance to empty based on fuel generator availability. By calculating these separately and then combining them, the system accurately reflects the actual running distance without overestimating, thus resolving the contradiction between measurement precision and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the distance to empty estimation based on real-time conditions, including battery charge state, fuel level, and generator power output characteristics. This dynamic calculation ensures the estimation remains accurate across varying operating conditions while maintaining reliability information for the driver.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the battery charge is depleted, then the vehicle can switch to generator power, but the vehicle cannot maintain required power output during high-load conditions

Engineering Contradiction:
Improvepower source switching capabilityVSAvoidpower output sufficiency
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The patent dynamically evaluates the vehicle's power capability by considering both battery charge state and generator power output. The system adapts the distance to empty calculation based on the current power configuration, recognizing when the generator alone can or cannot meet the required power output. This dynamic approach maintains adaptability in power source selection while providing realistic power sufficiency information.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the total distance to empty is calculated by simply adding battery-based and fuel-based distances, then the calculation is simple, but the result overestimates the actual running distance

Engineering Contradiction:
Improvecalculation method complexityVSAvoiddistance to empty accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the overall distance to empty into a first distance to empty (battery-dependent) and a second distance to empty (fuel-dependent). Rather than simply adding the two distances, the system processes them through a specific calculation that accounts for power output limitations, achieving accurate results without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system incorporates feedback regarding generator power output characteristics into the distance calculation process. By using the calculated first and second distances to empty along with generator power output information, the system refines the total distance estimate to reflect actual running capabilities, improving accuracy while maintaining reasonable computational complexity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3666586B1Method and device for controlling hybrid vehicle
Publication Date: 2024.02.28 NISSAN MOTOR CO LTD
  • EP3666586B1 patent drawingFigure 1
  • EP3666586B1 patent drawingFigure 2A~2B
  • EP3666586B1 patent drawingFigure 2C~2D

AI summary

According to a control method for a hybrid vehicle that is caused to run by a drive motor as a load being supplied with electric power of a battery and electric power generated by an electric generator, a total distance to empty is calculated on the basis of a shortage of a generating power output of the electric generator with respect to a required running power output and an amount of charge remaining in the battery. Specifically, a length of time for which the shortage of the generating power output of the electric generator with respect to the required running power output is covered by the amount of charge remaining in the battery is calculated, and a distance that the hybrid vehicle can run for this length of time is set as a total distance to empty.