Up-converter Control for Engine Startup Power

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Solution Overview

Problem

Existing load driving apparatuses for vehicles face challenges in ensuring engine startup power, especially at extremely low temperatures where battery output is reduced and cranking resistance increases, leading to potential engine failure due to increased power loss in the up-converter and starter motor systems.

Innovation Solution

A load driving apparatus comprising a power storage device, a boosting device, and a control device that restricts the voltage boosting rate to a prescribed value when starting the internal combustion engine, ensuring the output voltage remains substantially equal to the power storage device voltage, and stops boosting when the engine is started, thereby reducing power loss and ensuring sufficient startup power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the up-converter is operated to boost voltage for engine starting, then the startup power is improved, but the power loss in the up-converter and inverter increases

Engineering Contradiction:
Improveengine startup powerVSAvoidpower loss in up-converter and inverter
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

Instead of always operating the up-converter to boost voltage, the invention inverts the approach by detecting low-temperature conditions and stopping the up-converter operation when battery output is already sufficient. This reverses the conventional wisdom that voltage boosting is always necessary for engine starting.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention changes the operational parameter of the up-converter based on temperature conditions. When temperature is below a predetermined threshold, the up-converter is stopped entirely, changing its operational state from active voltage boosting to inactive, thereby eliminating power losses in the up-converter and inverter under specific conditions.

Inventive Principle:
Principle #35Parameter changes

2Power

If the up-converter is operated at extremely low temperatures, then voltage is boosted for starting, but the battery output is significantly reduced and cranking resistance increases

Engineering Contradiction:
Improvevoltage outputVSAvoidengine starting reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The invention uses temperature detection as feedback to control up-converter operation. The temperature detecting device provides real-time temperature information to the control device, which then decides whether to operate the up-converter based on the detected temperature, creating a closed-loop control system that adapts to environmental conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention makes the up-converter operation dynamic rather than static. Instead of always operating or never operating the up-converter, the system dynamically adjusts its operation based on real-time temperature conditions, stopping operation when temperature is low and battery output is sufficient.

Inventive Principle:
Principle #15Dynamics

3Loss of energy

If the up-converter operates intermittently to reduce power loss, then energy efficiency is improved, but the voltage may be insufficient for reliable engine starting

Engineering Contradiction:
Improvepower loss reductionVSAvoidvoltage output for starting
Core Design Contradiction:
Loss of energyVSPower

Solution Approach 1:

The invention performs preliminary action by detecting temperature conditions before engine starting attempts. The temperature detecting device identifies low-temperature conditions in advance, and the control device pre-decides to stop up-converter operation, preventing unnecessary power losses before the starting process begins.

Inventive Principle:
Principle #10Preliminary action

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 solution effectively reduces power loss in the boosting and driving devices, ensuring sufficient power to start the engine even in low temperature conditions, allowing for a smaller power storage device and reliable engine startup, even when the battery output is significantly reduced.

Implementation Method 1

a boosting device (10), capable of allowing boosting of a voltage from the power storage device (B)

Methodology Applied
Scientific EffectVoltage boosting: Electromagnetic Induction

Data Source

PatentEP2011710B1Load driving apparatus, vehicle incorporating the same, and control method for load driving apparatus
Publication Date: 2012.05.16 TOYOTA JIDOSHA KK
  • EP2011710B1 patent drawingFigure 1
  • EP2011710B1 patent drawingFigure 2
  • EP2011710B1 patent drawingFigure 3~4

AI summary

An ECU estimates an output allowable power (Pmax) of a power storage device based on the temperature and SOC of the power storage device (S40). The ECU also calculates a threshold power (Pth) based on the power required to start an engine (S50). When the ECU determines that the output allowable power (Pmax) is lower than the threshold power (Pth) (YES at S60), the up-converter is controlled such that the boosting rate of the up-converter is restricted to be below a prescribed value (S70).