Fuel Injection Control Device Voltage Stability

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Solution Overview

Problem

Existing fuel injection control devices face challenges in accurately controlling the boosted voltage applied to fuel injection valves, leading to variations in fuel injection amounts, especially when the width of the fuel injection driving pulse is small, and result in increased device size and cost due to the need for multiple capacitors and high current leakage.

Innovation Solution

A booster circuit with a voltage detection unit that starts the boosting operation at a predetermined timing when the detected voltage is higher than the threshold for starting boosting and lower than the threshold for stopping boosting, allowing for precise control of the boosted voltage applied to the fuel injection valve without increasing the device's size or cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the width of the fuel injection driving pulse is small, then the fuel injection amount can be precisely controlled, but the boosted voltage decreases significantly causing injection amount variation

Engineering Contradiction:

Improvefuel injection amount control precisionVSAvoidinjection amount consistency

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The boosting operation control circuit starts the boosting operation in advance before the fuel injection driving pulse is applied, ensuring that the boosted voltage has not yet significantly decreased when injection occurs. This preliminary action maintains voltage stability during small pulse width injections, preventing injection amount variation while preserving precise control capability.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If multiple capacitors are used to maintain voltage stability, then the fuel injection amount consistency is improved, but the device size and cost increase

Engineering Contradiction:

Improvefuel injection amount consistencyVSAvoiddevice size and component count

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using multiple capacitors to store energy, the system performs preliminary boosting before each fuel injection event. The boosting operation control circuit monitors the driven voltage and initiates boosting when voltage decreases, ensuring sufficient voltage is available for precise injection control without requiring additional capacitive energy storage components.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the passive energy storage approach (multiple capacitors) with an active voltage regulation approach (boosting operation control). The control circuit actively manages voltage levels by triggering boosting operations as needed, substituting the need for multiple energy storage capacitors with intelligent control of a single boosting system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the boosting operation starts only when voltage reaches the threshold for starting boosting, then the device complexity is reduced, but the fuel injection amount control precision deteriorates

Engineering Contradiction:

Improvecontrol circuit simplicityVSAvoidfuel injection amount control precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

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

This solution enables accurate control of the boosted voltage and fuel injection amount, reducing voltage decrease and ensuring consistent fuel injection, even with a small fuel injection driving pulse width, without increasing the device's size or cost.

Implementation Method 1

a booster circuit to generate high voltage from a battery voltage is generally included

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The fuel injection control device applies current to the boosting coil L1 by turning the switching element for boosting T1 on during boosting. By turning the switching element for boosting T1 off after energy is accumulated into the boosting coil L1, the fuel injection control device accumulates the energy, which is accumulated into the boosting coil L1, into the boosting capacitor C1 through the boosting diode D1.

Methodology Applied

Scientific EffectElectromagnetic energy storage: Inductor

Data Source

PatentEP3051109B1Internal-combustion-engine fuel injection control device

Publication Date: 2020.03.18 HITACHI AUTOMOTIVE SYST LTD

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AI summary

An internal-combustion-engine fuel injection control device which can accurately control a boosted voltage applied to a fuel injection valve during fuel injection and can control a variation in a fuel injection amount without increasing a size or a cost of the fuel injection control device even when a width of a fuel injection driving pulse to drive the fuel injection valve is small is provided. A fuel injection control device 127 includes a boosting operation control unit 15 configured to start a boosting operation at predetermined timing regardless of an amount of a detected voltage when the detected voltage is higher than a threshold voltage for starting boosting and is lower than a threshold voltage for stopping boosting.