Fuel Injection Device Pressing Part Exhaust Throttle Control

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Solution Overview

Problem

The existing fuel injection devices experience unintentional variations in fuel injection amount due to axial deviation of the displacement-transmitting pin, which affects the exhaust amount and thus the pressure reduction time in the control chamber, leading to inconsistent fuel injection.

Innovation Solution

A fuel injection device design that includes a control chamber, a valve chest connected through a control chamber channel, an exhaust channel with a throttle part, a control valve, and a pressing part with an abutment and depressed opposite parts. The depressed opposite part is positioned to ensure that the fuel discharge is defined by the exhaust throttle part rather than the gap between the pressing part and the passage, maintaining consistent fuel injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the displacement-transmitting pin is positioned close to the exhaust port to ensure proper fuel discharge control, then the exhaust amount is defined by the gap between the pin and passage rather than the throttle part, but this causes unintentional variation in fuel injection amount due to axial deviation

Engineering Contradiction:

Improvefuel injection amount consistencyVSAvoidexhaust amount stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary structure (the pressing part with specifically designed surface features) between the displacement-transmitting pin and the exhaust port. This intermediary ensures that the exhaust amount is consistently defined by the throttle part rather than varying with pin position, thereby resolving the contradiction between manufacturing precision and reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary action by pre-positioning the pressing part at a predetermined distance from the exhaust port. This preliminary positioning ensures that even when the displacement-transmitting pin deviates axially, the exhaust amount remains stable because the pressing part's position is established in advance to maintain proper clearance

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the displacement-transmitting pin is positioned away from the exhaust port to avoid plugging, then axial deviation has less impact on exhaust amount, but the gap between the pin and passage becomes larger causing inconsistent pressure reduction time

Engineering Contradiction:

Improveexhaust channel functionalityVSAvoidpressure reduction time consistency

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The pressing part serves as an intermediary that mediates between the displacement-transmitting pin and the exhaust port. It maintains a consistent relationship with the exhaust port through its predetermined positioning, ensuring that pressure reduction time remains consistent regardless of the pin's axial position

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the positional parameter of the pressing part relative to the exhaust port, establishing a predetermined distance that optimizes the balance between avoiding pin plugging and maintaining consistent pressure reduction time. This parameter change resolves the contradiction by finding an optimal intermediate position

Inventive Principle:

Principle #35Parameter changes

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 design stabilizes the fuel injection amount by ensuring that the exhaust amount is consistently defined by the exhaust throttle part, reducing variations in pressure reduction time and maintaining consistent fuel injection, thereby suppressing unintentional variations in the fuel injection amount.

Implementation Method 1

an exhaust throttle part 13a of the exhaust channel 13 throttling the exhaust channel 13 to limit a flow rate of fuel flowing through the exhaust channel 13

Methodology Applied

Scientific EffectThrottling: Pressure Drop

Implementation Method 2

fuel pressure of a control chamber is varied with entrance and exit of the fuel into/from the control chamber, so that a nozzle needle closes/opens the injection hole

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS10895230B2Fuel injection device

Publication Date: 2021.01.19 DENSO CORP

AI summary

The pressing part includes an abutment part capable of being in contact with the inner peripheral surface of the pressing passage, and a depressed opposite part that is opposed to the exhaust port at a position away from the exhaust port in a perpendicular direction perpendicular to the displacement direction due to an outer peripheral surface of the pressing part recessed from the abutment part even when the abutment part is in contact with the inner peripheral surface of the pressing passage. When the abutment part is in contact with the inner peripheral surface of the pressing passage, a depression dimension of the depressed opposite part relative to the abutment part is set, such that an amount of fuel discharged from the valve chest is defined by the exhaust throttle part instead of a gap between the depressed opposite part and the inner peripheral surface of the pressing passage.