Fuel Injection Pump Piston with Curved Control Edges

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Solution Overview

Problem

Existing fuel injection pumps in piston engines face challenges in optimizing fuel injection timing and pressure management across varying engine loads, leading to inefficiencies and potential excessive combustion pressure.

Innovation Solution

The piston of the fuel injection pump features two inclined control edges that adjust linearly in the axial direction to optimize fuel injection timing, advancing or retarding the start and end of fuel injection based on engine load, ensuring a smooth output curve between idle and full load, and managing combustion pressure effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the fuel injection timing is optimized for a certain engine load, then the engine efficiency is improved, but the injection timing becomes suboptimal for other load ranges

Engineering Contradiction:
Improveengine efficiencyVSAvoidinjection timing adaptability
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The piston is designed with a curved control edge that changes the axial distance between control edges dynamically based on piston position. This dynamic geometric change allows the injection timing to be automatically adjusted according to engine load without requiring multiple pistons or complex external control systems, resolving the contradiction between optimized performance at specific loads and adaptability across all loads.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the geometric parameter of the control edge from a straight line to a curved line with specific inclination variations. This parameter change allows the axial distance between control edges to vary non-linearly with piston position, enabling advanced injection timing at medium loads (60-85%) and retarded timing at high loads (85-100%), thus adapting injection timing to different operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Power

If the axial distance between control edges changes non-linearly, then injection timing can be optimized for specific loads, but the output curve of the injection pump develops discontinuities

Engineering Contradiction:
Improveinjection timing optimizationVSAvoidoutput curve continuity
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The control edge is designed with different local inclinations at different axial positions. The curvature creates locally different angles of the control edge relative to the axial direction, allowing advanced timing at medium loads while maintaining linear overall progression. This local quality variation enables load-specific optimization without creating discontinuities in the overall output characteristic.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The dynamic change in axial distance between control edges, achieved through the curved control edge geometry, allows the system to adapt injection timing continuously across the operating range. The curvature ensures that while the rate of change varies locally (enabling optimization), the overall relationship remains continuous and monotonic, preventing output curve discontinuities.

Inventive Principle:
Principle #15Dynamics

3Power

If the fuel injection starting time is advanced at medium load, then combustion efficiency is improved, but combustion pressure becomes excessive at high load

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidcombustion pressure
Core Design Contradiction:
PowerVSStress or pressure

Solution Approach 1:

The curved control edge creates a parameter change in the axial distance between control edges that varies with piston position. At medium loads (60-85%), the geometry produces a larger axial distance that advances injection timing for improved combustion efficiency. At high loads (85-100%), the geometry transitions to a smaller axial distance that retards timing, preventing excessive combustion pressure. This parameter change approach allows the system to adapt to different operating conditions automatically.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The dynamic geometric configuration of the control edge allows the injection timing to shift automatically with engine load. The curved profile ensures that at medium loads the injection is advanced for efficiency, while at high loads the timing is retarded to control peak pressure. This dynamic adaptation eliminates the need for separate control mechanisms for different load ranges.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2087226B1A piston of a fuel injection pump and a fuel injection pump
Publication Date: 2012.07.04 WARTSILA FINLAND OY
  • EP2087226B1 patent drawingFigure 1
  • EP2087226B1 patent drawingFigure 2

AI summary

A piston (4) of a fuel injection pump (1 ) of a piston engine, comprising a first inclined control edge (10) located at the side of the piston (4) for determining the starting time of the fuel injection of the injection pump (1) at a certain engine load, and a second inclined control edge (11) located at the side of the piston (4) for determining the ending time of the fuel injection of the injection pump (1) at a certain engine load. The distance between points of the first (10) and second (11) control edges corresponding to the same load in the axial direction (13) of the piston (4) changes linearly or essentially linearly at a range (A-D) corresponding to the engine idle speed and the full load.