Fuel Rail Heating System with Integrated Circulation Circuit

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Solution Overview

Problem

Existing fuel rail heating systems for internal combustion engines are complex and inefficient, particularly in providing precise fuel dosing and effective heating for cold starts, especially with alcohol-based fuels.

Innovation Solution

A fuel rail heating system comprising a main tube with a pipe forming a common pipe-fuel-rail-circuit, a heating device thermally coupled to the pipe and fuel rail, and a circulation pump for forced fuel circulation, enabling efficient heat transfer and fast fuel heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a conventional fuel rail heating system is used, then the fuel can be heated, but the heat transfer efficiency is low and the system is complex

Engineering Contradiction:
Improvefuel temperatureVSAvoidheating system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the heating element directly into the fuel rail structure, creating an integrated heating system where the heating element forms part of the fuel rail wall. This integration eliminates separate heating components and reduces system complexity while improving heat transfer efficiency to the fuel.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a thermal conductor or heat transfer medium between the heating element and the fuel rail cavity to improve heat transfer efficiency. This intermediary component facilitates more effective thermal energy transfer from the heating element to the fuel without requiring a complex heating system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the fuel rail volume is increased to reduce pressure fluctuations, then pressure stability improves, but the heating efficiency decreases

Engineering Contradiction:
Improvefuel pressure stabilityVSAvoidfuel heating efficiency
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The patent applies heating elements at specific locations within the fuel rail structure where fuel temperature control is most critical. By locally enhancing heat transfer at strategic positions rather than uniformly heating the entire large-volume fuel rail, the system achieves effective fuel heating while maintaining the larger rail volume needed for pressure stability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent divides the fuel rail into multiple heating zones with separate heating elements or thermal conductors positioned at different locations. This segmentation allows targeted heating of specific fuel regions, improving overall heating efficiency in large-volume rails while maintaining pressure stability through the distributed architecture.

Inventive Principle:
Principle #1Segmentation

3Productivity

If a circulation pump is added to improve fuel circulation and heat transfer, then heating efficiency improves, but device complexity increases

Engineering Contradiction:
Improvefuel heating rateVSAvoidcirculation system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent designs the fuel rail heating system to utilize the natural circulation of fuel through the rail structure for heat transfer. The heating elements are positioned to create natural convection currents that promote fuel circulation without requiring an external pump, thereby achieving effective heating while avoiding additional system complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent incorporates a controllable circulation pump that can be activated only when heating is required, rather than operating continuously or being permanently installed. This dynamic approach allows the system to achieve high heating rates when needed while maintaining simpler operation during normal fuel delivery, effectively balancing heating productivity with system complexity.

Inventive Principle:
Principle #15Dynamics

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 provides effective heat transfer, fast fuel heating, and improved cold start properties with minimal construction variations, resulting in a cost-effective and efficient fuel rail heating system, particularly suitable for engines using alcohol-based fuels.

Implementation Method 1

The heating device is thermally coupled to the main tube and/or the pipe and is designed to heat the fuel in the pipe-fuel-rail-circuit

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a good movement of the fuel in the pipe-fuel-rail-circuit is possible. Consequently, a fast heating of the fuel

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

The circulation pump is designed to enable a forced common fuel circulation in the pipe cavity and the fuel rail cavity. This has the advantage that a high heat transfer rate from the heating device to the fuel in the cavities is possible

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP2249023A1Fuel rail heating system of a combustion engine and fuel injection system
Publication Date: 2010.11.10 CONTINENTAL AUTOMOTIVE GMBH
  • EP2249023A1 patent drawingFigure 1
  • EP2249023A1 patent drawingFigure 2~3
  • EP2249023A1 patent drawing

AI summary

Fuel rail heating system (38) of a combustion engine (22) comprising a fuel rail (18) with a main tube (32), the main tube (32) having a longitudinal central axis (A), two axial ends (34a, 34b) and a fuel rail cavity (36) being designed to contain fuel, a pipe (40) being hydraulically arranged between the two axial ends (34, 34a, 34b) of the fuel rail (18) and having a pipe cavity (44), the pipe (40) and the fuel rail (18) forming a common pipe-fuel-rail-circuit (50) to enable a common fuel circulation in the cavities (36, 44), and a heating device (48). The heating device (48) is thermally coupled to the main tube (32) and/or the pipe (40) and is designed to heat the fuel in the pipe-fuel-rail-circuit (50).