Diesel Filter Joule Heating for Paraffin Clogging Prevention

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Solution Overview

Problem

The low pressure circuit of diesel pumping groups in internal combustion engines is prone to clogging due to paraffin deposition at temperatures below the Cold Filter Plugging Point (CFPP), which can prevent engine starting, especially during winter conditions.

Innovation Solution

A method involving a temperature sensor and control unit that delays engine starting and supplies electrical current to a metallic filter to heat it via the Joule effect, dissolving paraffin deposits before engine operation, ensuring the filter is clear before starting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the engine is started immediately in cold conditions, then the starting response is fast, but paraffin clogging occurs in the filter preventing diesel flow

Engineering Contradiction:
Improveengine starting delayVSAvoiddiesel flow reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The system performs preliminary heating of the filter before the engine start is attempted. The control unit activates the heating element in the filter housing when cold temperatures are detected, melting paraffin deposits in advance to ensure the filter passages are clear before diesel flow is required during engine starting.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system applies preliminary anti-action by heating the filter to prevent paraffin clogging before it can block diesel flow. The control unit monitors temperature and activates heating when the temperature is below the paraffin crystallization point, counteracting the clogging tendency before it affects engine starting.

Inventive Principle:
Principle #9Preliminary anti-action

2Reliability

If heating is applied to the filter, then paraffin clogging is prevented, but energy consumption increases

Engineering Contradiction:
Improvefilter unclogging effectivenessVSAvoidenergy consumption for heating
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system uses feedback control through a temperature sensor that continuously monitors the filter temperature. The control unit receives this temperature information and activates or deactivates the heating element based on whether the temperature is below or above the paraffin crystallization threshold, ensuring heating is applied only when necessary and minimizing energy consumption.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The heating is applied periodically or intermittently based on temperature conditions rather than continuously. The control unit activates heating only when cold temperatures are detected and deactivates it when the filter reaches the threshold temperature, creating a periodic on-off heating pattern that reduces overall energy consumption while maintaining effectiveness.

Inventive Principle:
Principle #19Periodic action

3Reliability

If a heating system is added to the filter, then paraffin dissolution is improved, but device complexity increases

Engineering Contradiction:
Improvecold temperature operation reliabilityVSAvoidheating system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The heating element is integrated into the existing filter housing structure, serving multiple functions: it heats the filter to dissolve paraffin, and its housing provides structural support and mounting for the temperature sensor. The control unit that manages heating also monitors temperature and controls engine starting, consolidating multiple functions into existing components to minimize added complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the heating function with the existing filter housing and control systems. The heating element is embedded in the filter housing, and the control unit that manages engine starting also manages the heating activation based on temperature sensor feedback, combining multiple functions into integrated subsystems rather than adding separate independent systems.

Inventive Principle:
Principle #5Merging (Combining)

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

Effectively prevents paraffin clogging by heating the filter to ensure diesel flow, allowing for reliable engine starting without prolonged delays, even in cold conditions.

Implementation Method 1

supplying electrical current to the electrical circuit connected to the filter for at least part of said period. In this way, the Joule effect means that the metallic filter supplied with electrical current heats up, leading to the breaking up of any paraffin deposited

Methodology Applied
Scientific EffectJoule effect: Joule Heating

Data Source

PatentEP3551868B1Group and method for unclogging a filter of a pumping group for pumping diesel to an internal combustion engine
Publication Date: 2023.03.29 ROBERT BOSCH GMBH
  • EP3551868B1 patent drawingFigure 1~2

AI summary

Unclogging group for unclogging a filter of a pumping group for pumping diesel to an internal combustion engine, the unclogging group comprising: - a metering unit comprising an electromagnetic head and a control valve for controlling the diesel flow; - a filter associated with the control valve made at least in part of metallic material; - a temperature sensor for measuring the ambient temperature; - a control unit coupled to the temperature sensor; - an electrical circuit controlled by the control unit for supplying electrical current to the filter; wherein the control unit is configured so once received the starting input of the pumping group it compares the temperature measured by the temperature sensor with a threshold value, and if the temperature measured by the temperature sensor is less than the threshold value the control unit commands a delay of the starting of the pumping group of a period wherein the control unit supplies electrical current to the electrical circuit connected to the filter.