Mechanical Pressure Control in High-Pressure Fuel Pumps

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Solution Overview

Problem

High-pressure fuel pumps for internal combustion engines often require complex and costly electronic control systems, additional hydraulic lines, and space-consuming designs, which increase costs and reduce efficiency.

Innovation Solution

A compact high-pressure fuel pump design that integrates a mechanical pressure control device between the low-pressure and high-pressure areas, eliminating the need for a quantity control valve and pressure sensor, using a spring-loaded check valve and throttle to maintain constant pressure, and allowing for eccentric placement of the pressure control valve within the pump housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a complex electronic quantity control system is used, then fuel pressure control precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvefuel pressure control precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the electronic quantity control system with a purely mechanical pressure control device. The pressure control valve uses a spring-loaded mechanism to mechanically regulate fuel pressure based on pressure differential across the valve, eliminating the need for electronic sensors, actuators, and control circuits while maintaining adequate pressure control for the application.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The pressure control device operates autonomously using the fuel pressure itself to actuate the control valve. When pressure in the high-pressure area exceeds the spring force, the valve automatically opens to relieve pressure, creating a self-regulating system that requires no external power source or electronic control.

Inventive Principle:
Principle #25Self-service

2Productivity

If a quantity control valve with electrical control line is added, then fuel quantity control is improved, but installation space and device complexity increase

Engineering Contradiction:
Improvefuel quantity controlVSAvoidinstallation space
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent extracts and eliminates the quantity control valve and its associated electrical control components from the fuel pump system. The design accepts that precise fuel quantity control is not necessary for the application, thereby removing the space-consuming valve assembly and electrical wiring from the engine compartment.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stress or pressure

If additional hydraulic lines are added for pressure control, then pressure regulation capability is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improvepressure regulation capabilityVSAvoidhydraulic line complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The patent merges the pressure control function directly into the existing fuel pump housing. The pressure control valve is integrated within the pump body, using the same hydraulic passages that already exist for fuel delivery. This eliminates the need for separate hydraulic lines and reduces the number of connection points and potential leak paths.

Inventive Principle:
Principle #5Merging (Combining)

4Measurement precision

If a pressure sensor and electronic control device are used, then pressure measurement precision is improved, but manufacturing cost and device complexity increase

Engineering Contradiction:
Improvepressure measurement precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive electronic pressure sensors and control units with an inexpensive mechanical spring-loaded valve. The mechanical device provides sufficient pressure regulation without requiring precision electronics, significantly reducing component cost and manufacturing complexity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The solution results in a cost-effective, space-efficient, and reliable high-pressure fuel pump that reduces wear and maintains constant pressure in the high-pressure area, eliminating the need for additional components and reducing engine power consumption.

Implementation Method 1

a mechanical pressure control device which is integrated in the high-pressure pump... a mechanical, for example spring-loaded, check valve

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

a mechanical throttle is arranged upstream of a valve element of the pressure control device, so that negative effects on the control behavior in the fuel rail, especially when using one-cylinder fuel pumps, due to undesirable pressure pulsations of the high-pressure pump are reduced

Methodology Applied
Scientific EffectThrottling: Pressure Drop

Data Source

PatentEP2344749B1High-pressure fuel pump for an internal combustion engine
Publication Date: 2016.05.04 ROBERT BOSCH GMBH
  • EP2344749B1 patent drawingFigure 1
  • EP2344749B1 patent drawingFigure 2
  • EP2344749B1 patent drawingFigure 3

AI summary

The invention relates to a high-pressure fuel pump (10) for an internal combustion engine with direct injection, comprising a pump housing (58), a low-pressure region (12) on the intake side, and a high-pressure region (14) on the output side. The high-pressure fuel pump (10) comprises a purely mechanical pressure regulating device (54) for regulating a constant pressure in the high-pressure region (14).