Fuel Injection Piston Pressure Balancing Without Restoring Spring
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Solution Overview
Problem
Existing fuel injection systems for compression ignition engines, such as those described in U.S. Pat. No. 6,805,101 B2, require additional components like restoring springs to increase fuel pressure, which increase manufacturing costs and are prone to wear under high pressures.
Innovation Solution
A fuel injection system with a piston that divides a housing into multiple chambers, allowing selective connection to high and low pressure fuel sources to balance forces and displace the piston without a spring, thereby increasing fuel pressure for injection into the combustion chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a restoring spring is used to return the piston to its initial position, then the piston can be returned after fuel pressure increase, but the manufacturing cost increases and the components experience wear due to high pressures
Solution Approach 1:
The patent removes the restoring spring from the system entirely. Instead of using a mechanical spring to return the piston, the system uses a solenoid assembly that can actively control piston displacement in both directions through electromagnetic force, eliminating the need for a restoring spring and its associated manufacturing costs and wear issues
Solution Approach 2:
The patent replaces the mechanical restoring spring system with an electromagnetic control system. The solenoid assembly uses electromagnetic fields to control piston movement, substituting a passive mechanical return mechanism with an active electromagnetic control mechanism that can precisely control piston position without mechanical wear
2Reliability
If a restoring spring is used to return the piston to its initial position, then the piston can be returned after fuel pressure increase, but the device complexity increases due to additional components
Solution Approach 1:
The patent removes the restoring spring from the system entirely. Instead of using a mechanical spring to return the piston, the system uses a solenoid assembly that can actively control piston displacement in both directions through electromagnetic force, eliminating the need for a restoring spring and its associated manufacturing costs and wear issues
Solution Approach 2:
The solenoid assembly performs multiple functions: it can displace the piston to increase fuel pressure, return the piston to its initial position, and potentially control the timing and duration of pressure increases. This multi-functional approach reduces the overall number of components needed in the system
3Stress or pressure
If additional components like restoring springs are added to increase fuel pressure, then fuel pressure can be increased, but the components are prone to wear under high pressures
Solution Approach 1:
The patent replaces the mechanical restoring spring system with an electromagnetic control system. The solenoid assembly uses electromagnetic fields to control piston movement, substituting a passive mechanical return mechanism with an active electromagnetic control mechanism that can precisely control piston position without mechanical wear
Solution Approach 2:
The system uses the high pressure fuel itself to help return the piston to its initial position. When the solenoid assembly opens the fuel passage, the high pressure fuel flows through the piston, utilizing the fuel's own pressure to reset the system without requiring additional mechanical components
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 system effectively increases fuel pressure for injection without the need for additional components like restoring springs, reducing manufacturing costs and wear, and allows for efficient fuel injection by balancing pressure forces within the system.
Implementation Method 1
selectively supplying fuel at the first pressure to the third chamber to displace the piston to a first position. The piston is movable to a second position when the third chamber is selectively connected to the low pressure fuel source
Implementation Method 2
balancing pressure forces within the system to displace the piston without a spring
Implementation Method 3
supplying fuel at a first pressure to the first chamber and the second chamber. The first pressure being greater than the second pressure
Data Source
AI summary
An assembly is disclosed having a high pressure fuel source, a low pressure fuel source, and a housing. The assembly also has a piston disposed within the housing and dividing the housing into a first chamber, a second chamber, a third chamber, and a fourth chamber. The first and second chambers are fluidly connected to the high pressure fuel source. The third chamber is selectively fluidly connected to the high pressure fuel source and the low pressure fuel source, and the fourth chamber is fluidly connected to the low pressure fuel source. The piston is movable from a first position when the third chamber is selectively connected to the high pressure fuel source. The piston is movable to a second position when the third chamber is selectively connected to the low pressure fuel source.