Introducing the Bright Principle

Dynamic systems use energy to do useful things. Energy must enter and exit the dynamic system for it to do useful things. Entry and exit are typically accompanied by "ringing," a phenomenon named after bells that ring after being struck.

QCW discovered how to energize a dynamic system without ringing by using the Bright Principle. This is like striking a bell without that bell ringing or plucking a guitar string without that string vibrating (ringing).

In many applications, undesirable ringing accompanies the desired dynamic system operation. Use the Bright Principle to eliminate undesirable ringing by not creating it.

Preliminaries

• Free Response. Ringing is the free response of a dynamic system. Without the Bright Principle, once a system begins to be energized the excess energy "sloshes" around until it dissipates. Various patches and filters long known in the art only partially mask and suppress the free response of dynamic systems caused by this sloshing. They can never be completely effective because they only treat the effect instead of its cause.
• Forced Response. QCW discovered how to avoid excess energy sloshing by shaping the rate at which energy enters to match the dynamic system. This is like striking the bell with a specified force over time to simply distort and/or undistort the bell without exciting it to ring. The specified force over time is the forcing function and the non-ringing distortion of the bell is its forced response. The forcing function is customized using the Bright Principle to exactly match the bell or other dynamic system.
• Transient. Flows of energy into and out of a dynamic system do not match.
• Steady State. Flows of energy into and out of a dynamic system match.
• Energy. Energy occurs in pairs of cause and effect:
  • Electrical: voltage and charge
  • Magnetic: field and flux
  • Mechanical: distance and force
  • Hydraulic: pressure and volume

Caveat. The discussion above excludes computers, which excel at iterations to empirically shape a non-ringing forced response. In contrast, using the Bright Principle to create a non-ringing forced response closed form forcing function provides all the benefits of physical insight.

Problem Statement

Traditional dynamic system mathematical modeling yields the traditional damped sinusoid solution. This has been adequate for steady-state operation of dynamic systems such as electrical transformers.

Still, modeling may yet be improved for transient energizations and de-energizations of some dynamic systems, including

• Variable Frequency Drives
• Pulse-Echo Imaging such as seismic or medical
• Aircraft Hydraulic Flight Controls

Example Solved by Discovery of Bright Principle

In the case of a diesel fuel injector, displacement or lift of the needle inside the injector, a mechanical transient, determines whether or not fuel is injected. The needle is presently operated by porting high pressure fuel to one side or the other of the needle, that porting accomplished by a small electrical solenoid valve. With this method, the needle is either closed, open, or traveling ballistically. The solenoid valve and porting create lift delays and allow only one fuel flow rate. That is, other than no or full flow, the rate at which fuel is injected cannot be modulated. By their effects on combustion, the time rate and distance of needle lift affect engine power, economy, emissions, and fuel flexibility.

QCW began an effort to reduce in-cylinder emissions generation by remedying the vintage 1913 solenoid deficiencies. Solenoids are either fast or strong. Speeding up needle lift requires both faster and strong. A durable faster and strong actuator was designed, built, and tested. (Magnetostrictive terfenol-d has a variable stiffness that can be magnetically modulated. This corresponds to the variable stiffness of an electrically modulated piezoelectric ceramic except terfenol-d offers long life on an engine.)

The new actuator was only meant to replace the solenoid, to speed up porting. The potential of this first actuator to very quickly and directly lift the needle the required distance, avoiding porting altogether, was immediately apparent in the first few tests.

Equally apparent was the need to accomplish the needle lift transient without ringing. Traditional modeling cannot accurately predict non-ringing design and operation parameters without tedious empirical iteration. Traditional modeling tends to cause overshoot and ringing when attempting a fast transient. Injector needle overshoot and ringing would be reflected by the undesired variation in the rate of fuel injection, causing engine operation problems. The amount of empirical iteration needed to accomodate lift transients with constantly changing engine load and speed became unworkable.

The focus then shifted to revising the traditional modeling, work that discovered and proved the Bright Principle. The Bright Principle solves for a forcing function that provides a forced response without need of masking and suppression of the free response of a dynamic system. The Bright Principle improves on traditional modeling by including all energy components and using polynomials instead of sinusoids. A world of lift profile possibilities has now been opened by making needle lift a scale of actuator electric input current.

Polynomial Solution

Polynomials unshackle the limitations of sinusoids. Boundary condition polarities and magnitudes may be set as desired for the chosen independent variable. For example, the injector needle velocity and acceleration can each be set to zero at both the beginning and end of a lift transient, avoiding overshoot and ringing no matter the lift or duration of the transient. The needle stops by Bright Principle input energy control through the set boundary conditions. Test proof of the Bright Principle has been obtained and published.

Summary of the Example Solved Case

To operate a very fast and continuously-variable-injection-rate diesel fuel injector, an underdamped spring-mass terfenol-d actuator directly lifts its needle. The combined actuator and needle move together as a scale of actuator input electric current. As a two-port energy in and energy out actuator, including all energy components encompasses force, distance, voltage, and charge. Any one of these components can be selected as the independent variable and the Bright Principle will solve for the remaining three dependent variables.

Application

Although developed and tested using an electromechanical actuator for a diesel fuel injector needle, the general-purpose Bright Principle applies to all dynamic systems. For the examples above

• Variable Frequency Drives may lower voltage and reduce electromagnetic interference.
• Pulse-Echo Imaging such as seismic or medical may resolve smaller features.
• Aircraft Hydraulic Flight Controls may improve ride quality.

Use of the Bright Principle eliminates the need for the trial-and-error computerized empirical approach to a non-ringing forcing function. The advantages of a closed-form solution are available, particularly those that aid dynamic system design, operation, and cost.