Method for assembling an apparatus, such as a fuel injector, using select fit of dimensional control features

A method of assembling an electronically-controlled fuel injector having a plurality of components wherein each component has an actual dimension, the injector being of the type including a set of input parameters comprising nozzle steady flow, a set of control parameters, and a set of observed performance parameters comprising timing and delivery, each control parameter being associated with one component, comprising the steps of:

• assembling a preselected number of the plurality of components into the injector wherein said preselected number is less than the number of said plurality of components;
• measuring the values of the set of input parameters, including nozzle steady flow;
• determining, for both timing and delivery observed performance parameters, the values of a corresponding set of cumulative variation parameters comprising a cumulative timing variation parameter and a cumulative delivery variation parameter using said nozzle steady flow parameter value wherein said cumulative timing and delivery variation parameters values are respectively substantially equal to a cumulative variation of a timing and delivery observed performance parameter values from timing and delivery performance parameter values in a set of predetermined target performance parameters for said assembled preselected number of components;
• determining the values of the set of control parameters as a function of said cumulative timing and delivery variation parameter values to compensate for said cumulative timing and delivery variation such that a completed assembly variation of observed timing and delivery performance parameter values from said target timing and delivery performance parameter values is reduced;
• selecting, for each control parameter, the one component associated therewith, the respective actual dimension being substantially equal to a respective desired dimension wherein said respective desired dimension is a function of said respective control parameter value;
• and,
• assembling the fuel injector by associating each selected component with nonselected ones of said plurality of components.

A method of assembling an electronically-controlled fuel injector having a plurality of components, each component having an actual dimension, the injector being of the type including a preselected set of observed performance parameters, a plurality of features wherein changes in the value of each feature are effective to vary, by a predetermined amount, the value of each observed performance parameter, each feature having a preselected set of components associated therewith, changes in the actual dimension of each component being effective to vary the value of the associated feature, comprising the steps of:

• identifying control parameters from the plurality of features for which said respective predetermined amounts are relatively large such that a set of observed performance parameter values are varied by relatively large amounts by varying a set of identified control parameter values;
• selecting, for each of said identified control parameters, components from said respectively associated sets of components whose actual dimension is sufficient to reduce, via a change in the value of the respective control parameter, an end of line variation of said observed performance parameter values from a respective parameter in a set of predetermined target performance parameter values;
• and
• assembling the fuel injector by associating said selected components with nonselected ones of said plurality of components.

A method for assembling fuel injector of the type including a set of input parameters, and a set of control parameters, comprising steps of:

• determining the values of a set of cumulative variation parameters using a set of input parameters;
• determining the value of each control parameter as a function of the set of determined cumulative variation parameter values and a set of target performance parameters such that a completed assembly of the fuel injector achieves the target performance parameters;
• and
• assembling the fuel injector such that each control parameter of the fuel injector has a value substantially equal to a respective determined control parameter value.

A method of assembling an apparatus having a plurality of components wherein each one of the components has an actual characteristic, the apparatus being of the type including a set of input parameters, a set of control parameters, and a set of observed resultant parameters, each parameter in the set of control parameters being associated with at least one of the components, the value of at least certain of each observed resultant parameter varying in relation to a change in the value of each control parameter, comprising the steps of:

• measuring the values of the set of input parameters;
• determining the values of the set of control parameters using said set of input parameter values such that a completed assembly variation of a set of observed resultant parameter values from a respective parameter in a set of predetermined target resultant parameter values is reduced;
• selecting, for each of the control parameters, the component associated therewith using the respective control parameter value determined in the step of determining the values of the set of control parameters and,
• assembling the apparatus by associating each selected component with the unselected ones of the plurality of components.