Abstract: A heated fuel injector system and controller that includes a temperature sensing means to provide closed-loop control of a heating element heating fuel dispensed by a heated fuel injector. Closed-loop control provides more accurate temperature control of the heating element so that fuel heating is provided as quickly as possible while also protecting the fuel from being boiled and protecting the heated fuel injector from being damaged by excessive temperature. By monitoring how the signal from the temperature sensing means varies over time, fault conditions such as a lack of fuel flow, and fuel ethanol percentage may be detected.

Abstract: A heated fuel injector system and controller that includes a temperature sensing means to provide closed-loop control of a heating element heating fuel dispensed by a heated fuel injector. Closed-loop control provides more accurate temperature control of the heating element so that fuel heating is provided as quickly as possible while also protecting the fuel from being boiled and protecting the heated fuel injector from being damaged by excessive temperature. By monitoring how the signal from the temperature sensing means varies over time, fault conditions such as a lack of fuel flow, and fuel ethanol percentage may be detected.

Abstract: An improved method and apparatus for opening and closing a high performance shape memory alloy (SMA) fuel injector that minimizes performance variations due to changes in ambient temperature. When opening the injector to commence fuel injection, a relatively high voltage is applied to an SMA element of the injector to quickly heat the element to its high temperature state, quickly opening the valve. The current level is monitored as a measure of the element resistivity, and when the determined resistivity indicates that the high temperature state transition is complete, the voltage is reduced to a hold value, sufficient to continue resistivity measurement. When the determined resistivity indicates that the element is beginning to transition back to the ambient temperature state, the high voltage is re-applied to begin a new control cycle. To close the injector, the electric heating is discontinued, and fuel circulating through the injector cools the element to its ambient temperature state.

Abstract: Internal combustion engine air/fuel ratio control provides for individual engine cylinder air/fuel ratio balancing through sensing of individual cylinder air/fuel ratio and through comparison of sensed individual cylinder air/fuel ratio to a target air/fuel ratio with air/fuel ratio control command correction prescribed on a cylinder-by-cylinder basis. The target air/fuel ratio may be determined as an overall average cylinder actual air/fuel ratio. An additional control loop is provided for driving a value representing overall engine air/fuel ratio toward a desired air/fuel ratio, such as the stoichiometric ratio. Correction values are learned gradually for each engine cylinder and stored and recalled as a function of an engine operating level.