Abstract: An adaptive fuel control system and method directed for use in a motor vehicle powered by a fuel-injected engine and having a fuel tank and a fuel rail and which is operative to run on a plurality of fuels and fuel blends. The system includes a refueling mixer which acts as a fluid damper to slowly introduce new fuel into the fuel rail and correspondingly slow the rate at which new fuel composition is mixed with existing fuel. A stratification mixer is also utilized to re-mix components of blended fuels which may have separated at cold temperatures. An Exhaust Gas Oxygen sensor (EGO) monitors engine exhaust gases and generates a corresponding electrical signal when the air/fuel mixture of the fuel switches between rich and lean. Finally, an electronic control assembly communicates with the EGO and the fuel injectors to generate and store in memory an updatable extended adaptive fuel control table of air/fuel ratio multipliers for selected engine load/engine speed cells.

Abstract: A heated exhaust gas oxygen sensor assembly for an internal combustion engine that changes the heater status in order to detect a malfunction of the heater. The assembly includes an oxygen sensor, heater, impedance sensor, and controller. The oxygen sensor has a sensing element and a pair of output leads. The sensing element detects the relative oxygen concentration in the exhaust gas and responsively provides an oxygen level signal on the output leads. The heater physically warms the oxygen sensor. The impedance sensor is interconnected to the output leads of the oxygen sensor and measures the impedance between them. The controller first activates and then deactivates the heater. The controller also receives the impedance signals representing the impedance of the oxygen sensor when the heater is both on and off.

Abstract: A heated exhaust gas oxygen sensor assembly that automatically detects whether the heater in the assembly is malfunctioning. The assembly includes an oxygen sensor, heater, impedance sensor, and controller. The oxygen sensor detects the relative oxygen concentration in the exhaust gas of an internal combustion engine and issues signal along a pair of output leads. The heater physically warms the oxygen sensor. The impedance sensor is interconnected to the output leads of the oxygen sensor and provides an impedance measurement to the controller. The controller compares the impedance to a predetermined threshold value to judge the effect of the heater in physically warming the sensor. If the impedance is above a predetermined threshold, the controller determines that the heater is not operating properly and issues an alarm signal.