Abstract: Techniques are presented for synchronous rectification control (SRC) of a DC-DC converter in an electrified vehicle (EV) can include determining a required output current for the DC-DC converter based on a secondary voltage of a secondary battery system of the EV, the DC-DC converter being configured to convert a primary voltage from a primary battery system of the EV to the secondary voltage. The techniques can include determining, at the controller, a switching frequency for the DC-DC converter that causes the DC-DC converter to output the required output current. The techniques can include determining turn-on and turn-off delays of the DC-DC converter based on the required output current and the switching frequency using one or more look-up tables. The techniques can also include controlling the DC-DC converter efficiency based on the turn-on and turn-off delays.

Abstract: Techniques are presented for synchronous rectification control (SRC) of a DC-DC converter in an electrified vehicle (EV) can include determining a required output current for the DC-DC converter based on a secondary voltage of a secondary battery system of the EV, the DC-DC converter being configured to convert a primary voltage from a primary battery system of the EV to the secondary voltage. The techniques can include determining, at the controller, a switching frequency for the DC-DC converter that causes the DC-DC converter to output the required output current. The techniques can include determining turn-on and turn-off delays of the DC-DC converter based on the required output current and the switching frequency using one or more look-up tables. The techniques can also include controlling the DC-DC converter efficiency based on the turn-on and turn-off delays.

Abstract: A method is provided for triggering a system for learning the percent alcohol content of a fuel used in a motor vehicle capable of operating on more than one type of fuel. The fuel composition learning system is triggered each time fuel is added to the vehicle's fuel tank, each time the engine is started when the fuel volume in the fuel tank falls below a given value or if a fuel level sending unit malfunction has been detected. The fuel composition learning system is also triggered if an error is detected in the value of the learned percent alcohol content of the fuel.

Abstract: The present invention provides a method of compensating for changing fuels in a flexible fueled vehicle using a fuel composition sensor. The methodology detects and models an alcohol concentration transition at fuel injector tips following a fuel addition. The methodology improves the accuracy of engine fueling during an alcohol concentration change by delaying the application of a fuel composition multiplier until the fuel analyzed by the fuel composition sensor actually reaches the injectors.

Abstract: The present invention provides a flexible fuel compensation system for controlling operating parameters of an internal combustion engine based on a learned value of the percent alcohol content of the fuel using an oxygen feedback system. The methodology determines a fuel composition multiplier based on the percent alcohol content and implements gasoline operating parameters for the internal combustion engine if the fuel composition multiplier is less than a first threshold value, mixed gasoline/alcohol operating parameters if the fuel composition multiplier is greater than the first threshold value, and high concentration alcohol operating parameters if the fuel composition multiplier is greater than a second threshold value for a number of comparison checks. After a predetermined period, the fuel composition multiplier is updated and re-compared to the first and second thresholds and the appropriate one of the aforementioned operating parameters is implemented.

Abstract: The present invention provides a method for controlling the combustion parameters of an internal combustion engine with an oxygen sensor prior to a closed loop operating condition. If the output voltage of the oxygen sensor indicates a lean air to fuel ratio condition, the percent alcohol content is incremented to a limit based on an E85 possibility curve. If the voltage output of the oxygen sensor indicates a rich air to fuel ratio condition, the percent alcohol content is decremented to a limit based on an E0 possibility curve. After the end of the fuel blending period or when the internal combustion engine reaches a closed loop mode, control of the combustion parameters of the internal combustion engine are returned to normal regime oxygen sensor feedback control.

Abstract: The present invention provides an apparatus for limiting the occurrence of knock conditions in an internal combustion engine. The apparatus includes a throttle sensor that detects transition of an engine throttle from a steady state throttle condition to a wide open throttle condition. Further, spark means is provided for generating a spark for an engine cylinder firing event, with the spark means generating the spark with an associated spark advance. Further, a controller is provided that is responsive to the wide open throttle condition detected by the throttle sensor and that causes the spark advance to incrementally advance to a maximum level over a predetermined time period, thereby minimizing the occurrence of engine knock conditions.

Abstract: A method of controlling a vapor storage canister for a purge control system of an internal combustion engine is provided. The method includes the steps of determining if predetermined conditions are right for controlling a vapor storage canister and maintaining normal fuel feedback operation if the predetermined conditions are not right for controlling the vapor storage canister. The method also includes the steps of determining if the vapor storage canister is loaded if the predetermined conditions are right for controlling the vapor storage canister, maintaining normal fuel feedback operation if the vapor storage canister is not loaded and modifying a duty cycle of a purge solenoid to maximize purge if the vapor storage canister is loaded. The method further includes the steps of updating a loaded canister total purge multiplier and using the total purge multiplier to vary the amount of fuel being delivered to the internal combustion engine.