Engine valve lift control systems and methods for reduced fuel consumption

A fuel control system of an engine comprising:

• a fuel economy module that:
• determines a first valve lift state and a second valve lift state of a valve of the engine,
• generates a first fuel consumption signal based on the first valve lift state and an engine torque request signal, and
• generates a second fuel consumption signal based on the second valve lift state and the engine torque request signal;
• and
• a valve lift state module that selects one of the first valve lift state and the second valve lift state based the first fuel consumption signal and the second fuel consumption signal,
• wherein the valve lift state module generates a valve lift select signal that indicates the selected one of the first valve lift state and the second valve lift state,
• wherein the fuel economy module determines a difference between the first fuel consumption signal and the second fuel consumption signal, and
• wherein the valve lift state module determines a magnitude of the difference and generates the valve lift select signal when the magnitude is greater than a threshold.

A method of controlling fuel consumption of an engine comprising:

• detecting that a first valve lift state is used for a valve of the engine and a second valve lift state is not used for the valve;
• generating a first fuel consumption signal based on first parameters associated with the first valve lift state and an engine torque request signal, wherein the first parameters include values of valve lift, valve timing, and spark timing associated with the first valve lift state;
• generating a second fuel consumption signal based on second parameters associated with the second valve lift state and the engine torque request signal, wherein the second parameters include values of valve lift, valve timing, and spark timing associated with the second valve lift state;
• and
• switching from the first valve lift state to the second valve lift state for the valve based on the first fuel consumption signal and the second fuel consumption signal.

A method of controlling fuel consumption of an engine comprising:

• detecting that a first valve lift state is used for a valve of the engine and a second valve lift state is not used for the valve;
• generating a first fuel consumption signal based on the first valve lift state and an engine torque request signal;
• generating a second fuel consumption signal based on the second valve lift state and the engine torque request signal;
• switching from the first valve lift state to the second valve lift state for the valve based on the first fuel consumption signal and the second fuel consumption signal;
• determining a difference between the first fuel consumption signal and the second fuel consumption signal;
• determining a magnitude of the difference;
• and
• switching from the first valve lift state to the second valve lift state when the magnitude is greater than a threshold.