Abstract: A system according to the principles of the present disclosure includes a first burn duration module and a spark control module. The first burn duration module determines a first duration of at least a portion of a fuel burn within a cylinder of an engine from a first time when a first predetermined percentage of a mass of fuel within the cylinder is burned to a second time when a second predetermined percentage of the fuel mass is burned. The spark control module controls a spark plug to adjust spark timing of the cylinder based on the first burn duration.

Abstract: An engine control system of a vehicle includes an estimation module and an actuator module. The estimation module estimates a crankshaft angle where 50 percent of a mass of fuel is burned during a combustion event based on: a combustion speed when a crankshaft of an engine is at a predetermined position during the combustion event; an engine speed; a mass of air per cylinder (APC); a spark timing; and a predetermined spark timing. The actuator module controls an engine actuator based on the crankshaft angle where 50 percent of the mass of fuel is burned during the combustion event.

Abstract: An engine control system of a vehicle includes an estimation module and an actuator module. The estimation module estimates a crankshaft angle where 50 percent of a mass of fuel is burned during a combustion event based on: a combustion speed when a crankshaft of an engine is at a predetermined position during the combustion event; an engine speed; a mass of air per cylinder (APC); a spark timing; and a predetermined spark timing. The actuator module controls an engine actuator based on the crankshaft angle where 50 percent of the mass of fuel is burned during the combustion event.

Abstract: A system according to the principles of the present disclosure includes a first burn duration module and a spark control module. The first burn duration module determines a first duration of at least a portion of a fuel burn within a cylinder of an engine from a first time when a first predetermined percentage of a mass of fuel within the cylinder is burned to a second time when a second predetermined percentage of the fuel mass is burned. The spark control module controls a spark plug to adjust spark timing of the cylinder based on the first burn duration.

Abstract: A system for an engine includes first, second, third, and fourth modules. The first module determines an expected response of crankshaft speed due to combustion within a cylinder of the engine. The second module determines a value based on the expected response and a measured response of crankshaft speed due to combustion within the cylinder of the engine. The third module estimates an indicated mean effective pressure (IMEP) for the cylinder of the engine based on the value. The fourth module selectively adjusts an operating parameter of the engine based in the estimated IMEP.

Abstract: A system for an engine includes first, second, third, and fourth modules. The first module determines an expected response of crankshaft speed due to combustion within a cylinder of the engine. The second module determines a value based on the expected response and a measured response of crankshaft speed due to combustion within the cylinder of the engine. The third module estimates an indicated mean effective pressure (IMEP) for the cylinder of the engine based on the value. The fourth module selectively adjusts an operating parameter of the engine based in the estimated IMEP.

Abstract: A vehicle may include a drive axle, an engine assembly, a coupling device, and an engine load management system. The engine assembly may include a valvetrain including a fixed-lobe camshaft and intake and exhaust valves supported by the engine assembly. The fixed-lobe camshaft may include a first lobe engaged with the intake valve to open the intake valve and a second lobe engaged with the exhaust valve to open the exhaust valve. The first and second lobes may be fixed relative to one another to define a constant valve overlap condition that provides for opening of the intake valve before the exhaust valve is fully closed, creating an engine operating condition that results in combustion instability below an engine load limit. The engine load management system may be in communication with the engine to prevent engine operation below the engine load limit.

Abstract: A method is disclosed for balancing work output from cylinder banks of an engine having a common crankshaft and separate intake camshafts with cam phasers for each bank. The method includes sensing a crankshaft rotational characteristic, such as instantaneous rotational speed or acceleration, during the power strokes of pistons of predetermined comparable cylinders (or all cylinders) of each bank, computing average crankshaft rotational characteristics for the power strokes of the comparable cylinders of each bank, and adjusting the phasing of at least one of the intake camshafts to obtain equal averages of the sensed characteristics of the crankshaft during the power strokes of the respective banks.

Abstract: A system for balancing first and second work outputs between first and second cylinder banks of an engine includes a first intake camshaft associated the first cylinder bank and a first fuel injector associated with the first cylinder bank. A controller trims a pulse-width of the first fuel injector until first and second A/F ratios of respective exhaust of the first and second cylinder banks are equivalent. The controller adjusts timing of the first intake camshaft to effect air flow into the first cylinder bank and trims the pulse-width to maintain equivalency of the first and second A/F ratios.

Abstract: A hydraulic valve lifter for an internal combustion engine is provided with a thin flexible valve disc, with a sharp edge orifice therethrough, that is operative to sense the oil flow rate between a hydraulic supply chamber and a pressure chamber within the lifter whereby to regulate the volume capacity of the pressure chamber and therefore the axial extent of the valve lifter as a function of engine speed.

Abstract: Variable overlap of the intake and exhaust valve opening periods for an internal combustion engine is obtained by providing a speed responsive yieldable link in the valve actuating mechanism that varies the effective valve lift with engine speed. The variation is accomplished by flow responsive valves, preferably incorporated in hydraulic tappets for actuating the valves and arranged to begin valve lift only when a predetermined lift rate of the valve actuating cam is reached. Since this rate is reached earlier as the engine speed increases, a greater portion of the cam lift curve is utilized with increased speed, thus increasing the valve lift and extending the valve opening period relative to crankshaft rotation. In this way, angular overlap of the intake and exhaust valve opening periods is varied as a function of engine speed.