A method for controlling continuously variable valve timing (CVVT), may include determining whether a CVVT control is started, detecting a position of a cam and a position of a crankshaft when the CVVT control is started, determining whether the cam is positioned at a locking position based on the positions of the cam and crankshaft, determining whether the cam is controlled to be positioned from the locking position to an advancing position or a holding position, when the cam is positioned at the locking position, and when the cam is controlled to be positioned from the locking position to the advancing position or the holding position and when a condition for performing the CVVT control is satisfied, determining whether a cam torque is negative and performing predetermined CVVT control after waiting a predetermined time when the cam torque is negative.

An engine controller controls a direct fuel-injection engine including a fuel injection valve for directly injecting a fuel into a cylinder and a valve overlap period adjusting mechanism for adjusting a valve overlap period between an open period of an intake valve and an open period of an exhaust valve. The engine controller is provided with an acceleration request sensor for detecting an acceleration request of a driver, and when the acceleration request occurs and a top surface temperature of a piston in the cylinder is lower than a predetermined temperature, the engine controller extends the valve overlap period between the open period of the intake valve and the open period of the exhaust valve, ranging before and after an exhaust top dead center.

An engine controller controls a direct fuel-injection engine including a fuel injection valve for directly injecting a fuel into a cylinder and a valve overlap period adjusting mechanism for adjusting a valve overlap period between an open period of an intake valve and an open period of an exhaust valve. The engine controller is provided with an acceleration request sensor for detecting an acceleration request of a driver, and when the acceleration request occurs and a top surface temperature of a piston in the cylinder is lower than a predetermined temperature, the engine controller extends the valve overlap period between the open period of the intake valve and the open period of the exhaust valve, ranging before and after an exhaust top dead center.

A hybrid vehicle includes a controller that executes catalyst warm-up control for warming up a catalyst, including first control that operates an internal combustion engine at a first operating point, and second control, after executing the first control, that operates the engine at a second operating point irrespective of driving force required to propel the vehicle. Engine output at the second point is larger than engine output at the first point. Ignition timing of the engine at the time when the first control is executed is controlled to a retarded side with respect to an ignition timing of the engine at the time when the second control is executed. When the second control is executed, at least one of a valve lift of an intake valve and a valve operating angle of the intake valve increases as charging of an electrical storage device is more limited.

It is intended to, when abnormality in either one of two rotation detection sections with different detection frequencies occurs, quickly and highly accurately detect the abnormality to favorably deal with abnormality occurring during low engine rotation. It is determined that abnormality is present in the rotation phase detection section, when an absolute value of difference between an actual VTC angle detected by a rotation phase detection section and an integrated value of a VTC change angle detected by motor rotation sensor 201 with the higher detection frequency than the frequency of detection of the actual VTC angle by the rotation phase detection section is equal to or greater than a predetermined value.

A controller of a hybrid vehicle is configured to operate the internal combustion engine with ignition timing of the internal combustion engine during the execution of the first warm-up control for operating the internal combustion engine at a first operating point further on a retard side than ignition timing of the internal combustion engine during the execution of the second warm-up control for operating the internal combustion engine at a second operating point, regardless of the driving force required for traveling after the execution of the first warm up control. The controller is configured to set the output of the internal combustion engine and the operation characteristic of the intake valve in accordance with a predetermined characteristic relationship in which the output of the internal combustion engine and the operation characteristic of the intake valve correspond to each other during the execution of the second warm-up control.

Additional approaches for the reduction of particulate emissions in gasoline engines using optimized port+direct injection are described. These embodiments include control of the amount of directly injected fuel so as to avoid a threshold increase in particulates due to piston wetting and reduction of cold start emissions by use of air preheating using variable valve timing.

A control system for an internal combustion engine has an intake valve, an exhaust valve, and an exhaust purifying catalyst that purifies exhaust gas after combustion of a fuel. During a fuel cut in which no fuel is supplied, a closing timing of the intake valve is controlled to a delayed angle side more than at a timing when the fuel is supplied and to a delayed angle side more than at a timing at a bottom dead center of an intake stroke, and an opening timing of the exhaust valve is controlled to an advanced angle side more than at the timing when the fuel is supplied and to an advanced angle side more than at the timing at the bottom dead center of an expansion stroke.

A system according to the principles of the present disclosure includes an engine start module and an exhaust throttle valve control module. The engine start module determines when an engine is started based on at least one of an input from an ignition system and the speed of the engine. The exhaust throttle valve control module selectively fully closes an exhaust throttle valve in an exhaust system of the engine when the engine is started to trap exhaust gas in the exhaust system.

Methods and systems are provided for controlling exhaust emissions by adjusting an injection profile for different fuels injected into an engine cylinder from different fuel injectors during engine start and crank. By splitting fuel injection during start and cranking so that fuel of lower alcohol content is port injected and fuel of higher alcohol content is direct injected as one or multiple injections, the soot load of the engine can be reduced and fuel economy can be improved.