1036 results about "Variable valve timing" patented technology

Improved exhaust gas recirculation system and methods that use one or more of the engine's cylinders as dedicated EGR cylinders. All of the exhaust from the dedicated EGR cylinders is recirculated back to the engine intake. Thus, the EGR rate is constant, but the EGR mass flow may be controlled by adjusting the air-fuel ratio of the dedicated EGR cylinders or by using various variable valve timing techniques.

A variable valve timing apparatus rotatably receives a rotor in a housing. The rotor can rotate within a predetermined angular range. In some cases, the rotor is locked by a lock pin at an intermediate position within the angular range. In this manner, it is possible to realize a suitable valve timing even when an engine is restarted after it is stopped. In some case, the rotor is prevented from moving to the largest delay angle position by a restricting pin. In this manner, it is possible to prevent the rotor from reaching the largest delay angle position before the engine is stopped. On the other hand, while the engine is operated, it is possible to rotate the rotor to the largest delay angle position and to realize a valve timing responsive to the state of operation.

Improved exhaust gas recirculation system and methods that use one or more of the engine's cylinders as dedicated EGR cylinders. All of the exhaust from the dedicated EGR cylinders is recirculated back to the engine intake. Thus, the EGR rate is constant, but the EGR mass flow may be controlled by adjusting the air-fuel ratio of the dedicated EGR cylinders or by using various variable valve timing techniques.

Lost motion systems and methods for providing engine valves with variable valve actuation for engine valve events are disclosed. The system may include a master piston hydraulically linked to a slave piston, and a dedicated cam operatively connected to the master piston. The slave piston may be disposed substantially perpendicular to the master piston in a common housing. The slave piston is adapted to actuate one or more engine valves. The slave piston may incorporate an optional valve seating assembly into its upper end. A trigger valve may be operatively connected to the master-slave hydraulic circuit to selectively release and add hydraulic fluid to the circuit.

A required valve timing change rate Vreq is calculated so as to make a deviation D between a target valve timing VTtg and an actual valve timing VT small and then a required speed difference DMCRreq between a motor 26 and a camshaft 16 is calculated on a basis of the required valve timing change rate Vreq. When the deviation D is larger than a predetermined value, a required motor speed Rmreq is calculated by adding the required speed difference DMCRreq to a camshaft speed RC and a motor control value is calculated so as to control the motor speed RM to the required motor speed Rmreq. When the deviation D is not larger than the predetermined value, the camshaft speed RC is set as the required motor speed Rmreq and the motor control value is calculated so as to control the motor speed RM to the camshaft speed RC.

In a control apparatus of a supercharged internal combustion engine, a variable valve actuation system interacts with an engine control system. A controller is configured or programmed to increase an intake-valve lift by a variable valve lift mechanism, which is provided for variably controlling at least the intake-valve lift of engine valves, when starting from a vehicle stand-still state or when accelerating from an idling state or a light load state. The controller is further configured or programmed to increase a valve overlap of intake and exhaust valves by a variable phase control mechanism, which is provided for variably phase-shifting a central phase angle of a valve lift characteristic curve of at least one of the intake and exhaust valves, while increasing a boost pressure of intake air introduced into an engine cylinder by a supercharging device, after the intake-valve lift has been increased.

A variable valve timing apparatus rotatably receives a rotor in a housing. The rotor can rotate within a predetermined angular range. In some cases, the rotor is locked by a lock pin at an intermediate position within the angular range. In this manner, it is possible to realize a suitable valve timing even when an engine is restarted after it is stopped. In some case, the rotor is prevented from moving to the largest delay angle position by a restricting pin. In this manner, it is possible to prevent the rotor from reaching the largest delay angle position before the engine is stopped. On the other hand, while the engine is operated, it is possible to rotate the rotor to the largest delay angle position and to realize a valve timing responsive to the state of operation.

Based on results of a knock control for adjusting ignition timing in accordance with the occurrence of knocking, an electronic control unit computes deposit required ignition timing akgrg, which is ignition timing determined by taking adhesion of deposits in an internal combustion engine into consideration. Based on the deposit required ignition timing akgrg, the electronic control unit reduces a vvt allowable variable range of a target VVT advancement amount, which is a control target value of a variable valve timing mechanism. The electronic control unit corrects a required ignition timing based on the actual VVT advancement amount vt, which is chanted according to the reduction of the allowable variable range of the target VVT advancement amount. As a result, problems resulting from the adhesion of deposits are effectively avoided.

A method for an engine capable of burning gaseous fuel, the engine also including a combustion chamber, at least one intake valve, and at least one exhaust valve, an injector to directly inject pressurized gaseous fuel into the combustion chamber, and a variable valve timing system coupled to the intake valves and exhaust valves, the method comprising closing the exhaust valve before top dead center of piston position to increase combustion chamber pressure achieved at top dead center and to trap exhaust gas in the cylinder; and starting injection of a gaseous fuel directly into the combustion chamber after the exhaust valve is closed and before the intake valve is opened.

A control method for transitioning from positive power to engine braking (and vice-versa) is disclosed. This transition may be made using variable valve actuation and two-stroke braking. The process may involve three engine operation modes: positive power (i.e., firing or non-braking), engine braking, and transition between engine braking and positive power. The intake and exhaust valve actuations provided for each of the different modes of operation may be different from each other.

A system for a vehicle with an engine having at least one cylinder with at least an intake valve and an exhaust valve, comprising of a hydraulic variable valve actuator system configured to vary a timing of the intake valve in a first range and a timing of the exhaust valve in a second range, said actuator system configured to have a default intake valve timing to which intake valve timing is held when insufficient hydraulic pressure is available to move intake valve timing, and a default exhaust valve timing to which exhaust valve timing is held when insufficient hydraulic pressure is available to move exhaust valve timing, where said default intake valve timing is in a retarded portion of said first range and said default exhaust valve timing is in a retarded portion of said second range, and a hybrid propulsion system coupled to the engine.

An internal combustion engine has a variable valve timing apparatus including a driving motor between a crankshaft and a camshaft. The driving motor rotates synchronously with the camshaft when the valve timing apparatus is not in operation. A motor rotation sensor produces a motor rotation signal. When the engine rotation speed is below a reference speed, the driving motor is not energized. Under this condition, the rotation speed and the rotation direction of the engine are calculated based on the motor rotation signal in place of a crank rotation signal produced by a crank angle sensor. Further, the rotation stop position of the engine is calculated based on the motor rotation signal when the engine is stopped.

Method and arrangement for providing a vehicle having a combustion engine (1) with valves (7, 8) adapted to have variable valve timing and / or valve lift height. The valves are provided with operating devices (9,10) that are controlled by electronic controlling devices (3), which are arranged, while the vehicle is being driven, with the aid of entered information about at least the gradient of the road and the throttle position, to calculate future resistance to forward motion and the period of time to a future transient in the engine's operating condition, for example in association with a future change of engine operating mode and / or a future gear change in a gearbox (2) connected to the engine. The controlling devices are arranged to control valve timing and / or the valve lift height during the period of time for optimization of the engine's performance, once the transient has arisen.

A variable valve timing control system of an internal combustion engine includes a hydraulically-operated phase converter disposed between a sprocket and a camshaft, and having a phase-advance hydraulic chamber and a phase-retard hydraulic chamber for changing an angular phase of the camshaft relative to the sprocket. An electric pump is provided to supply working fluid selectively to one of the hydraulic chambers via a directional control valve. Also provided is a check valve disposed in a discharge line of the pump for permitting flow in a direction that the working fluid flows from the pump to the directional control valve and preventing any flow in the opposite direction, so as to prevent a pulse pressure arising from alternating torque exerted on the camshaft from being transmitted from either one of the hydraulic chambers via the discharge line to a discharge port of the pump.

The present invention provides a variable valve timing device for an internal combustion engine having a double camshaft. A gas exchange valve control shaft is provided which has first and second concentrically arranged cam shafts that are adjustable in a rotatable manner with respect to each other, by which a cam of the first cam shaft is adjusted in terms of its angle towards a cam of the second cam shaft. A cam phasing device is provided which operates by rotatable vanes provoking a swivelling relative movement between a driven member and an output member. The cam phasing device comprises at least two pivotable vane adjusters. Each pivotable vane adjuster is assigned to one of the two cam shafts. The pivotable vane adjusters are arranged axially one after the other in a direction of a valve control shaft. Each pivotable vane adjuster may be designed as a rotor-type vane adjuster.

A method for determining cylinder air charge and / or cylinder burned gas for an internal combustion engine system. The engine system includes cylinders, each one of such cylinders having at least one intake valve and at least one exhaust valve in communication with such cylinder. The method determines one of a plurality of different scenarios, each one of the scenarios representing a geometrical relationship between opening and closing of the intake valve relative to closing of the exhaust valve. The cylinder air charge and / or cylinder burned gas is calculated in accordance with the determined one of the plurality of scenarios. In one embodiment, the engine system stores a plurality of different software modules. The method selects one of the plurality of software modules in accordance with the determined one of the plurality of scenarios. The cylinder air charge and / or cylinder burned gas calculation comprises executing the selected one of the modules. In one embodiment, a memory stores a relationship between volume occupied by residual gas in the at least one cylinders at a predetermined position of the at least one cylinder in the engine during the cycle determined in accordance with each one of the plurality of scenarios for each of a plurality of different intake valve opening and exhaust valve closing conditions. The method includes: determining from the memory the volume occupied by residual gas in the at least one cylinders at a predetermined position of the at least one cylinder in the engine during the cycle for the intake valve opening and exhaust valve closing conditions; and, determining from volume occupied by residual gas in the at least one cylinders at a predetermined position of the at least one cylinder in the engine during the cycle the cylinder air charge and / or cylinder burned gas.

The present invention relates to methods of improving engine braking of a reciprocating piston internal combustion engine by variable valve actuation. One embodiment of the present invention enables independent two-valve actuation for each cylinder, and engine braking horsepower can be optimized using two-valve braking at high engine speeds and one-valve braking at low speeds. Another embodiment of the present invention enables better a sequential valve actuation to reduce engine braking load and compliance. Another embodiment of the present invention enables better engine starting and warming up by controlling timing and lift of each valve.

Systems are provided for electromagnetic actuation of a valve mechanism. A valve is linearly moveable between a first closed position and a second open position. A first spring is compressed when the valve is in the first closed position, and a second valve spring is compressed when the valve is in the second open position. An electromagnetic actuation assembly and a permanent magnet is combined with the valve, such that the valve is latchable in either a closed or open position, and is readily movable between positions through application of energy to the electromagnetic circuitry. The electromagnetic circuitry is controllable to increase or decrease the local magnetic flux, such as to promote movement of the valve, or to provide a soft landing of the valve at either end of movement. Some system embodiments provide energy recovery, feed back, and / or feed forward sensing and control. The electromagnetic valve system can be implemented for a wide variety of engines, valves and actuators, such as for variable valve timing, valve disablement, and / or hybrid engine and energy storage applications.

A method for controlling the temperature and / or space velocity of exhaust gas passing through an aftertreatment device disposed in the exhaust system of a diesel engine provides an optimal environment for efficient conversion of NOx and undesirable emissions during transient and steady state engine operation. The method includes controlling intake and / or exhaust valve timing, either singly or in combination with fuel injection timing and selective individual cylinder cutout, in response to sensed engine operating parameters.

A variable valve timing control apparatus includes: a relative rotational phase adjusting mechanism capable of adjusting a relative rotational phase between a drive-side rotational member and a driven-side rotational member between the most advanced angle phase and the most retarded angle phase; and a lock mechanism capable of locking the relative rotational phase at an intermediate phase between the most advanced angle phase and the most retarded angle phase; a first pump operated by a driving force of an engine; and an electrically driven second pump operated as an electrically driven pump. Hydraulic fluid is supplied from at least one of the first pump and the second pump, and the second pump is capable of operating even if the first pump is inoperative when the engine is not running.

A control unit employed in a variable valve timing apparatus vibrates a control signal for controlling an oil-pressure control valve. If the vibration center of the duty value of the control signal for driving the oil-pressure control valve lies in a dead band, the vibration takes the duty value to the outside of the dead center temporarily. Thus, even if the center value of the control signal lies in the dead band, the valve timing of the oil-pressure control valve changes with variations in control signal. As a result, the width of the dead band appears small or to have a value of zero. Accordingly, the response characteristic of variations in valve timing to the variations in control signal is improved. The vibration of the control signal is also effective for detection of a width of the dead band.

A vacuum management system for an engine with variable valve lift includes a vacuum control valve at the entrance to the intake manifold to increase vacuum within the manifold as needed and preferably only when it can be done without impairing fuel economy or engine performance. Vacuum may then be used for any of various vacuum-assisted devices and functions, for example, boosting a vehicle braking system. The numerical relationships among important operating parameters are determined in a laboratory, and a programmable engine control module (ECM} is provided with algorithms and tables of such values by which the ECM is able to vary valve lift and vacuum control valve position to provide optimum flow across the intake valves and optimum manifold vacuum under all engine operating conditions.

The invention discloses a VVT (Variable Valve Timing) control method capable of combining self-learning feed-forward and active anti-interference feedback, which can improve the response speed of a VVT phase control, reduce the energy consumption of a regulating process and increase the adaptability to the operating environment change and the state change of an engine. The control method disclosed by the invention comprises the following steps of: carrying out a feed-forward control, an active anti-interference feedback control and a self-learning correction; regulating a hydraulic oil demandvolume of a solenoid valve and a demand current I of a VVT solenoid valve through the feed-forward control; and obtaining a control signal It of a VVT system through the active anti-interference feedback control. The self-learning correction comprises the steps of concluding and calculating a characteristic parameter of the VVT system according to a VVT control quantity (a duty ratio of a PWM (Pulse Width Modulation) wave) and a response characteristic yr of the VVT system during the regulation of the VVT system so as to correct a calculating coefficient in a feed-forward controller model, thereby continuously increasing the calculation accuracy of the feed-forward control, improving the control capability of the feed-forward control, reducing the dependence on the feedback control and effectively improving the response speed and the accuracy of the control of the VVT system.

The present invention discloses one kind of engine with changeable compression ratio and changeable fuel and its control method. The engine includes one combustion system, one fuel pressure regulating system, one liquid fuel providing system, one gas fuel providing system, one changeable gas valve timing mechanism, one electronic control unit and one sensor module. According to the acquired signal, the electronic control unit determines the current fuel type, regulates the compression ratio, combustion controlling strategy and gas distribution phase of the engine and regulates the pressure of the fuel injector, so as to fit the fuel. The engine of the present invention can burn gas fuel, liquid fuel and mixed fuel, and has compression ratio adjustable in 8-18 and high dynamic performance and economic performance in burning different types of fuel.

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 vacuum system for an engine with variable valve lift includes a controllable vacuum-forming valve at the entrance to the intake manifold and a programmable engine control module (ECM) to increase vacuum as desired within the manifold by modulating the valve as needed to optimize fuel economy. To provide vacuum brake assist, a brake booster diaphragm is connected conventionally to the manifold and a vacuum storage tank and check valve are disposed between the booster diaphragm and the manifold. During periods of vehicle deceleration, when engine load is low, the ECM may switch the VVL-controlled intake valves to a higher lift to increase the pumping capacity of the engine, while simultaneously partially closing the vacuum-forming valve to create vacuum in the intake manifold, the brake booster, and the vacuum storage tank at little or no expense to engine performance.