Abstract:
For the purpose of improving the fuel efficiency by lean combustion and enhancing the fuel efficiency improvement effects by performing compression ignition efficiently in some cylinders, a multi-cylinder spark ignition engine is constructed such that exhaust gas, that is exhausted from preceding cylinders 2A, 2D on the exhaust stroke side among pairs of cylinders whose exhaust stroke and intake stroke overlap in a low load, low rotational speed region, is directly introduced through an inter-cylinder gas passage 22 into following cylinders 2B, 2C on the intake stroke side and only gas exhausted from the following cylinders 2B, 2C is fed to an exhaust passage 20, which is provided with a three-way catalyst 24. Combustion controller is provided that controls the combustion of each of the cylinders such that combustion is conducted by forced ignition in a condition in which the air/fuel ratio is a lean air/fuel ratio which is larger by a prescribed amount than the stoichiometric air/fuel ratio in the preceding cylinders 2A, 2D and, in the following cylinders 2B, 2C, fuel is supplied to burnt gas of lean air/fuel ratio introduced from the preceding cylinders 2A, 2D and combustion is conducted by compression ignition.
Abstract:
Devices for modifying engine valve lift during an engine valve event are disclosed. In one embodiment, the device comprises: a housing having a hydraulic fluid dump port formed therein; a sleeve slidably disposed in a bore formed in the housing, the sleeve having a cavity formed therein; a piston slidably disposed in the sleeve cavity; and a clip passage formed in the piston, the clip passage in selective communication with the dump port.
Abstract:
A valve control system (13) for an internal combustion engine including a cylinder head (11), and a poppet valve (15). A camshaft (21) has a first cam profile (25) and a second cam profile (27), and a rocker arm assembly (29) includes a first cam follower (49) and a second cam follower (61) engageable with the second cam profile (27). The poppet valve (15) is disposed toward a first axial end of said rocker arm assembly (29), and there is a first fulcrum surface (39) toward a second axial end of the rocker arm assembly. The first and second axial ends of the rocker arm assembly are oppositely disposed about the first (49) and second (61) cam followers, and a first lash compensation device (83) is operably associated with the cylinder head and includes a first plunger (97) in engagement with the first fulcrum surface (39). The valve control system (13) is characterized by the rocker arm assembly (29) defining a second fulcrum surface (59) disposed axially between the first fulcrum surface (39) and the cam followers (49,61). A second lash compensation device (85) is operably associated with the cylinder head and includes a second plunger (99) in engagement with the second fulcrum surface (59) of the rocker arm assembly (29). Each of the first (83) and second (85) lash compensation devices is selectively switchable between a latched condition (FIG. 1) and an unlatched condition.
Abstract:
The current invention provides an inexpensive variable valve mechanism that includes a first intervening member which rotates a small angle rotation about an axis of a support shaft by being pressed by a rotating cam and a second intervening member which lifts a valve by making a small angle rotation about an axis of the support shaft together with the first intervening member thus pressing a cam corresponding part of a rocker arm. The variable valve mechanism further includes a control shaft which is provided concentrically with the support shaft, a slider which moves with the control shaft, a slanted part which is formed diagonally relative to the slider's movement direction and is in contact with the slider, and a relative rotation angle control device which varies the relative rotation angle of the first intervening member and the second intervening member by pressing the slanted part in a direction substantially perpendicular to the slider's movement direction by moving the slider together with the control shaft, thus varying the valve's lift and operating angle continuously.
Abstract:
A method of variably actuating a valve of an engine includes selecting one of three valve lift profiles dependent at least in part upon engine operating conditions and parameters. The selected valve lift profile is phased relative to the angular position of the engine crankshaft dependent at least in part upon engine operating conditions and parameters. The valve is actuated according to the selected and phased valve lift profile.
Abstract:
Methods and apparatus for providing bleeder-type and compression-release engine braking in an internal combustion engine are disclosed. For bleeder-type engine braking, the exhaust valve is maintained at a small and relatively constant lift throughout all or much of the engine cycle. The engine braking may be combined with exhaust gas recirculation, variable exhaust brake, and/or operation of a variable geometry turbocharger.
Abstract:
A shim attaching and detaching surface has a sectional portion with a smaller diameter than a base circle of a cam surface in a state in which the shim attaching and detaching surface of a cam is located on a tappet roller, and therefore the tappet roller and an arm member can be moved upward. Since an inner side of a top surface of a tappet guide is inclined, if the arm member is tilted along this inclination, one end of the arm member can be raised, and a clearance is formed in a space from a tappet shim. Accordingly, by inserting a slim plate-shaped or rod-shaped jig 128 from the clearance, the tappet shim 37EX can be attached and detached.
Abstract:
A valve system has a piston mounted in a cylinder in one of first and second rocker arms and is adapted to be forced by a return spring, and an engagement projection formed in the other one of the first and second rocker arms and is adapted to abut the piston to cause both of the first and second rocker arms to move in conjunction with each other. The return spring is disposed eccentrically with respect to the piston in such a direction as to get away from the engagement projection. Therefore, it is possible to ensure a sufficient stiffness of a power transmitting section of the valve system and a sufficient valve lift.
Abstract:
An overhead camshaft internal combustion engine is disclosed having a valve mechanism which comprises an intake or exhaust poppet valve 14 having a valve stem operated by two cams 16 and 18 mounted for rotation about a common axis. A first rocker 20 mounted on a pivot shaft 26 acts between the first cam 16 and the valve 14. A second rocker 28 is mounted in the engine on a fixed pivot shaft 30 and acts between the second cam 18 and the pivot shaft 26 of the first rocker 20, to raise and lower the pivot point 26 of the first rocker 20 cyclically in synchronism with the rotation of the second cam 18.
Abstract:
An internal combustion engine having at least one combustion cylinder that includes a combustion chamber provided with gas-exchange valves, and an electrohydraulic valve control device having valve actuators that actuate the gas-exchange valves. To reduce manufacturing costs and/or the installation space required for the electrohydraulic valve control device, at least two synchronously controlled gas-exchange valves are connected using a coupling element to a common valve actuator, and the connection sites of the gas-exchange valves are flexibly formed on the coupling element.