Patent Application
20130192547
The present disclosure relates to control of an internal combustion engine equipped with active fuel management.
Some internal combustion (IC) engines, such as those used in motor vehicles, employ selective deactivation of valves for specific engine cylinder(s), often called active fuel management, in order to reduce the engine's fuel consumption when full engine power and torque are not required.
Under extreme operating conditions, and as a by-product of power generation, IC engines typically generate elevated amounts of heat energy within their combustion chambers. Such heat energy may in turn cause significant thermal stresses. In order to reduce such thermal stresses, IC engines are generally cooled in order to maintain their operating temperature in a particular range and ensure the engine's efficient and reliable performance. In a majority of motor vehicles, IC engines are cooled by a circulating fluid, such as a specially formulated chemical compound mixed with water. Additionally, such engines are lubricated and cooled by oils that are generally derived from petroleum-based and non-petroleum synthesized chemical compounds.
The generated heat energy usually affects the entire engine structure, but is initially absorbed by the engine's pistons. Accordingly, for enhanced durability, IC engines, such as those equipped with active fuel management, may additionally employ piston squirters or oil jets to cool the pistons and permit the engine to reliably withstand elevated thermal stresses.
An internal combustion engine includes a fluid pump configured to pressurize oil and an engine cylinder configured to combust a mixture of fuel and air therein. The engine also includes a valve arrangement configured to deliver air or the mixture of fuel and air to, and exhaust post-combustion gases from, the cylinder. The engine additionally includes a first switching mechanism and a second switching mechanism in fluid communication with each other, and an oil gallery fluidly connecting the fluid pump and the second switching mechanism.
The engine additionally includes an oil squirter in fluid communication with the second switching mechanism and configured to spray the pressurized oil into the cylinder. The second switching mechanism is operated by the pressurized oil to selectively activate and deactivate operation of the valve arrangement. Moreover, the first switching mechanism is configured to alternately direct the pressurized oil to the second switching mechanism to deactivate the operation of the valve arrangement and to feed the oil squirter.
The second switching mechanism may be configured as a collapsible lifter. In the alternative, the second switching mechanism may also be configured as a lockable rocker-arm arrangement.
The first switching mechanism may be configured as a solenoid oil-control valve.
Operation of the first switching mechanism may be regulated by a controller. The controller may also regulate the mixture of fuel and air delivered to the cylinder when the first switching mechanism directs the pressurized oil to the oil squirter. Furthermore, the controller may cease delivery of the mixture of fuel and air to the cylinder when the first switching mechanism directs the pressurized oil to the second switching mechanism.
The cylinder may be defined by a cylinder bore and the cylinder may include a piston configured to reciprocate inside the cylinder bore. In such case, the oil squirter may be configured to spray the pressurized oil onto at least one of the cylinder bore and the underside of the piston.
A vehicle having such an engine and a method of controlling operation of such an engine are also disclosed.
The above features and advantages, and other features and advantages of the present disclosure, will be readily apparent from the following detailed description of the embodiment(s) and best mode(s) for carrying out the described invention when taken in connection with the accompanying drawings and appended claims.
Referring to the drawings, wherein like reference numbers refer to like components,
The sump 23 is attached to the cylinder block 22 for holding a body of oil. The cylinder block 22 houses a crankshaft 24 and cylinders 26. Each cylinder 26 is defined by a cylinder bore 27. The cylinders 26 are also provided with a valve arrangement 28 configured to deliver a mixture of fuel and air to, and exhaust post-combustion gases from, the cylinders. The valve arrangement 28 includes intake valves 29 and exhaust valves 30 that may be actuated by respective intake and exhaust camshafts 32, 34, as shown in
The intake valves 29 are configured to control a supply of air or of air and fuel into the respective cylinder 26, while the exhaust valves 30 are configured to control the removal of post-combustion exhaust gas from the respective cylinder. Each cylinder 26 also includes a piston 36 and a connecting rod 38. The pistons 36 are configured to reciprocate under the force of combustion inside their respective cylinder bores 27, and thereby rotate the crankshaft 24 via the connecting rods 38. Accordingly, rotation imparted onto the crankshaft 24 by one of the pistons 36 via its respective connecting rod 38 results in reciprocating motion of the remaining connecting rods and pistons associated with the other cylinders.
The crankshaft 24, camshafts 32, 34, connecting rods 38 and various other rotating or otherwise frequently moving components of the engine 12 are supported by specifically configured bearings (not shown). Typically, such bearings rely on a film of oil established between a surface of the bearing and the supported component to create a reliable low friction interface. Typically, the oil used in internal combustion engines is a specially formulated fluid that is derived from petroleum-based and non-petroleum chemical compounds. Such oil is mainly blended by using base oil composed of hydrocarbons and other chemical additives for a specific engine application.
The engine 12 also includes a fluid pump 40 configured to draw oil from the sump 23, and then pressurize and supply the oil to a main oil gallery 42. The main oil gallery 42, in turn, distributes the pressurized oil to the engine bearings of the crankshaft 24, camshafts 32, 34, connecting rods 38, and to other components that rely on the oil for lubrication, actuation, and/or cooling. Because the engine 12 requires a greater pressure and volume of oil at higher engine speeds and combustion pressures, the pump 40 is configured to generate a progressive increase in the amount of oil pressure as the speed of the engine 12 rises. The pump 40 may be driven mechanically by the engine 12, such as by the one of the camshafts 32, 34 or the crankshaft 24, or be operated electrically.
As shown in
As shown in
In order to deactivate a specific cylinder 26, the exhaust valve 30 may be prevented from opening after the piston's power stroke and the post-combustion exhaust gas is retained in the cylinder and compressed during the piston's exhaust stroke. Following the piston's exhaust stroke, the intake valve 29 is prevented from opening. Accordingly, the repeatedly expanded and compressed post-combustion exhaust gas acts like a gas spring inside the cylinder 26. Multiple cylinders may be shut off at the same time in multi-cylinder engines. In general, as multiple cylinders are shut off at a time, the power required for compression of the exhaust gas in one cylinder is countered by the decompression of retained exhaust gas in another. When more power is requested, an exhaust valve is reactivated and the previously unreleased exhaust gas is expelled during the exhaust stroke of the particular piston. Subsequently, an attendant intake valve is likewise reactivated and normal engine operation is resumed. The net effect of such cylinder deactivation is an improvement in fuel economy in the subject engine, as well as a concomitant reduction in exhaust emissions.
As shown in
With resumed reference to
As additionally shown in
The operation of the first switching mechanism 44 is regulated by a controller 58. The controller 58 may be a central processing unit (CPU), as shown in
A method 70 of controlling operation of the engine 12 in the vehicle 10 is shown in
In frame 76, the method includes directing via the first switching mechanism 44 at least a portion of the pressurized oil to feed the oil squirters 48 in order to spray the pressurized oil into the cylinder 26 while the mixture of fuel and air is being delivered to the cylinder. Following frame 76, the method proceeds to frame 78. In frame 78, the method includes directing via the first switching mechanism 44 the portion of the pressurized oil to the second switching mechanism 46 such that operation of the valve arrangement 28 is deactivated. Furthermore, in frame 78 the act of directing via the first switching mechanism 44 the pressurized oil to the second switching mechanism 46 is accomplished while ceasing to direct at least a portion of the pressurized oil to the oil squirters 48.
Following frame 78, the method may advance to frame 80, where the method may include regulating the mixture of fuel and air delivered to the cylinders 26 when the pressurized oil is directed to the oil squirters 48. Additionally, while regulating the fuel and air mixture, the method may include ceasing delivery of the fuel and air mixture to the cylinders 26 while the pressurized oil is being directed to the second switching mechanism 46. As described above with respect to
The detailed description and the drawings or figures are supportive and descriptive of the invention, but the scope of the invention is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed invention have been described in detail, various alternative designs and embodiments exist for practicing the invention defined in the appended claims.
