Patent Application
20180320630
This disclosure relates to internal combustion engines (ICEs), and in particular, to an ICE cylinder head integrated with tubular variable intake and exhaust systems.
A reciprocating internal combustion engine (ICE) includes two parts: an engine body (cylinder block) and a cylinder head. The cylinder block includes several cylinders for pistons to reciprocate within, typically moving in a four-stroke cycle of a four-stroke engine. For a four-stroke engine, the four strokes can include an intake stroke, a compression stroke, a power stroke (or an “expansion stroke”), and an exhaust stroke. In the intake stroke, air or an air/fuel mixture (AFM) is pulled by a piston into the cylinder through intake valves. In the compression stroke, the air or AFM is compressed by the piston in preparation for ignition. In the power stroke, the compressed AFM or air (or, for a diesel engine, diesel is injected into the compressed air in the cylinder) is ignited to push the piston for mechanical work production. In the exhaust stroke, exhaust gas is pushed out of the cylinder by the piston through exhaust valves. The piston is connected to a crankshaft through a connecting rod to convert its reciprocation into a revolution of the crankshaft for output.
The intake and exhaust valves and other related parts (collectively referred to as a “valvetrain”) are located in the cylinder head. The intake and exhaust valves are controllable to open and close in a timely order for the four-stroke cycles. Typically, the opening and closing timing (or simply “timing”) of the intake and exhaust valves are actuated by camshafts with cam lobes, which are driven by a timing belt/chain connected to the crankshaft. The valve timing depends on crankshaft angles and lob sharp angle. In addition, some modern ICEs use variable valve timing (VVT), variable valve lift (VVL), and direct fuel injection (FDI) to optimize fuel economy and power output, which can introduce complexity to the valvetrains. The valvetrains face growing challenges of increasing complexity, weight, friction, or manufacturing cost.
Disclosed herein are implementations of apparatuses and cylinder heads with tubular intake and exhaust systems.
In an aspect, an apparatus for intake and exhaust of an engine is disclosed. The apparatus includes an outer tube comprising an outer-tube close end, an outer-tube open end, and a first outer-tube aperture set comprising a first aperture and a first outer-tube aperture group comprising at least one aperture, an inner tube positioned in the outer tube about a concentric line, comprising an inner-tube close end, an inner-tube open end, and a first inner-tube aperture set comprising a second aperture and a first inner-tube aperture group comprising at least one aperture, wherein the inner-tube close end is proximate to the outer-tube close end, and a shaft connected to the inner-tube open end for rotating the inner tube in the outer tube about the concentric line, wherein when the inner tube rotates, the second aperture sweeps across a portion of the first aperture and the first inner-tube aperture group sweeps across a portion of the first outer-tube aperture group.
In another aspect, a cylinder head for an engine is disclosed. The cylinder head includes a cylinder head body, comprising a tubular cavity, a manifold port provided on the tubular cavity, connecting to a manifold of the engine, and a chamber port provided on the tubular cavity, connecting to a combustion chamber of the engine, and a tubular assembly, comprising an outer tube positioned in the tubular cavity, comprising an outer-tube close end, an outer-tube open end, and a first outer-tube aperture set comprising a first aperture and a first outer-tube aperture group comprising at least one aperture, an inner tube positioned in the outer tube, comprising an inner-tube close end, an inner-tube open end, and a first inner-tube aperture set comprising a second aperture and a first inner-tube aperture group comprising at least one aperture, wherein the inner-tube close end is proximate to the outer-tube close end, and a shaft connected to the inner-tube open end for rotating the inner tube in the outer tube, wherein the first aperture overlaps with a portion of the chamber port, the first outer-tube aperture group overlaps with a portion of the manifold port, and when the inner tube rotates, the second aperture sweeps across a portion of the first aperture and the first inner-tube aperture group sweeps across a portion of the first outer-tube aperture group.
The disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity.
ICEs face challenges to increase fuel efficiency and decrease emissions. Higher fuel efficiency can be achieved via better mechanical structures of engines (e.g., with less weight or friction) and more accurate valvetrain management. One technical solution for those challenges is to variably control valve timing and valve lift of an engine in response to revolutions per minute (RPM) of the engine.
To reduce fuel consumption for an engine working at a low RPM, the amount of fresh air inflow can be decreased. For example, the valve lift can be decreased at a low or intermediate RPM. The valve lift can be increased at a high RPM.
Many ICEs work in an Otto cycle. To increase fuel efficiency, some engines can be adapted to work in an Atkinson/Miller cycle. If the engine can only work in the Atkinson/Miller cycle, one of the challenges is that the engine is difficult to be started at a low RPM. One technical solution for the challenge is to variably control valve timing and valve lift of an engine in response to the RPM. In some engines, the valve lift can be increased when the engine is working at a high RPM. For example, the engine can be started at the Otto cycle, then changed to the Atkinson/Miller cycle by continuously controlling the valve timings as its RPM increases. Better mechanical structures (e.g., with less weight or friction) and more accurate valvetrain management are strived for increasing fuel efficiency and decreasing emissions.
Typically, intake valves and exhaust valves are actuated by camshafts with cam lobes, and the camshafts are driven by the crankshaft of the engine through a timing chain or timing belt. It is difficult to independently control the intake valves and the exhaust valves. In addition, it is also difficult to continuously control the valve timing and the valve lift in response to a continuously changing RPM.
In this disclosure, an ICE cylinder head with tubular intake and exhaust systems are introduced. The ICE cylinder head can perform the Atkinson/Miller cycle and simplify the valve train to have fewer parts, lower friction, and reduced total weight and dimensions. It can continuously switch the engine working cycles from the Otto cycle to the Atkinson/Miller cycle. It can also be made to be compatible to existing engines.
The tubular intake and exhaust system can include one or more tubular assemblies, each including an inner tube and an outer tube. The inner tube can be configured to distribute the intake air or AFM, and thus can be referred to as a “distribution tube.” For ease of explanation without causing ambiguity, the “AFM or air” is referred to as “air” hereinafter unless explicitly described. The distribution tube can have flow areas controllable to change continuously as the RPM changes. The outer tube can be configured to control timing or phase of the intake and exhaust, and can be referred to as a “timing tube.” Actuators of the timing tube and distribution tube can be used to control the valve timing and “valve lift” independently and continuously. For the cylinder head that has two tubular assemblies for intake and exhaust, the actuators of their timing tubes and distribution tubes can be controlled continuously. In the disclosed cylinder head, the conventional camshaft valvetrain is not used, therefore the term “valve lift” does not refer to a “lift” of an actual valve, but is related to an effect of the disclosed cylinder head that can cause air flow cross-sectional areas (“flow area”) to change, which is similar to the effect of valve lift control in a conventional valvetrain. The change of the flow area can be continuous. The flow area can also be changed as the RPM changes. By using the tubular assemblies, the flow area can be changed with low flow restriction. The disclosed cylinder head can have fewer parts, simpler mechanical structures, reduced weight, smaller size, or more space for installation of other systems (e.g., a hybrid system or other attached components). By using the disclosed cylinder head, an engine can have less friction, less air flow restriction, better turbulences for a gasoline direct injection (GDI) system, better fuel efficiency, lower emissions, lower noise, lower vibration, easier accessibility, or lower costs for manufacture and maintenance. In addition, the engine using the disclosed cylinder head can be configured to implement continuous VVL and VVT, implement independent VVL and VVT control for intake and exhaust, run in the Atkinson/Miller cycle, perform cylinder deactivation, perform engine brake for a diesel engine and/or a controlled combustion engine (CCE), or implement homogeneous charge compression ignition (HCCI) or controlled auto ignition (CAI).
The disclosed cylinder head is compatible with conventional engine bodies. It can be interfaced with a conventional engine body and other components (e.g., sensors, wire harness, or engine oil adding port), which can minimize manufacturing costs.
The disclosed cylinder head can be manufactured as one piece or several parts (e.g., an upper half and a lower half). The disclosed cylinder head can also use a design to include a cylinder head for a diesel engine (e.g., used for heavy trucks). In addition, the disclosed cylinder head can be compatible with existing passage designs for lubricating systems and cooling systems of the ICE.
The cylinder head can include one or more tubular systems for intake/exhaust. A tubular system can include a tubular assembly and other components (e.g., for sealing, lubrication, cylinder separation, or actuation of the tubular assembly).
A tubular system can include two concentrically assembled tubes: a timing tube (or an “outer tube”) and a distribution tube (or an “inner tube”). The timing tube can include a manifold port (referred to as an “outer manifold port”) that interfaces with an intake manifold to pull air from the intake manifold, or an exhaust manifold to push exhaust gas into the exhaust manifold. The timing tube can also include a chamber port (referred to as an “outer chamber port”) that interfaces with a combustion chamber of a cylinder to let the air into the chamber or to let the exhaust gas out from the chamber. The distribution tube can include a manifold port (referred to as an “inner manifold port”) that overlaps with the outer manifold port to pull the air into the distribution tube from the intake manifold, or to push the exhaust gas out from the distribution tube into the exhaust manifold. The distribution tube can also include a chamber port (referred to as an “inner chamber port”) that overlaps with the outer chamber port to let the air into the chamber out from the distribution tube, or to let the exhaust gas into the distribution tube out from the chamber. The timing tube can include one or more outer manifold ports and one or more outer chamber ports. The distribution tube can include one or more inner manifold ports and one or more inner chamber ports. The term “port” herein refers to any combination of any shape of inlets, outlets, entrances, exits, holes, apertures, slits, windows, or any other openings on a surface for gas to flow through.
The distribution tube and the timing tube can be controlled independently. The overlapping between the inner and outer manifold ports can be adjustable. The overlapping between the inner and outer chamber ports can also be adjustable. The overlapping can be referred to as “flow areas.” The relative position of the distribution tube and the timing tube can be optimized for different engine RPMs or working conditions (e.g., oil pressures). The timing tube can be actuated by hydraulic motors or electric motors.
The distribution tube can be driven by a shaft to rotate inside the timing tube. The shaft can be driven by a timing belt/chain connected to a crankshaft. The distribution tube can distribute air (e.g., for GDI engines) or AFM (e.g., for port fuel injection engines or PFI engines) into the combustion chambers of the cylinders. The distribution tube can also be used to control valve lift variably and continuously by adjusting the flow area under different engine working conditions or RPMs, such as by moving it axially (along the direction of the shaft) relative to the timing tube. The flow area can be controlled based on oil pressure (e.g., measured by an oil pressure sensor). For example, the flow area can be controlled by an ECU based on a signal of an oil pressure sensor. The flow area can be calibrated based on a performance curve (e.g., a calibrated curve map) of the engine. The distribution tube can use internal structures (e.g., turbines) for intra-cylinder swirls and tumbles. The edge design of the inner chamber ports can also be optimized based on computational fluid dynamics (CFD) for less air friction, less charging flow restriction, or more inner turbulence and swirl in the combustion chamber.
The timing tube can be axially fixed and angularly adjustable inside the cylinder head. The timing tube can be adjusted to variably control “valve timing,” and such adjustments can be made continuously under different engine working conditions. In the disclosed cylinder head, a conventional camshaft valvetrain is not used, therefore the term “valve timing” does not refer to timing of an actual valve, but is related to an effect of controlling the timing of the strokes (e.g., the intake stroke, the compression stroke, the power stroke, and/or the exhaust stroke), which is similar to the effect of valve timing control in a conventional valvetrain. The timing tube can be adjusted to advance or delay the opening and/or closing timings for intake and exhaust, which can cause the engine to work in an Atkinson/Miller cycle.
The distribution tube and the timing tube can have different designs for their degrees of freedom (DOF) of movement. In some implementations, the timing tube can be axially fixed and the distribution tube is axially movable. In some implementations, the distribution tube can be axially fixed and the timing tube is axially movable. For ease of explanation without causing ambiguity, unless explicitly described, this disclosure describes example implementations hereinafter in which the distribution tube is axially movable and the timing tube is axially fixed inside the tubular cavity. It should be noted that modifications, variations, or alterations for designs of DOF for components of the tubular systems can be derived from the description of this disclosure.
The distribution tube and the timing tube can be electrically or hydraulically actuated to block some or all of the cylinders (e.g., by blocking ports of the cylinders, which will be explained hereinafter) to implement engine brake function, such as for a diesel engine (e.g., for a heavy truck). When intake inflows and exhaust outflows are blocked for selected cylinders, the selected cylinders can be deactivated (referred to as “cylinder deactivation”). Partial cylinder deactivation (i.e., not all of the cylinders are deactivated) can be used to increase fuel economy. Full cylinder deactivation (i.e., all of the cylinders are deactivated) can be used to implement engine brake.
The outer wall of the distribution tube and the inner wall of the timing tube are separated and lubricated to minimize friction. Compared with friction introduced by the camshaft or valve in conventional cylinder heads, the friction introduced by the disclosed cylinder head can be greatly reduced. The space between the outer wall of the distribution tube and the inner wall of the timing tube and the space between the outer wall of the timing tube and the cylinder head are sealed to prevent or minimize air (or exhaust) crossing into neighboring cylinders.
The structures and functions of the disclosed cylinder head with the tubular intake and exhaust systems will be described with reference to the accompanying drawings as follows.
The cylinder head 102 includes a tubular intake system (not shown) and a tubular exhaust system (not shown). A crankshaft is located inside the engine body 104 and connected to a crankshaft sprocket/pulley 106 outside of the engine body 104. The crankshaft sprocket/pulley 106 drives a first sprocket/pulley 110 and a second sprocket/pulley 112 via a timing chain/belt 108. The first sprocket/pulley 110 and the second sprocket/pulley 112 are fixed on a shaft of the tubular intake system and a shaft of the tubular exhaust system, respectively. An intake manifold 114 can be interfaced with the cylinder head 102 for providing air into combustion chambers (e.g., between the pistons and the cylinder walls) inside the engine body 104. An exhaust manifold 116 can be interfaced with the cylinder head 102 for letting exhaust gas out from the cylinders. The intake and exhaust manifolds can be on top or on side in different combinations of the cylinder head 102.
The cylinder head body 300A includes two tubular cavities: a tubular cavity 306 and a tubular cavity 308. For example, the tubular cavity 306 can be used for placing an intake tubular assembly (not shown), and the tubular cavity 308 can be used for placing an exhaust tubular assembly (not shown). A shaft for each tubular assembly can be installed aligned with a center line of each tubular cavity. For example, the shaft for the intake tubular assembly can be installed aligned with a center line 310 in the tubular cavity 306. The tubular assemblies can be installed inside the cylinder head body via lock features (not shown). Seal grooves (not shown) for sealing and lubrication can be made on the inner surfaces of the tubular cavities. The seal grooves will be described in greater detail in the discussion of
The cylinder head body 300A can include intake ports 312, inlet ports 314, outlet ports 316, and exhaust ports 318. The intake ports 312 can be interfaced with (e.g., using bolts or screws) an intake manifold (not shown) to provide air into the intake tubular assembly. The inlet ports 314 can be interfaced with (e.g., using bolts or screws) combustion chambers of cylinders under the cylinder head body 300A to provide air into the combustion chambers from the intake tubular assembly. The outlet ports 316 can be interfaced with (e.g., using bolts or screws) the combustion chambers to discharge exhaust gas into the exhaust tubular assembly from the combustion chambers. The exhaust ports 318 can be interfaced with (e.g., using bolts or screws) an exhaust manifold (not shown) to discharge exhaust gas from the exhaust tubular assembly. For example, each cylinder can be interfaced with an inlet port and an outlet port. An air inflow 320 (shown as arrows) shows a route of the air flowing from the intake manifold through an intake tubular assembly (not shown) to the combustion chambers. An exhaust outflow 322 (shown as arrows) shows a route of the exhaust gas flowing from the combustion chambers through an exhaust tubular assembly (not shown) to the exhaust manifold.
For large ICEs (e.g., diesel engines), to facilitate manufacturing and installation, the cylinder head body can be manufactured in pieces. For example, in
The intake ports 312, inlet ports 314, outlet ports 316, and exhaust ports 318 can be configured in any size, placement, configuration, or profile, and can be positioned anywhere at the cylinder head body (e.g., the cylinder head bodies 300A and 300B), as long as they are compatible with installation of other components of the engine (e.g., sensors, OMS, or hydraulic solenoids). For example, the intake ports 312 and exhaust ports 318 can be placed on a side surface of the cylinder head (e.g., as shown in
When a manifold port has an overlap region with an intake (or exhaust) port, the air (or exhaust gas) can enter (or leave) the tubular assembly. When the manifold port has an overlap region with an inlet (or outlet) port, the air (or exhaust gas) can enter (or leave) the corresponding chamber. By arranging the manifold ports on the surface of the tubular assemblies in a periodical circular fashion, when the tubular assemblies rotate, the air (or exhaust gas) can periodically enter (or leave) the chamber, such as following the air inflow 320 (or the exhaust outflow 322). By arranging the manifold ports on determined azimuthal angles about the driving axes (e.g., the first and second shafts 118 and 122) and matching them with crank angles of the cylinders, a firing order for the cylinders can be implemented. The tubular assemblies 120 and 124 can each include two tubes: an outer tube (referred to as a “timing tube”) and an inner tube (referred to as a “distribution tube”). Each of the timing tube and the distribution tube can include manifold ports of its own. For example, the manifold port 326 or 328 can be formed by an outer manifold port on the timing tube and an inner manifold port on the distribution tube. More details of the tubular assemblies will be described in
The timing tube 500 includes outer manifold ports 502 and outer chamber ports 504. For example, when the timing tube 500 is installed in the cylinder head body, the outer manifold ports 502 can be configured to overlap with the intake ports 312 or the exhaust ports 318. The outer chamber ports 504 can be configured to overlap with the inlet ports 314 or the outlet ports 316. In
For example, when the timing tube 500 is used in the intake tubular assembly 406, the air can flow from the intake manifold 114 to the intake tubular assembly 406 through the intake ports 312 and the outer manifold ports 502. The air will be charged into combustion chambers by a distribution tube (not shown) through the outer chamber ports 504 and the inlet ports 314. For another example, when the timing tube 500 is used in the exhaust tubular assembly 410, the exhaust gas can exit from the combustion chambers to the exhaust tubular assembly 410 through the outlet ports 316 and the outer chamber ports 504, and be discharged to the exhaust manifold 116 through the outer manifold ports 502 and the exhaust ports 318 by the distribution tube (not shown).
In an implementation, the distributions of the outer manifold ports 502 and the outer chamber ports 504 on the timing tube 500 can follow an engine cylinder order. For example, the first cylinder for air intake can be a cylinder using the TDC as a crankshaft alignment point and the TDC with an advanced angle as a start point. It should be noted that relative positions of the outer manifold ports 502 and the outer chamber ports 504 can be arranged on different positions on the timing tube 500. The relative positions can depend on engine layout and space availability. For example, in
The timing tube 500 can be sealed (e.g., with a cap section) at a closed end 506 to prevent or minimize air or exhaust gas from escaping the timing tube 500 and provide mounting for exterior structures, such as a timing driving gear 508 (e.g., a half gear, a tap, or any other suitable gear). The timing driving gear 508 can be attached at the closed end 506 outside of the timing tube 500, and can be controllable to drive the timing tube 500 to rotate inside a tubular cavity (e.g., the tubular cavity 306 or the tubular cavity 308) about the center line 510. The center line 510 is also the axis with which a shaft (e.g., the first shaft 118 or the second shaft 122) of the distribution tube (not shown) is aligned.
The timing driving gear 508 can be actuated by various means. For example, the timing driving gear 508 can be actuated through a driving worm gear (not shown) by an electric actuator (e.g., an electric step motor), a pneumatic actuator (e.g., a vacuum actuator), or a hydraulic actuator (e.g., a hydraulic solenoid valve). The actuation of the timing driving gear 508 can be controlled by an engine control unit (ECU). By rotating the timing tube 500, overlapped openings between the outer chamber ports 504 and the inlet/outlet ports can be adjusted to change the timing of when air inflows enter the combustion chambers and when exhaust outflows exit the combustion chambers. The changed timing can be used to change the engine working mode, such as switching between an Otto cycle and an Atkinson/Miller cycle. The details of controlling the timing for intake/exhaust will be described in
The distribution tube 600 includes inner manifold ports 602 and inner chamber ports 604. The inner manifold ports 602 can match with the outer manifold ports 502. The inner chamber ports 604 can match with the outer chamber ports 504. When rotating, the inner manifold ports 602 can sweep across the outer manifold ports 502, and the inner chamber ports 604 can sweep across the outer chamber ports 504. In an implementation, the distribution tube 600 can be used for intake. When the inner manifold ports 602, the outer manifold ports 502, and the intake ports 312 (not shown in
In
When the distribution tube 600 is rotating inside the timing tube 500, the inner manifold ports 602 can sweep across the outer manifold ports 502, and the inner chamber ports 604 can sweep across the outer chamber ports 504. When the inner manifold ports 602 have overlap with the outer manifold ports 502, the flow areas between them form and the intake/exhaust manifold is pneumatically connected to the distribution tube 600. When the inner chamber ports 604 have overlap with the outer chamber ports 504, the flow areas between them form and the distribution tube 600 is pneumatically connected to the combustion chambers.
For the distribution tube 600, each cylinder can be associated with a corresponding port group. The port group can include a set of inner manifold ports and an inner chamber port. For example, the inner manifold ports 602 and the inner chamber ports 604 can be divided into 4 tube sections 601-607 corresponding to 4 respective cylinders, each tube section including a port group. In some implementations, separator plates (not shown) can be used to separate and seal between the tube sections to prevent or minimize air (or exhaust gas) in a tube section from entering neighboring tube sections.
The positions of the inner chamber ports 604 and/or the inner manifold ports 602 on the distribution tube 600 can be arranged to match a cylinder firing order. For example, the inner chamber ports of the tube sections 601-607 can be arranged to open the cylinder in a firing order of 1-2-4-3. It should be noted that relative positions of the inner manifold ports 602 and the inner chamber ports 604 can be arranged on different positions on the distribution tube 600. The relative positions can depend on engine layout, space availability, and can match the design of the timing tube. For example, in
In some implementations, the separator plates can utilize a turbine design for pushing the air inflow or pulling the exhaust outflow. The separator plates with turbine designs can be referred to as “turbo plates.” Functionally, the turbo plate 610 is similar to a turbocharger. The turbo plates can also help to create better turbulences inside the combustion chamber to improve the combustion.
Shapes of the turbines 618 and edges of the inner chamber ports 604 can be optimized (e.g., using CFD techniques) to achieve stronger tumbles and/or swirls in the combustion chambers. Strong turbulence can result in better air/fuel mixing, faster flame propagation, and more efficient combustion.
The configurations of the outer chamber ports 706 and the inlet/outlet ports of the cylinder head are determined based on the number of cylinders. For example, the tubular assembly 700A can be used for four cylinders. In other words, the distribution tube 704 can include 4 tube sections. The inner chamber ports 708 can be arranged to charge the cylinders in a designed firing order (e.g., 1-2-4-3). For example, on the azimuthal plane (i.e., a plane perpendicular to the shaft 710) of the tubular assembly 700A, assuming the outer chamber ports 706 are all arranged at 0°, if inner chamber ports of the tube sections 1-4 are arranged at 0°, 90°, 270°, and 180°, respectively, then the cylinders can be ignited in the firing order 1-2-4-3. By arranging the inner chamber ports 708 on the distribution tube at different azimuthal angles, the inner chamber ports 708 and the outer chamber ports 706 can overlap with each other at different timing, by which the cylinders can have different firing orders.
By rotating the timing tube 702 in the tubular cavity (e.g., using the timing driving gear 508 ), the timings of opening the flow areas between the outer chamber ports 706 and the inlet/outlet ports can affect timing of the air (or the exhaust gas) entering (or exiting) the chambers. This is similar to VVT control on a conventional ICE. By adjusting the timings relative to default timings, the air (or the exhaust gas) can enter (or exit) the chambers earlier or later. For example, by delaying discharging the exhaust, the expansion cycle can be prolonged, and the Atkinson/Miller cycle can be implemented.
The flow areas between the inner chamber ports 708 and the outer chamber ports 706 can affect cross-sectional areas of air inflows and exhaust outflows. The flow areas of the air inflows can be referred to as “intake flow areas.” The flow areas of the exhaust outflows can be referred to as “exhaust flow areas.” For ease of explanation without causing ambiguity, the term “flow area” used hereinafter can refer to an intake flow area, an exhaust flow area, or both. By changing the flow areas, the speed and/or amount of the air inflows and exhaust outflows can be controlled. This is similar to VVL (or duration) control on a conventional ICE. The flow areas can be adjusted by sliding the distribution tube 704 in a relative axial direction (axially inward or outward along the driving shaft 710 ) inside the timing tube 702. For example, the timing tube 702 can be axially fixed in the tubular cavity and the distribution tube 704 is slid. For another example, the distribution tube 704 can be axially fixed in the tubular cavity and the timing tube 702 is slid. It should be noted that it is effectively equivalent when either the distribution tube or the timing tube is axially fixed.
To actuate the distribution tube 704, a resilience means 714 (e.g., a wave spring) can be placed at a first end (referred to as a “spring end”) of the tubular assembly 700B between the inner wall of the timing tube 702 and the outer wall of the distribution tube 704. The resilience means 714 can push the distribution tube 704 axially outward along the axial direction 718. The resilience means can be any other means that can bounce the distribution tube 704 axially under pressure.
In
The shaft head 722 can include a shaft gear 726 (e.g., an external gear) fixed on a shaft head body 724. The shaft head body 724 can be placed inside the timing tube 702 against its inner wall. The shaft gear 726 can slidingly engage the tube gear 720. The shaft head 722 can drive the distribution tube 704 to rotate inside the timing tube 702. Because of the sliding engagement between the shaft gear 726 and the tube gear 720, the distribution tube 704 can move axially along the axial direction 718 while being driven by the shaft head 722. For example, pressurized oil can be used to push the distribution tube inward, and the resilience means 714 can push the distribution tube outward when the oil pressure is released. It should be noted that various ways can be implemented to slidingly engage the tube gear 720 and the shaft gear 726, such as one or more gear teeth or keys, not limited to gears.
In some implementations, to axially actuate the distribution tube 704, electrical actuators (e.g., a stepping motor or a solenoid valve) can be used. In some implementations, hydraulic actuators (e.g., a pressure oil chamber) can be used.
By adjusting the oil pressure, the distribution tube 704 can be controlled to move axially with the reaction of the resilience means 714. For example, the oil path can be connected to the oil system of the engine and the oil volume and pressure inside the pressure oil chamber 744 can be controlled as the engine RPM changes. When the RPM increases, the oil pressure of the oil system can also increase, and oil can be pumped into the pressure oil chamber 744, in which the distribution tube 704 can be pushed axially inward (i.e., towards the resilience means 714 ) by the hydraulic pressure of the oil. When the RPM increases, the oil pressure of the oil system can also decrease, and the oil can be pumped out of the pressure oil chamber 744, in which the distribution tube 704 can be pushed axially outward (i.e., away from the resilience means 714 ) by the resilience means 714. In some implementations, if the distribution tube 704 is axially fixed and the timing tube 702 is axially movable, similar schemes can be used for controlling axial movement of the timing tube 702 using the hydraulic pressure of the oil and the resilience means, which will not be detailed hereinafter.
In
For example, timing-tube seal grooves including an example seal groove 754 can be arranged on the outer wall of the timing tube 702. The timing-tube seal grooves can form sealed hydraulic chambers for angular movement of the timing tube 702 inside the tubular cavity. Seals installed in the seal groove 754 can withstand high temperature and pressure, which can seal potential leak from the sealed section, and form a gap between the outer wall of the timing tube 702 for cooling the engine and lowering the frictions. For another example, distribution-tube seal grooves including an example seal groove 755 can be arranged on the outer wall of the distribution tube 704. The distribution-tube seal grooves can form sealed hydraulic chambers for axial movements of the distribution tube 704 inside the timing tube 702.
Lubricative coatings can be applied on bearing surfaces in the tubular systems to lower frictions. For example, the inner wall of the tubular cavity, the inner wall and the outer wall of the timing tube 702, and the outer wall of the distribution tube 704 can be coated with a layer of diamond-like carbon (DLC).
In some implementations, the distribution tube 704 can be set at a default or neutral position by adjusting the hydraulic pressure of the oil. For example, in
In some implementations, the flow areas can be adjusted according to engine working conditions. For example, the flow areas can be adjusted by controlling the oil pump or oil valve by the ECU based on the engine working conditions. The engine working conditions can include engine working modes (e.g., an Otto cycle or an Atkinson/Miller cycle), engine RPMs, oil pressures, throttle positions, engine temperatures, transmission gears, mass air flows, driving modes set by a driver, or any suitable type of parameters. The engine working conditions can be monitored using various sensors and fed back to the ECU to determine appropriate flow areas. The control of the flow areas will be detailed in
For example, the default flow areas can be used when the engine is just started or running at low speed. The default flow areas can be set to be small, in which the engine can be easier to be started, more air can be charged into the chamber due to larger inertia, and the fuel efficiency can be increased. After starting the engine, the flow areas can be increased (e.g., continually or variably increased) to allow more air to be charged into the chamber. The flow areas can also be adjusted to change the valve timing for implementing the Atkinson/Miller cycle. In some implementations, the flow areas can be adjusted and controlled by the ECU in accordance with a calibrated performance map.
In some implementations, the size of the flow areas can be adjusted by adjusting the distribution tube axially. By adjusting the timing tube angularly, timings and/or phases for opening or closing the flow areas can be adjusted, such as intake opening timings, intake closing timings, exhaust opening timings, and exhaust closing timings. The intake/exhaust timings and phases herein refer to positions of the pistons and crankshafts of an engine when the intake/exhaust opens or closes. Details of adjusting the flow areas and the timings will be set forth in
In some implementations, if hydraulic actuators are used for the inner tube, when the RPM increases, the oil pressure also increases in the oil system that can cause oil to be pumped into the pressure oil chamber 744, by which the inner tube is pushed. In some other implementations, electric actuators can also be used for pushing the inner tube.
The delayed valve timing can be used for switching the engine from working in the Otto cycle to the Atkinson/Miller cycle.
In some implementations, the valve timing can be adjusted according to engine working conditions. For example, when the engine is just started, the default valve timing can be shown in
It should be noted that for an engine using two tubular systems for intake and exhaust, the flow areas and valve timing for the intake and exhaust tubular assemblies can be controlled independently or interdependently. For example, the valve timing of the intake and exhaust tubular assemblies can be delayed at different times (i.e., non-simultaneously). For another example, the flow areas of the intake and exhaust tubular assemblies can be different.
In
According to implementations of this disclosure, an engine can use the disclosed cylinder head with either one or two tubular systems. For small engine designs, the cylinder head can use a single-tube design that integrates intake sections and exhaust sections into a single-tube assembly. In the single-tube assembly, the timing of the charging and exhaust is determined by relative positions of the chamber ports. The single-tube assembly can further reduce weight and dimension of the cylinder head.
In some implementations, the timing tube of the tubular system can be used to implement engine braking and/or deactivating one or more cylinders (referred to as “cylinder deactivation”) by selectively blocking some or all of the cylinders. When a cylinder is blocked at its inlet or outlet port, the air inflow or the exhaust outflow of the cylinder is substantially stopped from entering or exiting the cylinder.
For example, in an implementation, the first outer chamber ports 1006 can be used by default, which activates the 4 cylinders. When the timing tube 1002 is rotated in the first direction 1012 for a first degree, the second outer chamber ports 1008 can align with the inlet/outlet ports of the cylinders 1 and 4, in which the cylinders 1 and 4 are activated (or the cylinders 2 and 3 are deactivated). When the timing tube 1002 is rotated in the second direction 1014 for a second degree, the third outer chamber ports 1010 can align with the inlet/outlet ports of the cylinders 2 and 3, in which the cylinders 2 and 3 are activated (or the cylinders 1 and 4 are deactivated). The timing tube 1002 is rotated in the first direction 1012 or the second direction 1014 for a third degree such that no outer chamber port aligns with the inlet/outlet ports of any of the cylinders 1-4, in which all of the cylinders 1-4 are deactivated and the engine braking function starts.
The disclosed cylinder head integrated with tubular systems can be controlled by an engine control unit (ECU). Engine working conditions can be measured by various sensors and fed back to the ECU. Based on the sensed engine working conditions, the flow areas and the timing positions can be automatically adjusted by the ECU through electric or hydraulic actuators. The ECU is also upgradeable to adapt to performance needs of the engine via software development. Compared with conventional VVL and VVT techniques, the disclosed cylinder head can control the intake flow area and the exhaust flow area independently. The disclosed cylinder head can also control the flow areas and the timing positions independently. The disclosed cylinder head can achieve more precise and continuous control for the flow areas and the intake/exhaust timings, better engine performance, and higher fuel economy.
In some implementations, the sensors can include an engine coolant temperature sensor, an oil pressure sensor, an oil pressure control valve sensor, a throttle position sensor, a crankshaft position sensor, a mass air flow sensor, an intake tube timing sensor, a timing tube position sensor, a distribution tube position sensor, an angularity sensor, a transmission/gear sensor, an RPM sensor, or any other sensor for measuring engine working conditions. The data collected by the sensors can be inputted to the ECU to determine actual tube positions (e.g., the flow areas and timing positions), and calculate target tube positions for a target flow area and a target timing position for optimization of fuel economy and emission reduction while maintaining the power output of the engine.
For example, based on an oil pressure collected by the oil pressure sensor, the ECU can determine an engine working condition (e.g., at a low RPM), and actuate (e.g., via a hydraulic valve or an electric solenoid valve) one or more timing tubes to axially move with respect to their corresponding distribution tubes to change the intake/exhaust flow areas. In addition, the ECU can also actuate the timing tubes to change the timing positions for switching the engine to work in different modes (e.g., the Atkinson/Miller cycle and the Otto cycle). For example, when the engine decreases its RPMs, the flow areas can be automatically decreased, and the timing positions can be automatically set for the engine to run in an Atkinson/Miller cycle. When the engine increases its RPMs, the flow areas can be automatically increased, and the timing positions can be automatically set for the engine to run in an Otto cycle. For another example, based on the sensed engine working conditions, the cylinder head can be automatically or manually switched to implement engine brake and/or cylinder deactivation functions.
It should be noted that
The target flow areas and the target timing positions can be calibrated using designed working conditions (e.g., sample RPMs, loadings, torques, or throttle body positions) and stored in the ECU. The calibration can generate map data between the corresponding working conditions, the target flow areas, and the target timing positions.
Table A shows an example calibrated control map between target timing positions and their corresponding working conditions. The values of the calibrated control map can be optimized for fuel efficiency. It should be noted that all values in Table A are examples only.
Actual values of the parameters in Table A can be optimized according to real engine working conditions.
The implementations herein can be described in terms of functional block components and various processing steps. The disclosed processes and sequences can be performed alone or in any combination. Functional blocks can be realized by any number of hardware and/or software components that perform the specified functions. For example, the described implementations can employ various integrated circuit components (e.g., memory elements, processing elements, logic elements, look-up tables, and the like), which can carry out a variety of functions under the control of one or more microprocessors or other control devices. Similarly, where the elements of the described implementations are implemented using software programming or software elements, the disclosure can be implemented with any programming or scripting languages, with the various algorithms being implemented with any combination of data structures, objects, processes, routines, or other programming elements. Functional aspects can be implemented in algorithms that execute on one or more processors. Furthermore, the implementations of the disclosure could employ any number of conventional techniques for electronics configuration, signal processing and/or control, data processing, and the like. The steps of all methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly indicated by the context.
In this disclosure, the terms “signal,” “data,” and “information” are used interchangeably. The use of “including” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” “coupled,” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
The term “example” is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “example” is not necessarily to be construed as being preferred or advantageous over other aspects or designs. Rather, use of the word “example” is intended to present concepts in a concrete fashion.
In addition, the articles “a” and “an” as used in this disclosure and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from the context to be directed to a singular form. Moreover, use of the term “an aspect” or “one aspect” throughout this disclosure is not intended to mean the same implementation or aspect unless described as such. Furthermore, recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein.
As used in this disclosure, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or” for the two or more elements it conjoins. That is, unless specified otherwise, or clearly indicated otherwise by the context, “X includes A or B” is intended to mean any of the natural inclusive permutations thereof. In other words, if X includes A; X includes B; or X includes both A and B, then “X includes A or B” is satisfied under any of the foregoing instances. The term “and/or” as used in this disclosure is intended to mean an “and” or an inclusive “or.” That is, unless specified otherwise, or clearly indicated otherwise by the context, “X includes A, B, and/or C” is intended to mean X can include any combinations of A, B, and C. In other words, if X includes A; X includes B; X includes C; X includes both A and B; X includes both B and C; X includes both A and C; or X includes all of A, B, and C, then “X includes A and/or B” is satisfied under any of the foregoing instances. Similarly, “X includes at least one of A, B, and C” is intended to be used as an equivalent of “X includes A, B, and/or C.”
The aspects shown and described herein are illustrative examples of the disclosure and are not intended to otherwise limit the scope of the disclosure in any way. For the sake of brevity, conventional electronics, control systems, software development, and other functional aspects of the systems (and components of the individual operating components of the systems) cannot be described in detail herein. Furthermore, the connecting lines or connectors shown in the various figures presented are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements. Many alternative or additional functional relationships, physical connections, or logical connections can be present in a practical device.
While this disclosure has been described with reference to certain embodiments, it is to be understood that the disclosure is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope is to be accorded the broadest interpretation as is permitted under the law so as to encompass all such modifications and equivalent arrangements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201710661831.7 | Aug 2017 | CN | national |
This application claims priority to Chinese Patent Application No. 201710661831.7, filed on Aug. 4, 2017, which claims priority to U.S. Provisional Patent Application Ser. No. 62/501,403, filed on May 4, 2017, the contents of both of which are hereby incorporated by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| 62501403 | May 2017 | US |
