Patent Application
20170321622
The present disclosure relates generally to powertrain systems for motor vehicles. More specifically, aspects of this disclosure relate to internal combustion engines with a cylinder head configuration having an integrated exhaust manifold.
Conventional motor vehicles, such as the modern-day automobile, include a powertrain that operates to propel the vehicle and power the onboard vehicle electronics. The powertrain, which is inclusive of and sometimes improperly referred to as a drivetrain, is generally comprised of an engine that delivers driving power to the vehicle's final drive system (e.g., rear differential, axle, and wheels) through a multi-speed power transmission. Automobiles have traditionally been powered by a reciprocating-piston type internal combustion engine (ICE) because of its ready availability and relatively inexpensive cost, light weight, and overall efficiency. Such engines include two or four-stroke compression-ignited diesel engines and four-stroke spark-ignited gasoline engines. Hybrid vehicles, on the other hand, utilize alternative power sources, such as electric motor-generators, to propel the vehicle, minimizing reliance on the engine for power and increasing overall fuel economy.
A typical over-head valve internal combustion engine includes an engine block with cylinder bores each having a piston reciprocally movable therein. Coupled to a top surface of the engine block is a cylinder head that cooperates with the piston and cylinder bore to form a variable-volume combustion chamber. These reciprocating pistons are used to convert pressure, generated by igniting a fuel-and-air mixture in the combustion chamber, into rotational forces to drive a crankshaft. The cylinder head defines intake ports through which air, provided by an intake manifold, is selectively introduced to the combustion chamber. Also defined in the cylinder head are exhaust ports through which exhaust gases and byproducts of combustion are selectively evacuated from the combustion chamber to an exhaust manifold. The exhaust manifold, in turn, collects and combines the exhaust gases for recirculation into the intake manifold, delivery to a turbine-driven turbocharger, or evacuation from the ICE via an exhaust system.
A conventional cylinder head (or heads, if the engine has multiple banks of cylinders) is an aluminum or iron casting that is detachable from the engine block, and contains the ICE's spark plugs, inlet valves, exhaust valves, and, in some instances, a camshaft. Typically, the exhaust manifold is affixed to the side of the cylinder head, e.g., by bolts and a manifold gasket. The exhaust manifold communicates with the exhaust ports to deliver exhaust gases to an exhaust after treatment system and exhaust silencer for subsequent release to the atmosphere. The exhaust manifold, which is typically formed from stainless steel or cast iron, includes runners coupled with the cylinder head exhaust ports. An exhaust manifold collector volume is in downstream fluid communication with the runners to pool the exhaust gases prior to delivery to the components of the vehicle exhaust system. Recently, cylinder heads have been designed with the exhaust manifold, i.e., the exhaust runners and exhaust collector volume, internally defined by the cylinder head casting to integrally form an integrated exhaust manifold (IEM).
Disclosed herein are integrated exhaust manifold (IEM) cylinder heads for a motor vehicle engine, methods for making and methods for using IEM cylinder heads, and motor vehicles with an internal combustion engine (ICE) including one or more IEM cylinder heads. By way of example, and not limitation, an improved cylinder head for an ICE of a motor vehicle is disclosed. The cylinder head, which may be of a 6-cylinder V-type configuration (most commonly referred to as a “V6”), has an integrated exhaust manifold with multiple distinct exhaust runners designed to reduce “manifolding effect” within the cylinder head. As an example, the cylinder head is cast with an integrally formed individual runner for each of the cylinders (e.g., one runner per two cylinder exhaust ports). These runners are fluidly isolated and physically segregated from each other to exit the cylinder head without any fluid blending of the exhaust gases from the other cylinders. To accommodate this design, the cylinder head has a separate, fluidly isolated runner exit port for each runner at the flanged exit of the cylinder head manifold. These runner exit ports can optionally be lengthened further within the geometry of the turbo housing, e.g., for increased thermal dissipation and further reduction of manifolding effect (i.e., reduced internal blending of exhaust gas evacuated from multiple cylinders).
Attendant benefits for at least some of the disclosed concepts include optimization of fuel trim for each cylinder by means of sampling the individual exhaust runners in an integrated exhaust manifold instead of calculating an average of multiple runners. The fueling for each cylinder would feed back by virtue of individualized oxygen sensor determination of the oxygen content in the fuel exhaust for that specific cylinder. Individualized sampling within the dedicated exhaust port runner allows for a more accurate fuel trim calculation and air/fuel ratio adjustment for each cylinder. This, in turn, helps to enable improved fuel economy and increased power since all of the cylinders can be run, for example, at substantially identical air/fuel ratios. This design also accommodates an option to “offset” the runner exit ports for turbo or exhaust manifold, e.g., to improve component packaging within the engine compartment. The multi-port IEM cylinder head exit allows for improved cooling of the metallic material at the exhaust port runner flange. When compared to traditional cylinder head and exhaust manifold assemblies, an IEM cylinder head configuration as disclosed herein can also offer reduced emissions, reduced engine weight and width, and the elimination of traditional manifold assembly parts, such as the gasket, heat shield, and manifold fasteners.
Aspects of the present disclosure are directed to exhaust manifolds and cylinder heads for motor vehicle engines. Disclosed, for example, is an IEM cylinder head for a motor vehicle with an engine and an exhaust system. The engine includes an engine block with a multiple cylinder bores and a multiple pistons. Each piston is disposed in a respective one of the cylinder bores. The IEM cylinder head includes a cylinder head body that is configured to attach to the engine block. The cylinder head body integrally defines: a plurality of chamber surfaces, each of which is configured to align with a respective one of the cylinder bores and pistons to cooperatively define a combustion chamber; a plurality of exhaust ports, each of which is configured to communicate with a respective one of the cylinder bores and evacuate exhaust gas therefrom; a plurality of runner exit ports, each of which is configured to communicate with the exhaust system to evacuate exhaust gas from the cylinder head body; and a plurality of exhaust runners, each of which extends from an exhaust port to one of the runner exit ports. The exhaust runners are segregated and fluidly isolated from each other such that each runner transmits exhaust gases from a single cylinder bore to the exhaust system through a single runner exit port.
Other aspects of the present disclosure are directed to motor vehicles with one or more integrated exhaust manifolds. A “motor vehicle,” as used herein, may include any relevant vehicle platform, such as passenger vehicles (internal combustion engine (ICE), hybrid, etc.), industrial vehicles, buses, all-terrain vehicles (ATV), motorcycles, farm equipment, boats, airplanes, etc. In one example, a motor vehicle is disclosed that includes a vehicle body with an engine compartment. An exhaust system with an exhaust discharge pipe is attached to the vehicle body. Disposed within the vehicle's engine compartment is an internal combustion engine (ICE) assembly. The ICE assembly includes an engine block having a cylinder bank with a series of cylinder bores. A piston is reciprocally movable within each one of these cylinder bores. In a V-type engine configuration, the ICE assembly would include multiple cylinder banks.
The ICE assembly also includes an integrated exhaust manifold (IEM) cylinder head with a single-piece unitary cylinder head body that is attached to the engine block on top of the cylinder bank. In a V-type engine configuration, the ICE assembly may include multiple IEM cylinder heads, e.g., one for each cylinder bank. The cylinder head body integrally defines: a series of chamber surfaces, each of which is aligned with a respective cylinder bore and piston to cooperatively define a combustion chamber; a series of exhaust ports, each of which is fluidly coupled to one of the cylinder bores to evacuate exhaust gas therefrom; a flange region that projects from an outer surface of the cylinder head body and includes a series of runner exit ports fluidly coupled to the exhaust discharge pipe to evacuate exhaust gas from the cylinder head body; and a series of exhaust runners, each of which extends from an exhaust port to one of the runner exit ports. The runner exit ports are segregated and fluidly isolated from each other such that each exit port evacuates to the exhaust system the exhaust gases from a single one of the exhaust runners. Likewise, the exhaust runners are segregated and fluidly isolated from each other such that each runner evacuates through a single one of the runner exit ports exhaust gases from a single one of the cylinder bores.
According to other aspects of the present disclosure, methods of making and methods of using engine cylinder heads are presented. For instance, a method of constructing an IEM cylinder head for a motor vehicle is disclosed. The motor vehicle includes an engine and an exhaust system. The engine includes an engine block with multiple cylinder bores and a piston disposed in each one of the cylinder bores. The method includes: forming a cylinder head body that is configured to attach to the engine block; forming on the cylinder head body a plurality of chamber surfaces, each of which is configured to align with a respective one of the cylinder bores and pistons to cooperatively define a combustion chamber; forming on the cylinder head body a plurality of exhaust ports, each of which is configured to communicate with a respective one of the cylinder bores and evacuate exhaust gas therefrom; forming on the cylinder head body a plurality of runner exit ports, each of which is configured to communicate with the exhaust system to evacuate exhaust gas from the cylinder head body; and forming in the cylinder head body a plurality of exhaust runners, each of which extends from a respective one of the exhaust ports to a respective one of the runner exit ports. The exhaust runners are segregated and fluidly isolated from each other to each transmit exhaust gases from a single one of the cylinder bores, through a single one of the runner exit ports, to the exhaust system. In at least some embodiments, the forming steps of the method include casting the cylinder head body—including the chamber surfaces, the exhaust ports, the runner exit ports, and the exhaust runners—from a metallic material (e.g., cast aluminum, stainless steel or cast iron) as a single-piece, unitary structure.
The above summary is not intended to represent every embodiment or every aspect of the present disclosure. Rather, the foregoing summary merely provides an exemplification of some of the novel aspects and features set forth herein. The above features and advantages, and other features and advantages of the present disclosure, will be readily apparent from the following detailed description of representative embodiments and modes for carrying out the present disclosure when taken in connection with the accompanying drawings and the appended claims.
The present disclosure is susceptible to various modifications and alternative forms, and some representative embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the novel aspects of this disclosure are not limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, combinations, subcombinations, and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.
This disclosure is susceptible of embodiment in many different forms. There are shown in the drawings and will herein be described in detail representative embodiments of the disclosure with the understanding that the present disclosure is to be considered as an exemplification of the principles of the disclosure and is not intended to limit the broad aspects of the disclosure to the embodiments illustrated. To that extent, elements and limitations that are disclosed, for example, in the Abstract, Summary, and Detailed Description sections, but not explicitly set forth in the claims, should not be incorporated into the claims, singly or collectively, by implication, inference or otherwise. For purposes of the present detailed description, unless specifically disclaimed: the singular includes the plural and vice versa; the words “and” and “or” shall be both conjunctive and disjunctive; the word “all” means “any and all”; the word “any” means “any and all”; and the words “including” and “comprising” and “having” mean “including without limitation.” Moreover, words of approximation, such as “about,” “almost,” “substantially,” “approximately,” and the like, can be used herein in the sense of “at, near, or nearly at,” or “within 3-5% of,” or “within acceptable manufacturing tolerances,” or any logical combination thereof, for example.
Referring now to the drawings, wherein like reference numbers refer to like features throughout the several views, there is shown in
There is shown in
First and second integrated exhaust manifold (IEM) cylinder heads 18A and 18B are respectively mounted to the first and second cylinder banks 17A, 17B, e.g., via threaded fasteners (not shown). Chamber surfaces 23, integrally formed along the bottom of each IEM cylinder head 18A, 18B, are positioned to each align with one of the cylinder bores 19, as well as the piston 15 disposed therein, to cooperatively define a variable-volume combustion chamber. This pair of IEM cylinder heads 18A, 18B defines a corresponding number of exhaust ports 21 (e.g., one or two ports per combustion chamber) through which exhaust gases and byproducts of combustion are selectively evacuated from the cylinder bores 19. Each exhaust port 21 communicates exhaust gases—such as through a dedicated exhaust runner 20—to a respective runner exit port 22, all of which are defined within the cylinder head 18A, 18B. The runner 20 and exit port 22 features of the IEM are formed integrally with the respective cylinder heads 18A, 18B, thereby obviating the need for fasteners and gaskets typically required for exhaust manifold attachment. In so doing, the exhaust runners 20 are extensions of the exhaust ports 21 for connecting each exhaust port 21 to an exit port 22 in the cylinder head 18A, 18B to evacuate exhaust gas from the engine 12. A respective discharge pipe 26 is in fluid communication with each integral exhaust manifold, namely the runner exit port 22. Potential exhaust gas leak paths during operation of the ICE assembly 12 are reduced by integrally forming the IEM features are with the cylinder heads 18A, 18B.
In the example illustrated in
Referring to
The cylinder head 112 has an integrated exhaust manifold 130 (
In the illustrated example, the runner exit ports 136A-136C are the only exhaust outlets of the integrated exhaust manifold 130. Thus, each of the cylinders 116A-116C has a separate, dedicated exhaust runner 132A-132C, respectively, and thus a physically segregated, fluidly isolated unique flow path through the integrated exhaust manifold 130. At no point do any of the runners merge, for example, at an internal exhaust manifold collector volume to form a common flow passage before exiting the IEM cylinder head 112. This design allows for individual cylinder trim while accommodating an option to offset the runner exit ports, which helps to improve fuel economy, engine power, and engine packaging. It should be recognized that the number of inlet point(s) 134A-134C per runner 132A-132C will typically depend on the number of exhaust ports in each cylinder 116A-116C. Likewise, the number of runners and commensurate number of exits can be modified, for example, to accommodate engines with a different cylinder count.
Similar to the IEM cylinder heads 18A, 18B illustrated in
As seen in
Turning back to
While aspects of the present disclosure have been described in detail with reference to the illustrated embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the scope of the present disclosure. The present disclosure is not limited to the precise construction and compositions disclosed herein; any and all modifications, changes, and variations apparent from the foregoing descriptions are within the spirit and scope of the disclosure as defined in the appended claims. Moreover, the present concepts expressly include any and all combinations and subcombinations of the preceding elements and features.
