Water jacket for an internal combustion engine

A water jacket having a coolant flow crossing the space over the cylinder head is provided for an internal combustion engine of an automotive system. The internal combustion engine is equipped with a cylinder and a cylinder head. The water jacket includes a lower water jacket having side passages surrounding the cylinder and connected together by a plurality of branches disposed over the cylinder head, so as to create the coolant flow crossing the space over the cylinder head.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Great Britain Patent Application No. 1503699.9, filed Mar. 4, 2015, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure pertains to a water jacket for an internal combustion engine.

BACKGROUND

It is known that internal combustion engines are equipped with a cooling system. The cooling system is generally provided for cooling down the internal combustion engine, as well as other engine fluids, such as for example the exhaust gas in the EGR cooler and/or the lubricating oil in the oil cooler.

The cooling system schematically includes a coolant pump that delivers a coolant fluid, typically a mixture of water and antifreeze, from a coolant tank to a plurality of cooling channels internally defined by the engine block and the cylinder head and forming a so-called cylinder water jacket.

Once the coolant is circulated through a cylinder water jacket, it may be diverted to another portion of the internal combustion engine, namely the cylinder head, to remove additional excess heat or it may be pumped to a heat exchanger where heat is removed from the coolant prior to being returned to the engine.

In a known embodiment, a cylinder block of an internal combustion engine has an inner side wall defining the cylinder bores and an outer side wall surrounding the inner side wall. A cylinder block water jacket is defined by the inner side wall and the outer side wall. A cooling water inlet is formed in one end of the cylinder block. Cooling water flows through the cooling water inlet into the cylinder block water jacket. The cooling water supplied through the cooling water inlet into the cylinder block water jacket is divided into two cooling water streams, one for each side of the cylinder block, by means of two side passages through which the cooling water flows in a longitudinal direction from the cooling water inlet to a cooling water outlet.

Known water jackets for internal combustion engines leave open a series of issues. A first issue is that the coolant flows in the engine block on both sides of the cylinder head, namely the intake and exhaust side, leading to difficulties in managing and calibrating both coolant flows in the deck cooling area, in order to have good balancing among cylinders. Furthermore, known water jackets are penalized by a high pressure drop and need a significant volume of coolant to operate properly. Finally, known water jackets may be costly to produce due to casting and manufacturing difficulties.

SUMMARY

In accordance with the present disclosure a water jacket for an internal combustion engine having a calibrated coolant flow and improved efficiency of the flow without using external devices and an internal combustion engine in which all its main features are integrated in the same head casting.

An embodiment of the disclosure provides a water jacket for an internal combustion engine of an automotive system, the internal combustion engine being equipped with a cylinder and a cylinder head. The water jacket includes a lower water jacket having side passages surrounding the cylinder. The side passages are connected together by a plurality of branches disposed over the cylinder head, so as to create a coolant flow crossing the space over the cylinder head. An advantage of this embodiment is that it transforms the longitudinal flow of the coolant fluid into a cross flow coolant fluid over the cylinder head and at the same time allows calibration of the coolant flow and improvement of the efficiency of coolant flow.

According to another embodiment of the present disclosure, the side passages are connected together, in their closest mutual position, by a couple of connecting branches. An advantage of this embodiment is that it allows to create part of the cross flow of the coolant fluid over the cylinder head. According to another embodiment of the present disclosure, the branches connecting together the side passages include, for each cylinder, a longitudinal branch positioned over the cylinder head and crossing a part of the a middle portion thereof. An advantage of this embodiment is that it forms part of a structure allowing cross flow of the coolant fluid over the cylinder head.

According to still another embodiment of the present disclosure, each longitudinal branch is connected to the connecting branches by middle branches positioned over the cylinder head and crossing a part thereof. An advantage of this embodiment is that it completes a structure allowing cross flow of the coolant fluid over the cylinder head.

According to still another embodiment of the present disclosure, the lower water jacket includes dedicated channels for the coolant to reach components of the automotive system to be cooled, each dedicated channel stemming from one of the side passages and being configured to reach a specific component. An advantage of this embodiment is that is cools only the components of interest of the automotive system and, at the same time, calibrates the sectional areas of the dedicated channel in order to optimize the coolant flow.

According to another embodiment of the present disclosure, the lower water jacket is in fluid communication with an upper water jacket by means of passages, which derive the coolant from ports in the side passages of the lower water jacket. An advantage of this embodiment is that the coolant fluid flows from the lower water jacket to the upper water jacket and, at the same time, permits inspection of the connection between lower and upper portions of the water jacket.

According to another embodiment of the present disclosure, the lower water jacket is in fluid communication with the upper water jacket by inclined branches that are connected to the connecting branches. An advantage of this embodiment is that the structure allows the flow of the coolant fluid from the lower water jacket to the upper water jacket.

According to another embodiment of the present disclosure, the upper water jacket includes dedicated channels for the coolant to reach a specific component of the automotive system to be cooled. An advantage of this embodiment is that it cools only the components of interest of the automotive system from above.

According to another embodiment of the present disclosure, the upper water jacket is superimposed to the lower water jacket in such a way to create a cage structure for an exhaust manifold of the internal combustion engine, the cage structure including the dedicated channels of the lower water jacket and the dedicated channels of the upper water jacket. An advantage of this embodiment is that it allows to calibrate the integrated exhaust manifold cooling circuit independently from the deck cooling.

According to a further embodiment of the present disclosure, the upper water jacket and the lower water jacket are in fluid communication with a ring which is proximal to a coolant outlet of the water jacket.

Another embodiment of the present disclosure includes an automotive system including a water jacket for an internal combustion engine. The components of the automotive system to be cooled by the coolant fluid flowing in the water jacket are a turbine flange, an EGR valve element and an EGR valve flange.

DETAILED DESCRIPTION

Some embodiments may include an automotive system100, as shown inFIGS. 1 and 2including an internal combustion engine (ICE)110having an engine block120defining at least one cylinder125having a piston140coupled to rotate a crankshaft145. A cylinder head130cooperates with the piston140to define a combustion chamber150. A fuel and air mixture (not shown) is disposed in the combustion chamber150and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston140. The fuel is provided by at least one fuel injector160and the air through at least one intake port210. The fuel is provided at high pressure to the fuel injector160from a fuel rail170in fluid communication with a high pressure fuel pump180that increases the pressure of the fuel received from a fuel source190. Each of the cylinders125has at least two valves215, actuated by a camshaft135rotating in time with the crankshaft145. The valves215selectively allow air into the combustion chamber150from the port210and alternately allow exhaust gases to exit through a port220. In some examples, a cam phaser155may selectively vary the timing between the camshaft135and the crankshaft145.

The air may be distributed to the air intake port(s)210through an intake manifold200. An air intake duct205may provide air from the ambient environment to the intake manifold200. In other embodiments, a throttle body330may be provided to regulate the flow of air into the manifold200.

In still other embodiments, a forced air system such as a turbocharger230, having a compressor240rotationally coupled to a turbine250, may be provided. Rotation of the compressor240increases the pressure and temperature of the air in the duct205and manifold200. An intercooler260disposed in the duct205may reduce the temperature of the air. The turbine250rotates by receiving exhaust gases from an exhaust manifold225that directs exhaust gases from the exhaust ports220and through a series of vanes prior to expansion through the turbine250. The exhaust gases exit the turbine250and are directed into an exhaust system270. This example shows a variable geometry turbine (VGT) with a VGT actuator290arranged to move the vanes to alter the flow of the exhaust gases through the turbine250. In other embodiments, the turbocharger230may be fixed geometry and/or include a waste gate.

The exhaust gases of the engine are directed into an exhaust system270. The exhaust system270may include an exhaust pipe275having one or more exhaust aftertreatment devices280. The aftertreatment devices may be any device configured to change the composition of the exhaust gases. Some examples of aftertreatment devices280include, but are not limited to, catalytic converters (two and three way), oxidation catalysts, lean NOxtraps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, and particulate filters. Other embodiments may include an exhaust gas recirculation (EGR) system300coupled between the exhaust manifold225and the intake manifold200. The EGR system300may include an EGR cooler310to reduce the temperature of the exhaust gases in the EGR system300. An EGR valve320regulates a flow of exhaust gases in the EGR system300.

The automotive system100may further include an electronic control unit (ECU)450in communication with one or more sensors and/or devices associated with the ICE110and with a memory system, or data carrier, and an interface bus. The ECU450may receive input signals from various sensors configured to generate the signals in proportion to various physical parameters associated with the ICE110. The sensors include, but are not limited to, a mass airflow and temperature sensor340, a manifold pressure and temperature sensor350, a combustion pressure sensor360, coolant and oil temperature and level sensors380, a fuel rail pressure sensor400, a cam position sensor410, a crank position sensor420, exhaust pressure and temperature sensors430, an EGR temperature sensor440, and an accelerator pedal position sensor445. Furthermore, the ECU450may generate output signals to various control devices that are arranged to control the operation of the ICE110, including, but not limited to, the fuel injectors160, the throttle body330, the EGR Valve320, a Variable Geometry Turbine (VGT) actuator290, and the cam phaser155. Note, dashed lines are used to indicate communication between the ECU450and the various sensors and devices, but some are omitted for clarity.

Referring now toFIG. 3, a water jacket500for the internal combustion engine110, according to an embodiment of the present disclosure, is represented as applied to a three cylinders engine. The water jacket500is subdivided in a lower water jacket510and an upper water jacket520, the lower water jacket510being positioned on top of the cylinder head130and the upper water jacket520being positioned on top of the lower water jacket510. The upper water jacket520is superimposed onto the lower water jacket510in such a way to create a cage structure530for the exhaust manifold225(not represented inFIG. 3for simplicity) of the internal combustion engine110.

The coolant, typically a mixture of water and antifreeze, enters into the cylinder block (not represented inFIG. 3for simplicity) through coolant inlet540and, after circulation through the lower water jacket510and the upper water jacket520, exits through coolant outlet550in correspondence of EGR valve320.

InFIG. 4, a top view of the lower water jacket510is represented. The lower water jacket510surrounds the cylinder block120and has a portion which is subdivided in two side passages600,601, one for each side of the cylinder block120, whereby side passages600,601substantially follow the external shape of the cylinders125. The coolant entering the cylinder block120from inlet540follows the path represented with arrows F1and F2in FIG.6and reaches outlets620and630in the lower water jacket510from which the coolant respectively flows through side passages600,601.

The lower water jacket510also includes, between each cylinder125, connecting branches615and625that connects together side passage600with side passage601, preferably joining them in their closest mutual position. Furthermore, the lower water jacket510also includes, for each cylinder125, a longitudinal branch610which is disposed over the cylinder head130and is connected, on one side to side passage601and to the other side to middle branches606and608, each middle branch606and608stemming either from connecting branches615and625or from a couple of side branches602and604. More specifically, the water jacket500include, for each cylinder125, a longitudinal branch610positioned over the cylinder head130and crossing a part of the middle portion thereof. Moreover, each longitudinal branch610is connected to the connecting branches615,625by means of the middle branches606,608positioned over the cylinder head130and crossing a part thereof.

The above described configuration has the effect of creating a structure suitable for transforming a longitudinal flow of the coolant on both sides of the cylinder block into a cross flow of the coolant over the cylinder head130, which allows calibrated coolant fluid flow and improved efficiency of coolant flow without using external devices. More specifically, calibration of the diameters and shapes of the various described branches allows to optimize the coolant flow velocity in the various areas of the water jacket.

FIG. 5is a top view of the lower water jacket510ofFIG. 3. The lower water jacket510is represented as provided with outlet channels. More specifically, the lower water jacket510is provided, in correspondence with each cylinder125, with two channels each, and each channel having a calibrated section to optimize the balance of the coolant flow. In particular, a first couple of channels800,810runs from side passage601towards an area where a flange900for the turbine250is positioned.

A second couple of channels820,830runs from side passage601towards an area where an EGR valve element910is positioned and a third couple of channels840,850runs from side passage601towards an area where an EGR valve flange920is positioned. Each couple of channels may converge in a single duct before reaching the respective element to be cooled. Furthermore, this configuration allows to cool only the elements in the critical areas including the turbine flange900, the EGR valve element910and the EGR valve flange920.

Referring now toFIG. 7, a further embodiment of the present disclosure is disclosed, wherein the lower water jacket510and the upper water jacket520are connected by means of passages700which derive the coolant from ports705in the lower water jacket510. The ports705are disposed in the side passages600,601in their closest mutual position. Furthermore, the lower water jacket510is connected to the upper water jacket520by means of inclined branches710that are connected to connecting branches615and625. The particular shape of passages700allows for easy inspection of the connection between lower and upper water jackets510ad520in inspection point703.

FIG. 8is a side view of the water jacket ofFIG. 3where a particular shape of the combination of the lower water jacket510and of the upper water jacket520can be seen. InFIG. 8, straight line C defines the separation between the cylinder block120and the deck, namely the upper portion of the engine110. In this configuration, a ring940is formed in an area of connection of the lower water jacket510with the upper water jacket520, the ring940being formed by a lower portion950, belonging to the lower water jacket510, and by an upper portion960belonging to the upper water jacket520.

As a result, the lower jacket is dedicated to deck cooling only, allowing for better cooling capability for the most critical area. On the other hand, this configuration allows for dedicated cooling for the integrated exhaust manifold225and leaves open the possibility to add a control valve at the outlet. Furthermore the lower portion950and the upper portion960of the ring940form dedicated channels around the exhaust manifold for its cooling and do not affect deck cooling.

InFIG. 9a bottom view of the water jacket500is represented showing the couple of channels800,810,820,830and840,850. InFIG. 10is shown a top view of the water jacket ofFIG. 3where corresponding couple of channels805,815,825,835and845,855are shown.

In operation, the coolant is circulated inside the water jacket500by means of a pump (not represented) and enters into the cylinder block120. As mentioned above, the coolant entering the cylinder block120from inlet540(arrow F3inFIG. 4) follows the path represented with arrows F1and F2inFIG. 6and reaches outlets620and630in the lower water jacket510from which the coolant respectively flow through side passages600,601following a longitudinal flow as represented by arrows F4.

However, once the coolants exits from outlets620and630, the longitudinal flow is transformed into a coolant flow crossing the space over the cylinder head130(horizontal arrows F5ofFIG. 4). Following the small arrows ofFIG. 5, the coolant flows through connecting branches615and625that connects side passage600with side passage601, through middle branches606and608and side branches602and604and, finally, through longitudinal branches610and then exits the portion of the lower water jacket510surrounding the cylinders125.

In particular, a portion of the coolant flow exits through the couple of channels800,810that flow toward the turbine flange900, through the second couple of channels820,830towards the position of the EGR valve element910and through a third couple of channels840,850towards the EGR valve flange920.

A second portion of the coolant flow reaches the upper water jacket520by exiting through ports705and following passage700, while a third portion of the coolant flow fluid exiting from outlets620and630and passing through connecting branches615,625flows through inclined branch710to reach the upper water jacket520. The second and third portions of the coolant flow that have reached the upper water jacket520exit through the couple of channels805,815that flow toward the turbine flange900, through the second couple of channels825,835towards the position of the EGR valve element910and through the third couple of channels845,855towards the EGR valve flange920. Finally both coolant flows unite in the ring940flowing through the lower ring portion950and through the upper ring portion960and exit the water jacket500through coolant outlet550in correspondence of EGR valve320to be recirculated by the pump.