An internal combustion engine includes a combustion chamber having an inlet port and an outlet (exhaust) port. A fuel oxidant (usually air) mixture is introduced into the combustion chamber where it is ignited either by a spark or pressure. Combustion of the fuel oxidant mixture results in expansion of high-temperature and high-pressure (exhaust) gases that directly apply a force to a piston component of the engine. The exhaust gases are then allowed to exit the combustion chamber through the exhaust port and are replaced with a fresh fuel oxidant mixture ready for the next combustion cycle. The process of replacing the exhaust gas in a combustion chamber of an internal combustion engine with the fresh air/oxidant mixture is known as scavenging. If the scavenging process is incomplete remaining exhaust gases in the chamber reduce the level of desired fuel-oxidant charge and can cause improper combustion for the next cycle, leading to reduced power output of the engine.

In naturally aspirated engines the scavenging process is largely driven by the outflow of exhaust gases into the engine's exhaust system. The flow of gas is driven by pressure a gradient so that when the exhaust port of the combustion chamber is opened high-pressure gases in the chamber flow out into the exhaust system where they are ultimately discharged into the atmosphere. The engine must overcome hydraulic resistance, known in the art as backpressure, within the exhaust system in order to fully discharge exhaust gases from within the combustion chamber. Exhaust systems are 'tuned' to assist in filling the combustion chamber with the next intake charge using exhaust scavenging by, depending on engine cycle type, the use of expansion chambers and/or extractors or headers to minimise back-pressure by optimising the exhaust gas velocity away from the combustion chamber.

It is a first object of the present invention to provide an exhaust device and/or an internal combustion engine exhaust system and/or a method for improving the effectiveness of an internal combustion engine exhaust. It is a second object of the present invention to provide an exhaust device and/or an internal combustion engine exhaust system and/or a method of operating an exhaust, which at least provides the public with a useful alternative to exhausts and exhaust systems known hitherto.

According to a general aspect of the invention there is provided an exhaust or exhaust device including an injector arranged in an exhaust duct connected with an internal combustion engine, a reservoir for housing a coolant fluid, a pump fluidical ly connected between the reservoir and the injector for increasing a pressure of the coolant fluid supplied from the reservoir to the injector, and a controller operable to activate the injector during a selected period of a combustion cycle of the internal combustion engine. Generally, the selected period of a combustion cycle includes the exhaust cycle of the engine and more specifically a period where timing of inlet and exhaust valves overlap to scavenge the combustion chambers of the engine. Generally, the coolant fluid is water. Generally, the injector is arranged at a location adjacent an expansion chamber or resonator of the exhaust duct.

According to a first particular aspect of the invention there is provided an exhaust device for an internal combustion engine, the engine having an inlet valve, a chamber for combustion of a fuel and oxidiser mixture, and exhaust valve and an exhaust system in communication with the exhaust valve for carrying high-temperature and high-pressure gases produced by the combustion from within the chamber. The exhaust device includes: i) a reservoir for housing a coolant fluid, ii) an injector arranged to selectively deliver coolant fluid from the reservoir into an internal combustion engine exhaust, iii) a pump for increasing a pressure of the coolant fluid supplied from the reservoir to the injector, and iv) a controller connected with the injector and arranged to activate the injector to selectively deliver coolant fluid from the reservoir under predetermined operating conditions.

Preferably, the controller includes an input for receiving signals from an internal combustion engine controller, the signals representing one or more of a rotational speed of the internal combustion engine, a desired inlet volume of a fuel oxidiser mixture, a position of the inlet valve and a position of the outlet valve. Preferably, the predetermined operating conditions include one or more of a rotational speed of the internal combustion engine, a desired inlet volume of a fuel oxidiser mixture, a position of the inlet valve and a position of the outlet valve.

Preferably, the controller is arranged to selectively activate the injector to deliver coolant fluid into an internal combustion engine exhaust when one of a rotational speed of the internal combustion engine or a desired inlet volume of a fuel oxidiser mixture are above a predefined value.

Preferably, the controller is arranged to selectively activate the injector to deliver coolant fluid into an internal combustion engine exhaust when an open position of an inlet valve overlaps with an open position of an exhaust valve.

Preferably, the exhaust device is connected with the exhaust system of an internal combustion engine.

Preferably, the controller is part of an internal combustion engine controller.

Preferably, the coolant fluid is water.

Preferably, the injector is located adjacent an expansion chamber or resonator of the exhaust system.

According to a second particular aspect of the invention there is provided an internal combustion engine exhaust system including: i) an exhaust duct arranged to carry high-temperature and high-pressure gases produced by combustion in an internal combustion engine, ii) a water tank, iii) an injector fluidically connected to the water tank and arranged to selectively inject water from the tank into the exhaust duct, iv) a pump for increasing a pressure of the water supplied from the tank to the injector, and v) a controller connected with the injector and arranged to activate the injector to selectively deliver water from the tank under predetermined operating conditions of a connected internal combustion engine.

Preferably, the predetermined operating conditions include one or more of: a rotational speed of the internal combustion engine being above a predefined speed, or a desired inlet volume of a fuel oxidiser mixture being above a predefined value, or when an open position of an inlet valve overlaps with an open position of an exhaust valve of the internal combustion engine.

Preferably, the exhaust duct includes an expansion chamber or resonator, and wherein the injector is arranged to selectively inject water from the tank into the exhaust duct upstream of the expansion chamber or resonator.

According to a third particular aspect of the invention there is provided a method of improving the effectiveness of an internal combustion engine exhaust including an exhaust duct arranged to carry high-temperature and high-pressure gases produced by combustion in the internal combustion engine, the method including: providing in an exhaust duct an injector arranged to selectively deliver coolant fluid into the duct, f luidica lly connecting the injector with a pressurised supply of coolant fluid, and selectively activating the injector to deliver coolant fluid into the exhaust duct under predetermined operating conditions of the internal combustion engine.

Preferably, selectively activating the injector is based on one or more of: a rotational speed of the internal combustion engine being above a predefined speed, or a desired inlet volume of a fuel oxidiser mixture being above a predefined value, or when an open position of an inlet valve overlaps with an open position of an exhaust valve of the internal combustion engine. Preferably, providing in the exhaust duct and expansion chamber or resonator, and positioning the injector to deliver coolant fluid into the exhaust duct upstream of the expansion chamber or resonator.

Further aspects of the invention, which should be considered in all its novel aspects, will become apparent to those skilled in the art upon reading of the following description and viewing the attached drawings, which are given by way of example only to illustrate the invention.

Examples of some aspects of the invention are illustrated in the attached drawings, in which:

Figure 1 is a first schematic illustration of an internal combustion engine and exhaust having an exhaust device according to the invention,

Figure 2 is a second schematic illustration of an internal combustion engine and exhaust having an exhaust device according to the invention,

Figure 3 is a graphical representation of potential power benefits using the device or method of the invention,

Figure 4 is a graphical representation of potential torque benefits using the device or method of the invention, and

Figure 5 is a partial second schematic illustration of an internal combustion engine and exhaust having an exhaust device according other examples of the invention.

List of elements indicated in the drawings.

Internal combustion engine 10 (100)

Combustion chamber 12

Cylindrical wall 14

Piston 16

Conrod 18

Crankshaft 20

Inlet port 22

Inlet valve 24

Inlet cam 26

Inlet manifold 28 Fuel air mixture (charge) 30

Sparkplug 32

Outlet (exhaust) port 34

Outlet (exhaust) valve 36

Outlet (exhaust) cam 38

Outlet (exhaust) manifold 40

Exhaust gases 42

Exhaust duct (pipe) 44

Resonator (or expansion chamber) 46

Exhaust tip 48

Injector 50

Pump 52

Reservoir 54

Conduit 56

Fill-port 58

Controller 60

Engine control unit (ECU) 62

Turbo turbine 70

Turbo generator 72

Turbo compressor wheel 74

Secondary water injector 76

Air charge 78

Charged air injection 80

Referring to figures 1 and 2 there is shown a schematic view of an internal combustion engine 10 (100) includes at least one cylinder having a cylinder wall 14 defining a combustion chamber 12 in a top portion of the cylinder. The combustion chamber 12 has an inlet port 22 and an outlet (exhaust) port 34. The inlet port 22 is selectively opened and closed by an inlet valve 24 controlled by an inlet valve cam 26. The outlet port 34 is selectively opened and closed by an outlet valve 36 controlled by an outlet valve cam 38. An inlet manifold 28 communicates with the inlet port for the introduction of a fuel and oxidant (usually air) mixture 30 into the combustion chamber 12 during an open period of the inlet port 22. The fuel air mixture 30 is ignited either by a sparkplug 32, or in some instances pressure. Combustion of the fuel air mixture 30 results in expansion of high-temperature and high-pressure (exhaust) gases that directly apply a force to a piston 16 of the engine. The piston 16 is connected with a crankshaft 20 via a conrod 18 such that linear movement of the piston 16 within the cylinder is translated to a rotational output of the engine 10 (100). After combustion gases have moved piston 16 down the cylinder the exhaust gases are then allowed to exit the combustion chamber 12 through the exhaust port 34 into an exhaust manifold 28 connected with the exhaust port 34. The exhaust manifold 40 interconnects with an exhaust pipe (duct) 44 of a vehicle exhaust system which guides the exhaust gases 42 away from the engine 10 (100) to an exhaust tip 48 where they are vented to the open air.

The present invention is predicated in part on the skilled effort and experimentation of the inventor in identifying previously unrecognised benefit to the power and efficiency of an internal combustion engine that results from the selective injection of a coolant fluid into the exhaust system of the engine. Preferred examples of the invention include injecting the coolant fluid, in a preferred example water, into an internal combustion engine exhaust under predetermined operating conditions. As the coolant fluid, such as water, is injected into the exhaust flow it turns from a liquid into gas (e.g. steam) and in doing so absorbs heat from the exhaust gases around it. The exhaust gases are cooled which reduces the hydraulic resistance (back-pressure) of the exhaust system and increases peak power.

In some examples the invention delivers a coolant fluid into an exhaust at a time when an open position of an inlet valve overlaps with an open position of an exhaust valve. In some examples the invention delivers a coolant fluid into an exhaust at a time when a rotational speed of the engine 10 (100) is above a predetermined value. In some examples the invention delivers a coolant fluid into an exhaust at a time when a desired inlet volume of the fuel oxidiser mixture 30 is above a predetermined value. A desired inlet volume of the fuel oxidiser mixture 30 can be inferred from a position of the engine throttle or position of a component of a carburettor or throttle body.

Referring again to figure 1 and 2, in preferred examples the invention provides a device for an internal combustion engine exhaust, or in some examples an exhaust system, having a reservoir 54 for housing the coolant fluid such as water. A pump 52 is fluidically connected with the reservoir 54 and is used to increase the pressure of the coolant fluid. An injector 50 is fluidically connected with the pump 52 by conduit 56. The injector is arranged in a wall of the exhaust pipe 44 to selectively deliver coolant fluid from the reservoir into the exhaust pipe 44. A controller is connected with the injector 50 and pump 52 and is arranged to activate the injector 50 to selectively deliver coolant fluid from the reservoir under desired operating conditions of the engine. In some examples the controller may be programmed to continuously inject cooling fluid into the exhaust. However, in practice the size of the reservoir 54 may dictate that coolant fluid is only injected into the exhaust pipe 44 during predefined operating conditions of the engine 10 (100). These operating conditions may be during certain operating demands required of the engine, such as higher operating speeds or where higher power is requested. The selected periods may be during the whole operating cycle of the engine or only during periodic shorter periods of the operating cycle such as during a brief period when an open position of an inlet port 22 overlaps with an open position of an exhaust port 34 to assist with scavenging the combustion chamber 12.

The exhaust system for most internal combustion engines 10 (100) has a resonator 46, or on some engine types an expansion chamber. The skilled effort and experimentation of the inventor has identified the previously unrecognised benefit of injecting the coolant fluid into the exhaust pipe 44 at a location adjacent to an expansion chamber or resonator 46 of the exhaust system. In preferred examples the adjacent location is immediately upstream of the expansion chamber or resonator 46.

In some examples the controller 60 has inputs to received signals representing operating conditions of the engine, including but not limited to signals representing one or more of a rotational speed of the internal combustion engine, a desired inlet volume of a fuel oxidiser mixture, a position of the inlet valve and a position of the outlet valve. In other examples the controller 60 functions may be performed by or be part of an engine control unit (ECU) 62.

In some examples a fill-port 58 may also be provided for refilling the reservoir 54. In other examples an on-board water generation means may be provided as part of the vehicle or engine. Such means may harvest water from air condition condensate, or from exhaust gases condensate at the tail pipe (water vapour is a by-product of combustion of petrol/gasoline), or by collecting rain water from the vehicle body. An on-board water generation means may be fully closed loop, or may also include a fill port to supplement the on-board water generation means.

The invention may be applied to both 2 and 4 stroke engines and to engines have one or more cylinders.

Figures 3 and 4, graphically illustrates power and torque curves for an internal combustion engine operating under normal conditions (line A) and with selective injection of water into the exhaust system (line B) according to the invention. The internal combustion engine of the test setup was a 1991 Toyota 1.3L (1,295 cc) model '2E' 4-cylinder 4-stroke engine. A fan-type injector was located immediately upstream of the engine exhaust resonator. The injector had a rated flow of 22.31 to 223 ml/sec (21.21 to 212 gph) and pressure rage of 5 to 500 psi (3.52 to 352 m H2O). Water was delivered by a pump rated at 6.38 litre/minute at 107 psi. As evidenced by the graphs, using a water injection according to the invention increased both peak power output and torque of the engine at normal highway speeds (lOOkmh) for the engine. Accordingly, in some examples of the invention water injection will occur at higher rotational speeds of the engine, and/or when the throttle or throttle body is opened to allow higher volumes of fuel/air mixture into the engine.

Referring to figure 5, in some examples of the invention the exhaust system may include a downstream turbo unit comprising a exhaust gas driven turbine wheel 70. In some examples the turbine 70 is spun by exhaust gases flowing in the exhaust pipe 44 towards the tail pipe tip 48. In some examples the turbine shaft is connected with a turbine generator 72 which is spun by the turbine 70 and is used to generate an electrical charge. In some examples the electrical charge is transferred to a storage unit such as a battery (not shown) for use at a later time. In some examples the electrical charge may be at 12 volts. In some examples the electrical charge may be at may be higher than 12 volts. In some examples the electrical charge may be used to operate electrically controlled components of the vehicle. In some examples the electrically controlled components may be an auxiliary electric motor such as in a hybrid type vehicle. In some examples the electrically controlled components may be electrically controlled suspension damping components and the like. Is some examples, in addition to the turbine generator 72, the turbine 70 may also spin a turbine compressor 74. The turbine compressor 74 is used to generate an air charge 78. In some examples the air charge 78 may be returned to the engine air intake as is known. In some examples the air charge 78 is directed through a charge pipe to a charged injection port in the exhaust pipe 44 downstream of the turbine 70. The injection of charged air into the exhaust downstream of the turbine aids in the extraction of exhaust gases towards the exhaust tip 48.

And some examples, there may be a second water injection port 76 in the exhaust pipe 44 downstream of the turbine 70. The second water injection port 76 may be operated from the same supply as the first water injection port 50 or from its own supply and pump in the same manner as first injection port 50. The injection of water downstream of the turbine 70 has the same or similar benefits is the first water injection port 50 of aiding the extraction of exhaust gases towards the exhaust tip 48.

In some examples the turbine 70 may be a second turbine. In such examples a first turbine may be positioned earlier in the exhaust flow and used to charge air for the engine intake. In such examples the second turbine 70 is used to turn a generator 72 only. In some examples the second turbine 70 is used to turn a second compressor wheel 74 only. In some examples the second turbine 70 is used to turn both a generator 72 and a second compressor well 74.

In some examples the turbine 70 may be near the exhaust tip 48. In some examples the charged air inlet 80 may be near the exhaust tip 48. In some examples the second water jet 76 may be near the exhaust tip 48.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference. Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred examples described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention