WO2007019649A1

WO2007019649A1 - Engine management systems and method

Info

Publication number: WO2007019649A1
Application number: PCT/AU2006/001199
Authority: WO
Inventors: Timothy Standke; David Martin May
Original assignee: Powergen International Pty Ltd
Priority date: 2005-08-18
Filing date: 2006-08-18
Publication date: 2007-02-22
Also published as: EP1937959A1

Abstract

An engine management system for controlling operation of an engine using hydrogen assisted combustion in which hydrogen replaces at least some of the more conventional fuel and methods of operating an engine are described in which the engine management system includes a main process controller for controlling the admission of fuel or fuel components to the engine in which the engine management system is provided with a knock sensor for monitoring the onset of knock occurring within the engine as a result of combustion so that the amount of hydrogen admitted to the engine can be adjusted to allow the engine to be operated on the knock limit of the engine thereby allowing the engine to develop increased power whilst minimising the amount of pollutant emissions being exhausted from the engine.

Description

ENGINE MANAGEMENT SYSTEMS AND METHOD

Field of the Invention

The present invention relates to engine management systems for use in controlling the operation of engines using hydrogen assisted combustion of a fuel or fuel component containing hydrogen and to methods of controlling operation of engines using hydrogen assisted combustion of a fuel containing hydrogen.

In one embodiment of the present invention, the engine management system is a fuel control system which controls the amount of hydrogen or other component of the fuel mixture admitted to the engine so as to reduce the risk of detonation pccurring within the engine during combustion whilst allowing the engine to develop increased power.

In one embodiment, the fuel control system uses a vibration sensor or pressure sensor to monitor the behaviour of combustion occurring within the engine to control the amount of hydrogen admitted to the engine as the fuel or part of the fuel for the engine.

Although the present invention will be described with particular reference to one form of the engine management system and method of operating the system involving the use of a vibration or pressure detector or sensor in the form of a knock sensor to control the amount of hydrogen being admitted to the engine as part of the fuel mixture, it is to be noted that the present invention is not limited to the described embodiment or embodiments but rather the scope of the present invention is more extensive so as to include other engine management systems, other fuel control systems, other methods and other arrangements for controlling operation of the engine and the use of such methods and systems and arrangements in other applications, including the control of variables or parameters other than hydrogen.

With the increase in fuel prices and the reduction of fuel reserves as well as environmental concerns, engine designers are faced with the dual requirement of developing more powerful engines that are more economical to operate whilst being less polluting, particularly less polluting with respect to the emission of oxides of nitrogen. However, in many cases the two objectives of increased power and lower exhaust emissions are mutually antagonistic to each other since developing more power usually requires combusting more fuel and the more fuel that is used, the more pollutants are formed that must be exhausted from the engine as emissions such as oxides of nitrogen (NOx) , carbon dioxide (C02) , hydrocarbons (HC) or the like.

One way of tackling the dual problems of providing increased power with reduced emissions is to use fuel systems other than purely hydrocarbon based fuels or fuels containing hydrocarbons only. In the past, one suggestion was to use hydrogen as an additive to hydrocarbon fuels as a substitute for or replacement of conventional hydrocarbons so as to reduce the proportion of hydrocarbons in the fuels. The thinking behind this substitution being that the presence of less hydrocarbon would produce less pollutants. The use of hydrogen as a fuel or as one component of a fuel as a replacement for at least a part of the hydrocarbons in convention fuel is referred to as hydrogen assisted combustion.

The selection of hydrogen as a fuel component and the introduction of hydrogen into a compression ignition engine, particularly into the compression stroke or ignition cycle or stages in the overall combustion process, can reduce the amount of pollution and CO2 emissions generated by an engine whilst simultaneously developing increased power. The reduction in pollution and CO2 emissions is achieved in two main ways. Firstly, the combustion of hydrogen produces less of the complex combustion products, such as for example, less of the complex combustion products containing carbon chains than are produced by the combustion of complex hydrocarbons alone, and also the use of hydrogen results in the production of by-products that are more stable than the by-products of hydrocarbon combustion and thus these more stable products are less likely to be broken down readily into toxic products or the like. Thus, when using hydrogen as a partial replacement for hydrocarbon fuels there is a reduced tendency for compounds contained within the emissions from the engine to convert or rearrange into more polluting products.

Secondly, the ratio of hydrogen atoms to carbon atoms in a fuel determines the amount of carbon dioxide that is formed on combustion of the fuel and emitted from the exhaust. Ideal combustion of normal hydrocarbon fuel systems results in the generation of water and carbon dioxide. However, the ideal combustion of hydrogen alone results in the generation of water alone. Therefore, introducing hydrogen into a fuel as one. component of the fuel mixture of a compression ignition engine in place of hydrocarbons reduces the amount of carbon dioxide that is produced by combustion within the engine at any given performance point since water is formed in preference to carbon dioxide. Thus, theoretically the more hydrogen that can be introduced into a fuel to replace hydrocarbons, the less the amount of toxic or noxious emissions are produced as a result of combustion of the fuel.

However, it has been discovered that the replacement of conventional hydrocarbon fuel and fuel components with hydrogen cannot be carried out indiscriminately or without limit, since such uncontrolled replacement causes additional problems to arise so that it is not merely a simple matter of directly replacing the hydrocarbon content of a fuel with an equivalent amount of hydrogen. Compression ignition engines are typically designed to operate at compression ratios that allow the fuel being used to combust without detonation i.e. to burn evenly to produce controlled power. The addition of hydrogen to the fuel changes the combustion characteristics of the fuel so that there is a greater risk of detonation occurring during combustion. Usually, the more hydrogen that is added, the greater the risk of detonation occurring.

Therefore, there is a limit to the quantity of hydrogen that can be added to the base hydrocarbon fuel for use in a compression ignition engine before the onset of detonation. Clearly, the occurrence of detonation is to be avoided if at all possible because of the damage to the engine caused by detonation. In the past, the occurrence of detonation limited the amount of hydrogen that could be used in hydrogen assisted combustion and accordingly limited the power that engines can develop using hydrogen assisted combustion.

Detonation within an engine is also referred to as "engine knock" or simply just "knock" or "knocking" . Knock is a term that is used to refer to radical combustion of the charge in the cylinder of a combustion engine resulting in unacceptably high cylinder pressure spikes, sometimes referred to as explosions or the like. The production of the excessive pressure within the combustion chamber of the engine can damage the engine and is highly undesirable and to be avoided if at all possible since detonation has many of the characteristics of an explosion with the attendant damage that explosions can cause, often demonstrated by the engine ^Λbackfiring' .

Therefore, there is a need to be able to use hydrogen as at least a partial replacement of hydrocarbons in a hydrocarbon based fuel for use in compression engines in such a manner that the engine can be operated substantially without engine knocking occurring together with no appreciable loss in power being developed by the engine whilst there is no appreciable increase in pollutants emitted from the engine.

Therefore, it is an aim of the present invention to provide an engine management system and methods using such engine management systems that are able to control operation of the engine in such a manner so as to reduce or eliminate engine knock occurring thereby enabling the engine to develop increased power whilst having reduced exhaust emissions. According to the present invention there is provided an engine management system having the capability of controlling operation of an engine using hydrogen assisted combustion, said engine management system including a main management unit having an input for receiving information from the engine about combustion processes occurring within the engine, and at least one output for transmitting information to a second management device for controlling the amount of at least one component of the fuel mixture being introduced into the engine, wherein the information about the combustion process occurring within the engine includes information about the combustion characteristics of combustion occurring within the engine.

According to another aspect of the present invention, there is provided a method of introducing hydrogen to an engine or a method of controlling the amount of hydrogen being added to an engine comprising the steps of monitoring within the engine one or more conditions or characteristics of combustion occurring during operation of the engine using a sensor, producing a signal in accordance with the condition or characteristic within the engine detected by the sensor, inputting the signal from the sensor into a main management unit, using the main management unit to adjust the amount of at least one fuel component being introduced into the engine in accordance with the value sensed by the sensor wherein the engine is operated to produce power substantially without detonation occurring during operation of the engine.

Typically, the main engine management device and/or the second management device, is a processor and/or controller unit. More typically, the processor and/or controller unit is a real time embedded computer with signal conditioned input and outputs designed to integrate with sensors and actuators. Even more typically, the processor and/or controller unit completes the physical embodiment of the engine management system and can survive in an engine's physical environment with respect to but not limited to temperature cycles, chemical spray, vibration, handling, pressure spikes and other variables, such as for example, conditions and/or parameters of the type disclosed in SAE Standards J1455, particularly the conditions referred to in this standard as the automotive underhood environmental conditions .

Typically, the engine management system of the present invention is a fuel control system for controlling the amount and composition of fuel being admitted to the engine .

Typically, the at least one component of the fuel is hydrogen. More typically, the hydrogen is newly formed hydrogen, recycled hydrogen or is hydrogen formed in any manner.

Typically, another component of the fuel is propane or other similar gas or liquid either as a replacement or partial replacement for hydrogen.

Typically, in one embodiment of the present invention, the engine management system or fuel control system used in spark ignition engines includes a detonation sensor in the form of a ''knock' sensor or ^knocking sensor' for detecting the presence of knock being developed within the engine as a result of the combustion process occurring — β — within the engine. More typically, the knock sensor is used to manipulate or adjust the ignition timing to reduce the occurrence of knock developing within the engine. Often, the presence of knock within an engine prevents spark ignition engines from operating at their peak power or developing their peak power owing to the reduced efficiency of burning of the fuel. Also, the knock is damaging to the engine components within the cylinders of the engine and can quickly render the engine inoperable. Consequently, control systems must often retard the spark timing to prevent knock at the sacrifice of power to prevent damage to the engine. The technique of operating at the ignition-timing threshold of knock is known as operating at the knock limit of the engine. More typically, the engine management system of the present invention operates more or less continually to adjust the flow of hydrogen to the engine so that the amount of hydrogen added is less than, preferably just less than the amount that is required for significant detonation in accordance with the operating parameters of the engine.

Even more typically, the engine management system of the present invention is used to control operation of the engine at the or just below the knock limit of the engine.

Typically, the engine to which the present invention is applicable is an internal combustion engine, a compression engine, an ignition engine, a diesel engine, a petrol or gasoline engine, a spark engine, alternative fuel engine or any other engine or the like. More typically, the engine is a stationary or fixed engine such as for generating power in the form of electricity or is a mobile engine for driving a vehicle or similar, including a land, sea or air vehicle. Typically, the fuel is petrol, gasoline, diesel, natural gas, ethanol, bio-diesel, hydrogen, or any other alternative fuel or the like including combinations of two or more different types of fuels or components of the fuel. More typically, hydrogen and propane are added as one component of the fuel either separately or jointly. Even more typically, the engine operates under conditions of hydrogen assisted combustion in which hydrogen replaces at least some of the hydrocarbon content of the fuel.

Typically, the control systems of the present invention used in compression ignition engines manipulates or adjusts the ignition timing by adjusting the time or duration over which the fuel is injected into the engine during the cycle of fuel introduction into the engine, i.e. the injection time of the fuel admitted to the engine each cycle. Since the engines are designed not to experience knock during operation, there is not the need for manipulation of the injection time to prevent knock and consequently, there is no operation at the knock limit of the engine with respect to ignition timing.

Typically, the time or duration of the time of injection of the fuel is from about 20 degrees before cylinder top dead centre to about 30 degrees before cylinder top dead centre, more preferably from about 40 degrees before cylinder top dead centre to about 45 degree before cylinder top dead centre depending upon the type of engine and its characteristics.

Typically, the present invention is a means of controlling the amount of hydrogen added to a compression ignition engine to achieve, maintain and increase the power and torque performance of the engine while minimising C02 and pollutant emissions whilst at the same time not damaging the engine due to detonation occurring.

Typically, the engine can operate from at very low fuel to air ratios (very lean operation) up to very high fuel to air ratios (rich operation) . More typically, the engine operates at lean fuel to air ratios since hydrogen addition allows for leaner operation without detonation.

The system and method of the present invention can be used with fuel mixtures having a fuel to air ratio varying from about 5:1 to 40:1.

Typically, increased turbulence of the fuel or fuel mixture may be induced in the engine cylinder to improve combustion and prevent knock either during or after admission to the engine cylinder.

Typically, the engine control system of the present invention monitors the engine speed with engine rotational position sensors locatable on rotating parts of the engine, such as for example, on the flywheel of the engine. More typically, the rotational speed of the engine is one of the inputs to the management unit, preferably the main management unit.

Typically, the engine control system of the present invention monitors the load upon the engine using suitable monitors. One example of the monitoring devices are current measurements on electrical generators provided on the engines and fuel flow on load based engines, such as for example, stationary engines. This is another typical example of the input to the management unit .

Typically/ the detonation sensor or detector of the present invention for sensing *knocking' within the engine is a pressure sensor, vibration sensor or similar for monitoring the combustion characteristics of combustion occurring within the engine, preferably within the combustion chamber or upper cylinder of the engine. More typically, the sensor monitors the pressure within or variations of the pressure within the combustion chamber of the engine. Even more typically, the sensor or detector senses or detects peaks of pressure or developing pressure peak within the cylinders of the engine.

Typically, the pressures that would be developed commonly within the cylinder of a diesel engine would be in the range of 3000 to 8000 KPA. Accordingly, the pressure sensor of the present invention would need to be able to withstand and measure pressures within this range. A particularly preferred pressure detector is a glow plug pressure sensor provided by Seimens VDO Trading GmbH of Germany which is a cylinder pressure sensor integrated in a glow plug to monitor the pressure during the compression and the combustion stroke. The glow plug pressure sensor provides a more accurate measurement as it senses the pressure through the tip of the glowing element. Optionally, the glow plug pressure sensor is provided with a ceramic heating element. Typical properties of the glow plug sensor include the following:

Typically, the engine control system of the present invention monitors for the presence of knock in the engine with one or more knock sensors or pressure sensors located at selected locations within the engine. It is to be noted that knock is associated with pressure spikes occurring within the cylinders of the engine.

Based on the engine speed and engine load, the control system of the present invention typically calculates a pre-defined flow rate of one or more components of the fuel, including hydrogen for hydrogen assisted combustion to take place without detonation occurring. Typically, the flow rate of hydrogen is calculated by the management unit. More typically, the secondary control unit adjusts the flow of hydrogen.

Based on the magnitude of knock measured in the system, either using a vibration sensor, pressure sensor or both, the control system adjusts the hydrogen flow rate to ensure that knock does not occur. When a significant knock is measured by the control system, the calculated flow of hydrogen to the engine is reduced. When an insignificant knock is measured by the control system, the calculated flow of hydrogen will be increased to allow the engine to develop greater power, including peak power whilst reducing or eliminating the risk of detonation.

Typically, the fuel system of the engine includes a mixer unit in which hydrogen is mixed with other components of the fuel . More typically, the other components of the fuel include hydrocarbon fuel, water, preferably in the form of mist, oxygen in the form of air, additives or the like. Typically, the mixer has a multitude of inputs for receiving respective ones of the individual fuel components and an outlet for discharging the mixed or combined fuel either directly or indirectly to the engine.

Typically, the engine control system of the present invention actuates a hydrogen-metering device to dispense the calculated amount of hydrogen to the mixer for introduction into the engine along with metered amounts of other components.

Typically, the hydrogen flow rate is recalculated at each control cycle of the engine control system. Typically, the control cycle of the engines is from about 1 Hz to about 100 kHz, preferably from about 100 Hz to about 100 kHz, more preferably from about 1 kHz to about 100 kHz.

The invention will now be described by way of non-limiting example with reference to the accompanying drawings in which:

Figure 1 is a schematic flow diagram of one embodiment of the engine management system in accordance with the present invention showing some of the key aspects of the system.

Fuel, typically conventional hydrocarbon fuel, such as for example, petrol, gasoline, diesel, natural gas or the like including mixtures or combinations of two or more different types of fuel including alternative fuels, is provided in a fuel tank of a motor vehicle (not shown) . Fuel from the fuel tank is conveyed generally to the engine of the vehicle for admission to the upper cylinders of the engine where combustion takes place in any desired or convenient manner by suitable pipe work, conduits, hoses or the like and by a suitable pump, such as for example, an electric fuel pump or the like, particularly a high pressure fuel pump. The fuel may be added directly or indirectly to the fuel intake system of the vehicle, such as for example to the fuel injection system, carburettor, intake manifold, mixer chamber or similar depending upon circumstances such as the type of engine and the exact nature of the fuel system, including how the fuel mixture is introduced into the combustion chambers of the engine, such as for example, in sequence in accordance with the firing order of the engine in order to supply fuel to the engine to allow the engine to operate. An engine management system in the form of a fuel control system generally denoted as 2, is provided for controlling the introduction of fuel and fuel components to the engine in such a manner to allow the engine to develop sufficient power without detonation occurring.

In one embodiment fuel is provided from the fuel tank 10 and piped via a fuel flow controller 11 to the inlet 14 of a mixer, generally denoted as 12, for mixing with other components of the fuel to form a fuel mixture before being admitted to the combustion chambers of the engine.

Hydrogen gas from a suitable source and/or of a suitable type is provided in a suitable hydrogen supply, reservoir or storage device, such as for example, hydrogen storage tank 16 or similar. Hydrogen in hydrogen tank 16 can be produced on board the vehicle, such as for example, by a converter converting hydrocarbon fuel or the like to hydrogen, a reformer producing a reformate gas containing hydrogen, or other suitable production device or production means for producing hydrogen either alone or in combination with other components, such as for example, the by-products of hydrogen gas production, or the hydrogen may be provided from an external source, such as for example, from a service station, filling station or the like having a bulk hydrogen supply produced in situ or at a remote location and delivered to the filling station much in the manner of conventional hydrocarbon fuel.

Hydrogen from tank 16 is conveyed to a hydrogen flow controller 18 for controlling the flow of hydrogen to mixer 12 through inlet 19 in accordance with the requirements of the engine as will be described in more detail later in this specification.

A pressurised water supply 20 is provided on the vehicle for providing water under pressure in the form of a water mist, spray, atmosphere or similar containing droplets of water. The pressurised water in whatever form is passed to water mist flow controller 22 for introduction through inlet 21 into mixer 12.

If required, or optionally, mixer 12 is provided with other inlets (not shown) for admitting other components of the overall fuel mixture to the mixer for mixing with the hydrogen, water and hydrocarbon fuel to form the fuel mixture, such as for example, octane boosters, injector cleaners, anti- foaming agents, or other similar additives or the like. The other components can be introduced into the mixer individually or can be introduced jointly or in combination through separate inlets or through combined inlets .

A main processor or controller 26 is provided connected to all of the flow controllers, such as for example, the fuel flow controller 11, the hydrogen flow controller 16 and the water mist flow controller 22 for controlling the introduction of some or all of the individual components of the fuel mixture. In one embodiment, main controller 26 takes the form of a National Instruments Compact RIO realtime controller equipped with appropriate modules for interfacing with sensors required to measure engine speed, engine load, fuel flow, water flow, knock, pressure and other parameters or characteristics of the engine and/or fuel system or the like. In one embodiment, the controller is connected to actuators required for metering hydrogen and water, safety lock off solenoids, safety devices and the like.

Main controller 26 is provided with an input for receiving a signal from a suitable detector or sensor. One example of the sensor is a knock sensor, generally denoted as 30, or knock indicator for detecting the onset of detonation or knocking occurring during combustion within the engine. When the onset of knock is detected by the sensor 30, or when the pressure within the combustion chambers of the engine reaches a threshold amount or a predetermined value is detected by the sensor, a signal is produced by the sensor and conveyed to the main controller 26 through input 31.

The knock sensor is a vibration sensor 52, a pressure sensor or other suitable sensor or similar. It is to be noted that a single sensor or two or more different sensors may be provided to detect the onset of knock either as a result of change in vibration or as a change in pressure. In one embodiment, there is a vibration sensor provided within the block 50 of the engine 36 or a pressure sensor provided in the cylinder head of the engine or both.

Further, it is to be noted that the pressure sensor detects the development of peak pressure within the combustion chamber.

Mixer 12 is provided with a suitable inlet 32 for admitting air into the mixer, 12 for mixing with the other components of the fuel prior to delivery to intake manifold 34 and then into engine 36. The air supply to be provided to the engine to assist in combustion is optionally connected to main controller 26 for monitoring the amount of air being admitted to the mixer and accordingly adjusting and/or controlling the fuel: air ratio so as to achieve optimal or desired combustion conditions within engine 36 in accordance with the type of engine.

Additionally, the engine management system 2 is provided with flame detector 40 located within intake manifold 34 and connected to main controller 26 to assist in monitoring the combustion conditions so that if required, the engine can be safely shutdown to avoid damage or injury. Thus, flame detector 40 monitors for the presence of flames or fire within the intake stream or inlet to the engine .

In one embodiment, when the fuel being used is diesel fuel and the engine is a diesel engine, the management system includes a diesel injection controller, generally denoted as 42, comprising a governor 44, for determining the speed of the engine, an actuator 46, for controlling the amount of diesel fuel being admitted to engine 36 by an injection pump 48, all for controlling the amount of diesel fuel introduced into the combustion chambers of the engine.

Engine 36 is provided with an engine block 50 having a vibration sensor 52 located at a suitable location within the block for sensing the type, amount, frequency or similar of any vibration being developed within the engine during operation. In one embodiment the vibration sensor takes the form of an NGK Wide Band Knock Sensor which is designed to detect vibration frequencies between one and twenty kilohertz which span the knock frequencies found in internal combustion engines. This is one example of the knock sensor. Another example of the sensor is a pressure sensor.

One embodiment of the engine knock sensor 30 for detecting the onset of detonation includes an amplifier/signal conditioner 56, a band-pass frequency filter 58, a filtering vibration level sensor 60, and a knock indicator 62 connected in sequence with one another to provide a suitable electrical signal to the processor 26 via input 31.

Engine knock sensor 30 is connected to main controller 26 to provide an input signal for the main controller to operate the engine in accordance with requirements . The signal from sensor 30 contributes to the operation of the flow controllers 11, 18 and 22, all of which are electrically connected to controller 26.

In operation, the engine is operated in accordance with normal operating conditions under the control of the engine management system 2 of the present invention. When the vehicle is required to work harder so as to deliver more power, such as for example, when accelerating, when climbing a gradient, or under increased load, the main controller 26 reacts by increasing the amount of hydrogen introduced into the fuel mixture to enable the engine to develop the greater power required. However, there is a limit to the amount of hydrogen that can be added to mixer 12. The amount of hydrogen is increased until the onset of detonation or until detonation is imminent as detected by vibration sensor 52 or pressure sensor or both whereupon vibration sensor 52 and/or the other sensors detect the increase in vibration within the engine caused by detonation or the pressure sensor detects the increase of pressure at the onset of detonation and sends a signal to main controller 26 to reduce the flow of hydrogen passing through the hydrogen flow controller 18 for admission to mixer 12 thereby reducing the amount of hydrogen being introduced into the engine which in turn reduces the incidence of vibration or lowers the pressure thereby reducing the amount of power being developed by the engine. This reduction in the amount of hydrogen incorporated into the fuel reduces the amount of detonation occurring and can be used to avoid the onset of detonation within the combustion chambers of the engine running on the knock limit. In this manner, the amount of hydrogen added to the fuel of the engine is continually being adjusted and monitored to allow the engine to operate at peak power or maximum capacity for any given set of conditions existing at any time.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention.

Claims

1. An engine management system having the capability of controlling operation of an engine using hydrogen assisted combustion, characterised in that the engine management system includes a main management unit having an input for receiving information from the engine about combustion processes occurring within the engine, and at least one output for transmitting information to a second management device for controlling the amount of at least one component of the fuel mixture being introduced into the engine, wherein the information about the combustion process occurring within the engine includes information about the combustion characteristics of combustion occurring within the engine.

2. A method of introducing hydrogen to an engine or a method of controlling the amount of hydrogen being added to an engine characterised in that the method comprises the steps of monitoring within the engine one or more conditions or characteristics of combustion occurring during operation of the engine using a sensor, producing a signal in accordance with the condition or characteristic within the engine detected by the sensor, inputting the signal from the sensor into a main management unit, using the main management unit to adjust the amount of at least one fuel component being introduced into the engine in accordance with the value sensed by the sensor wherein the engine is operated to produce power substantially without detonation occurring during operation of the engine.

3. An engine management system or method according to any preceding claim characterised in that the main engine management device and/or the second management device is a processor and/or controller unit which is a real time embedded computer with signal conditioned inputs and outputs to integrate the sensors and actuators .

4. An engine management system or method according to any preceding claim characterised in that the processor and/or controller unit is designed to survive in the physical environment of the engine with respect to parameters such as temperature cycles, chemical spray, vibration, handling, pressure spikes and other variables, particularly conditions and/or parameters of the type disclosed in SAE Standards J1455 referred to as the Automotive Underhood Environmental Conditions .

5. An engine management system or method according to any preceding claim characterised in that the engine management system of the present invention is a fuel control system for controlling the amount and composition of fuel and/or fuel components being admitted to the engine.

6. An engine management system or method according to any preceding claim characterised in that at least one component of the fuel is hydrogen.

7. An engine management system or method according to any preceding claim characterised in that one of the combustion characteristics of combustion occurring within the engine is ^engine knock' or ^knocking' which is detected by a knock sensor for monitoring or detecting the onset or presence of knocking or detonation occurring within the engine as a result of combustion of the fuel .

8. An engine management system or method according to any preceding claim characterised in that the knock sensor is used to manipulate or adjust the ignition timing of the engine to reduce the occurrence of knock developing within the engine.

9. An engine management system or method according to any preceding claim characterised in that the knock sensor monitors the combustion occurring within the engine so that the engine can be operated at the knock limit of the engine.

10. An engine management system or method according to any preceding claim characterised in that the engine management system operates more or less continually to adjust the amount of hydrogen being admitted to the engine so that the amount of hydrogen added is less than, preferably just less than and more preferably on the limit of the amount that is required for substantial detonation occurring within the engine .

11. An engine management system or method according to any preceding claim characterised in that the fuel is petrol, gasoline, diesel, natural gas, ethanol, bio- diesel, hydrogen or any other conventional or alternative fuel including combinations of two or more different types of fuels or components of a fuel.

12. An engine management system or method according to any preceding claim characterised in that the engine operates under conditions of hydrogen assisted combustion in which at least a part of the hydrocarbon content of the fuel has been replaced with hydrogen, or preferably hydrogen and propane in which the hydrogen and propane are admitted separately or jointly in combination.

13. An engine management system or method according to any preceding claim characterised in that the control system used in compression ignition engines manipulates or adjusts the ignition timing of the engine by adjusting the time or duration over which the fuel is injected into the engine during the cycle of fuel introduction into the engine.

14. An engine management system or method according to any preceding claim characterised in that the engine can operate from a very low fuel to air ratio or at a very lean operation up to very high fuel to air ratio or rich operation, particularly in the fuel to air ratio range of from about 5:1 to about 40:1.

15. An engine management system or method according to any preceding claim characterised in that the knock sensor or detector is a pressure sensor, vibration sensor or similar for monitoring the combustion characteristics occurring within the engine.

16. An engine management system or method according to any preceding claim characterised in that the knock sensor monitors the pressure including variations of the pressure within the combustion chamber of the engine to detect or sense increase of pressure or pressure peaks developing within the engine during operation.

17. An engine management system or method according to any preceding claim characterised in that the engine control system has one or more knock sensors located at one or more spaced apart locations within the engine to detect pressure spikes.

18. An engine management system or method according to any preceding claim characterised in that the fuel system of the engine includes a mixer unit in which hydrogen is mixed with other components of the fuel.

19. An engine management system or method according to any preceding claim characterised in that the other components of the fuel include hydrocarbons, water in the form of a mist, spray, droplets or the like, oxygen and/or other additives.

20. An engine management system or method according to any preceding claim characterised in that the engine control system activates the hydrogen measuring device to dispense a calculated amount of hydrogen to the mixer for introduction to the engine along with metered amounts of the other components of the fuel mixture .

21. An engine management system or method according to any preceding claim characterised in that the hydrogen flow rate is recalculated at each control cycle of the engine control system, typically from about 1 Hz to about 100 kHz, more preferably from about 100 Hz to about 100 kHz, most preferably from about 1 kHz to about 100 kHz.

22. An engine management system or method according to any preceding claim characterised in that the hydrogen is produced in situ or is introduced from a supply located remote from the engine management system.

23. An engine management system or method according to any preceding claim characterised in that the knock sensor is a vibration sensor, a pressure sensor or other suitable sensor and that there is one or more sensors located at one or more different locations within the engine to detect the onset of knock either as a result of change in vibration or as a change in pressure.

24. An engine management system or method according to any preceding claim characterised in that the vibration sensor is provided within the block of the engine whereas the pressure sensor is provided in the cylinder head of the engine.

25. An engine management system or method according to any preceding claim characterised in that the fuel control system includes a mixer for mixing the components of the fuel for introduction to the engine .

26. A vehicle having an engine management system according to any preceding claim.

27. An engine when operated in accordance with the method of any preceding claim.

28. An engine management system substantially as herein described with reference to the accompanying drawing.

29. A method of introducing hydrogen to an engine or a method of controlling the amount of hydrogen being admitted to an engine substantially as herein described with reference to the accompanying drawing.

30. A method of operating an engine using an engine management system before introducing hydrogen to the engine substantially as herein described with reference to the accompanying drawing.