GB2526246A

GB2526246A - Multiple fuel engine

Info

Publication number: GB2526246A
Application number: GB1404212.1A
Authority: GB
Inventors: Phillip Bevan; Daniel Monaghan
Original assignee: TRIDENT TORQUE MULTIPLICATION TECHNOLOGIES Ltd
Current assignee: TRIDENT TORQUE MULTIPLICATION TECHNOLOGIES Ltd
Priority date: 2014-03-10
Filing date: 2014-03-10
Publication date: 2015-11-25
Anticipated expiration: 2034-03-10
Also published as: GB201404212D0; GB2526246B; WO2015136270A1

Abstract

A compression injection engine arranged to obtain fuel from, and to return fuel to a fuel tank. The engine comprises a cylinder 14 a fuel characteristic determiner 2, 6 to determine a fuel characteristic, such as viscosity, and a temperature control means adapted to increase the operating temperature of the cylinder towards a detonation or combustion temperature selected based on the characteristic, and to limit that temperature increase based on the characteristic to inhibit at least one of a detonation of unburnt fuel during an exhaust phase of an engine cycle or premature detonation of fuel in an injection phase of an engine cycle. The temperature control means can be a fuel heater 34 or an injection control means that varies the frequency, timing and/or duration of the fuel injection into the cylinder. Also disclosed is a data processor configured to control such an engine. The invention allows the engine to operate on a variety of fuels.

Description

Multiple Fuel Engine The present invention relates to methods and apparatus for operating an engine, and more particularly for operating a compression injection engine, and more particularly for enabling such engines to operate with a variety of fuels. Still more particularly the disclosure relates to determining at least one characteristic of a fuel and adjusting the operation of an engine depending on the at least one characteristic.

In an internal combustion engine, the optimum conditions of the cylinder, (for example those which provide the most efficient combustion of a fuel), are dependent on the combustion characteristics of the fuel. Cylinder temperature can be adjusted to improve combustion. For example, glow plugs can be used during cold start conditions to raise the temperature of the fuel and/or the cylinder.

There is an increasing need to use a variety of fuels as the availability of fossil fuels decreases, and their price increases. There is a desire to reduce emissions of carbon dioxide, as it is associated with anthropogenic climate change. There is also a desire to increase the efficiency of combustion to improve the economy of performance of engines.

Aspects and examples of the invention are set out in the appended claims.

The disclosure is explained, by way of example only, with reference to the accompanying drawings, in which: Figure la shows a schematic diagram of a compression injection engine with a temperature control; Figure lb shows a schematic illustration of a common rail compression ignition engine; Figure 2 shows a schematic diagram of the injection of the fuel from the fuel line into the cylinder by a fuel injector; and Figure 3 shows a flow diagram of the method of controlling the temperature of the cylinder according to the composition of the fuel mixture.

Embodiments of the disclosure relate to determining one or more characteristics of a fuel and adjusting the operating conditions of cylinders of the engine based on those characteristics.

A characteristic of a fuel can be sensed by a fuel characteristic determiner coupled to a fuel filling line used to fill a vehicle's fuel tank. A characteristic of a fuel can also be sensed by a fuel characteristic determiner coupled to a fuel return line 28 used to return excess fuel from a cylinder to the vehicle's fuel tank. One characteristic which may be used for this purpose is the viscosity of the fuel which may be determined using a viscosity sensor such as a viscosity cup.

The characteristic of the fuel can be used to determine its detonation temperature, also referred to as its detonation point or combustion temperature. The operating conditions of a cylinder of the engine can then be controlled to increase the cylinder temperature toward the detonation temperature of the fuel as far as possible without causing detonation. This may increase the efficiency of the combustion of fuel, and so contribute to the improving the efficiency of the engine and reducing undesirable emissions.

The fuel temperature in the cylinder can be controlled by adjusting the frequency and duration of fuel injections into the cylinder, and/or by controlling time the fuel is in the cylinder. An embodiment of the disclosure will now be described with reference to Figure la and Figure lb. Figure la shows a compression injection engine arranged to obtain fuel from a fuel tank 20, and to return fuel to said fuel tank 20, the engine comprises a cylinder 14 having a compression ratio, a fuel characteristic determiner 1 arranged to determine a characteristic of the fuel, and a heater 34 adapted to increase the operating temperature of the cylinder 14 towards a detonation temperature selected based on the characteristic, and to limit that temperature increase based on the characteristic to inhibit at least one of detonation of unburnt fuel during an exhaust phase of an engine cycle, and premature detonation of fuel in an injection phase of an engine cycle.

The compression injection engine of Figure la is described in more detail with reference to Figure lb, with the highlighted components in Figure lb referring to the compression injection engine of Figure la.

Figure lb shows a common rail fuel system fol a vehicle.

The apparatus illustrated in Figure lb comprises a compression injection engine and a fuel tank 20. The engine is arranged to obtain fuel from the fuel tank 20, and to return fuel to said fuel tank 20.

As illustrated, the engine comprises cylinders 14, a controller 30, a first fuel characteristic determiner 2, a second fuel characteristic determiner 6, fuel injectors 8, a fuel level gauge 21, a common lail 24, a first fuel line 4, a heater 34, a fuel pump 22 and a fuel return line 28.

The engine also comprises an exhaust gas coupling 12, and an exhaust gas temperature sensor 10.

The apparatus illustrated in Figure lb further comprises a fuel tank filling inlet 36 coupled to the fuel tank 20.

The first fuel characteristic determiner 2 is coupled to the fuel tank filling inlet 36. The first fuel line 4 couples the fuel tank 20 to the fuel pump 22. The fuel pump 22 is coupled to the common rail, which in turn is coupled to the fuel injectors 8. Each of the fuel injectors 8 is arranged to couple the common rail 24 to a corresponding one of the cylinders 14. The heater 34 is coupled between the cylinders 14 and the fuel injectors 8.

The fuel return line 28 is arranged to return excess fuel from the fuel injectors 8 to the fuel tank 20. The fuel level gauge 21 is coupled to the fuel tank 20. The second fuel characteristic determiner 6 is coupled to the fuel return line 28.

The exhaust gas coupling 12 is coupled to the cylinders 14, and the exhaust gas temperature sensor 10 is coupled to the exhaust gas coupling 12, and to the controller 30.

The controller 30 is coupled to the first fuel characteristic determiner 2, the second fuel characteristic determiner 6, the exhaust gas temperature sensor 10, the heater 34, the fuel level gauge 21, and to the fuel injectors 8.

The fuel tank filling inlet 36 is arranged to allow fuel to be added to the tank.

The first fuel characteristic determiner 2 is operable to obtain samples of fuel added to the fuel tank 20 via the fuel tank filling inlet 36, and configured to determine a characteristic of the samples, and to provide a signal to the controller 30 based on the determined characteristic.

The first fuel line 4 is configured to carry fuel from the fuel tank 20 to the fuel pump 22. The fuel pump 22 is operable to pump the fuel from the tank to common rail, and to provide a selected operating pressure in the common rail. The common rail 24 is configured to hold the fuel at the operating pressure, and each of the fuel injectors 8 is operable to inject fuel from the common rail 24 into a corresponding one of the cylinders 14.

The exhaust gas coupling 12 is operable to allow combustion gases to leave the cylinders 14, and the exhaust gas temperature sensor 10 is operable to sense the temperature of the exhaust gas, and to provide a signal to the controller based on the sensed temperature.

The fuel return line 28 is configured to allow excess fuel to be returned from the fuel injectors 8 to the fuel tank 20. The second fuel characteristic determiner 6 is coupled to the fuel return line 28, and operable to obtain a sample of fuel from the fuel return line 28, and to determine a characteristic of the fuel based on the obtained sample. The second fuel characteristic determiner 6 is further configured to provide a signal to the controller 30 based on the determined characteristic.

The controller 30 is configured to obtain a first signal from the first fuel characteristic determiner 2, and to obtain a second signal from the second fuel characteristic determiner 6.

The controller 30 is configured to store a relationship between: (a) fuel characteristics sensed by the first fuel characteristic determiner 2, (b) fuel characteristics sensed by the second fuel characteristic determiner 6, and (c) a target temperature associated with those two characteristics, (a) and (b). The target temperature comprises a temperature toward the detonation temperature of the fuel. This relationship may be stored, for example, in the form of a two dimensional look-up table. This enables the controller 30 to use the two characteristics to determine a target temperature for operation of the cylinders 14.

The controller 30 is configured to obtain a temperature signal from the exhaust gas temperature sensor 10, and determined the cylinder temperature using a pre-determined relationship between the exhaust gas and temperature of the cylinder 14. The controller 30 is configured to control the temperature control means based on this temperature signal to reduce the difference between the temperatule of the fuel in the cylinder 14 and the target temperature.

The temperature control means is operable to control temperature by varying the combustion cycle to change the length of time the fuel is in the cylinder 14 and/or to control the frequency and/or duration of fuel injection pulses applied by the injectors 8 to inject fuel into the cylinders 14. The temperature control means may also be configured to alter the temperature of the fuel in the cylinder 14 by controlling the degree of heating applied to the fuel prior to its entry to the cylinder 14, for example using a glow plug or other heater.

In operation, the controller 30 receives a signal characteristic of the fuel from the first fuel characteristic determiner 2 and the second fuel characteristic determiner 6. The controller 30 determines the target temperature based on the received signals and the stored relationship.

The controller 30 also obtains a temperature signal from the exhaust gas temperature sensor 10 and compares the temperature signal to the target temperature. The controller 30 then sends a signal to control the temperature control means to increase, or decrease, the temperature of the fuel in the cylinder 14 based on the difference between the target temperature and the sensed cylinder temperature. The temperature control means, upon receiving a signal from the controller, controls the heat transferred to the fuel by the heater 34 and/or controls the combustion cycle of the cylinder 14 by altering the duration, frequency, and/or timing of the injection of fuel into the cylinder 14.

In operation the first fuel line 4 carries fuel from the fuel tank 20 to the fuel pump 22. The pressurised fuel is received by the common rail 24 from the fuel pump 22 and the fuel injector 8 injects fuel from the common rail 24 to the cylinder 14. As described above, the injector 8 injects fuel into the cylinder 14 according to the signal received from the temperature control means. Fuel is returned from the injector 8 to the fuel tank 20 using a second fuel line.

The pressure of the fuel in the common rail 24 can be altered according to a signal received by the pump from the controller. For example, the injection of fuel into the cylinder 14 may be controlled by altering the common rail pressure and the combustion cycle modified accordingly.

One example of control of the temperature of the fuel is explained in more detail below with reference to Figure 2 and Figure 3.

Figure 2 comprises a controller 30, a cylinder 14, a piston 18, a combustion chamber 16, a first fuel line 4, a fuel pump 22, a fuel level gauge 21, a common rail 24, a first fuel characteristic determiner 2, a second fuel characteristic determiner 6, a fuel injector 8, a heater 34, a cylinder exhaust 12, a temperature sensor 10, a fuel tank 20, and a fuel tank filling inlet 36.

As shown above with reference to Figure la and lb, the fuel tank filling inlet 36 is coupled to the first fuel characteristic determiner 2 and the fuel tank 20. The first fuel line 4 couples the fuel tank 20 to the fuel pump 22. The fuel level gauge 21 is coupled to the fuel tank 20. The common rail 24 is coupled to the fuel pump 22, and the fuel injector 8. The fuel injector 8 is coupled to the fuel return line 28, which in turn is coupled to the second fuel characteristic determiner 6 and the fuel tank 20. The fuel injector 8 is coupled to the cylinder 14 via the heater 34. The cylinder 14 is coupled to a piston 18, which in turn is coupled to a crankshaft (not shown). The cylinder exhaust 12 is coupled to the cylinder 14 and the temperature sensor 10. The controller 30 is coupled to the temperature sensor 10, the fuel level gauge 21, the first fuel characteristic determiner 2, the second fuel characteristic determiner 6, the fuel injector 8, the fuel pump 22, and the heater 34.

The controller 30 has two modes of operation. The first mode corresponds to the fuel tank 20 being topped-up via the fuel tank filling inlet 36, the second mode corresponds to the fuel tank 20 receiving excess fuel from the injector 8 via the fuel return line 28. The controller 30 is operable to store an indication of the fuel level in the fuel tank 20, and a characteristic of the fuel in the fuel in the fuel tank 20.

In the first mode of operation, the controller 30 is configured to receive a fuel characteristic from the first fuel characteristic determiner 2. corresponding to a characteristic of the fuel received by the tank via the fuel tank filling inlet 36, and to receive a fuel tank level signal from the fuel level gauge 21. The controller 30 is operable to determine a characteristic of the fuel in the fuel tank 20 from the characteristic and quantity of fuel in the tank prior to top- up, and the characteristic of the fuel and quantity of fuel added to the fuel tank 20 during top-up. The controller 30 is configured to receive a characteristic of the fuel from the first fuel characteristic determiner 2 and the change in the fuel tank level, due to the top-up of the tank with fuel, according to the received signal from the fuel level gauge 21 prior to topping-up and after the top-up.

In the second mode of operation, the controller 30 is configured to receive a fuel characteristic from the second fuel characteristic determiner 6, corresponding to a characteristic of the fuel returned from the injector 8 to the fuel tank 20 via the fuel return line 28, and to receive a fuel tank level signal from the fuel level gauge 21. The controller 30 is operable to determine a characteristic of the fuel in the fuel tank 20 from the characteristic of the fuel and quantity of fuel in the tank prior to the return of fuel to the tank from the fuel return line 28, and the characteristic of the fuel and quantity of fuel added to the fuel tank 20 from the injector 8 to the fuel tank 20 via the return line. The controller 30 is configured to receive a fuel characteristic from the second fuel characteristic determiner 6 and the change in the fuel tank level, due to the return of fuel to the tank from the injectors 8, according to the received signal from the fuel level gauge 21 before fuel is returned to the tank and after fuel is returned to the tank.

In a typical cycle of operation of the engine, the fuel is initially received during filing of the fuel tank 20. When the fuel tank 20 is topped up fuel is received by the fuel tank 20 from the fuel tank filling inlet 36. During top-up, the first characteristic determiner measures a characteristic of the fuel received by the tank via the fuel tank filling inlet 36 and the fuel level gauge 21 measures the change in the quantity of fuel in the fuel tank 20. The controller 30 receives a signal from the fuel level gauge 21 corresponding to the quantity of fuel in the fuel tank 20 and a signal from the first characteristic determiner corresponding to the measured characteristic of the fuel. The controller 30 determines a characteristic of the fuel in the fuel tank 20 after topping-up from the characteristic of the fuel and the quantity of fuel in the fuel tank 20 prior to topping-up, and the characteristic of the fuel and quantity of fuel added to the fuel tank 20 during top-up.

When the engine is operated the fuel pump 22 pumps fuel from the fuel tank 20 to the common rail. The fuel pump 22 increases the pressure of the fuel according to the pressure of the fuel in the common rail. The common rail 24 stores the pressurised fuel, and the controller 30 controls the injector 8 to inject fuel from the common rail 24 into the cylinder 14.

After fuel is injected from the common rail 24 into the cylinder 14 some fuel remains in the fuel injector 8, this excess fuel is returned to the fuel tank 20 via the fuel return line 28. A characteristic of the returned excess fuel is determined by the second fuel characteristic determiner 6. The controller 30 receives a signal from the fuel tank level corresponding to the quantity of fuel in the fuel tank 20 due to the returned fuel, and a signal from the second characteristic determiner corresponding to the characteristic of the fuel received by the tank via the fuel return line 28. The controller 30 determines a characteristic of the fuel in the fuel tank 20 after receiving the returned fuel from the characteristic of the fuel and the quantity of fuel in the fuel tank 20 prior to the return of fuel from the injectors 8, and the characteristic of the fuel and quantity of fuel returned to the fuel tank 20.

The addition of fuel to the fuel tank 20 may alter the characteristic of the fuel in the fuel tank 20. As described above, the controller 30 updates the characteristic of the fuel in the fuel tank 20 when fuel is received by the fuel tank 20, for example, during fuel tank top-up or the return of excess fuel.

The controller 30 compares the determined characteristic of the fuel to a stored relationship between the fuel characteristic and fuel combustion characteristics. This comparison is used to determine the combustion characteristics of the fuel, and the corresponding detonation temperature. The controller 30 determines a target temperature according to the determined combustion characteristics of the fuel.

The controller 30 controls the temperature control means to adjust the temperature of the fuel in the cylinder 14 towards the target temperature. The controller 30 determines the temperature of the cylinder 14 from the sensed exhaust gas temperature. The controller 30 determines the difference in the temperature of the cylinder 14 and the target temperature, and controls the temperature control means to vary the temperature of the cylinder 14 to reduce this difference.

The temperature control means varies the temperature of the fuel in the cylinder 14 according to the signal received from the controller. The temperature control means heats the fuel prior to entering the cylinder 14 using the heater 34, and/or send a signal to the injector 8 to modify the combustion cycle by altering the duration, frequency, and/or timing of injection of fuel into the cylinder 14. This controls the length of time the fuel is in the cylinder 14, and when the fuel is in the cylinder 14 for a greater length of time more heat is transferred from the cylinder 14 to the fuel, therefore increasing the temperature of the fuel.

Figure 3 shows a flow chart of the cylinder temperature adjustment according to the detonation temperature of the fuel.

Fuel is received by the fuel tank 20 via a fuel tank filing inlet, 400. The insertion of fuel into the fuel tank 20, for example via a user filling the tank, alters the level of fuel in the fuel tank.

A characteristic of the fuel in the fuel tank filling inlet 36 is measured by the first characteristic determiner. The measured characteristic and the change in the fuel tank level are sent to the controller, 402. The controller, upon receiving the measured characteristic of the fuel in the fuel tank filling inlet 36 and the change in the fuel tank level updates the determined characteristic of the fuel in the fuel tank 20, 404. The fuel in the fuel tank 20 is updated according to the characteristic of the fuel and quantity of fuel in the fuel tank 20 prior to filling, and the characteristic of the fuel and quantity of fuel added via the fuel tank filling inlet 36 during top-up.

The fuel pump 22 pumps fuel from the fuel tank 20 to the common rail, with the pressure of the fuel received from the pump by the common rail 24 determined by the common rail pressure, 406. The pressurised fuel is held in a common rail 24 and injector 8 injects fuel from the common rail 24 into the cylinder 14 where the injected fuel is combusted, 408.

The excess fuel in the injector 8 after the injection of fuel into the cylinder 14 is returned to the fuel tank 20 via the fuel return line 28, 410. A characteristic of the fuel and quantity of fuel returned to the tank via the fuel return line 28 is measured, and a signal corresponding to the measured characteristic and the change in fuel tank level is sent to the controller, 412.

The controller, upon receiving the measured characteristic of the fuel in the fuel return line 28 and the change in the fuel tank level, updates the determined characteristic of the fuel in the fuel tank 20, 414. The fuel in the fuel tank 20 is updated according to the characteristic of the fuel and quantity of fuel in the fuel tank 20 prior to the return of fuel to the fuel tank 20, and the characteristic of the fuel and quantity of fuel returned to the tank. The determined characteristic of the fuel is used to determine a target temperature of the fuel in the cylinder 14 according to a relationship between the characteristic of the fuel and the combustion characteristic of the fuel, 416.

The controller 30 determines the cylinder temperature from a signal corresponding to the exhaust gas temperature. A feedback mechanism compares the determined cylinder temperature to the target temperature of the fuel in the cylinder 14, and sends a signal to the temperature control means, 418. The temperature control means, upon receiving the signal from the controller, adjusts the temperature of the fuel in the cylinder 14. The temperature of the fuel is adjusted by controlling a heater 34 to heat the fuel received by the chamber, and/or controlling an injector 8 to alter the duration, frequency, and/or timing of the injection of fuel into the cylinder 14, 420. The adjustment of the temperature of the cylinder 14 is described in more detail above.

A measurement of the viscosity of the fuel in the fuel line arriving at the injector 8 from the fuel tank 20 and returning to the fuel tank 20 from the injector Swill measure changes in the fuel composition. The composition the fuel injected into the cylinder 14 may not correspond to the composition of the fuel in the fuel tank 20. For example, a mixture of fuels with a large difference in viscosity may have a difference in flow of each fuel. The fuel injected into the cylinder 14 may therefore have a higher composition of the lower viscosity fuel.

The error in the cylinder temperature measurement determine from the exhaust gas temperature is dependent on the distance between the exhaust gas temperature sensor 10 and the cylinder 14. A calibration of the temperature sensor value with the cylinder temperature allows the cylinder temperature determined from the exhaust gas temperature sensor 10 to be corrected according to the location of the temperature sensor.

In the examples described above, the characteristic of the fuel is determined by a fuel characteristic determiner. The fuel characteristic determiner may directly measure the characteristics of the fuel by receiving a sample of the fuel and analysing the sample of fuel.

The fuel characteristic determiner may measure the characteristics of the fuel indirectly, for example by measuring an output signal such as the composition of the exhaust gases, and/or the torque output of the engine.

The characteristic of the fuel may be measured directly using a viscosity measurement, an IR spectroscopy sensor, and/or a mass spectrometer.

The viscosity of the fuel may be measured using one or more viscosity cups, and/or the transmission of light or sound through the fuel.

In the examples described above the level of fuel in the fuel tank 20 is determined from the output of the fuel level gauge 21. The output of the fuel level gauge 21 is used to determine the quantity of fuel in the tank prior to top-up or return of fuel, and the quantity of fuel received by the tank during top-up and the return of fuel from the injectors 8. The quantity of fuel may also be measured using a flow meter, for example, to determine the quantity of fuel flowing into the tank from the fuel return line 28 and the fuel tank filling inlet 36.

In the examples described above, the temperature of the cylinder 14 is determined from the temperature of the exhaust gases. The temperature of the cylinder 14 may also be determined from a temperature sensor on the cylinder 14, from a sensor to analyse the exhaust gases, and/or from the torque output of the engine.

In the examples described above the temperature of the exhaust gases are measured using a temperature sensor, the sensor may comprise a thermocouple, a thermistor, and/or IR sensor.

In the examples described above, the controller 30 determines the detonation temperature of the fuel from a two dimensional look-up table, the detonation temperature may also be determined from a calculation relating the characteristic of the fuel to the detonation temperature, a user input, and/or a remote input to the controller.

In the examples described above, the target temperature is determined from the detonation temperature of the fuel. The target temperature may also be determined from external temperature conditions, the required vehicle performance as well as the detonation temperature of the fuel.

The engine may further comprise a fuel temperature sensor, wherein controller receives the sensed fuel temperature and determines the output of the temperature control means is determined according to the fuel temperature. In the examples described above, the fuel is heated prior to entering the cylinder 14 by a heater 34. The heater 34 may be a glow plug, an inductor device, an electromagnetic radiation device, and/or a resistance heater.

In the examples described above, the heater 34 is coupled between the cylinder 14 and the injector. The heater may also be coupled to the common rail, between the common rail 24 and the cylinder 14, between the fuel pump 22 and the common rail 24, between fuel tank 20 and the fuel pump 22, to the fuel tank 20, and/or to the fuel cylinder 14.

In the examples described above, the injector 8 injects fuel upon receiving a signal from the controller 30. The injection of fuel may also be altered by varying the power received by the injector 8.

In the examples described above, the combustion cycle is altered according to the target temperature, the combustion cycle may also be altered according to the vehicle load, vehicle performance, and/or exhaust gas output.

In the examples described above, the temperature control means is controlled according to the difference between the cylinder temperature and the target temperature. The temperature control means may also be controlled according to the temperature of the fuel in the fuel tank 20, and/or the external temperature.

With reference to the drawings in general, it will be appreciated that schematic functional block diagrams are used to indicate functionality of systems and apparatus described herein.

It will be appreciated however that the functionality need not be divided in this way, and should not be taken to imply any particular structure of hardware other than that described and claimed below. The function of one or more of the elements shown in the drawings may be further subdivided, and/or distributed throughout apparatus of the disclosure. In some embodiments the function of one or more elements shown in the drawings may be integrated into a single functional unit.

The above embodiments are to be understood as illustrative examples. Further embodiments are envisaged. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

In some examples, one or more memory elements can store data and/or program instructions used to implement the operations described herein. Embodiments of the disclosure provide tangible, non-transitory storage media comprising program instructions operable to program a processor to perform any one or more of the methods described and/or claimed herein and/or to provide data processing apparatus as described and/or claimed herein.

The activities and apparatus outlined herein may be implemented with fixed logic such as assemblies of logic gates or programmable logic such as software and/or computer program instructions executed by a processor. Other kinds of programmable logic include programmable processors, programmable digital logic (e.g., a field programmable gate array (FPGA), an erasable programmable read only memory (EPROM), an electrically erasable programmable read only memory (EEPROM)), an application specific integrated circuit, ASIC, or any other kind of digital logic, software, code, electronic instructions, flash memory, optical disks, CD-ROMs, DVD ROMs, magnetic or optical cards, other types of machine-readable mediums suitable for storing electronic instructions, or any suitable combination thereof.

Claims

CLAIMS1. A compression injection engine arranged to obtain fuel from a fuel tank, and to return fuel to said fuel tank, the engine comprising: a cylinder, a fuel characteristic determiner arranged to determine a characteristic of the fuel, and a temperature control means adapted to increase the operating temperature of the cylinder towards a detonation temperature selected based on the characteristic, and to limit that temperature increase based on the characteristic to inhibit at least one of: (i) detonation of unburnt fuel during an exhaust phase of an engine cycle, and (U) premature detonation of fuel in an injection phase of an engine cycle.
2. The apparatus of claim 1 wherein the fuel characteristic determiner is arranged to determine the characteristic based on a characteristic of fuel to be supplied to the engine, and based on a characteristic of fuel returned from the engine.
3. The apparatus of claim 1 or 2 wherein the fuel characteristic determiner comprises a sensor coupled to sense the characteristic of the fuel returned from the engine.
4. The apparatus of claim 1, 2, or 3 wherein the fuel characteristic determiner is coupled to sense a characteristic of fuel provided to the fuel tank via a fuel tank filling inlet.
5. The apparatus of any preceding claim, wherein the temperature control means comprises a heater arranged to heat the fuel,
6. The apparatus of any preceding claim, wherein the temperature control means comprises an injection control means arranged to vary the frequency and/or the timing of the injection of fuel into the cylinder.
7. The apparatus of any preceding claim, wherein the temperature control means comprises an injection control means arranged to vary the duration of the injection of fuel into the cylinder.
8. The apparatus of any preceding claim, wherein temperature control means further comprises a temperature sensor arranged to sense the temperature of the cylinder; wherein the temperature control means is arranged to adjust the operating temperature of the cylinder according to the sensed temperature of the cylinder and the detonation temperature of the fuel.
9. The apparatus of any preceding claim, wherein the engine is a common rail injection engine, wherein the apparatus is configured to vary the pressure of the fuel in the common rail based on the determined characteristic of the fuel.
10. The apparatus of any preceding claim, wherein the fuel characteristic determiner comprises a fuel viscosity sensor.
11. The apparatus of claim 8 to 10, wherein the temperature sensor is arranged to sense the exhaust gas temperature.
12. A data processor configured to control a compression injection engine, wherein the processor is configured to: obtain a fuel characteristic signal indicating a characteristic of the fuel; and to provide a signal to a temperature control means for controlling the temperature of a cylinder based on the characteristic of the fuel, to increase the operating temperature of the cylinder towards a detonation temperature selected based on the characteristic, and to limit that temperature increase based on the characteristic to inhibit at least one of: (i) detonation of unburnt fuel during an exhaust phase of an engine cycle, and (U) premature detonation of fuel in an injection phase of an engine cycle.
13. The data processor of claim 12 wherein the fuel characteristic signal is based on a characteristic of fuel to be supplied to the engine, and based on a characteristic of fuel returned from the engine.
14. The data processor of claims 12 or 13 wherein the fuel characteristic signal comprises a sensed characteristic of the fuel returned from the engine.
15. The data processor of claim 12, 13, or 14 wherein the fuel characteristic signal comprises a sensed characteristic of fuel provided to the fuel tank via a fuel tank filling inlet.
16. The data processor of claims 12 to 15, wherein the temperature control means comprises a heater arranged to heat the fuel.
17. The data processor of claims 12 to 16, wherein the temperature control means comprises an injection control means arranged to vary the frequency and/or the timing of the injection of fuel into the cylinder.
18. The data processor of claims 12 to 17, wherein the temperature control means comprises an injection control means arranged to vary the duration of the injection of fuel into the cylinder.
19. The data processor of claims 12 to 18, wherein temperature control means further comprises a temperature sensor arranged to sense the temperature of the cylinder; wherein the temperature control means is arranged to adjust the operating temperature of the cylinder according to the sensed temperature of the cylinder and the detonation temperature of the fuel.
20. The data processor of claims 12 to 19, wherein the engine is a common rail injection engine, wherein the apparatus is configured to vary the pressure of the fuel in the common rail based on the determined characteristic of the fuel.
21. The data processor of claims 12 to 20, wherein the characteristic of the fuel the viscosity of the fuel.
22. The data processor of claims 12 to 21, wherein the temperature sensor is arranged to sense the exhaust gas temperature.
23. A computer program product comprising program instructions operable to program a processor to provide data according to claims 12 to 22.
24. An apparatus substantially as described herein with reference to the accompanying drawings.