GB2471890A

GB2471890A - Control unit for synchronizing fuel injection in an internal combustion engine

Info

Publication number: GB2471890A
Application number: GB0912415A
Authority: GB
Inventors: Alessandro Catanese; Gerhard Landsmann
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2009-07-17
Filing date: 2009-07-17
Publication date: 2011-01-19
Also published as: GB0912415D0

Abstract

An engine control unit 31 which synchronizes fuel injection of a cylinder 11 of an internal combustion engine, eg a diesel engine, comprises a port for receiving an in-cylinder pressure measurement, a port for receiving information, eg rotational angle, of a crankshaft 22, and a storage unit for storing the in-cylinder pressure measurement. Further, the engine control unit 31 comprises a determination unit for determining a run-time parameter of the cylinder 11 using the in-cylinder pressure measurement and the information of the crankshaft 22, and a cylinder control unit for controlling a run-time parameter unit using the determined run-time parameter. The run-time parameter can include the timing and amount of fuel injection, ignition timing and valve movement timing. Engine production cost can be reduced as a camshaft sensor is not required.

Description

An improved internal coithustion engine.

The application relates to an engine control unit for an in-ternal combustion engine. In particular, it relates a method for synchronising fuel injection of the internal combustion engine.

In a four-stroke combustion engine, a complete combustion cy-cle requires two complete crankshaft revolutions that cover an intake phase, a compression phase, an expansion phase and an exhaust phase. One crankshaft revolution is also called an engine revolution. Knowledge of crankshaft angular position alone is not sufficient to determine engine timings for syn-chronising fuel injection at the compression phase.

Often, sensors are mounted on camshafts to provide this in- formation. Camshaft position information together with crank- shaft position information enable determination of the com- pression phase for correct timing of fuel injection. The po-sition of a crankshaft is an absolute or relative angle of the crankshaft. The same applies to the camshaft position, which is camshaft angle. Once the engine is synchronized for fuel injection and combustion starts, the camshaft sensor in-formation is not needed any more if a calculation unit is maintaining the engine phase synchronisation with the crank-shaft position.

Different methods have been proposed to achieve engine syn- chronization without usage of the camshaft sensor. One exam-pie of this is Us 6,889,663 B2. These methods often monitor certain parameters that indicate or relate to engine firing.

Fuel is injected into the engine based on a measured crank-shaft position and on an assumed camshaft position, whilst engine performance parameters, such as engine speed, are monitored. If engine operational performance improves, then it is confirmed that the assumed camshaft position is correct and that the synchronization is achieved. Otherwise, the as-sumed camshaft position is varied by 180 degrees andnew fuel is injected. The process is repeated until the monitored op-erational performance improves.

If the initial fuel injection position is incorrect, fuel is wasted or is consumed to locate the correct fuel injection position. This thus results both in increased fuel consump-tion and in increased exhaust emission. Moreover, cranking time is increased significantly. These consequences could be acceptable in industrial and in heavy engine implementation where occurrence of engine cranking is very low, but may not be acceptable in commercial engine application where small engines are often switched off and on several times in a same day.

The present application aims to provide a simple and reliable method for synchronising fuel injection of the combustion en-gine at low cost.

Using the application, cost associated with production of a diesel engine can be reduced as the engine does not need a camshaft sensor.

The application provides an engine control unit. The engine control unit is used to synchronize fuel injection of a cyl-inder of an internal combustion engine. The fuel can ignite via compression ignition mechanism wherein pressure and tem- perature of the cylinder ignites or burns the fuel. The in- ternal combustion engine employs a four-stroke combustion cy-cle. The subject matter of the application is applicable for diesel engines, for petrol engines, for fuel engines, for gas engines with or without fuel injection system.

The engine control unit comprises, a. first port and a second port. The first port is used forreceiving an in-cylinder pressure measurement of the cylinder of the internal combus- tion engine whilst the second port is used for receiving po- sition information of a crankshaft of the cylinder. The posi-tion information includes angular positions of the crankshaft during crankshaft revolutions.

The in-cylinder pressure measurement and the position infor-mation of the crankshaft are used to determine a time point to inject fuel into the cylinder. The time point occurs dur-ing a compression phase of a combustion cycle. The crankshaft information alone cannot distinguish a compression phase of the combustion cycle from its exhaust phase. However, the in-cylinder pressure measurement is able to differentiate the compression phase from the exhaust phase as combustion pres- sure increases in the compression phase but not in the ex-haust phase. Hence, the crankshaft position information and the combustion pressure together can be used to identity the compression phase for fuel injection.

* 30 Further, the engine control unit includes a storage unit for storing the in-cylinder pressure measurement and the informa- tion of the crankshaft. The storage unit facilitate the proc- essing of the in-cylinder pressure measurement and of the in-formation of the crankshaft to determine a fuel injection time point.

The engine control unit also includes a determination unit.

S The determination unit is for determining a run-time parame- ter of the cylinder using the in-cylinder pressure measure-ment and the information of the crankshaft. The determination unit can include or be in the form of a computer central processing unit.

The run-time parameter can include timing of fuel injection.

For a more complete engine management, the run-time parameter can comprise amount of fuel injection, ignition timing, and valve movement timing. In a diesel engine, the ignition tim-ing comprises a glow plug powering on/off timing. In a petrol engine, the ignition timing refers to a sparking timing or a spark timing for applying a high voltage to a spark plug for ignition. For controlling a run-time parameter unit of the cylinder of the internal combustion engine, the engine con- trol unit further includes a cylinder control unit using de-termined run-time parameter.

To release fuel into the cylinder, the run-time parameter unit can comprise a fuel injection unit.

The information of a crankshaft of the cylinder can include or be in the form of a crankshaft rotation angle.

The engine control unit can also include a port for receiving one or more engine parameters, such as engine temperature or crankshaft rotation speed. The determination unit uses the engine parameter for adjusting the run-time parameter of the cylinder. The adjustment is intended to improve or tweak en- gine performance. This is also called variable fuel injec- tion. The adjustment can be for only a small degree of crank-shaft rotation.

This adjustment is easy to implement as most parts required for the adjustment is already present in the application. A software upgrade may only be needed to implement this adjust-ment.

The fuel control unit can control the fuel injection via us- ing a high-pressure valveof a fuel line of the internal com-bustion engine or a fuel-rail pressure regulator of the fuel line of the internal combustion engine. Other means of ad-justment is also possible.

The application also provides an internal combustion engine and a vehicle that comprises such an internal combustion en- gine. The internal combustion engine comprises the above-mentioned engine control unit. The internal combustion engine also includes a cylinder that comprises an in-cylinder pres- sure sensor unit, a crankshaft sensor, and a run-time parame-ter unit.

In particular, the in-cylinder pressure sensor unit transmits an in-cylinder pressure measurement to the engine control unit whilst the crankshaft sensor transmits information of the crankshaft to the engine control unit. The run-time pa-rameter unit is provided in the cylinder characterised in that the engine control unit controls the run-time parameter unit.

The vehicle comprises a set of wheels that is connected to the internal combustion engine via a transmission unit. The transmission unit includes gears and one or more clutches for transmitting rotational forces of the internal combustion en-gine to the wheels.

S Further, the application provides a method for synchronising fuel injection of an internal combustion engine. The method comprises the step of measuring in-cylinder pressure of a cylinder of the internal combustion engine and the step of collecting position information of a crankshaft of the inter-nal combustion engine.

Later, a run-time parameter of the cylinder is determined us- ing the in-cylinder pressure measurement and the position in- formation of the crankshaft. The run-time parameter can in-dude a fuel injection time point information. Afterwards, an operation of the internal combustion engine is regulated us-ing the determined run-time parameter.

In particular, the regulating of the operation of the cylin-der can occur after the cylinder pressure measurement exceeds a pre-determined synchronisation value and occurs when the information of the crankshaft indicates that the cylinder is a compression stroke of a combustion cycle. The regulating can include adjusting fuel injection timing and amount, crankshaft revolution speed, spark timing or glowing timing, valve operation timing, cooling rate and other relevant pa-rameters for operating the internal combustion engine.

To improve engine performance or fuel consumption, the method can include the step of collecting a parameter of the inter- nal combustion engine, such as engine temperature. The run-time parameter of the cylinder is then adjusted using this parameter of the internal combustion engine. In essence, run-time parameter can be adjusted to delay or bring forward fuel ignition to achieve the said objective. The run-time parame-ter adjustment can also change amount of injected fuel.

Fuel injection point for a second cylinder of the internal combustion engine can be derived from the above-mentioned runtime parameter. Put differently, run-time parameter of one cylinder can be used for another cylinder.

In one instance, a combustion cycle of the second cylinder is degrees crankshaft rotation behind the said cylinder. The fuel injection time point of the second cylinder can be de-termined or computed as equal to the first determined fuel injection time point plus 180 degrees of rotation. The term "plus 180 degrees of rotation" refers to a time duration for the crankshaft to turn 180 rotate 180 degrees at current ro-tation speed of the crankshaft.

In most application, the run-time parameter of one cylinder is determined once and then it is used repeatedly for multi- pie engine cycles of an operation of the engine, as appropri-ate.

In the following description, details are provided to de-scribe an embodiment of the application. It shall be apparent to one skilled in the art, however, that the embodiment may be practised without such details.

Fig. 1 illustrates an embodiment of an engine for a vehi-cle that comprises a plurality of cylinders, Fig. 2 illustrates a schematic view of the cylinder of Fig. 1, Fig. 3 illustrates a valve assembly of the cylinder of Figs. 1 and 2, Fig. 4 illustrates a method of operating the cylinder of Figs. 1 and 2, Fig. 5 illustrates a method of operating multiple cylind-ers of the engine of Fig. 1, and Fig. 6 illustrates an engine control unit for the cylinder of the engine of Fig. 1.

Figs. 1 to 6 have similar parts. The similar parts have same name or same reference number. The description of the similar part is thus incorporated by reference.

Fig. 1 depicts a compression ignition engine 10 for a vehicle that comprises a plurality of combustion cylinders 11, 12, 13, and 15. The engine 10 is intended for driving or for turning wheels of the vehicle to transport goods or passen-gers. The cylinders 11, 12, 13, and 15 are used to convert diesel fuel to kinetic energy. The cylinders 11, 12, 13, and 15 are similar to each other and have similar parts.

Fig. 2 shows a schematic view of a cylinder assembly 14 that includes the cylinder 11 of Fig. 1. The cylinder 11 has a cylinder head 17. An in-cylinder pressure sensor 16 is in-stalled in the cylinder head 17 whilst a piston 18 is slidably disposed in a bore 19 of the cylinder 11. The cylin- der head 17, the piston 18, and the bore 19 define or sur-round a space that is called a combustion chamber 21.

The piston 18 is connected to a crankshaft 22 via a connect- ing rod 23. A position sensor 50 is attached to the crank-shaft 22 whilst an output of the crankshaft position sensor is connected to a port 34 of an engine control unit 31.

An inlet valve 25 is provided at an end of an intake passage 28 of the cylinder head 17 whilst an exhaust' valve 26 is pro-vided at an end of an exhaust passage 29 of the cylinder head 17. A fuel injector 30 is fixed to the cylinder head 17 such that an outlet of the fuel injector 30 is disposed in the combustion chamber 21. The inlet valve 25 and the exhaust valve 26 are placed next to camshafts 47 in a manner as shown in Fig. 3. A position camshaft 47 refers to its rotatipnal angle a as shown in Fig. 3.

Referring to the fuel injection 30 of Fig. 2, it is connected to a tank 32 via a supply line 33 that is also called a com-mon rail. Disposed in line to the supply line 33 are a filter 35, a pump 36, a high-pressure valve 38, and a fuel-rail pressure regulator 40. The high-pressure valve 38 is con-nected to a port 45 of the electronic engine controlunit 31 whilst the fuel-rail pressure regulator 40 is connected a port 46 to the electronic engine control unit 31. A return line 41 also leads from the fuel injector 30 to the tank 32.

Referring to the in-cylinder pressure sensor 16, it includes a sensor head 42 that is connected to a signal conditioner 43 via two cables 44. The sensor head 42 is located within the combustion chamber 21 whilst the signal conditioner 43 is lo-cated outside of the cylinder 11. An output of the signal conditioner 43 is connected to a port 51 of the engine con-trol unit 31.

In a general sense, although the in-cylinder pressure sensor 16 is shown as being installed directly in the cylinder head 17, it could also be integrated into the fuel injector 30 or be integrated into a glow plug of the cylinder 11. The glow plug, which is not shown in the figure, can serve to heat the cylinder 11 to ease starting of the engine 10 from an idle state, especially when the engine 10 is cold.

Although the cylinder assembly 14 is intended for pressure ignition operation, it a broad sense, can include other parts for spark ignition operation. The cylinder assembly 14 can receive fuel or gas for its operation.

Functionally, the camshafts 47 are intended for actuating the valves 25 and 26. The actuation opens the inlet valve 25 to take in air or gases into the combustion chamber 21 or opens the exhaust valve 26 to exhaust the gases out of the cornbus-tion chamber 21. Put differently, the camshaft 47 modulates supply of the air to the combustion chamber 21 as well as modulates exhaust of combustion products from the combustion chamber 21.

The in-cylinder pressure sensor 16 measures pressure within the combustion chamber 21 and it sends the measured pressure readings to the engine control unit 31. The pressure sensor 16 is capable of withstanding heat and pressure associated with operation of the compression ignition engine 10 and is capable of operating in presence of volatile gases in the combustion chamber 21. Further, the pressure sensor 16 has a high sensitivity and a high signal-to-noise ratio. It is also imrnunes to electromagnetic interference and produces linear readings to within a certain tolerance.

The fuel injector 30 can be in the form of an electro- hydraulic fuel injector or in the form of a pressure-intensified accumulator-type injector. The fuel injector 30 is used to supply or fill the combustion chamber 21 with di- esel fuel or the like from the tank 32. The supply is con- trolled by the engine control unit 31 via the fuel-rail pres-sure regulator 40 and the high-pressure value 38.

S The cylinder 18 is moved, by the crankshaft 22 to change vo-lume of the combustion chamber 21. The volume can be reduced to increase its pressure and temperature to ignite the fuel that is supplied by the fuel injector 30. The injected fuel ignites or burns at a particular temperature and pressure.

The ignition, which is also called combustion, sends an ex-plosive onto the cylinder 18 to turn the crankshaft 22. The position or rotational angle of the crankshaft 22 is trans- mitted to the engine control unit 31 by the crankshaft posi-tion sensor 50.

The engine control unit 31 controls or governs the release of the fuel via the fuel-rail pressure regulator 40 and the high-pressure valve 38 to the combustion chamber 21. The con-trol is based on information from the in-cylinder pressure sensor 16 and information from the crankshaft position sensor 50. The information is used to determine a state or phase of a combustion cycle of the engine 10.

Moreover, the engine control unit 31 can use other additional information of the engine 10 to control the fuel release. The additional information includes temperature, speed, or air intake volume. The control can also relate to timing, dura-tion, or quantity of fuel release.

In a generic sense, the camshaft 47 can be removed from the engine 10 so that the valves 25 and 26 are not controlled or actuated by the camshaft 47 but by an electro-hydraulically means.

Fig. 4 shows graphs that illustrate a method of synchronisa-tion fuel injection into the cylinder 11 of the engine 10.

The method uses information from the in-cylinder pressure sensor 16 and information from the crankshaft 23 to determine a time point for injecting fuel into the cylinder 11. Without engine firing, pressure in the cylinder 11 increases always when its volume is decreased whilst its intake valve 25 and its exhaust valve 26 are closed.

As shown in Fig. 4, a full engine combustion cycle 54 com- prises a first crankshaft revolution 55 and a second crank- shaft revolution 56. The first crankshaft revolution 55 com-prises an intake stroke 58 and a compression stroke 59 whilst the second crankshaft revolution -56 comprises an expansion stroke 60 and a compression stroke 61. The strokes 58, 59, 60, and 61 are also called a phase or a state. Each stroke 58, 59, 60, or 61 extends for 180 degrees rotation of the crankshaft 22.

The method uses chamber pressure information and crankshaft information to determine when to inject fuel into the combus-tion chamber 21.

A crankshaft position signal 63 cannot be used solely to de-termine the fuel injection point. The crankshaft position signal 63 has a distinctive feature of a first spike 64 and a second spike 65. Since the crankshaft spike occurs in both the compression phase 59 and the exhaust 61, it cannot be used solely to determine the fuel injection point.

The combustion cycle 54 commences at 0-degree rotation point of the crankshaft 22 whilst the crankshaft position sensor 50 generates the crankshaft signal 63 generates a spike at every 330-degree point of the rotation of the crankshaft 22. The spike has a very large, value in comparison with other normal non-spike situation. In particular, the' crankshaft 22 has the first spike, 64 at the 330-degree point of crankshaft rotation and t'he second spike 65 at the 540-degree point of the crank-shaft rotation.

Considering the combustion cycle, the intake stroke 58 starts at a 0-degree point of rotation of the crankshaft 22 and it ends at a 180-degree point. During this phase, the intake valve 25 is opened and the exhaust valve 26 is closed allow-ing gases or air to fill the combustion chamber 21. A volume graph 68 shows a volume of the combustion chamber 21 that in-creases throughout the phase and that it reaches a first peak at the end of the phase. A pressure graph 72 that depicts pressure within the combustion chamber 21 remains relatively constant throughout the phase.

The compression stroke 59 afterward commences at the 180-degree point of crankshaft rotation and ends a 360-degree point of crankshaft rotation. The intake valve 25 and the ex-haust valve 26 are closed during this phase enclosing the gases within the combustion chamber 21. During this phase, the volume decreases whilst the pressure increases and reaches at a peak 75 at the end of this phase. Correspond- ingly, temperature within the combustion chamber 21 also in-creases.

Just before the peak 75, the crankshaft signal 63 has the first spike 64 at 330-degree point of the compression stroke 59. The chamber pressure at point A of the pressure graph 72 that corresponds to a 330-degree point 48 is above the syn-chronization threshold 73. The engine control unit 31 uses a simultaneous occurrence of the crankshaft spike and of cham- ber pressure above the synchronisation threshold 73 to re-lease fuel into the cylinder 11. The point 48 is also called a fuel injection point.

Then, the expansion stroke 60 starts at the 360-degree point of crankshaft rotation and it ends at a 540-degree point of crankshaft rotation. Due to the high temperature, and the high pressure within the combustion chamber 21, the injected fuel ignites during this stroke 60. The intake valve 25 and the exhaust valve 26 are closed allowing the ignited fuel to ex-ert a large force on the piston 18 and thereby turning the crankshaft 22 with the large force. As the crankshaft 22 turns, the volume of the combustion chamber 21 increases to reach a peak whilst the pressure of the combustion chamber 21 decreases rather quickly.

Later, the exhaust stroke commences at the 540-degree point and ends a 720-degree point. The intake valve 25 is closed and the exhaust valve 26 is opened allowing exhaust of the ignited fuel to leave the combustion chamber 21. The volume of the combustion chamber 21 starts to decrease whilst the pressure within the combustion chamber remains relatively constant throughout this stroke 61. The crankshaft signal 63 has the second spike 65 at 690-degree point of the exhaust stroke 61. However, the pressure at point B of the pressure graph 72 that corresponds to a 690-degree point 49 is below the synchronisation threshold 73. Hence, the engine control unit 31 does not release fuel into the combustion chamber 21.

This method enables the compression phase to be distinguished from the exhaust phase so that correct engine position or en- gine phase can be identified for injecting fuel using the in- cylinder pressure measurements. Injection of fuel at the in-correct engine phase or timing will not result in successful firing of engine since the engifle'S pressure and temperature does not support combuStiOfl at the incorrect engine phase.

This embodiment has certain benefits. As compared with the other synchronization methods, it is possible to eliminate one camshaft sensor if the camshaft sensor is not used for any other controls. Moreover, it is believed that in the near future, the cylinder pressure sensor 16 is part of engine im-plementations to monitor and to control combUstiOfl process.

This means that the cylinder pressure sensor 16 will anyway be part of the engine 10 and that no additional cost or de-sign is needed.

In addition, the embodiment has the benefit that the fuel is [ injected only if the engine phase or engine timing has been determined with certain preciSiofl. Therefore, no fuel is wasted. Only necessary fuel with corresponding emission is spent. This is different from a solution that is based on monitoring of engine firing, wherein fuel is spent to deter-mine the correct engine phase.

In a special embodiment, the engine control unit 31 uses only the �n-cylinder pressure measurements to derive the fuel in-jection point 48. The fuel injection point 48 is determined such that in-cylinder pressure measurement value is above the synchronisation threshold 73 and that a rate of change of the pressure measurement values is positive.

This embodiment has the advantage that the crankshaft poSi tion sensor 50 is not needed and thus removing the crankshaft position sensor 50 as a point of failure. Further, cost asso-ciated with implementing the crankshaft sensor 50 is avoided.

Fig. 5 shows a method of operating multiple cylinders 11, 12, 13, and 15 of the engine 10 of Fig. 1.

Fig. 5 shows the different strokes or phases of the cylinder 11 that are described in Fig. 4. As shown in Fig. 5, the phases of the cylinder 12 occur 180 degrees of crankshaft ro-tation later than the phases of the cylinder 11. Similarly, the phases of the cylinder 13 occur 180 degrees of crankshaft rotation later than the phases of the cylinder 14.

One method to synchronise the injection phases of the differ-ent cylinders 11, 12, 13, and 15 comprises the engine control unit 31 determining or deriving a first fuel injection point for one cylinder 11 using the method as described in Fig. 4.

Then, the engine control unit 31 determines a second fuel in- jection point for the cylinder 12 from the first fuel injec-tion point by adding 180 degrees to the first fuel injection point. Similarly, the engine control unit 31 determines a third fuel injection point for the cylinder 13 from the first fuel injection point by adding 360 degrees to the first fuel injection point. A fourth fuel injection point for the cylin-der 15 is determined or derived from the first fuel injection point by adding 540 degrees to the first fuel injection point.

This method has the advantage that only one in-cylinder pres-sure measurement and corresponding crankshaft information is needed to derive fuel injection time-points for the multiple cylinders of the same engine.

Fig. 6 showS the engine control unit 31 for the cylinder 11 of the engine 10 of Fig. 1.

The engine control unit 31 comprises a central processing unit 80 that is connected to a computer memory 82. The cen-tral processing unit 80 is connected to the ports 45, 46, 51, 34, and a port 84.

The central processing unit 80 receives information from the crankshaft position sensor 50 via the port 34 and in-cylinder pressure measurements from the in_cylinder pressure sensor 16 via the port 51. Then, the central processing unit 80 stores the crankshaft information and the pressure measurements in the computer memory 82 for processing. The process determines the fuel injection time point. It can also determine a quan tity of the fuel injection and duration of the fuel injec-tion. After this, the central proceSSifl unit 80 controlS or releases the fuel injection using the high_pressure valve 38 via the port 45 and using the fuel-rail pressure regulator 40 via port 46. The central processing unit 80 has electrical current drivers for the control that is not shown in the fig-ure.

Further, the central processing unit 80 receives other engine parameteri such as engine temperature from engine sensors via the port 84. The central processing 80 can use the engine pa-rameter to adjust the fuel injection time point to improve engine performance.

For example, the engine control unit 31 can inject the fuel a bit earlier or later depending on a temperature of the engine 10. This method is easy to implement, as most hardware to support this implementation is already present in the ernbodi-ment. Moreover, the method produces a means to improve or to optimize engine performance.

In an alternative embodiment, the glow plug in the diesel en-gine 10 is replaced by a spark plug in a petrol engine. The alternative embodiment comprises parts with same reference numbers that are similar to these.of the first embodiment.

bescription of these parts is incorporated by reference where.

necessary. A crankshaft 22 of the petrol engine rotates at 6000 rpm (round per minute) in a typical operation. An engine control unit 31 is connected to the spark plug for determin-ing spark timing.

During operation, a sensor head *42 measures internal pressure of a cylinder 11 and sends pressure signals to the engine control unit 31 continuously. In the mean time, the engine control unit 31 receives signals from a position sensor 50 on the crankshaft 22 for determining crankshaft positions during the engine operation.

The engine control unit 31 determines if the petrol engine is operating in a compression phase when internal pressure of the cylinder keeps increasing within one engine revolution.

The internal pressure increases if a later pressure is higher than its previous pressure value within one engine revolu-tion, which is 0.01 second. Time interval between the two pressure measurements is less than that of one engine revolu-tion. The engine control unit 31 further checks if any of the internal pressure measurements reaches a predetermined syn- chronisation threshold. The engine control unit 31 can con-firm that the petrol engine operates within the compression phase if the pressure increases within one engine revolution.

The spark plug is applied with a high voltage beyond 20,000 volts when the engine control unit 31 ascertains that the petrol engine operates within the compression phase and an internal pressure of the cylinder 11 has reached the synchro-nisation threshold. Injection of a predetermined amount of petrol is also synchronised by the engine control unit 31 for ignition.

Additionally, in determining whether the petrol engine oper-ates at the compression phase, a position sensor 50 sends signals to the engine control unit 3l if the crankshaft 22 is at the angle of 330 degree of one engine revolution. The spark plug is fired at 20,000 volts if the crankshaft reaches the angle of 330 degree during the compression phase and the internal pressure reaches the synchronisation threshold.

Although the above description contains much specificity, these should not be construed as limiting the scope of the embodiments but merely providing illustration of the foresee-able embodiments. Especially the above stated advantages of the embodiments should not be construed as limiting the scope of the embodiments but merely to explain possible achieve-ments if the described embodiments are put into practise.

Thus, the scope of the embodiments should be determined by the claims and their equivalents, rather than by the examples given.

Key to the Drawings Reference numbers engine 11 cylinder 12 cylinder 13 cylinder 14 assembly cylinder 16 pressure sensor 17 cylinder head 18 piston 19 bore 21 combustion chamber 22 crankshaft 23 connecting rod valve 26 valve 28 intake passage 29 exhaust passage 30 fuel injector 31 engine control unit 32 tank 33 supply line 34 port 35 filter 36 pump 38 high-pressure valve fuel-rail pressure regulator 41 return line 42 sensor head 43 signal conditioner 44 cable port 46 port 47 camshaft 48 point 49 point 50 position sensor 51 port 54 engine combustion cycle crankshaft revolution 56 crankshaft revolution 58 stroke 59 stroke stroke 61 stroke 63 crankshaft signal 64 spike spike 68 volume graph peak 71 peak 72 pressure graph 73 synchronisation threshold peak central processing unit 82 memory 84 port

Claims

CLAIMS1. Engine control unit (31) comprising -a port (51) for receiving an in-cylinder pressure measurement of a cylinder (11) of an internal com-bustion engine (10), -a port (34) for receiving, information of a crank-shaft (22) of the cylinder (11), - -a storage unit (82) for storing the in-ôylinder io pressure measurement and the information of a crankshaft (22) of the cylinder (11)., -a determination unit (80) for determining a run-time parameter (48) of the cylinder (11) using the in-cylinder pressure measurement and the informa-tion of the crankshaft (22), and -a cylinder control unit (80) for controlling a run-time parameter unit (80) of the cylinder (11) of the internal combustion engine (10) using the de-termined run-time parameter (48).
2. Engine control unit (31) of claim 1 characteriSed in that the run-time parameter comprises a timing of fuel injec-tion.
3. Engine control unit (31) of claim 1 or 2 characteriSed in that the run-time parameter unit comprises a fuel injection unit (30)
4. Engine control unit (31) of one of preceding claims characteriSed in that the information of a crankshaft (22) of the cylinder (11) comprises a crankshaft rotation angle.
5. Engine control unit (31) of one of preceding claims further comprising a port (84) for receiving at least one engine parameter wherein the at least one engine parameter is used by the io determination unit for adjusting the run-time parameter (48).
6. Engine control unit (31) of one of preceding claims characterised in that the cylinder control unit (80) controls the fuel injec-tion via using a valve (38) of a fuel line (33) of the internal combustion engine (10).
7. Engine control unit (31) of one of preceding claims characterised in that the cylinder control unit (80) controls the fuel injec-tion via using a fuel-rail pressure regulator (40) of the fuel line (33) of the internal combustion engine (10)
8. Internal combustion engine (10) comprising -an engine control unit (31) of one of claims 1 to 5.-a cylinder (11) that comprises an in-cylinder pres- sure sensor unit (16) for transmitting an in-cylinder pressure measurement to the engine control unit (31), -a crankshaft sensor (50) for transmitting informa-tion of the crankshaft (22) to the engine control unit (31), and -a run-time parameter unit (30) that is provided in the cylinder (11) wherein the run-time parameter unit (30) is controlled by the engine control unit (31)
9. Vehicle comprising -an internal combustion engine (10) of claim 6 and -a set of wheels that is connected to the internal combustion engine (10) via a transmission unit.
10. Method for synchronising fuel injection of an internal combustion engine (10), the method comprising -measuring in-cylinder pressure of a cylinder (11) of the internal combustion engine (10), -collecting information of a crankshaft (22) of the internal combustion engine (10), -determining a run-time parameter (48) of the inter-nal combustion engine (10) using the in-cylinder pressure measurement and the information of the crankshaft (22), and -regulating an operation of the internal combustion engine (10) using the determined run-time parameter (48)
11. Method of claim 10 characterised in that the run-time parameter comprises, a fuel injection time point (48)
12. Method of claim 10 or 11 charactérised in that the regulating of the operation of the cylinder (11) oc-curs after the cylinder pressure measurement exceeds a pre-determined synchronisation value and occurs when the information of the crankshaft (22) indicates,that the cylinder (11) is a compression stroke (59) of an cornbus-tiori cycle (54).
13. Method of one of claims 10 to 12 further comprising -collecting a parameter of the internal combustion engine (10) and -adjusting the run-time parameter (48) of the cylin- der (11) using the parameter of the internal com-bustion engine (10).
14. Method of one of claims 10 to 13 further comprising determining a further run-time parameter of another cyl-inder (12; 13; 15) of the internal combustion engine (10) using the determined run-time parameter (48)
15. Method of one of claims 10 to 14 further comprising regulating repeatedly the run-time parameter of the cyl-inder (11) using the determined run-time parameter (48) during operation of the engine.