Patent Publication Number: US-2019178170-A1

Title: Method and system for determining an uncontrolled behaviour of an internal combustion engine of a vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application (filed under 35 § U.S.C. 371) of PCT/SE2017/050575, filed May 30, 2017 of the same title, which, in turn, claims priority to Swedish Application No. 1650884-8 filed Jun. 22, 2016; the contents of each of which are hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a method determining an uncontrolled behavior of an internal combustion engine of a vehicle according to the preamble of claim  1 . The invention also relates to a system for determining an uncontrolled behavior of an internal combustion engine of a vehicle. The invention also relates to a vehicle. The invention in addition relates to a computer program and a computer program product. 
     BACKGROUND OF THE INVENTION 
     A diesel engine comprises a cylinder having a space arranged to receive air and fuel, a piston disposed in the cylinder, and a crankcase being in fluid communication with the cylinder. An uncontrolled behavior due to unintentional combustion of fluid flowing between the crankcase and the cylinder space may occur. The risk increases for engines having a closed crankcase since the fluid flow, e.g. gases, are returned to the inlet of the cylinder. 
     A known way of determining uncontrolled behavior is to look at the engine speed, wherein uncontrolled behavior is determined when the engine speed has reached a certain high level. A problem with detecting uncontrolled behavior based upon the engine speed having reached a certain high level is that the level needs to be sufficiently high in order to be able to operate the vehicle at relatively high engine speeds, this resulting in detection at such a certain high level, e.g. about 2900 rpm, at which engine speed level it may be very difficult to prevent severe failure. It may in even be too late to prevent severe failure which may cause fire in the engine. 
     US2013087111 discloses a method for controlling an internal combustion engine, wherein a controller coupled to an actuator is configured to close a valve for controlling flow of air into a cylinder of the engine when an uncontrolled condition for the engine is determined. US2013087111 further discloses determining such uncontrolled condition by e.g. monitoring engine acceleration or torque along with parameters including vehicle weight and road grade. 
     There is however a need for improving the detection of uncontrolled behavior of an internal combustion engine of a vehicle due to unintentional combustion of fluid flowing between a crankcase and a cylinder space of said combustion engine. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a method for determining uncontrolled behavior of an internal combustion engine in a vehicle in due time in order to be able to prevent severe failure of the engine. 
     An object of the present invention is to provide a system for determining uncontrolled behavior of an internal combustion engine in a vehicle in due time to be able to prevent severe failure of the engine. 
     These and other objects, apparent from the following description, are achieved by a method, a system, a vehicle, a computer program and a computer program product, as set out in the appended independent claims. Preferred embodiments of the method and the system are defined in appended dependent claims. 
     Specifically an object of the invention is achieved by a method for determining an uncontrolled behavior of an internal combustion engine of a vehicle due to unintentional combustion of fluid flowing between a crankcase and a cylinder space of said combustion engine. The combustion engine comprises a cylinder having a space arranged to receive air and fuel, a piston disposed in the cylinder, and a crankcase being in fluid communication with the cylinder. A powertrain for said vehicle is configured to provide an engaged and a disengaged state. Said method comprises the step of determining at least one vehicle related condition wherein the step of determining said at least one vehicle related condition comprises the steps of: determining whether a powertrain for said vehicle is in an engaged or a disengaged state; determining whether the engine speed is increasing; and determining whether said cylinder space is receiving fuel. The method further comprises the step of determining that an uncontrolled behavior is at hand if the conditions that: said powertrain is disengaged, the engine speed is increasing and said cylinder space is not receiving any fuel, are fulfilled. 
     By thus using said conditions comprising the condition that the powertrain shall be disengaged it can by high certainty be determined that an increase in engine speed is due to an uncontrolled behavior which then may be determined in due time to prevent severe failure of the engine. 
     According to an embodiment of the method the step of determining at least one vehicle related condition comprises the step of determining the time period the engine speed is increasing, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the engine speed is increasing is fulfilled during a predetermined time period. The method thus comprises the step of determining whether the condition that the engine speed is increasing is fulfilled during a predetermined time period. Hereby a more robust determination of an uncontrolled behavior is obtained thus reducing the risk of erroneously determining an uncontrolled behavior. 
     According to an embodiment of the method the step of determining at least one vehicle related condition comprises the step of determining the time period the cylinder space is not receiving any fuel for a non-receiving fuel condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period. The method thus comprises the step of determining whether the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period. Hereby a more robust determination of an uncontrolled behavior is obtained thus reducing the risk of erroneously determining an uncontrolled behavior. 
     According to an embodiment of the method the step of at least one vehicle related condition comprises the step of determining the resulting engine speed for an increasing engine speed condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the engine speed is increasing has resulted in a predetermined engine speed. The method thus comprises the step of determining whether the condition that the engine speed is increasing has resulted in a predetermined engine speed. Hereby a more robust determination of an uncontrolled behavior is obtained thus reducing the risk of erroneously determining an uncontrolled behavior. 
     According to an embodiment the method the step of determining at least one vehicle related condition comprises the step of integrating the engine acceleration during an increasing engine speed condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that engine speed has reached a certain level. Herby a fast engine speed increase will result in a quicker determination of uncontrolled behavior than a slow engine increase. 
     Specifically an object of the invention is achieved by a system for controlling an internal combustion engine of a vehicle. The combustion engine comprises a cylinder having a space arranged to receive air and fuel, a piston disposed in the cylinder, and a crankcase being in fluid communication with the cylinder. The system comprises means for determining an uncontrolled behavior of an internal combustion engine of a vehicle due to unintentional combustion of fluid flowing between a crankcase and a cylinder space of said internal combustion engine. A powertrain for said vehicle is configured to provide an engaged and a disengaged state. The system further comprising means for determining at least one vehicle related condition. The for determining at least one vehicle related condition comprises means for determining whether a powertrain for said vehicle is in an engaged or a disengaged state; means for determining whether the engine speed is increasing; and means for determining whether said cylinder space is receiving fuel. The system further comprises means for determining that an uncontrolled behavior is at hand if the conditions that: said powertrain is disengaged, the engine speed is increasing and said cylinder space is not receiving any fuel, are fulfilled. 
     According to an embodiment of the system the means for determining at least one vehicle related condition comprises means for determining the time period the engine speed is increasing for an increasing engine speed condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the engine speed is increasing is fulfilled during a predetermined time period. The system thus comprises means for determining whether the condition that the engine speed is increasing is fulfilled during a predetermined time period. 
     According to an embodiment of the system the means for determining at least one vehicle related condition comprises means for determining the time period the cylinder space is not receiving any fuel for a non-receiving fuel condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period. The system thus comprises means for determining whether the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period. 
     According to an embodiment of the system the means for determining at least one vehicle related condition comprises means for determining the resulting engine speed for an increasing engine speed condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the engine speed is increasing has resulted in a predetermined engine speed. The system thus comprises means for determining whether the condition that the engine speed is increasing has resulted in a predetermined engine speed. 
     According to an embodiment of the system the means for determining at least one vehicle related condition comprises means for integrating the engine acceleration during an increasing engine speed condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that engine speed has reached a certain level. 
     The system for controlling an internal combustion engine of a vehicle is adapted to perform the method as set out herein. 
     The system according to the invention has the advantages according to the corresponding method. 
     Specifically an object of the invention is achieved by a vehicle comprising a system according to the invention as set out herein. 
     Specifically an object of the invention is achieved by a computer program for determining an uncontrolled behavior of an internal combustion engine of a vehicle due to unintentional combustion of fluid flowing between a crankcase and a cylinder space of said internal combustion engine, said computer program comprising program code which, when run on an electronic control unit or another computer connected to the electronic control unit, causes the electronic control unit to perform the method according to the invention. 
     Specifically an object of the invention is achieved by a computer program product comprising a digital storage medium storing the computer program. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the present invention reference is made to the following detailed description when read in conjunction with the accompanying drawings, wherein like reference characters refer to like parts throughout the several views, and in which: 
         FIG. 1  schematically illustrates a side view of a vehicle according to the present invention; 
         FIG. 2  schematically illustrates a powertrain for a vehicle according to an embodiment of the present invention; 
         FIG. 3  schematically illustrates a turbocharged internal combustion engine according to an embodiment of the present invention; 
         FIG. 4  schematically illustrates an internal combustion engine according to an embodiment of the present invention; 
         FIGS. 5 a  and 5 b    schematically illustrate engine speed over time approaching an uncontrolled behavior according to exemplary embodiments of the present invention; 
         FIG. 5 b    schematically illustrates control of engine speed by intermittent activation and deactivation of exhaust brake after a determined uncontrolled behavior according to an exemplary embodiment of the present invention; 
         FIG. 6  schematically illustrates a system for controlling an internal combustion engine of a vehicle according to an embodiment of the present invention; 
         FIG. 7  schematically illustrates a block diagram of a method for controlling an internal combustion engine of a vehicle according to an embodiment of the present invention; and 
         FIG. 8  schematically illustrates a computer according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter the term “link” refers to a communication link which may be a physical connector, such as an optoelectronic communication wire, or a non-physical connector such as a wireless connection, for example a radio or microwave link. 
     Hereinafter the term “fluid” in connection to “fluid flow between the crankcase and the cylinder space” refers to any possible fluid that may occur comprising a gaseous fluid, a liquid fluid and/or a solid fluid. Gaseous fluid may e.g. comprise a volatile fuel such as ethanol having boiled and being returned to the cylinder space as a gas, and/or blow-by-gases, i.e. gases escaping past the piston from the cylinder space to the crankcase space, due to high pressure in the crankcase which could be caused by blow-by gases. The term “vehicle related conditions” refers to any possible condition or state of the vehicle, for example related to engine speed, powertrain state, fuel injection etc. 
     The engine according to the present invention could be any suitable internal combustion engine with any suitable number of cylinders. The internal combustion engine according to the present invention could for example be a 5-cylinder engine, a 6-cylinder engine or an 8-cylinder engine. The cylinders could be in any suitable alignment, for example inline engine or a V-engine. In  FIG. 3  an embodiment for a 6-cylinder engine is described. 
       FIG. 1  schematically illustrates a side view of a vehicle  1  according to the present invention. The exemplified vehicle  1  is a heavy vehicle in the shape of a truck. The vehicle according to the present invention could be any suitable vehicle such as a bus or a car. The vehicle is driven by means of an internal combustion engine. The vehicle  1  comprises a system I for controlling an internal combustion engine of the vehicle according to an embodiment of the present invention. 
       FIG. 2  schematically illustrates a powertrain for a vehicle according to an embodiment of the present invention. The powertrain PT is according to an embodiment a powertrain of the vehicle  1  in  FIG. 1 . 
     The powertrain PT comprises an internal combustion engine E. The internal combustion engine E is a diesel engine. The internal combustion engine E has a closed crankcase configuration in which the fluid flow is returned to the inlet of the cylinder and back to the cylinder space. 
     The powertrain PT comprises a transmission T. The transmission T may be any suitable transmission comprising any suitable gearbox. 
     The powertrain PT comprises a clutch arrangement C. The clutch arrangement C is connected to the engine E via a crankshaft CS and a flywheel (not shown). The clutch arrangement C is connected to the transmission T. The clutch arrangement C is arranged to provide an engaged state in which power is transferred from the engine E to the transmission T for transmitting torque to at least one pair of tractive wheels W 1 , W 2 . The clutch arrangement C is arranged to provide a disengaged state in which the engine may be operated without affecting the tractive wheels W 1 , W 2 . 
     The powertrain PT for said vehicle  1  is thus configured to provide an engaged and a disengaged state. 
       FIG. 3  schematically illustrates a turbocharged diesel engine E. 
     In this example an engine E with six cylinders C 1 , C 2 , C 3 , C 4 , C 5 , C 6  is shown. The engine E comprises an engine block  12  for housing the cylinders and other engine operation components. 
     The engine E is arranged to provide a four stroke cycle. The complete four stroke cycle forms a single thermodynamic cycle from which mechanical work will be extracted for operating a vehicle. 
     The strokes comprise an intake stroke filling the respective cylinder C 1 -C 6  with air, a compression stroke where the air is compressed and at the end of which fuel is injected for combustion, here illustrated with injection of fuel F into cylinder C 6 , an expansion stroke where the combustion is completed and an exhaust stroke. 
     The engine E further comprises an air filter  20  through which ambient air Al is arranged to pass so that filtered air A 2  is obtained. 
     The engine E comprises a turbocharger  30  having a compressor  32 , a turbine  34  and a shaft  36  operably connecting the compressor  32  and turbine  36 . The compressor  32  is arranged to compress the filtered air A 2  so that compressed air A 3  is obtained. 
     The engine E comprises an intercooler  40  for cooling the compressed air A 3  such that cooled compressed air A 4  is obtained. 
     The engine E comprises an intake manifold  50  for distributing the air, i.e. the compressed air A 4  to the cylinders C 1 -C 6 . 
     The engine E comprises a throttle valve V 1  arranged to control the distribution of air A 4  to the cylinders C 1 -C 6 . The engine E according to this embodiment comprises a throttle V 1 , however, the engine according to the present invention may be an engine without a throttle. 
     The engine E comprises an exhaust manifold  60  for distributing exhaust gas G 1  from the cylinders C 1 -C 6  to the turbine  34 , the exhaust gas being arranged to pass the turbine  34  for operating the turbocharger  30  such that the compressor  32  compresses the filtered air A 2 . 
     The exhaust manifold  60  comprises a waste gate  62  for allowing exhaust gas to bypass the turbine  34  and further to the exhaust pipe  64 . The engine E comprises a valve V 2  arranged to control the distribution of exhaust gas through the waste gate  62 . 
     The engine E comprises an exhaust brake V 3  arranged downstream of the turbine and downstream of the waste gate. When activated, the exhaust brake V 3  is configured to provide an exhaust back pressure by rendering exhaust gas flow through the exhaust pipe  64  more difficult. The exhaust back pressure is used for braking the engine speed. The exhaust back pressure thus created increases engine temperature due to the thus increased load. The exhaust back pressure may be used for increasing engine temperature and exhaust gas temperature, this being used at low engine speeds as the exhaust gases at low engine speeds do not reach high enough temperatures in order for the exhaust treatment to function efficiently. The exhaust brake V 3  comprises a valve configuration for controlling the exhaust gas flow through the exhaust pipe  64 . 
     The engine E comprises an exhaust treatment system  70  arranged to treat the exhaust gas in order to reduce emissions so that treated exhaust gases G 2  exits the exhaust gas pipe  64 . 
       FIG. 3  thus illustrates the gas flow through the turbocharged diesel engine E. Ambient air A 1  enters through the air filter  20 , is compressed in the compressor  32  and led through the intercooler  40  to the intake manifold  50  before entering the cylinders C 1 -C 6 . Fuel F is added by injection into the cylinders and after combustion, the exhaust gas G 1  pass through the turbine  34  to the exhaust treatment system  70 . 
     The respective cylinder C 1 -C 6  thus has a space arranged to receive air A 4  and fuel F. The engine E comprises a piston, not shown, disposed in the respective cylinder C 1 -C 6 , and a crankcase, not shown, being in fluid communication with the cylinder. The engine E has a closed crankcase configuration in which the fluid flow is returned to the inlet of the cylinder and back to the cylinder space. Such a configuration where the fluid is returned to the inlet of the cylinder is called a Closed Crankcase Ventilation, CCV. The engine according to this embodiment thus has a Closed Crankcase Ventilation, CCV, however the invention is not limited to such an engine but is applicable to any engine where such an uncontrolled behavior may occur. The risk of an uncontrolled behavior, however, increases with an engine having a Closed Crankcase Ventilation, CCV. An uncontrolled behavior due to fluid flow between the crankcase and the cylinder space and combustion of such fluid may occur and may be determined in accordance with the present invention as described with reference to e.g.  FIGS. 6 and 7 . 
     If an uncontrolled behavior has been determined it is determined whether the vehicle is in a safe position. 
     If the vehicle is in a safe position an emergency stop is performed. The emergency stop according to this embodiment involves closing the throttle valve V 1  such that the flow of air to the cylinder C 1 -C 6  is stopped resulting in the uncontrolled behavior being terminated due to lack of air for the combustion wherein the combustion is terminated. The emergency stop according to this embodiment may further involve activating the exhaust brake. For an engine not having a throttle valve, the emergency stop involves activating the exhaust brake. For an engine not having an exhaust brake, the emergency stop involves activating the throttle valve. 
     If it is determined that the vehicle is not in a safe position, the engine E is operated by controlling the exhaust brake of the vehicle by intermittently activating and deactivating said exhaust brake V 3 . The exhaust brake V 3  is intermittently activated and deactivated and thus regulated about a certain engine speed. The engine is operated by controlling the exhaust brake is performed by activating said exhaust brake V 3  at a certain high engine speed and deactivating said exhaust brake V 3  at a certain low engine speed. 
       FIG. 4  schematically illustrates an internal combustions engine E according to an embodiment of the present invention. 
     The internal combustion engine E is a diesel engine. The engine E comprises a cylinder C 1 . The cylinder C 1  has a space O 1  arranged to receive air A via an air intake Ai and fuel via a fuel injector  11 . 
     The engine E comprises a piston P 1  disposed in the cylinder C 1 . 
     The engine E comprises a crankshaft CS connected to a flywheel, not shown, a set of cylinders, of which one cylinder C 1  is shown, being distributed along said crankshaft CS for rotating said crankshaft CS during operation of the engine. 
     The cylinder C 1  is connected to the crankshaft via a connecting rod R 1  connected to the piston P 1  of the cylinder C 1 . 
     The engine E thus comprises fuel injectors for injecting fuel into the cylinder C 1  for combustion, one fuel injector  11  being shown. 
     The engine E is arranged to provide a stroke cycle, e.g. a four stroke cycle, from which mechanical work will be extracted for operating a vehicle. 
     When the piston is farthest from the crankshaft CS is known as the top dead centre and when the piston P 1  is closest to the crankshaft CS is known as the bottom dead centre. 
     The strokes comprise an intake stroke filling the cylinder C 1  with air, a compression stroke where the air is compressed and at the end of which fuel is injected for combustion, an expansion stroke where the combustion is completed and an exhaust stroke. 
     The engine E comprises an exhaust outtake XG for releasing exhaust gas G. A valve Vx is disposed in the exhaust outtake XG for controlling flow of exhaust gas out of the cylinder space O 1 . 
     A valve Vi is disposed in the air intake Ai for controlling flow of air into the cylinder space O 1 . 
     The engine E comprises a crankcase CC for housing the crankshaft CS. The crankcase CC is in fluid communication with the cylinder C 1 . The crankcase CC has a space O 2 . The crankcase CC is a so called closed crankcase. The crankcase CC according to the embodiment shown in  FIG. 4  is in fluid communication with the air intake Ai via return pipe RP. 
     An uncontrolled behavior due to fluid flow between the space O 2  of the crankcase CC and the cylinder space O 1  and combustion of such fluid in the space O 1  may occur. The fluid flow may comprise unburned fuel and exhaust gases escaping around the piston P 1  into the space O 2 . 
     Only one cylinder C 1  with one piston P 1  disposed is shown in  FIG. 4  for ease of understanding. However, the engine E may comprise any suitable number of cylinders with pistons disposed therein. 
       FIGS. 5 a  and 5 b    schematically illustrates engine speed N over time t approaching an uncontrolled behavior according to exemplary embodiments of the present invention. 
     According to the invention determining an uncontrolled behavior comprises determining whether the powertrain is disengaged, determining whether the engine speed is increasing and determining whether said cylinder space is receiving fuel. If all these conditions are fulfilled, i.e. drivetrain is disengaged, engine speed is increasing and cylinder space is not receiving any fuel, it is determined that an uncontrolled behavior is at hand. 
     In  FIG. 5 a    the powertrain is disengaged and cylinder space is not receiving any fuel. The engine speed starts to increase from an engine speed N 0 . 
     In order to be certain that an uncontrolled behavior is at hand the condition that the cylinder space is not receiving any fuel has to be fulfilled during a predetermined time period. 
     At the engine speed N 0  the engine is controlled by an idle regulator being configured to control injection of fuel such that sufficient fuel is injected in order to keep the engine running at that engine speed. If an uncontrolled behavior then arises the engine speed will increase. The engine speed will then stop requesting fuel injection since it wants to lower the engine speed to the idle speed. According to an embodiment the determination of the cylinder space not receiving any fuel comprises determining that the idle regulator has stopped requesting fuel. 
     In order to be certain that an uncontrolled behavior is at hand the increasing engine speed must reach a predetermined engine speed N 1  before it is considered as a possible approaching uncontrolled behavior. 
     According to an embodiment illustrated in  FIG. 5 a   , in order to improve determination that an uncontrolled behavior is at hand, integration  11  of the engine acceleration is initiated at a certain time T 0  after the predetermined engine speed N 1  has been reached. When the engine speed has reached a certain level N 2  an uncontrolled behavior is determined. Herby a fast engine speed increase will result in a quicker determination of uncontrolled behavior than a slow engine increase. As mentioned the other conditions, e.g. that the powertrain is disengaged and the cylinder space is not receiving fuel, need to be fulfilled. 
     According to an embodiment illustrated in  FIG. 5 b   , in order to improve determination that an uncontrolled behavior is at hand, the condition that the engine speed is increasing from the predetermined engine speed N 1  during a predetermined time period T 1  should be fulfilled. Thus, in  FIG. 5 b   , an uncontrolled behavior is determined at the point where the engine speed has increased from an engine speed N 1  during a time period T 1  to an engine speed N 2 . As mentioned the other conditions, e.g. that the powertrain is disengaged and the cylinder space is not receiving fuel, need to be fulfilled. 
       FIG. 5 c    schematically illustrates control of engine speed N by intermittent activation and deactivation of exhaust brake after a determined uncontrolled behavior according to an exemplary embodiment of the present invention. 
     Thus, If it is determined that the vehicle is not in a safe position, the engine is operated by controlling the exhaust brake of the vehicle by intermittently activating and deactivating the exhaust brake. The exhaust brake is intermittently activated and deactivated and thus regulated about a certain engine speed N 3 . The engine is operated by activating the exhaust brake at a certain high engine speed NH and deactivating the exhaust brake at a certain low engine speed NL. 
       FIG. 6  schematically illustrates a system I for controlling an internal combustion engine of a vehicle according to an embodiment of the present invention. 
     The combustion engine comprises a cylinder having a space arranged to receive air and fuel, a piston disposed in the cylinder, and a crankcase being in fluid communication with the cylinder. The combustion engine could be the combustion engine E illustrated in  FIGS. 2, 3 and 4 . A powertrain for said vehicle is configured to provide an engaged and a disengaged state. The powertrain could e.g. be the powertrain in  FIG. 2 . 
     The system I comprises an electronic control unit  100 . 
     The system I comprises means  110  for determining at least one vehicle related condition. 
     The means  110  for determining at least one vehicle related condition comprises means  112  for determining whether the powertrain is disengaged. The means  112  for determining whether the powertrain is disengaged may comprise any suitable means comprising any suitable sensor. 
     The means  110  for determining at least one vehicle related condition comprises means  114  for determining whether the engine speed is increasing. The means  114  for determining whether the engine speed is increasing may comprise any suitable detector unit for detecting engine speed. 
     The means  110  for determining at least one vehicle related condition comprises means  116  for determining whether said cylinder space is receiving fuel. The means  116  for determining whether said cylinder space is receiving fuel comprises determining a non-request of fuel injection from the engine control unit. 
     The means  114  for determining whether the engine speed is increasing comprises means  114 - 1  for determining the time period the engine speed is increasing for an increasing engine speed condition. The means  110  for determining at least one vehicle related condition thus comprises means  114 - 1  for determining the time period the engine speed is increasing for an increasing engine speed condition. An uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the engine speed is increasing is fulfilled during a predetermined time period. 
     The system I comprises means  120  for determining whether the condition that the engine speed is increasing is fulfilled during a predetermined time period. 
     The means  114  for determining whether the engine speed is increasing comprises means  114 - 2  for determining the resulting engine speed for an increasing engine speed condition. The means  110  for determining at least one vehicle related condition thus comprises means  114 - 2  for determining the resulting engine speed for an increasing engine speed condition. An uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the engine speed is increasing has resulted in a predetermined engine speed. 
     The system I comprises means  130  for determining whether the condition that the engine speed is increasing has resulted in a predetermined engine speed. 
     The means  116  for determining whether said cylinder space is receiving fuel comprises means  116 - 1  for determining the time period the cylinder space is not receiving any fuel for a non-receiving fuel condition. The means  110  for determining at least one vehicle related condition thus comprises means  116 - 1  for determining the time period the cylinder space is not receiving any fuel for a non-receiving fuel condition. An uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period. 
     The system I comprises means  140  for determining whether the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period. 
     The system I comprises means  150  for determining that an uncontrolled behavior is at hand if the conditions that: said powertrain is disengaged, the engine speed is increasing and said cylinder space is not receiving any fuel, are fulfilled. 
     The means  150  for determining that an uncontrolled behavior is at hand further comprises determining that the conditions that: the that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period that the engine speed is increasing is fulfilled during a predetermined time period; the condition that the engine speed is increasing has resulted in a predetermined engine speed. 
     According to an embodiment of the system I the means  110  for determining at least one vehicle related condition comprises means for integrating the engine acceleration during an increasing engine speed condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that engine speed has reached a certain level. 
     The system comprises means  160  for determining, if an uncontrolled behavior has been determined, whether the vehicle is in a safe position. The means  160  for determining whether the vehicle is in a safe position may comprise means for determining whether the vehicle speed is low/zero and/or means for determining whether the parking brake is activated, a safe position, i.e. indication of no intention from the operator of the vehicle to move the vehicle, being determined if the speed is very low/zero and/or the parking brake is activated. The means  160  for determining whether the vehicle is in a safe position may comprises any suitable means for determining the position of the vehicle such as a Global Navigation Satellite System, GNSS, e.g. a global positioning system, GPS, for continuously determining the position of the vehicle and/or any suitable detector unit for detecting the surrounding of the vehicle and/or manually by an operator of the vehicle. 
     The system comprises means  170  for performing an emergency stop if the vehicle is in a safe position. The means  170  for performing emergency stop comprises according to an embodiment closing a throttle valve so as stop the flow of air to the cylinder and hence stopping the uncontrolled behavior. 
     The system comprises means  180  for operating the engine by controlling the exhaust brake of the vehicle by intermittently activating and deactivating said exhaust brake if the vehicle is not in a safe position. The means for operating the engine by controlling the exhaust brake may comprise any suitable control unit. The means for operating the engine by controlling the exhaust brake is according to an embodiment comprised in the electronic control unit  100 . 
     The means  180  for operating the engine by controlling the exhaust brake of the vehicle by intermittently activating and deactivating said exhaust brake comprises means  182  for activating said exhaust brake at a certain high engine speed and means  184  for deactivating said exhaust brake at a certain low engine speed. 
     The electronic control unit  100  is operably connected to the means  112  for determining whether the powertrain is disengaged via a link  112   a.  The electronic control unit  100  is via the link  112   a  arranged to receive a signal from said means  112  representing data whether the powertrain is disengaged. 
     The electronic control unit  100  is operably connected to the means  114  for determining whether the engine speed is increasing via a link  114   a.  The electronic control unit  100  is via the link  114   a  arranged to receive a signal from said means  114  representing data whether the engine speed is increasing. 
     The electronic control unit  100  is operably connected to the means  114 - 1  for determining the time period the engine speed is increasing for an increasing engine speed condition via a link  114 - 1   a.  The electronic control unit  100  is via the link  114 - 1   a  arranged to receive a signal from said means  114 - 1  representing data for time period the engine speed is increasing. 
     The electronic control unit  100  is operably connected to the means  120  for determining whether the condition that the engine speed is increasing is fulfilled during a predetermined time period via a link  120   a.  The electronic control unit  100  is via the link  120   a  arranged to send a signal to said means  120  representing data for time period the engine speed has been increasing. 
     The electronic control unit  100  is operably connected to the means  120  for determining whether the condition that the engine speed is increasing is fulfilled during a predetermined time period via a link  120   b.  The electronic control unit  100  is via the link  120   b  arranged to receive a signal from said means  120  representing data for engine speed increase being fulfilled during a predetermined time. 
     The electronic control unit  100  is operably connected to the means  114 - 2  for determining the resulting engine speed for an increasing engine speed condition via a link  114 - 2   a.  The electronic control unit  100  is via the link  114 - 2   a  arranged to receive a signal from said means  114 - 2  representing data for resulting engine speed. 
     The electronic control unit  100  is operably connected to the means  130  for determining whether the condition that the engine speed is increasing has resulted in a predetermined engine speed via a link  130   a.  The electronic control unit  100  is via the link  130   a  arranged to send a signal to said means  130  representing data for resulting engine speed. 
     The electronic control unit  100  is operably connected to the means  130  for determining whether the condition that the engine speed is increasing has resulted in a predetermined engine speed via a link  130   b.  The electronic control unit  100  is via the link  130   b  arranged to receive a signal from said means  130  representing data for engine speed increase having resulted in a predetermined engine speed. 
     The electronic control unit  100  is operably connected to the means  116  for determining whether said cylinder space is receiving fuel via a link  116   a.  The electronic control unit  100  is via the link  116   a  arranged to receive a signal from said means  116  representing data whether said cylinder space is receiving fuel. 
     The electronic control unit  100  is operably connected to the means  116 - 1  for determining the time period the cylinder space is not receiving any fuel for a non-receiving fuel condition via a link  116 - 1   a.  The electronic control unit  100  is via the link  116 - 1   a  arranged to receive a signal from said means  116  representing data time period the cylinder space is not receiving any fuel. 
     The electronic control unit  100  is operably connected to the means  140  for determining whether the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period via a link  140   a.  The electronic control unit  100  is via the link  140   a  arranged to send a signal to said means  140  representing data for time period cylinder space has not been receiving any fuel. 
     The electronic control unit  100  is operably connected to the means  140  for determining whether the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period via a link  140   b.  The electronic control unit  100  is via the link  140   b  arranged to receive a signal from said means  140  representing data for cylinder space not receiving any fuel being fulfilled during a predetermined time period. 
     The electronic control unit  100  is operably connected to the means  150  for determining that an uncontrolled behavior is at hand via a link  150   a.  The electronic control unit  100  is via the link  150   a  arranged to send signals to said means  150  representing data for conditions for uncontrolled behavior being fulfilled comprising data for powertrain disengaged, engine speed increasing and cylinder space not receiving any fuel. The data may further comprise data for cylinder space not receiving any fuel being fulfilled during a predetermined time period, engine speed increasing being fulfilled during a predetermined time period; and engine speed increasing having resulted in a predetermined engine speed. 
     The electronic control unit  100  is operably connected to the means  150  for determining that an uncontrolled behavior is at hand via a link  150   a.  The electronic control unit  100  is via the link  150   a  arranged to receive a signal from said means  150  representing data for determined uncontrolled behavior. 
     The electronic control unit  100  is operably connected to the means  160  for determining whether the vehicle is in a safe position via a link  160   a.  The electronic control unit  100  is via the link  160   a  arranged to send a signal to said means  160  representing data for determined uncontrolled behavior. 
     The electronic control unit  100  is operably connected to the means  160  for determining whether the vehicle is in a safe position via a link  160   b.  The electronic control unit  100  is via the link  160   b  arranged to receive a signal from said means  160  representing data for whether the vehicle is in a safe position. 
     The electronic control unit  100  is operably connected to the means  170  for performing an emergency stop if the vehicle is in a safe position via a link  170   a.  The electronic control unit  100  is via the link  170   a  arranged to send a signal to said means  170  representing data for vehicle being in a safe position. 
     The electronic control unit  100  is operably connected to the means  180  for operating the engine by controlling the exhaust brake of the vehicle by intermittently activating and deactivating said exhaust brake if the vehicle is not in a safe position via a link  180   a.  The electronic control unit  100  is via the link  180   a  arranged to send a signal to said means  180  representing data for vehicle being in an unsafe position. 
     The electronic control unit  100  is operably connected to means  182  for activating said exhaust brake at a certain high engine speed via a link  182   a.  The electronic control unit  100  is via the link  182   a  arranged to send a signal to said means  182  representing data for engine speed having reached a certain high engine speed. 
     The electronic control unit  100  is operably connected to means  184  for deactivating said exhaust brake at a certain low engine speed via a link  184   a.  The electronic control unit  100  is via the link  184   a  arranged to send a signal to said means  184  representing data for engine speed having reached a certain low engine speed. 
       FIG. 7  schematically illustrates a block diagram of a method determining an uncontrolled behavior of an internal combustion engine E of a vehicle  1  due to unintentional combustion of fluid flowing between a crankcase CC and a cylinder space O 1  of said combustion engine E according to an embodiment of the present invention. The combustion engine comprises a cylinder having a space arranged to receive air and fuel, a piston disposed in the cylinder, and a crankcase being in fluid communication with the cylinder. A powertrain for said vehicle is configured to provide an engaged and a disengaged state. 
     According to the embodiment, the method for controlling an internal combustion engine of a vehicle comprises a step S 1 . In this step at least one vehicle related condition is determined. 
     According to the embodiment step, S 1  of determining at least one vehicle related condition comprises a step S 1   a.  In this step it is determined whether a powertrain PT for said vehicle is in an engaged or a disengaged state. 
     According to the embodiment, step S 1  of determining at least one vehicle related condition comprises a step S 1   b.  In this step it is determined whether the engine speed is increasing. 
     According to the embodiment, step S 1  of determining at least one vehicle related condition comprises a step S 1  c. In this step it is determined whether said cylinder space is receiving fuel. 
     According to the embodiment, the method for method for determining an uncontrolled behavior of an internal combustion engine E of a vehicle  1  comprises a step S 2 . In this step it is determined that an uncontrolled behavior is at hand if the conditions that: said powertrain is disengaged, the engine speed is increasing and said cylinder space is not receiving any fuel, are fulfilled. 
     According to an embodiment of the method the step of determining at least one vehicle related condition comprises the step of determining the time period the engine speed is increasing, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the engine speed is increasing is fulfilled during a predetermined time period. The method thus comprises the step of determining whether the condition that the engine speed is increasing is fulfilled during a predetermined time period. 
     According to an embodiment of the method the step of determining at least one vehicle related condition comprises the step of determining the time period the cylinder space is not receiving any fuel for a non-receiving fuel condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period. The method thus comprises the step of determining whether the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period. 
     According to an embodiment of the method the step of determining at least one vehicle related condition comprises the step of determining the resulting engine speed for an increasing engine speed condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that the condition that the engine speed is increasing has resulted in a predetermined engine speed. The method thus comprises the step of determining whether the condition that the engine speed is increasing has resulted in a predetermined engine speed. 
     According to an embodiment the method the step of determining at least one vehicle related condition comprises the step of integrating the engine acceleration during an increasing engine speed condition, wherein an uncontrolled behavior is fulfilled if said conditions further comprises that engine speed has reached a certain level. Herby a fast engine speed increase will result in a quicker determination of uncontrolled behavior than a slow engine increase. 
     According to an embodiment the method, if an uncontrolled behavior has been determined, comprises the steps of: determining whether the vehicle is in a safe position, and, if the vehicle is in a safe position; performing an emergency stop, and if the vehicle is not in a safe position; operating the engine by controlling the exhaust brake of the vehicle by intermittently activating and deactivating said exhaust brake. The step of determining whether the vehicle is in a safe position may comprise determining whether the vehicle speed is low/zero and/or whether the parking brake is activated, a safe position, i.e. indication of no intention from the operator of the vehicle to move the vehicle, being determined if the speed is very low/zero and/or the parking brake is activated. The step of determining whether the vehicle is in a safe position may comprises any suitable means for determining the position of the vehicle such as a Global Navigation Satellite System, GNSS, e.g. a global positioning system, GPS, for continuously determining the position of the vehicle and/or any suitable detector unit for detecting the surrounding of the vehicle and/or manually by an operator of the vehicle. The exhaust brake is intermittently activated and deactivated and thus regulated about a certain engine speed. Such an engine speed may be in any suitable range in is according to an embodiment in the range of about 1300 rpm. 
     According to an embodiment of the method the step of operating the engine by controlling the exhaust brake of the vehicle by intermittently activating and deactivating said exhaust brake is performed by activating said exhaust brake at a certain high engine speed and deactivating said exhaust brake at a certain low engine speed. The certain high engine speed is according to an embodiment a predetermined high engine speed and the certain low engine speed a predetermined low engine speed. The engine speed may be regulated about a certain engine speed wherein the high engine speed corresponds to a certain engine speed above the certain engine speed about which the regulation takes place and the certain low engine speed corresponds to a certain engine speed below the certain engine speed about which the regulation takes place. The high engine speed may be about 100 rpm above the certain engine speed about which the regulation takes place and the low engine speed about 100 rpm above the certain engine speed about which the regulation takes place. 
     With reference to  FIG. 8 , a diagram of an apparatus  500  is shown. The system I described with reference to  FIG. 6  may according to an embodiment comprise apparatus  500 . Apparatus  500  comprises a non-volatile memory  520 , a data processing device  510  and a read/write memory  550 . Non-volatile memory  520  has a first memory portion  530  wherein a computer program, such as an operating system, is stored for controlling the function of apparatus  500 . Further, apparatus  500  comprises a bus controller, a serial communication port, I/O-means, an A/D-converter, a time date entry and transmission unit, an event counter and an interrupt controller (not shown). Non-volatile memory  520  also has a second memory portion  540 . 
     A computer program P is provided comprising routines for determining an uncontrolled behavior of an internal combustion engine E of a vehicle. The combustion engine comprises a cylinder having a space arranged to receive air and fuel, a piston disposed in the cylinder, and a crankcase being in fluid communication with the cylinder. A powertrain for said vehicle is configured to provide an engaged and a disengaged state. The program P comprises routines for determining an uncontrolled behavior due to fluid flow between said crankcase and said cylinder space and combustion of such fluid and routines for determining a vehicle related condition. The routines for determining a vehicle related condition comprises routines for determining whether the powertrain is disengaged. The routines for determining a vehicle related condition comprises routines for determining whether the engine speed is increasing. The routines for determining a vehicle related condition comprises routines for determining whether said cylinder space is receiving fuel. The program P comprises routines for determining that an uncontrolled behavior is at hand if the conditions that: said powertrain is disengaged, the engine speed is increasing and said cylinder space is not receiving any fuel, are fulfilled. The program P comprises routines for determining whether the condition that the engine speed is increasing is fulfilled during a predetermined time period. The program P comprises routines for determining whether the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period. The program P comprises routines for determining whether the condition that the engine speed is increasing has resulted in a predetermined engine speed. The program P comprises routines for determining, if an uncontrolled behavior has been determined, whether the vehicle is in a safe position. The program P comprises routines for performing an emergency stop if the vehicle is in a safe position. The program P comprises routines for operating the engine by controlling the exhaust brake of the vehicle by intermittently activating and deactivating said exhaust brake if the vehicle is not in a safe position. The routines for operating the engine by controlling the exhaust brake of the vehicle by intermittently activating and deactivating said exhaust brake comprises routines for activating said exhaust brake at a certain high engine speed and deactivating said exhaust brake at a certain low engine speed. The computer program P may be stored in an executable manner or in a compressed condition in a separate memory  560  and/or in read/write memory  550 . 
     When it is stated that data processing device  510  performs a certain function it should be understood that data processing device  510  performs a certain part of the program which is stored in separate memory  560 , or a certain part of the program which is stored in read/write memory  550 . 
     Data processing device  510  may communicate with a data communications port  599  by means of a data bus  515 . Non-volatile memory  520  is adapted for communication with data processing device  510  via a data bus  512 . Separate memory  560  is adapted for communication with data processing device  510  via a data bus  511 . Read/write memory  550  is adapted for communication with data processing device  510  via a data bus  514 . To the data communications port  599  e.g. the links connected to the control units  100  may be connected. 
     When data is received on data port  599  it is temporarily stored in second memory portion  540 . When the received input data has been temporarily stored, data processing device  510  is set up to perform execution of code in a manner described above. The signals received on data port  599  can be used by apparatus  500  for determining an uncontrolled behavior due to fluid flow between said crankcase and said cylinder space and combustion of such fluid and for determining a vehicle related condition. The signals used for determining a vehicle related condition are used for determining whether the powertrain is disengaged. The signals used for determining a vehicle related condition are used for determining whether the engine speed is increasing. The signals used for determining a vehicle related condition are used for determining whether said cylinder space is receiving fuel. The signals received on data port  599  can be used by apparatus  500  for determining that an uncontrolled behavior is at hand if the conditions that: said powertrain is disengaged, the engine speed is increasing and said cylinder space is not receiving any fuel, are fulfilled. The signals received on data port  599  can be used by apparatus  500  for determining whether the condition that the engine speed is increasing is fulfilled during a predetermined time period. The signals received on data port  599  can be used by apparatus  500  for determining whether the condition that the cylinder space is not receiving any fuel is fulfilled during a predetermined time period. The signals received on data port  599  can be used by apparatus  500  for determining whether the condition that the engine speed is increasing has resulted in a predetermined engine speed. The signals received on data port  599  can be used by apparatus  500  for determining, if an uncontrolled behavior has been determined, whether the vehicle is in a safe position. The signals received on data port  599  can be used by apparatus  500  for performing an emergency stop if the vehicle is in a safe position. The signals received on data port  599  can be used by apparatus  500  for operating the engine by controlling the exhaust brake of the vehicle by intermittently activating and deactivating said exhaust brake if the vehicle is not in a safe position. The signals used for operating the engine by controlling the exhaust brake of the vehicle by intermittently activating and deactivating said exhaust brake are used for activating said exhaust brake at a certain high engine speed and deactivating said exhaust brake at a certain low engine speed. 
     Parts of the methods described herein can be performed by apparatus  500  by means of data processing device  510  running the program stored in separate memory  560  or read/write memory  550 . When apparatus  500  runs the program, parts of the methods described herein are executed. 
     The foregoing description of the preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated.