Description:FIELD OF THE INVENTION
[001] This disclosure relates generally to controlling vehicles and more particularly, relates to a system and a method for controlling an engine of a vehicle.

BACKGROUND OF THE INVENTION
[002] Typically, an Integrated Starter Generator (ISG) machine is used to replace conventional starter and generator functions into a single machine. In order to control the ISG machine, a control unit may be used. During cranking operation, the ISG machine acts in motoring state by cranking the ISG machine to a required rpm. During charging operation, the ISG machine acts in generator state. The voltage produced by the ISG machine during charging is converted to about 14.3V ± 0.3V by the control unit and used to charge the battery. In vehicle starting condition, the ISG machine’s phase current is crossing a threshold limit of a driver unit which may be inside the control unit. The driver unit senses the overcurrent and raises an error signal. A fault signal is trigged by the control unit upon receiving the error signal. Once the fault signal is triggered, the control unit sends a signal to cut-off ignition for stopping an engine of the vehicle. Once the ignition cut-off, the vehicle will gets switched off.
[003] The overcurrent fault from the driver unit occurs because of transition from cranking to charging state as the ISG machine draws more current to go from 800 RPM (cranking) to 1200 RPM (charging). The spike current is observed for only one instance in the entire key on cycle. In the existing systems, if ISG machine’s phase current crosses a threshold limit for 1 time, a fault is triggered, and vehicle is switched off. Thus, leading to problems for the users to restart the ignition multiple times.
[004] In one kind of existing system, an engine idle stability is controlled by monitoring the excitation current. If the excitation current is greater than threshold value, an engine output compensation is done. The processor controls the throttle valve associated with the air intake of the engine, engine ignition timing to increase the engine output torque to compensate for a predicted alternator output torque value. A second threshold value is measured and if it is less than first threshold value, engine output compensation is disabled. Thus, this system is trying to overcome the increased load on alternator due to increased electric load which could lead to engine idle fluctuation.
[005] In another kind of existing system, an ignition state of the vehicle is monitored by sampling voltage level of vehicle electrical system powered by a battery. Based on current voltage level and threshold limit, ignition on/off state is defined. It is determined whether current voltage sample has sufficiently dropped from preceding voltage sample. If the current voltage sample is below a specified threshold, then it is inferred as vehicle engine ignition off state.
[006] In yet another existing system, a phase current or output current of starter/alternator is monitored and compared with predetermined overload failure threshold current value. The output voltage of starter/alternator is reduced when monitored current value exceeds predetermined overload failure current value. Further, output voltage is increased if the value is below predetermined set point for output voltage. Thereby limiting the current supplied by alternator in generation mode.
[007] Thus, there is a need in the art for providing a system and a method for controlling an engine which addresses the aforementioned problems and limitations.

SUMMARY OF THE INVENTION
[008] In one aspect, the present invention is directed a system for controlling an engine. The system comprises a driver unit. The driver unit is electrically coupled to an ISG machine. The driver unit being configured to detect a current passing through the driver unit and generate an error signal if the current passing through the driver unit exceeds a threshold current. The system further comprises a control unit electrically coupled to the driver unit. The control unit is configured to receive the error signal from the driver unit. The control unit is further configured to determine a number of times the error signal received by the control unit since a last ignition ON event. The control unit is further configured to generate a fault signal if the number of times the error signal received by the control unit exceeds a predefined number of times, and shut down the engine in response to the fault signal.
[009] In an embodiment, the control unit being configured to receive the error signal when the ISG machine is in at least one of a cranking operation and when the ISG machine transitions from a cranking operation to a generating operation.
[010] In a further embodiment, the control unit being configured to receive the error signal for a first predefined time period after transitioning to the generating operation from the cranking operation. The first predefined time period being 1 second.
[011] In a further embodiment, the control unit is configured to determine a time period for which the current passing through the driver unit exceeds the threshold current. The control unit is further configured to determine whether the time period exceeds a second predefined time period. The control unit is further configured to identify the error signal as a fault signal if the time period exceeds the second predefined time period and increment a count associated with the number of times the error signal received by the control unit.
[012] In a further embodiment, the control unit being configured to identify the error signal as a noise signal if the time period is within the second predefined time period. The noise signal being ignored by the control unit.
[013] In a further embodiment, the control unit being configured to not increment a count associated with the number of times the error signal received by the control unit when the identified the error signal is the noise signal.
[014] In a further embodiment, the driver unit being configured to generate the error signal if the current passing through the driver unit exceeds the threshold current. The threshold current ranges between 185 Amperes to 190 Amperes.
[015] In a further embodiment, the control unit being configured to generate the fault signal if the number of times the error signal received by the control unit exceeds the predefined number of times. The predefined number of times for the error signal being received by the control unit since the last ignition ON event being 3.
[016] In a further embodiment, the control unit being configured to determine whether the time period exceeds the second predefined time period. The second predefined time period for which the driver unit receives the current greater than the threshold current is ranging between 10 ms to 15 ms.
[017] In a further embodiment, the ISG machine being in the cranking operation when rotational speed of the engine being below 750 RPM, and the ISG machine being in the generating operation when rotational speed of the engine being above 1200 RPM.
[018] In a further embodiment, the control unit being configured to generate an alert for a user to turn the ignition OFF to shut down the engine, disable the cranking operation, and generate an alert for restarting of the vehicle, in response to the fault signal.
[019] In a further embodiment, the control unit comprises an Engine Control Unit (ECU) of the vehicle.
[020] In another aspect, the present invention is directed to a method for controlling an engine. The method comprises detecting, by a driver unit, a current passing through the driver unit. The method further comprises generating, by the driver unit, an error signal if the current passing through the driver unit exceeds a threshold current. The method further comprises receiving, by a control unit, the error signal from the driver unit. The method further comprises determining, by the control unit, a number of times the error signal received by the control unit since a last ignition ON event. The method further comprises generating, by the control unit, a fault signal if the number of times the error signal received by the control unit exceeds a predefined number of times The method further comprises shutting down the engine, by the control unit, in response to the fault signal.
[021] In a further embodiment, the method comprises generating an alert by the control unit for a user to turn the ignition OFF to shut down the engine, disabling the cranking operation, and generating an alert for restarting of the vehicle, in response to the fault signal.

BRIEF DESCRIPTION OF THE DRAWINGS
[022] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figures 1 illustrates a block diagram of a system for controlling an engine, in accordance with an embodiment of the present invention.
Figure 2, Figures 3A to 3C illustrate flowcharts of a method for controlling the engine, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
[023] Various features and embodiments of the present invention here will be discernible from the following further description thereof, set out hereunder.
[024] Present invention generally relates to a system and method for controlling an engine.
[025] Figures 1 illustrates a schematic block diagram of a system 100 for controlling an engine 16, in accordance with an embodiment of the present invention. In some embodiments, the engine 16 may be applicable for a vehicle (not shown). The vehicle may include, but not limited to, a two-wheeled straddle, or any other kind of a two-wheeled vehicle like a motorcycle or a scooter. In some embodiments, the vehicle may also include a three-wheeled vehicle or a four wheeled vehicle. The term ‘engine’ used herein is an Internal Combustion (IC) engine, which provides a driving force for movement of the vehicle. In some other embodiments, the vehicle may be a hybrid vehicle driven by a combination of power from an IC engine and a motor through a battery source (not shown).
[026] The system 100 for controlling the engine 16 illustrated in Figure 1 comprises a driver unit 12. The driver unit 12 is an electrical component through which a current is passed from or to the battery of the vehicle during operations like cranking or generating. In an exemplary embodiment, the driver unit 12 may be, but not limited to, a Brushless DC electric motor (BLDC motor) / driver. In an embodiment, the driver unit 12 is configured to detect a current passing through the driver unit 12. The driver unit 12 may include one or more sensing elements including, but not limited to, a transistor. In some embodiments, hardware components including, but not limited to, relay circuits and other electrical components are used to ensure that there is no damage done due to overload of current. The hardware components trip and switches off to prevent long lasting damage. The current passing through the driver unit 12 is monitored by a protection relay circuit or similar circuits which senses abnormal condition in an electrical circuit and proactively closes the contact. The driver unit 12 is further configured to generate an error signal if the current passing through the driver unit 12 exceeds a threshold current. In an exemplary embodiment, the threshold current ranges between 185 Amperes to 190 Amperes.
[027] In the embodiment shown in Figure 1, the driver unit 12 is electrically coupled to an Integrated Starter Generated (ISG) machine 10. The ISG machine 10 may be supported and connected to a frame (not shown) of the vehicle. In an embodiment, the ISG machine 10 is in the cranking operation when rotational speed of the engine 16 is below 750 RPM. The ISG machine 10 is in the generating operation when rotational speed of the engine 16 is above 1200 RPM. During the generating operation, the battery of the vehicle will be in charging mode and during the cranking operation the current from the battery is being supplied to the ISG machine 10 for cranking the engine for starting the vehicle from an off condition.
[028] Referring further to the Figure 1, the system 100 for controlling the engine comprises a control unit 14. In an embodiment, the control unit 14 comprises the Engine Control Unit (ECU) of the vehicle. In some exemplary embodiments, the control unit 14 transfers the data using a CAN communication. In some other embodiments, the control unit 14 may include one or more additional components such as, but not limited to, a memory unit (not shown), an input/output module (not shown), a pre-processing module (not shown) etc. In yet another embodiment, the vehicle may include more than one of same or similar control unit(s). In another embodiment, the control unit 14 may include only a processor which may be required to process the received instructions / signals from one or more inputs device like a drive unit 12 and / or an ISG machine 10 and process the same. In yet another embodiment, the control unit 14 may be in communication with an analytic module (not shown) which is configured to perform additional analysis of the communication information received from the driver unit 12 and / or the ISG machine 10.
[029] In some embodiments, the memory unit in communication with the control unit 14 is capable of storing machine executable instructions. Further, the control unit 14 is capable of executing the machine executable instructions to perform the functions described herein. The control unit 14 is in communication with components such as the pre-processing module and the analytic module. In another embodiment, the control unit 14 is embodied as a multi-core processor, a single core processor, or a combination of one or more multi-core processors and one or more single core processors. For example, the control unit 14 is embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, or the like. In yet another embodiment, the control unit 14 is configured to execute hard-coded functionality. In still another embodiment, the control unit 14 is embodied as an executor of instructions, where the instructions are specifically configured to the control unit 14 to perform the steps or operations described herein for controlling the engine 16 of the vehicle.
[030] In the embodiment shown in Figure 1, the control unit 14 is electrically coupled to the driver unit 12. The driver unit 12 is configured to communicate signals to the control unit 14. In an exemplary embodiment, the drive unit 12 communicates an error signal when the current passing through the driver unit 12 is exceeding a threshold current. In an embodiment, the control unit 14 is configured to receive the error signal from the driver unit 12. In an embodiment, the control unit 14 is configured to receive the error signal when the ISG machine 10 is in at least one of the cranking operation and when the ISG machine 10 transitions from a cranking operation to a generating operation.
[031] The control unit 14 is further configured to determine a number of times the error signal received by the control unit 14 since a last ignition ON event. The term ‘last ignition’ used herein is defined as a condition of the engine after the engine is stopped. That is to say, the engine is in off condition due to turning off the vehicle by vehicle’s key or due to a signal communicated by the control unit 14 to the engine 16. In some other embodiments, the control unit 14 may further be configured to communicate a signal to the ECU (EMS ECU) of the vehicle for controlling operation of the engine 16. The embodiment of the ECU being configured for controlling the operation should not be meant to be limiting the scope of the present invention. In another embodiment, the control unit 14 can independently be configured to control operations of the engine 16 of the vehicle. Thus, it should be understood that, the operations of the engine 16 may be directly controlled by the control unit 14 or may also be done through the ECU. In some other embodiments, the ECU of the vehicle may be configured or updated through a programming or a software for controlling operations of the engine 16 through the signal received from the driver unit 12. Thus, it may be contemplated that the system 100 may include the control unit 14 and/or the ECU for controlling the operations of the engine 16. In some other embodiments, the system 100 may include one or more control units 14 and/or an ECU for controlling the operations of the engine 16 of the vehicle.
[032] The control unit 14 is further configured to generate a fault signal if the number of times the error signal received by the control unit 14 exceeds a predefined number of times. If the number of times the error signal is exceeding the predefined number of times, then the control unit 14 shuts down the engine 16 in response to the fault signal, thereby switching off or stopping the vehicle. In an exemplary embodiment, the predefined number of times for the error signal being received by the control unit 14 since the last ignition ON event is 3.
[033] In an embodiment, the control unit 14 is configured to determine a time period for which the current passing through the driver unit 12 exceeds the threshold current and determine whether the time period exceeds a second predefined time period. In an exemplary embodiment, the second predefined time period for which the driver unit 12 receives the current greater than the threshold current is ranging between 10 milliseconds to 15 milliseconds. The control unit 14 is further configured to identify the error signal as a fault signal if the time period exceeds the second predefined time period and increment a count associated with the number of times the error signal received by the control unit 14. That is to say, if the control unit 14 identifies the error signal as a fault signal when the time period exceeds the second predefined time period, then the control unit 14 will check whether the error signal is received for a first instance. Similarly, if the control unit 14 identifies the error signal as a fault signal when the time period exceeds the second predefined time period, then the control unit will check whether the error signal is received for a second instance. In the same manner, if the control unit 14 identifies the error signal as a fault signal when the time period exceeds the second predefined time period, then the control unit will check whether the error signal is received for a third instance. The control unit 14 is configured to identify the error signal as a fault signal if the time period exceeds the second predefined time period and the count associated with the number of times the error signal received by the control unit 14 is three.
[034] In an embodiment, the control unit 14 does not identify the error signal as a fault signal when the time period exceeds the second predefined time period and the count associated with the number of times the error signal received by the control unit 14 is either one or two. Thus, the error signal is identified as a noise signal and ignored by the control unit 14.
[035] In an embodiment, the control unit 14 is configured to generate an alert for a user to carry-out the operations including, but not limited to, turn the ignition OFF to shut down the engine 16, disable the cranking operation, and generate an alert for restarting of the vehicle, in response to the fault signal.
[036] In an exemplary embodiment, the control unit 14 is configured to identify the error signal as a noise signal if the time period is within the second predefined time period. Then the noise signal is ignored by the control unit 14 and does not generate any fault signal. Further, the control unit 14 is configured to not to increment a count associated with the number of times the error signal received by the control unit 14 when the identified error signal is the noise signal.
[037] In a further exemplary embodiment of the present invention, the control unit 14 is configured to receive the error signal for a first predefined time period after transitioning to the generating operation from the cranking operation. The first predefined time period is 1 second.
[038] Figure 2 illustrates a flowchart of a method 200 for controlling the engine 16, in accordance with an embodiment of the present invention. The method 200 at a step 202 comprises detecting, by the driver unit 12 a current passing through the driver unit 12. At a step 204, generating, by the driver unit 12, an error signal if the current passing through the driver unit 12 exceeds a threshold current.
[039] At a step 206, receiving, by the control unit 14, the error signal from the driver unit 12. At a step 208, determining, by the control unit 14, a number of times the error signal received by the control unit 14 since a last ignition ON event. At a step 210, generating, by the control unit 14, a fault signal if the number of times the error signal received by the control unit 14 exceeds a predefined number of times, and at a step 212, shutting down 212 the engine, by the control unit 14, in response to the fault signal.
[040] In an embodiment, the method 200 further comprises receiving, by the control unit 14 the error signal when the ISG machine 10 is in at least one of a cranking operation and when the ISG machine 10 transitions from a cranking operation to a generating operation. In a further embodiment, the method 200 comprises receiving, by the control unit 14, the error signal for a first predefined time period after transitioning to the generating operation from the cranking operation, the first predefined time period being 1 second.
[041] In an embodiment, the method 200 comprises determining, by the control unit 14, a time period for which the current passing through the driver unit 12 exceeds the threshold current; determining, by the control unit 14, whether the time period exceeds a second predefined time period; and identifying, by the control unit 14, the error signal as a fault signal if the time period exceeds the second predefined time period and increment a count associated with the number of times the error signal received by the control unit 14.
[042] In an embodiment, the method 200 comprises identifying the error signal, by the control unit 14 as a noise signal if the time period is within the second predefined time period, the noise signal being ignored by the control unit 14. The method 200 comprising a step of not incrementing a count associated with the number of times the error signal received by the control unit 14.
[043] In another embodiment, the method 200 comprises determining, by the control unit 14 whether the time period exceeds the second predefined time period. The second predefined time period for which the driver unit 12 receives the current greater than the threshold current is ranging between 10 milliseconds to 15 milliseconds.
[044] The method 200 comprises generating an alert by the control unit 14 for a user to turn the ignition OFF to shut down the engine 16, disabling the cranking operation, and generating an alert for restarting of the vehicle, in response to the fault signal.
[045] Referring now to Figures 3A and 3B, during a start of the vehicle, the ignition key is switched ON and the vehicle condition is checked by the control unit 14 or the ECU for starting the vehicle. Once the vehicle is found to be ready to start, an electric start input for starting the vehicle is switched ON. Upon receiving the electric start input, the ISG machine draws current to increase the RPM. For cranking operation, the RPM of the engine 16 is less than 750.
[046] When the RPM of the engine is less than 750, the driver unit 14 determines the current passing through the driver unit 12 and if the current passing is less than the threshold current, normal operation of cranking the vehicle is continued. Thus, the engine 16 is not shut down.
[047] However, once the current passing through the driver unit 12 crosses the threshold current for one time (one count), an error signal is generated by the driver unit 12 and the error signal is sent to the control unit 14. In an embodiment, the control unit 14 upon receiving the error signal, a fault signal should be triggered by the control unit 14. However, the error signal received by the control unit is ignored by the control unit 14 for the first two error signal counts, and there will be no change in the operation of the vehicle because the fault signal is not triggered by the control unit. That is to say, the control unit 14 is configured to not generate the fault signal and communicate to the engine if the number of times the error signal received is one or two.
[048] Further, when the error count received by the control unit 14 reaches to three, a fault signal is generated or triggered by the control unit 14, which controls the operation of the engine to shut down. In some embodiments, when the error count received by the control unit 14 reaches to three, a fault signal is generated or triggered by the control unit 14 and the control unit 14 sends a signal to the ECU (EMS ECU) for stopping the engine, which then cuts off the ignition and vehicle stops.
[049] In some embodiments, after ignition key is reset, the fault count is reset to zero (if any) and the vehicle continues to operate in normal operation.
[050] In the embodiment shown in Figures 3A and 3C, when the RPM of the engine 16 is greater than 900 RPM and it is present for a first predefined time (1 second) of charging and if the current passing through the driver unit 12 is less than the threshold current, the vehicle will continue its normal operation. However, once the current crosses the threshold current for one time, an error signal is generated by the driver unit and communicated to the control unit 14. The error signal is ignored for first two counts and thus there will be no change in vehicle operation because the fault signal is not triggered by the control unit 14.
[051] Advantageously, the present invention solves the problems of avoiding immobilisation of vehicle due to noise or spike interruptions. Present invention prevents false fault trigger, prevents the vehicle from switch off. According to existing system, if ISG machine’s phase current crosses a threshold limit, the driver unit raises or generates an error signal. However, in the system disclosed in the present invention, even if the ISG machine’s current crosses the threshold limit for one time, a fault is not declared by the control unit. The fault is declared by the control unit only when threshold limit is crossed for three times in a single key on cycle. Through this system, the vehicle switch off is prevented and thus providing a better customer satisfaction. By the present system, there is no damage to the driver unit and/or the ISG controller as the spike is for a very little duration. Thus, the present system eliminates the need for higher specification driver unit and/or the ISG controller by reducing cost and prevention of additional driver unit.
[052] The system and method disclosed in the present invention provides technical advantages of increasing performance, increasing durability, preventing false fault trigger, can be applicable to vehicles including, but not limited to, all 2W, 3W, 4W vehicles, reduces the cost, prevent usage of additional parts.
[053] The present system and method provide advantages over existing designs. In the existing system, during vehicle starting condition and during transition from cranking to charging / generating condition, the ISG machine usually pulls more current from the battery to start the battery or to enter charging state, respectively. During this operation, the current flowing through the driver unit exceeds the threshold limit of the driver unit because of which a fault is triggered. This spike is for a very short duration and thus the driver unit may not have any monitoring for this current. However, once the driver unit senses the current above threshold limit it raises a fault. In the present system and method, if the current crosses the threshold limit, an error is raised by driver unit, but the fault declaration is controlled by the control unit. The fault is declared only if the threshold limit is crossed for three times in a single key on cycle. Thus, the system and method disclosed in the present invention optimises the current carrying capability of the driver unit.
[054] The fault count is reset to zero if any after every ignition OFF and ignition ON. If the spike or fault count is observed for one time in a key ON cycle, after ignition key OFF / ON, the fault will get reset.
[055] The present invention provides advantages of no hardware damage to the control unit because of the system and method in the present invention comprises the spike duration of the current for milliseconds. Thus, the same hardware can be used in the system by changing the programming or updating the software basis the method disclosed in the present invention. On the other hand, a higher specification of the driver unit may be required in order to prevent the damaging that would have caused to the driver unit due to overcurrent flow which leads to cost increase and hardware changes.
[056] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

List of Reference Numerals and Characters:
10: ISG machine
12: Driver unit
14: Control unit
16: Engine
100: System for controlling an engine
200: Method for controlling an engine
202: Step
204: Step
206: Step
208: Step
210: Step
212: Step
, Claims:1. A system (100) for controlling an engine (16), the system (100) comprising:
a driver unit (12), the driver unit (12) electrically coupled to an ISG machine (10), the driver unit (12) being configured to:
detect a current passing through the driver unit (12); and
generate an error signal if the current passing through the driver unit (12) exceeds a threshold current;
a control unit (14) electrically coupled to the driver unit (12), the control unit (14) being configured to:
receive the error signal from the driver unit (12);
determine a number of times the error signal received by the control unit (14) since a last ignition ON event;
generate a fault signal if the number of times the error signal received by the control unit (14) exceeds a predefined number of times; and
shut down the engine (16) in response to the fault signal.

2. The system (100) as claimed in claim 1, wherein the control unit (14) being configured to receive the error signal when the ISG machine (10) is in at least one of a cranking operation and when the ISG machine (10) transitions from a cranking operation to a generating operation.

3. The system (100) as claimed in claim 2, wherein the control unit (14) being configured to receive the error signal for a first predefined time period after transitioning to the generating operation from the cranking operation, the first predefined time period being 1 second.

4. The system (100) as claimed in claim 1, wherein the control unit (14) being configured to:
determine a time period for which the current passing through the driver unit (12) exceeds the threshold current;
determine whether the time period exceeds a second predefined time period; and
identify the error signal as a fault signal if the time period exceeds the second predefined time period and increment a count associated with the number of times the error signal received by the control unit (14).

5. The system (100) as claimed in claim 4, wherein the control unit (14) being configured to identify the error signal as a noise signal if the time period is within the second predefined time period, the noise signal being ignored by the control unit (14).

6. The system (100) as claimed in claim 5, wherein the control unit (14) being configured to not increment a count associated with the number of times the error signal received by the control unit (14) when the identified the error signal is the noise signal.

7. The system (100) as claimed in claim 1, wherein the driver unit (12) being configured to generate the error signal if the current passing through the driver unit (12) exceeds the threshold current, the threshold current ranges between 185 Amperes to 190 Amperes.

8. The system (100) as claimed in claim 1, wherein the control unit (14) being configured to generate the fault signal if the number of times the error signal received by the control unit (14) exceeds the predefined number of times, the predefined number of times for the error signal being received by the control unit (14) since the last ignition ON event being 3.

9. The system (100) as claimed in claim 4, wherein the control unit (14) being configured to determine whether the time period exceeds the second predefined time period, wherein the second predefined time period for which the driver unit (12) receives the current greater than the threshold current is ranging between 10 ms to 15 ms.

10. The system (100) as claimed in claim 2, wherein the ISG machine (10) being in the cranking operation when rotational speed of the ISG machine (10) being below 750 RPM, and the ISG machine (10) being in the generating operation when rotational speed of the ISG machine being above 1200 RPM.

11. The system (100) as claimed in claim 1, wherein the control unit (14) being configured to generate an alert for a user to turn the ignition OFF to shut down the engine (16), disable the cranking operation, and generate an alert for restarting of the vehicle, in response to the fault signal.

12. The system (100) as claimed in claim 1, wherein the control unit (14) comprises an Engine Control Unit (ECU).

13. A method (200) for controlling an engine (16), the method (200) comprising:
detecting (202), by a driver unit (12), a current passing through the driver unit (12);
generating (204), by the driver unit (12), an error signal if the current passing through the driver unit (12) exceeds a threshold current;
receiving (206), by a control unit (14), the error signal from the driver unit (12);
determining (208), by the control unit (14), a number of times the error signal received by the control unit (14) since a last ignition ON event;
generating (210), by the control unit (14), a fault signal if the number of times the error signal received by the control unit (14) exceeds a predefined number of times; and
shutting down (212) the engine, by the control unit (14), in response to the fault signal.

14. The method (200) as claimed in claim 13 comprising receiving, by the control unit (14) the error signal when the ISG machine (10) is in at least one of a cranking operation and when the ISG machine (10) transitions from a cranking operation to a generating operation.

15. The method (200) as claimed in claim 14 comprising receiving, by the control unit (14), the error signal for a first predefined time period after transitioning to the generating operation from the cranking operation, the first predefined time period being 1 second.

16. The method (200) as claimed in claim 13 comprising:
determining, by the control unit (14), a time period for which the current passing through the driver unit (12) exceeds the threshold current;
determining, by the control unit (14), whether the time period exceeds a second predefined time period; and
identifying, by the control unit (14), the error signal as a fault signal if the time period exceeds the second predefined time period and increment a count associated with the number of times the error signal received by the control unit (14).

17. The method (200) as claimed in claim 16 comprising identifying the error signal, by the control unit (14) as a noise signal if the time period is within the second predefined time period, the noise signal being ignored by the control unit (14).

18. The method (200) as claimed in claim 17 comprising a step of not incrementing a count associated with the number of times the error signal received by the control unit (14).

19. The method (200) as claimed in claim 13 comprising generating the error signal, by the driver unit (12) if the current passing through the driver unit (12) exceeds the threshold current, the threshold current ranges between 185 Amperes to 190 Amperes.

20. The method as claimed in claim 13 comprising generating the fault signal by the control unit (14) if the number of times the error signal received by the control unit (14) exceeds the predefined number of times, the predefined number of times for the error signal being received by the control unit (14) since the last ignition ON event being 3.

21. The method (200) as claimed in claim 16 comprising determining, by the control unit (14) whether the time period exceeds the second predefined time period, wherein the second predefined time period for which the driver unit (12) receives the current greater than the threshold current is ranging between 10 ms to 15 ms.

22. The method (200) as claimed in claim 14 wherein during the cranking operation of the ISG machine (10), rotational speed of the ISG machine (10) being below 750 RPM, and during the generating operation of the ISG machine (10), rotational speed of the ISG machine being above 1200 RPM.

23. The method (200) as claimed in claim 1 comprising generating an alert by the control unit (14) for a user to turn the ignition OFF to shut down the engine (16), disabling the cranking operation, and generating an alert for restarting of the vehicle, in response to the fault signal.