Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:

Field of the invention:
[0001] The present disclosure relates to a controller to detect knocking in an engine of a vehicle and a method thereof.

Background of the invention:
[0002] An engine knocking is an undesirable mode of combustion. The engine knocking is caused due to premature combustion or auto ignition of compressed air-fuel mixture in engine cylinder leading to erratic pressure oscillations and high-pressure peaks. With increased or frequent knocking, durability of engine reduced and would be giving an undesirable drive behavior. To detect engine knock one or more dedicated knock sensors that measure certain engine parameters e.g. engine vibration, pressure, etc. are deployed. When an engine knock is detected by an Engine Control Unit (ECU), certain measures like ignition retard, change in injection parameters, etc. are effected so as to avoid knocking. However with increased cost, packaging constraints and maintenance, having a methodology to detect engine knock without a sensor would be a feasible solution.

[0003] A patent literature US5822710 discloses a method of detecting engine speed for detecting misfires in an internal combustion engine. The invention is directed to a method for detecting combustion misfires in a multicylinder internal combustion engine. The method includes the steps of forming a criterion for the rough running of the engine for each cylinder individually on the basis of time intervals during which the crankshaft passes through predetermined angular ranges; and, forming corrective values from rough-running values for each cylinder individually during misfire-free operation so that the rough-running values for each individual cylinder coupled to said corrective values become equal with respect to each other.

Brief description of the accompanying drawings:
[0004] An embodiment of the disclosure is described with reference to the following accompanying drawing,
[0005] Fig. 1 illustrates a block diagram of the controller to detect knocking in an engine of a vehicle, according to an embodiment of the present invention, and
[0006] Fig. 2 illustrates a method for detecting knock in the engine of the vehicle, according to the present invention.

Detailed description of the embodiments:
[0007] Fig. 1 illustrates a block diagram of the controller to detect knocking in an engine of a vehicle, according to an embodiment of the present invention. The controller 110 configured to measure engine speed through an input signal detected by a crankshaft position sensor 104 positioned in proximity of a trigger wheel (not shown), characterized in that, the controller 110 configured to determine engine speed at each tooth of the trigger wheel within a measurement window 126, calculate engine speed differences using the determined engine speeds in the measurement window 126, and store the engine speed differences in an array 116, 120, 124. The controller 110 then detects knocking based on comparison of an output value obtained from the engine speed differences stored in the array 116, 120, 124 with a threshold value. The output value is obtained by processing the engine speed differences using mathematical operations as per later defined criteria. The measurement window 126 is represented by two vertical lines having a predefined number of teeth of the trigger wheel. The measurement window 126 is shown only for a part of complete crankshaft position signal. In Fig. 1, the measurement window 126 is shown only for the first crankshaft position signal 114 which comprises two engine cycles, where each engine cycle comprises suction stroke through exhaust stroke. Although not shown, but the measurement window 126 is applicable for a second crankshaft position signal 118 and a third crankshaft position signal 122 as well, which are described later. The first crankshaft position signal 114, the second crankshaft position signal 118 and the third crankshaft position signal 122 are generated by the same crankshaft position sensor 104 at different instant of time, where the measurement window 126 with two different tooth range are shown.

[0008] According to an embodiment of the present invention, the measurement window 126 is calibratable and defined with reference to at least one of a Top Dead Center (TDC) and a Bottom Dead Center (BDC) of the engine 102. The engine speed difference is calculated between two teeth within the measurement window 126. The two teeth are selected as a pair until the last tooth in the measurement window 126 is reached. The two teeth are selected as per at least one criteria from a group comprising a first criteria, a second criteria and a third criteria. The first criteria comprises same tooth in consecutive/successive engine cycles shown by the first crankshaft position signal 114. The implementation of the first criteria is shown by a first array 116 which stores plurality of engine speed differences using the teeth detected in the first crankshaft position signal 114. In the first array 116, the engine speed differences are represented by respective tooth number, such as, a third tooth in first engine cycle (T1.3) and the third tooth in the second engine cycle (T2.3). The second criteria comprises consecutive/successive/adjacent tooths in the same engine cycle. The implementation of second criteria is shown with reference to the second crankshaft position signal 118 and a second array 120. The engine speed differences are stored in the second array 120, and represented by respective tooth number, such as second tooth (T2) and the first tooth (T1) in the same engine cycle. The third criteria comprises non-consecutive tooths in same engine cycle. The implementation of the third criteria is shown with reference to the third crankshaft position signal 122 and a third array 124. The engine speed differences are stored in the third array 124 and represented by respective tooth numbers, such as a third tooth (T3) and a first tooth(T1), a fourth tooth (T4) and a second tooth (T2), and the like, in the same engine cycle. The tooth considered need not be restricted only to alternate. The examples of other non-consecutive tooth pair comprises, first tooth and every second tooth from the first tooth or (every alternate tooth), first tooth and every third tooth from the first tooth, first tooth and fourth tooth from the first tooth, and first tooth and every nth tooth from the first tooth, where n is integer and non-consecutive to first tooth. For example, the pair of first tooth and every third tooth comprises a T1 and T4, T2 and T5, T3 and T6, T4 and T7, T5 and T8, and T6 and T9. In another example, the pair of first tooth and every fifth tooth comprises T1 and T6, T2 and T7, T3 and T8, T4 and T9.

[0009] According to an embodiment of the present invention, the output value is dynamically calculated in at least one manner selectable from a group comprising a first manner which comprises calculation of a maximum value of engine speed differences in a calibratable number of engine cycles, a second manner which comprises calculation of an average of maximum engine speed differences from each of calibratable number of engine cycles, a third manner which comprises calculation of a maximum value of engine speed difference in the array 116, 120, 124, a fourth manner which comprises calculation of a maximum value of absolute speed difference in the array 116, 120, 124, a fifth manner which comprises calculation of an average or integration of only positive values of engine speed difference in the array 116, 120, 124, and a sixth manner which comprises an average or integration of absolute values of engine speed differences in the array 116, 120, 124.

[0010] The controller 110 comprises input/output interfaces having pins or ports, memory element 106 such as Random Access Memory (RAM) and/or Read Only Memory (ROM), Analog-to-Digital Converter (ADC) and vice-versa Digital-to-Analog Convertor (DAC), clocks, timers and at least one processor (capable of implementing machine learning) connected with each other and to other components through communication bus channels or suitable wirings. The memory element 106 is pre-stored with logics or instructions or programs or applications and/or threshold values 108 or manners or predetermined criteria 112, which is/are accessed by the at least one processor as per the defined routines. The internal components of the controller 110 are not explained for being state of the art, and the same must not be understood in a limiting manner. The controller 110 may also comprise communication units to communicate with a server or cloud through wireless or wired means such as Global System for Mobile Communications (GSM), 3G, 4G, 5G, Wi-Fi, Bluetooth, Ethernet, serial networks, and the like.

[0011] According to an embodiment of the present invention, the controller 110 is any one of the Engine Management System (EMS) control unit, a Transmission Control Unit (TCU), or other internal control unit capable of executing the instructions, or an external control unit which is interfaced with the controller 110 such as over Controller Area Network (CAN).

[0012] In accordance to an embodiment of the present invention, the controller 110 is implementable in vehicle 100 comprising a two-wheeler such as a motorcycle, a moped, etc., a three-wheeler such as an Auto-rickshaw, a four-wheeler such as car, and other vehicles 100 such as trucks, buses, snow mobiles, motorboats, and the like.

[0013] According to the present invention, a working of the controller 110 is envisaged. Consider a vehicle 100 as motorcycle shown in Fig. 1. The trigger wheel (also known as tooth wheel) is fixed to the crankshaft of the engine 102. The crankshaft position sensor 104 detects the trigger wheel on rotation and sends the detected signal to the controller 110 as the input signal. The controller 110 receives the signal from the crankshaft position sensor 104 and determines the engine speed at each/every tooth of the predefined calibratable measurement window 126. For example, consider the first crankshaft position signal 114, where the measurement window 126 is defined between first tooth (T1) and sixth tooth (T6). So, as per the first crankshaft position signal 114, the controller 110 determines engine speed at each tooth T1, T2, T3, T4, T5 and T6. The remaining tooths are not shown for simplicity. In the second crankshaft position signal 118, the measurement window 126 is defined between first tooth (T1) and a ninth tooth (T9) and the other tooths are not shown for simplicity in understanding. So, as per the second crankshaft position signal 118, the controller 110 determines engine speed at each tooth T1, T2, T3, T4, T5,T6, T7, T8 and T9. Alternatively, the engine speed is determined at each tooth of the trigger wheel, but the those within the measurement window 126 are considered/taken for further processing.

[0014] The controller 110 calculates the engine speed differences as per selected criteria. If the controller 110 is configured with the first criteria, then the engine speed differences are calculated with reference to the first crankshaft position signal 114 and stored in the first array 116. For example, in the first array 116, a storage area A1 is stored with engine speed difference as T2.1-T1.1, which signifies that the engine speed at first tooth in first engine cycle (T1.1) is subtracted from the engine speed at the same first tooth but in a second engine cycle (T2.1). Similarly, A2 is stored with engine speed difference which is represented by T2.2-T1.2, A3 is stored with the engine speed difference which is represented by T2.3-T1.3, A4 is stored with the engine speed difference which is represented by T2.4-T1.4, A5 is stored with engine speed difference which is represented by T2.5-T1.5 and A6 is stored with the engine speed difference which is represented by T2.6-T1.6.

[0015] If the controller 110 is configured with the second criteria, then the second array 120 stores the engine speed differences with reference to the second crankshaft position signal 118. In the second array 120, A1 is stored with engine speed difference corresponding to T2-T1, which signifies that engine speed at first tooth is subtracted from engine speed at second tooth in the same engine cycle. Similarly, A2 is stored with the engine speed difference corresponding to T3-T2, A3 is stored with engine speed difference corresponding to T4-T3, A4 is stored with engine speed difference corresponding to T5-T4, A5 is stored with engine speed difference corresponding to T6-T5, A6 is stored with engine speed difference corresponding to T7-T6, A7 is stored with engine speed difference corresponding to T8-T7, A8 is stored with engine speed difference corresponding to T9-T8, etc.

[0016] Similarly, if the controller 110 is configured with the third criteria, then the third array 124 stores the engine speed differences with reference to the third crankshaft position signal 122. In the third array 124, A1 is stored with engine speed difference corresponding to T3-T1, which signifies that the engine speed at first tooth is subtracted from the engine speed at the third tooth. Similarly, A2 is stored with engine speed difference corresponding to T4-T2, A3 is stored with engine speed difference corresponding to T5-T3, A4 is stored with engine speed difference corresponding to T6-T4, A5 is stored with engine speed difference corresponding to T7-T5, A6 is stored with engine speed difference corresponding to T8-T6 and A7 is stored with engine speed difference corresponding to T9-T7. The third criteria is described with pair of every alternate tooth; however the third criteria is configurable to use other pairs of non-consecutive tooths as well such as pair of every third tooth from the first tooth, or pair of every fourth tooth from the first tooth, or pair of every nth tooth from the first tooth.

[0017] Once the engine speed differences are calculated as per at least one of the criteria, the controller 110 then obtains the output value from the array 116, 120, 124, which is compared with reference to the threshold value for detection of knocking. The dynamically calculated output value is a function of any one or at least one of the array 116, 120, 124 whichever is in use. For example, if the first array 116 is in use, then the controller 110 is configurable to use the second manner of calculating the threshold value 108 which comprises average of maximum difference from each engine cycle. For example, if “k” number of first arrays 116 are stored in the memory element 106, then the controller 110 calculates the average of “k” engine speed differences which are maximum in respective array, i.e. the first array 116. Similarly, the controller 110 is configurable to calculate the output value as per fifth manner which comprises an average or integration of only positive values of engine speed difference in the first array 116. For example, only the positive values of engine speed differences stored in the single first array 116 is averaged/integrated. Similarly, the controller 110 is configurable to use any or combination of the other manner of calculation such as the first manner, the third manner, the fourth manner and the sixth manner or a combination thereof.

[0018] Once the knocking is detected, the controller 110 performs corrective actions to eliminate the knocking.

[0019] Fig. 2 illustrates a method for detecting knock in the engine of the vehicle, according to the present invention. The vehicle 100 comprises the engine 102 with the trigger wheel coupled to the crankshaft of the engine 102. The method comprises plurality of steps of which a step 202 comprises measuring engine speed through the input signal detected by the crankshaft position sensor 104 positioned in proximity of the trigger wheel. The method is characterized by a step 204 which comprises determining engine speed at each/every tooth of the trigger wheel within the measurement window 126. A step 206 comprises calculating the engine speed differences using the determined engine speeds, and storing the engine speed differences in an array 116, 120, 124. A step 208 comprises detecting knock after comparing the output value obtained from the engine speed differences stored in the array 116, 120, 124 with the threshold value. The output value is obtained by applying mathematical operation/function over the stored engine speed differences in the array 116, 120, 124 and then comparing the result with the threshold value.

[0020] According to the method, the measurement window 126 is calibratable and defined with reference to at least one of the Top Dead Center (TDC) and the Bottom Dead Center (BDC) of the engine 102. Further, the engine speed difference is calculated between two teeth from the measurement window 126. The two teeth are selected from at least one criteria from the group comprising the first criteria, the second criteria and the third criteria. The first criteria comprises same tooth in consecutive engine cycle, the second criteria comprises successive tooths in same engine cycle, and the third criteria comprises non-consecutive tooths in same engine cycle.

[0021] According to the method, the engine speed information at each/every tooth, is stored in the array 116, 120, 124 for the defined measurement window 126 for every engine cycle. Further in the method, the output value is dynamically calculated in at least one manner selected from the group comprising the first manner through the sixth manner. The first manner comprises calculating the maximum value of engine speed difference in the calibratable number of engine cycles, the second manner comprises calculating the average of maximum difference from each engine cycle, the third manner comprises maximum value of engine speed difference in the array 116, 120, 124, the fourth manner comprises calculating the maximum value of absolute speed difference in the array 116, 120, 124, the fifth manner comprises calculating the average or integration of only positive values of engine speed differences in the array 116, 120, 124, and the sixth manner comprises calculating average or integration of absolute values of engine speed differences in the array 116, 120, 124.

[0022] According to the present invention, the engine 102 of the vehicle 100 is interfaced with the crankshaft position sensor 104 (or crank speed sensor), the input signal of which is used for multiple control operations. In the present invention, the controller 110 and method uses engine speed recorded for every tooth of the trigger wheel and based on certain calculations knock is detected, which is accordingly controlled (to reduce or eliminate knock) further on by the controller 110. The calculations are done in a specific measurement window 126 (or crank angle window) before and after ignition/compression TDC or BDC. The array 116, 120, 124 stores differences in tooth-based engine speed as per three criteria as described before. As per the first criteria, the difference in engine speed is calculated between every tooth of current engine cycle and corresponding tooth of previous engine cycle. As per the second criteria, the difference in engine speed is calculated between current tooth and previous tooth in the same engine cycle. As per the third criteria, the difference calculated between the engine speed of current tooth under consideration and the non-consecutive tooth (non-adjacent) before the current tooth. Based on the criteria selected for calculating the engine speed differences, the controller 110 then processes the array 116, 120, 124 to obtain the output value which is then compared with the respective predefined threshold value, with knock being detected when the threshold value is breached. The manner of calculating the value for comparing with the threshold values is also configurable based on the requirement. In the first manner, the maximum value of difference in certain number of complete engine cycles (e.g. if 10 cycles are considered, maximum value of difference from 10 cycles is compared). In the second manner, in certain number of complete engine cycles, average of maximum difference from each complete engine cycle (e.g. if 10 cycles are considered, average of maximum difference from each of the 10 cycles is compared).

[0023] Additionally, engine knock is detectable using one or multiple of the below values obtained from other manners. The output value that is compared with the predefined threshold is possible from each power cycle basis or the maximum value in certain defined number of engine power cycles or the average of values in certain defined number of engine cycles, with knock being confirmed once the output value crosses the predefined threshold value. In the third manner, the maximum value of speed difference in the array 116, 120, 124 is considered. In the fourth manner, the maximum value of absolute speed difference in the array 116, 120, 124 is considered. In the fifth manner, the average or integration of only positive values of engine speed difference in the array 116, 120, 124 is considered. In the sixth manner, the average or integration of absolute values of engine speed difference in the array 116, 120, 124 is considered. The trigger wheel may be of any number of tooth as known in the art such as 24-2, 36-2, etc. Further, the first tooth may start from tooth number seven or thirteen, for example.

[0024] According to the present invention, a simplified method for detecting engine knock is disclosed. The controller 110 and the method provides cost effective solution for new and existing vehicles 100.

[0025] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.
, Claims:
We claim:
1. A controller (110) to detect knocking in an engine (102) of a vehicle (100), said controller (110) configured to:
measure engine speed through an input signal detected by a crankshaft position sensor (104) positioned in proximity of a trigger wheel, characterized in that,
determine engine speed at each tooth of said trigger wheel within a measurement window (126);
calculate engine speed difference using said determined engine speeds, and store the engine speed differences in an array (116, 120, 124), and
detect knocking based on comparison of an output value obtained from said engine speed differences stored in said array (116, 120, 124) with a threshold value.

2. The controller (110) as claimed in claim 1, wherein said measurement window (126) is calibratable and defined with reference to at least one of a Top Dead Center (TDC) and a Bottom Dead Center (BDC) of said engine.

3. The controller (110) as claimed in claim 1, wherein said engine speed difference is calculated between two teeth from said measurement window (126), said two teeth are chosen as per at least one criteria selected from a group comprising a first criteria, a second criteria and a third criteria, wherein said first criteria comprises same tooth in consecutive engine cycle, said second criteria comprises successive tooths in same engine cycle, and third criteria comprises non-consecutive tooths in same engine cycle.

4. The controller (110) as claimed in claim 1, wherein engine speed information at each tooth is stored in said array (116, 120, 124) for said defined measurement window (126) for every engine cycle.

5. The controller (110) as claimed in claim 1, wherein said output value is dynamically calculated as per at least one manner selected from a group comprising a first manner which comprises calculation of a maximum value of engine speed differences in a calibratable number of engine cycles, a second manner which comprises calculation of an average of maximum engine speed differences from each of calibratable number of engine cycles, a third manner which comprises calculation of a maximum value of engine speed difference in said array (116, 120, 124), a fourth manner which comprises calculation of a maximum value of absolute speed difference in said array (116, 120, 124), a fifth manner which comprises calculation of an average or integration of only positive values of engine speed difference in said array (116, 120, 124), and a sixth manner which comprises an average or integration of absolute values of engine speed differences in said array (116, 120, 124).

6. A method for detecting knock in an engine (102) of a vehicle (100), the method comprising the steps of:
measuring engine speed through an input signal detected by a crankshaft position sensor (104) positioned in proximity of a trigger wheel, characterized by,
determining engine speed at each tooth of a trigger wheel within a measurement window (126);
calculating engine speed differences using said determined engine speeds, and storing said engine speed differences in an array (116, 120, 124), and
detecting knock after comparing an output value obtained from said engine speed differences stored in said array (116, 120, 124) with a threshold value.

7. The method as claimed in claim 6, wherein said measurement window (126) is calibratable and defined with reference to at least one of a Top Dead Center (TDC) and a Bottom Dead Center (BDC) of said engine (102).

8. The method as claimed in claim 6, wherein said engine speed difference is calculated between two teeth from said measurement window (126), said two teeth are selected based on at least one criteria from a group comprising a first criteria, a second criteria and a third criteria, wherein said first criteria comprises same tooth in consecutive engine cycle, said second criteria comprises successive tooths in same engine cycle, and third criteria comprises non-consecutive tooths in same engine cycle.

9. The method as claimed in claim 6, comprises storing said engine speed information at each tooth in said array (116, 120, 124) for said defined measurement window (126) for every engine cycle.

10. The method as claimed in claim 6, wherein said output value is dynamically calculated in at least one manner selected from a group comprising a first manner which comprises calculating maximum value of engine speed difference in a calibratable number of engine cycles, a second manner which comprises calculating average of maximum difference from each of calibratable number of engine cycle, a third manner comprises calculating maximum value of engine speed difference in said array (116, 120, 124), a fourth manner comprises calculating maximum value of absolute speed differences in said array (116, 120, 124), a fifth manner comprises calculating average or integration of only positive values of engine speed difference in said array (116, 120, 124), and a sixth manner comprises average or integration of absolute values of engine speed differences in said array (116, 120, 124).