FIELD OF INVENTION:
[001] The present subject matter described herein, relates to a method and a 5 system for detecting malfunction in vehicle speed measurement and controlling maximum speed of vehicle.
BACKGROUND AND PRIOR ART:
[002] In vehicle industry, specifically, heavy vehicle, there is widespread interest in limiting vehicle speed to improve fuel efficiency. Government issues 10 notifications for speed limit which can reduce costs and encourage safe vehicle operation by limiting the maximum allowable speed of a vehicle. Generally, vehicle drivers oppose and resist use of vehicle speed limiting systems because they tend to increase the time required to transport shipments that may marginally reduce their efficiency and productivity. Some operators have been known to 15 attempt to frustrate the vehicle speed limiting devices and systems by damaging, disconnecting or modifying such devices and systems.
[003] Conventionally, governors were originally proposed for speed limiting that were integrated with vehicle fuel systems to limit the quantity of fuel supplied to a vehicle engine. These systems were easy to remove or re-calibrate rendering them 20 ineffective.
[004] With the introduction of electronically controlled engines, more sophisticated approaches towards vehicle speed limiting have been developed. Algorithms have been proposed for such control systems that provide effective vehicle speed limiting without limiting the engine speed so that the full engine 25 power is available in low gear ranges. These sophisticated systems require multiple inputs that make them substantially more difficult to disable or override vehicle speed limiting systems.
3
[005] Conventionally, governors or limiters have been developed and utilized to manage various aspects of vehicle operation. Whether mechanical or electronic, governors are often used to limit one or more operating parameters to achieve a goal, such as protecting vehicle components, maintaining safe vehicle operation, or improving operating efficiency. For example, an engine speed limiter or 5 governor may impose an upper limit on engine speed to prevent damage to various engine or vehicle components. A vehicle speed or road speed limiter may impose an upper limit on the ground speed of the vehicle in an attempt to restrict unsafe operation of the vehicle.
[006] US patent 7286917 titled, “Method of detecting vehicle speed sensor 10 failure”. The method of detecting vehicle speed sensor failure is disclosed. The method is intended to prevent or discourage tampering with a vehicle's speed limiting system. The method includes the steps of determining whether the transmission is in neutral or whether the transmission is in its converter mode to prevent false indications of speed sensor failure under certain circumstances. This 15 system and method takes input from only few sensors, such as rpm sensor, vehicle speed sensor. This system might not be robust enough to detect malfunction in all the possible driving conditions such as acceleration, deceleration or cruising. There might also be chance of fault misdetection.
[007] Existing solutions and technologies are not robust enough to detect 20 malfunction in all driving style, such as acceleration, deceleration, and constant speed. Sometime, vehicle malfunction detection system indicates false indicators in error, for example, if there is any mud on the sensor, which results in vehicle service procedures. When a fault is logged by an engine control system, the source of the fault must be determined that requires additional service operations. 25
[008] Further, a control system is required which can limit the speed of the vehicle upto a specified limit even when vehicle speed sensor is not working or vehicle speed sensor has been removed.
[009] In view of the above, it is beneficial to have a robust method and system to detect malfunction in the vehicle speed measurement. Therefore, there is a need in 30
4
the art to provide a method and a system that is more simple and inexpensive, and which can be implemented in the ECU to control the speed of the vehicle and to detect malfunction in the vehicle speed measurement.
OBJECTS OF THE INVENTION:
[0010] The principal object of the present invention is to detect malfunction in 5 vehicle speed measurement.
[0011] Another object of the present subject matter is to provide a method and a system in Engine Control Unit (ECU) to detect malfunction in vehicle speed measurement.
[0012] Another object of the present subject matter is to provide a method and a 10 system in Engine Control Unit (ECU) to detect malfunction in the vehicle speed measurement and controlling vehicle maximum speed.
[0013] Another object of the present subject matter is to control the speed of the vehicle when vehicle speed sensor is tampered or even the vehicle speed sensor is removed. 15
[0014] Yet another object of the present subject matter is to detect malfunction in acceleration, deceleration and cruising condition of the vehicle.
[0015] Yet another object of the present invention is to provide a simple and inexpensive system for detecting malfunction in the vehicle speed measurement and controlling maximum speed of the vehicle. 20
SUMMARY OF THE INVENTION:
[0016] The subject matter disclosed herein relates to a method and a system for detecting malfunction in the vehicle speed measurement, specifically, vehicle speed sensor and controlling vehicle maximum speed. The system is implemented in the Engine Control Unit (ECU) of the vehicle. The ECU has a processor which 25 is communicatively coupled with hardware interface and a memory for receiving and processing various inputs from the sensor to determine running conditions of the sensors. Further, the ECU controls fuel injection and air intake manifold
5
pressure for controlling the speed of the vehicle. The system has clutch pedal switch, vehicle speed sensor, engine speed sensor, air intake manifold pressure sensor, and coolant temperature sensor. All these sensors are coupled with the ECU via hardware interface. All these sensors provide its inputs to the ECU for detecting malfunction in the vehicle speed sensor based on the inputs and 5 controlling the maximum speed of the vehicle by limiting the quantity of fuel injected and air intake from the manifold. The ECU has a control logic based on several inputs, such as engine speed, clutch pedal status, air intake manifold pressure, fueling injection rate, and rate of change of engine speed. The ECU compares the determined vehicle speed with threshold vehicle speed value 1 and 10 threshold vehicle speed value 2 and gives the output to ECU having AND logic. The ECU compares the determined engine speed with threshold engine speed value 1 and threshold engine speed value 2 and gives output to AND logic of ECU. The ECU compares the determined air intake manifold pressure or boost pressure in turbo charger with the threshold air intake manifold pressure value 1 15 and threshold air intake manifold pressure value 2 and gives output to the AND logic of ECU. The rate of change of engine speed is compared with the threshold value 1 and threshold value 2 and output is given to the AND logic of the ECU. Further, the fuel injection rate is also compared with the threshold fuelling rate value 1 and the threshold fuelling rate value 2 and output is given to the AND 20 logic of the ECU. Based on all these conditions, the ECU determines the malfunction in vehicle speed sensor when it actually happens. Further, based on these conditions, the ECU controls the speed of the vehicle when vehicle speed sensor indicates false values. The ECU controls input of the fuel injection rate and the air intake manifold pressure for controlling maximum speed of the vehicle. 25 The ECU compares all the determined conditions with the predefined threshold limits and check whether all these conditions with AND logic are true for a predefined time period. The present system is robust enough that it does not indicate malfunction in neutral conditions. The present system diagnosis the vehicle in acceleration and deceleration mode. 30
6
[0017] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS 5
[0018] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number 10 identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to refer like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which: 15
[0019] Fig. 1 illustrates speed control system of a vehicle with Engine Control Unit along with hardware embodiments for detecting malfunction in vehicle speed measurement, in accordance with an embodiment of the present subject matter;
[0020] Fig. 2 illustrates a method of detecting malfunction in the vehicle speed measurement based on a plurality of parameters, in accordance with an 20 embodiment of the present subject matter; and
[0021] Fig. 3 illustrates Engine control Unit with embodiments to detect malfunction in vehicle speed measurement and control vehicle maximum speed, in accordance with an embodiment of the present subject matter.
[0022] The figures depict embodiments of the present subject matter for the 25 purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
7
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0023] The subject matter disclosed herein relates to a method and a system for detecting malfunction in the vehicle speed measurement, specifically, vehicle speed sensor and controlling vehicle maximum speed. The system is implemented in the Engine Control Unit (ECU) of the vehicle. The ECU has a processor which 5 is communicatively coupled with hardware interface and a memory for receiving and processing various inputs from the sensor to determine running conditions of the sensors. Further, the ECU controls fuel injection and air intake manifold pressure for controlling the speed of the vehicle. The system has clutch pedal switch, vehicle speed sensor, engine speed sensor, air intake manifold pressure 10 sensor, and coolant temperature sensor. All these sensors are coupled with the ECU via hardware interface. All these sensors provide its inputs to the ECU for detecting malfunction in the vehicle speed sensor based on the inputs and controlling the maximum speed of the vehicle by limiting the quantity of fuel injection and air intake from the manifold. The ECU has a control logic based on 15 several inputs, such as engine speed, clutch pedal status, air intake manifold pressure, fueling injection rate, rate of change of engine speed. The ECU compares the determined vehicle speed with threshold vehicle speed value 1 and threshold vehicle speed value 2 and gives the output to ECU having AND logic. The ECU compares the determined engine speed with threshold engine speed 20 value 1 and threshold engine speed value 2 and gives output to AND logic of ECU. The ECU compares the determined air intake manifold pressure or boost pressure in turbo charger with the threshold air intake manifold pressure value 1 and threshold air intake manifold pressure value 2 and gives output to the AND logic of ECU. The rate of change of engine speed is compared with the threshold 25 value 1 and threshold value 2 and output is given to the AND logic of the ECU. Further, the fuel injection rate is also compared with the threshold fuelling rate value 1 and the threshold fuelling rate value 2 and output is given to the AND logic of the ECU. Based on all these conditions, the ECU determines the malfunction in vehicle speed sensor when it actually happens. Further, based on 30 these conditions, the ECU controls the speed of the vehicle when vehicle speed
8
sensor indicates false values. The ECU controls input of the fuel injection rate and the air intake manifold pressure for controlling speed of maximum speed of the vehicle. The ECU compares all the determined conditions with the predefined threshold limits and check whether all these conditions with AND logic are true for a predefined time period. The present system is robust enough that it does not 5 indicate malfunction in neutral conditions. The present system diagnosis the vehicle in acceleration and deceleration mode.
[0024] In another aspect of the present subject matter, the ECU controls maximum speed of the vehicle by controlling fuel injection rate and air intake manifold in the engine during acceleration of the vehicle. 10
[0025] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those 15 skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the 20 concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the 25 following description when considered in connection with the accompanying figures.
[0026] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject 30
9
matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0027] The present subject matter discloses a system and a method for detecting malfunction in vehicle speed sensor and controlling maximum speed of the 5 vehicle in case no speed sensor is active. In the present subject matter, the ECU is coupled with a plurality of sensors to receive inputs and applies method/logic on the received inputs to detect malfunction in the speed sensor. The ECU determines the malfunction only when all the conditions are true with AND logic for a predefined time period. 10
[0028] Fig. 1 illustrates speed control system of a vehicle with Engine Control Unit along with hardware embodiments for detecting malfunction in vehicle speed measurement, in accordance with an embodiment of the present subject matter. The speed control system has an Engine Control Unit (ECU) 100 which has a processor 103, hardware interface 102, and a memory 101 for storing logics and 15 doing calculations to determine the objective. The ECU 100 is coupled with clutch pedal switch 105, vehicle speed sensor 106, engine speed sensor 107, coolant temperature sensor 108, and air intake manifold pressure sensor 109 via hardware interface 102. The clutch pedal switch 105 provides the status, i.e., pressed or released of the clutch pedal to the ECU 100. On the basis of the clutch pedal status 20 and gear engagement, the ECU 100 determines whether the vehicle is in running mode or in neutral mode. The present speed control system or system is activated only when vehicle is in running condition which is determined by the clutch pedal status.
[0029] The vehicle speed sensor 106 coupled with the ECU 100 via the hardware 25 interface 102 to provide vehicle speed input. The ECU 100 receives the input from the vehicle speed sensor 106 and determines the speed of the vehicle. The ECU 100 stores the determined speed of the vehicle by the vehicle speed sensor 106 for detecting malfunction of the vehicle speed sensor 106. In another aspect of the present subject matter, if the vehicle speed sensor 106 is inaccurate, the 30
10
ECU 100 controls the maximum speed of the vehicle. The ECU 100 has an engine speed sensor 107 coupled via hardware interface 102. The engine speed sensor 107 provides engine speed, i.e., is in RPM inputs to the ECU 100 for calculation. The air intake manifold pressure sensor 109 gives input to the ECU 100 for calculation and control of the vehicle speed. The ECU 100 has a control logic, i.e., 5 AND logic which checks all determined conditions for detecting malfunction in the vehicle speed sensor 106.
[0030] The ECU 100 has a sequence of steps to analyze and detect malfunction of the vehicle speed sensor. Further, the ECU 100 receives all inputs from the plurality of sensors and detects malfunction based on the received inputs. Further 10 the ECU 100 controls the speed of the vehicle when vehicle speed sensor is not available or active or has malfunction.
[0031] Referring to fig. 2 which describes a method for detecting malfunction in the vehicle speed measurement based on a plurality of parameters, in accordance with an embodiment of the present subject matter. The method 200 discloses how 15 the present system works to detect malfunction in the vehicle speed sensor based on other parameters. Referring to step 201 of the figure 2, the ECU 100 determines clutch switch status by the clutch pedal switch 105. The status of the clutch pedal can be whether pressed or released. Where the pressed status gives input that the vehicle is in either neutral condition or deceleration condition. In 20 that condition, vehicle speed control is not required, therefore, the present system does not work in this condition. When the clutch pedal is released along with gear engagement, it gives input that vehicle is in motion. The system activates when clutch pedal is pressed and vehicle is in motion.
[0032] Referring to step 202, the engine speed sensor 107 measures the speed of 25 the engine and gives output to the ECU 100. The ECU 100 compares the measured/determined engine speed with threshold engine speed value 1 and threshold engine speed value 2. If the engine speed is in between the threshold engine speed value 1 and the threshold engine speed value 2, the ECU 100 gives the engine speed input to AND logic of the ECU 100. For example, the threshold 30
11
engine speed value 1 is 1000 RPM and the threshold engine speed value 2 is 5000 RPM. Further, the threshold value of the engine speed depends on the engine capacity and other factors, such as fuel type and vehicle type. In order to make the present system more robust in detecting the malfunction and not indicate wrong values when vehicle is not moving, the two threshold values are given. The lower 5 threshold value, i.e., value 1 is achieved when vehicle is actually in moving condition. During cranking also, the engine rotates and gives engine speed. In order to avoid reading of engine speed during cranking and acceleration of vehicle in neutral condition, the two threshold limits are given. Therefore, the system ensures that diagnosis of the malfunction starts only when the engine speed is in 10 between the given range. By giving range, the system avoids unnecessary engine speed inputs.
[0033] At step 203, the vehicle speed sensor 106 gives input about the vehicle speed to the ECU 100. The ECU 100 compares the speed of the vehicle given by the vehicle speed sensor 106 with the threshold vehicle speed value 1 and 15 threshold vehicle speed value 2. Further, the ECU 100 stores the vehicle speed for comparison to detect malfunction in the vehicle speed sensor 106. If the vehicle speed is in between the threshold vehicle speed value 1 and the threshold vehicle speed value 2, the ECU 100 gives the vehicle speed input to the AND logic of the ECU 100 for further calculations. If the vehicle speed sensor 106 gives false input 20 due to tampering, the speed control system detect the malfunction based on several parameters as explained in the present subject matter and indicates the same. Further, the present system controls the maximum speed of the vehicle. For example, the threshold vehicle speed value 1 is 0 KM/H and the threshold vehicle speed value is 120 KM/H. 25
[0034] At step 204, the ECU 100 determines the rate of change of engine speed by the engine speed sensor 107. The ECU 100 stores all the inputs given by the engine speed sensor 107 and then calculates the rate of change of engine speed. The ECU 100 compares the determined rate of change of engine speed with threshold rate of change of engine speed value 1 and threshold rate of change of 30
12
engine speed value 2. If the rate of change of engine speed is in between the threshold rate of change of engine speed value 1 and the threshold rate of change of engine speed value 2, the ECU 100 gives the rate of change of engine speed input to AND logic of the ECU 100. For example, the rate of change of engine speed threshold values lies in between -3RPM/s to 6 RPM/s. 5
[0035] At step 205, the air intake manifold pressure sensor 109 gives value of pressure to the ECU 100. The ECU 100 determines air intake manifold pressure which is boost pressure of the engine and stores the same for calculation by the logics. When the boost pressure is high, it indicates that engine is loaded and vehicle is moving. In the turbocharger equipped vehicles, the turbocharger has 10 two parts, one is turbine and other is compressor. The turbine is coupled with the exhaust gases of the engine. If there is high exhaust gases with high pressure, there will be high boost pressure. Generally, the high boost is required to increase the pick and to run the vehicle in high speed. The ECU 100 compares the determined boost pressure with threshold boost pressure or air intake manifold 15 pressure value 1 and threshold boost pressure or air intake manifold pressure value 2. If the boost pressure is in between the threshold value 1 and the threshold value 2, the ECU 100 gives the boost pressure input to AND logic of the ECU 100. For example, the boost pressure is in range of 900 mbar to 2300 mbar. Further, the range of the boost pressure depends upon the engine capacity and fuel 20 type of the vehicle.
[0036] At step 206, the ECU 100 determines the fueling injection rate of the engine. The ECU 100 compares the determined fueling injection rate with threshold fueling injection rate value 1 and threshold fueling injection rate value 2. If the determined fueling injection rate is in between the threshold value 1 and 25 the threshold value 2, the ECU 100 gives the fueling injection rate input to AND logic of the ECU 100 for further calculation and detection. For example, the fueling injection rate is in range of 10 mm3/str to 45 mm3/str. Further, the range of the fueling injection rate depends upon the engine capacity and fuel type of the vehicle. 30
13
[0037] At step 207, the ECU calculates the engine operating time for activating the speed control system. The ECU 100 determines whether the engine operating time is more that the predefined threshold time period. If the determined engine operating time period is more that than the threshold time period, the ECU 100 gives the input to AND logic of the ECU 100 for further calculation and detection. 5
[0038] At step 208, the ECU 100 determines whether idle control is activated or not. To activate the system, it should not be active.
[0039] At step 209, the coolant temperature sensor 108 give information about the coolant temperature to the ECU 100. The ECU 100 determines whether the coolant temperature is above the threshold level of the coolant temperature. If the 10 coolant temperature is more than the threshold level, the ECU 100 gives the input to AND logic of the ECU 100 for further calculation and detection. The coolant temperature helps to determine the condition of the engine and actual status of the vehicle running.
[0040] Referring to step 210, the step 210 is an AND logic which receives the 15 inputs from step 201 to 209. If all the conditions are satisfied by the AND logic and vehicle speed indicated by the speed sensor 106 does not match with the parameters as explained. Based on the combination of all the comparisons, the ECU 100 detects malfunction in the vehicle speed sensor 106 when output of all steps 201-209 are true for a predefined time period as shown in step 211. The 20 ECU 100 confirms the fault in the vehicle speed sensor 106.
[0041] At the step 213, the ECU 100 limits the maximum speed of the vehicle when vehicle speed sensor 106 is not working properly. Based on the inputs from a plurality of sensors, the ECU 100 controls the fuel injection rate and the air intake manifold pressure to control the speed of the vehicle. When ECU confirms 25 error in vehicle speed sensor signal, it limits the engine torque by limiting the fuel quantity to be injected. In engine, if fuel is limited, limited torque will be generated, then it would not be possible to run vehicle at more than 80 Km/h speed in any gear.
14
[0042] Fig. 3 illustrates Engine control Unit with embodiments to detect malfunction in vehicle speed measurement and control vehicle maximum speed, in accordance with an embodiment of the present subject matter. The ECU 300 has a processor 301, a hardware interface 302, a memory 303, an engine speed determining module 305, a vehicle speed determine module 306, air intake 5 pressure sensing module 307, fuelling module 308, and coolant temperature module 309. All these modules are govern by the respective sensors, such as engine speed sensor, vehicle speed sensor, air intake pressure sensor, and fuel injection rate sensor via hardware interface 302. The processor(s) 301 may be implemented as one or more microprocessors, microcomputers, microcontrollers, 10 digital signal processors, central processing units, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the processor(s) 301 is configured to fetch and execute computer-readable instructions stored in the memory 303.
[0043] The functions of the various elements shown in the figure, including any 15 functional blocks labeled as “processor(s)”, may be provided through the use of dedicated hardware as well as hardware capable of executing computer readable instructions or logics in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which 20 may be shared. Moreover, explicit use of the term “processor” should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read only memory (ROM) for storing software, 25 random access memory (RAM), non-volatile storage. Other hardware, conventional and/or custom, may also be included.
[0044] The hardware interface 302 may include a variety of software and hardware interfaces, for example, interfaces for peripheral device(s), such as sensors, actuators, and an external memory. The hardware interface 302 is suitable 30
15
for interfacing with the sensor and actuators as referred in the figure 1. The memory 303 can include any computer-readable medium known in the art including, for example, volatile memory, such as static random access memory (SRAM) and dynamic random access memory (DRAM), and/or non-volatile memory, such as read only memory (ROM), erasable programmable ROM, flash 5 memories, hard disks, optical disks, and magnetic tapes. Generally construction of the ECU 100 is well known in the art. The processor 301 is operatively coupled with the memory 303 and the hardware interface 302 to execute the instructions for running the ECU 100. These instruction or logics may be encoded in the programs that are stored in the memory 303. Further, all the output of the system 10 and calculation of the ECU are also stored in the memory 303 for future determinations.
[0045] As shown in the figure 1, the plurality of sensors provides various signals to the ECU 100 (300) via hardware interface 102 (302).
[0046] The engine speed determine module 305 coupled with the engine speed 15 sensor 107 to determine the engine speed stores the engine speed into the memory 303. Similarly, the vehicle speed determine module 306 coupled with the vehicle speed sensor 106 to determine the vehicle speed and compares the vehicle speed with the predefined vehicle speed in the ECU 100. The air intake pressure sensing module 307 coupled with the air intake pressure sensor 109 to determine boost 20 pressure and compares the determined boost pressure with the threshold values as stored in the memory of the ECU 300. Further, the fueling module 308 coupled with the fueling injection rate sensor to determine fuel injection rate compares the determined fuel injection rate with the predefined fuel injection rate stored in the memory of the ECU 300. The coolant temperature module 309 coupled with the 25 coolant temperature sensor 108 to determine the coolant temperature of the engine and compares the coolant temperature with the predefined threshold value as stored in the memory of the ECU 100.
[0047] All inputs of the sensors are given to AND logic of the ECU 300, and if outputs of all the comparisons are true in AND logic for a predetermined or 30
16
predefined time period, the ECU 300 detects the malfunction in the vehicle speed sensor 106 and indicate the same. Further, the ECU 300 controls the speed of the vehicle by controlling the air intake manifold pressure and fuel injection rate.
[0048] It is easy to build the present ECU and speed control system with a plurality of sensors in the vehicle. The present system is cost efficient as 5 compared to other existing solutions. Further, the present exhaust system is robust which can effectively work even when the vehicle speed sensor is not working for controlling speed of the vehicle.
[0049] It will be further appreciated that functions or structures of a plurality of components or steps may be combined into a single component or step, or the 10 functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. Plural structural components or steps can 15 be provided by a single integrated structure or step. Alternatively, a single integrated structure or step might be divided into separate plural components or steps. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for any 20 given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein. The use of “comprising” or “including” also contemplates embodiments that 25 “consist essentially of” or “consist of” the recited feature.
[0050] The term “vehicle” as used throughout this detailed description and in the claims refers to any moving vehicle that is capable of carrying one or more human occupants and is powered by any form of energy. The term “vehicle” is a motor
17
vehicle which includes, but is not limited to: cars, trucks, vans, minivans, hatchback, sedan, MUVs, and SUVs.
[0051] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, 5 the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:
1. A system for detecting malfunction in vehicle speed measurement, the system comprising:
an Engine Control Unit (ECU) (100) having a processor (103) communicatively coupled with hardware interface (102) and a memory 5 (101);
a vehicle speed sensor (106) coupled with the ECU (100) for determining speed of vehicle;
an engine speed sensor (107) coupled with the ECU (100) for determining speed of engine; 10
an air intake manifold pressure sensor (109) coupled with the ECU (100) for determining pressure of air intake manifold during turbo boost;
a clutch pedal switch (105) coupled with the ECU (100) for generating a signal indicative of clutch pedal operation; and
a coolant temperature sensor (108) coupled with the ECU (100) for 15 determining temperature of coolant, wherein
the ECU (100) compares the determined vehicle speed with threshold vehicle speed value 1 and the threshold vehicle speed value 2,
the ECU (100) compares the determined engine speed with the threshold engine speed value 1 and the threshold engine speed value 2, 20
the ECU (100) compares the determined air intake manifold pressure with the threshold air intake manifold pressure value 1 and the threshold air intake manifold pressure value 2, and
the ECU (100) compares the determined coolant temperature with threshold coolant temperature value, 25
based on the combination of all comparisons, the ECU (100) detects a malfunction signal in the vehicle speed sensor (106) when outputs of all the comparisons are true for a predetermined time period.
19
2. The system as claimed in claim 1, wherein the processor (103) of the ECU (100) coupled with the hardware interface (102) and the memory (101) determines whether fueling rate of the engine is in between range threshold fueling rate value 1 and the threshold fueling rate value 2. 5
3. The system as claimed in claim 1, wherein the system limits speed of the vehicle by controlling fuel injection and limiting engine speed.
4. The system as claimed in claim 1, wherein the ECU (100) determines 10 whether engine operating time is above threshold value of engine operating time and generates a signal for computing.
5. The system as claimed in claim 1, wherein the ECU (100) determines status 15 of idle control and generates a signal for detecting malfunction in the vehicle speed sensor (106).
6. A method (200) for detecting malfunction in vehicle speed measurement, the method (200) comprising: 20
determining (201), by clutch pedal switch (105), whether clutch pedal is pressed;
determining (202), by engine speed sensor (107), whether engine speed is between threshold engine speed value 1 and threshold engine speed value 2; 25
determining (203), by vehicle speed sensor (106), whether vehicle speed is between threshold vehicle speed value 1 and threshold vehicle speed value 2;
determining (205), by air intake manifold pressure sensor (109), whether air intake manifold pressure is between threshold air intake 30
20
manifold pressure value 1 and threshold air intake manifold pressure value 2;
determining (209), by coolant temperature sensor (108), whether coolant temperature is above a threshold value;
determining (210) that the vehicle speed sensor (106) has fault when 5 the determined engine speed is in the threshold ranges, the determined vehicle speed is in the threshold ranges, the determined air intake manifold pressure is in the threshold ranges, the coolant temperature is above the threshold value;
detecting, by ECU (100), based upon the determination (210) that a 10 fault in the vehicle speed sensor (106) has occurred when all determinations are true for a predefined time period.
7. The method (200) as claimed in claim 6, wherein the method (200) further comprises:
determining (204), by the engine speed sensor (107), whether rate of 15 change of engine speed is in range between the threshold value 1 and the threshold value 2; and
determining (207) whether engine operating time is more than threshold value;
wherein the rate of change of engine speed determines acceleration 20 pattern of the engine when vehicle is in gear.
8. The method (200) as claimed in claim 6, wherein the method (200) further comprises:
detecting (211), by ECU (100), a malfunction in the vehicle speed sensor (106) when output of all the determination are true for a 25 predetermined time period.
21
9. The method (200) as claimed in claim 6, wherein the method (200) further comprises:
limiting (213) speed of the vehicle by controlling fuel injection and limiting engine speed.
5
10. The method (200) as claimed in claim 6, wherein the method (200) further comprises:
determining (206) whether fuel injection quantity is above a minimum threshold fuel injection value during acceleration of vehicle;
wherein the fuel injection quantity determines actual acceleration of 10 the engine even when the vehicle speed sensor (106) is not working.