TECHNICAL FIELD
[00011 The present subject matter relates generally to an internal combustion engine for a two wheeled vehicle. More particularly but not exclusively, the present-subject matter relates to an ignition system and method for the internal combustion engine of the two wheeled vehicle.
BACKGROUND
|0002] In general, a two-wheeled vehicle with an internal combustion (IC) engine either is mounted to a frame assembly or is swingably supported by a frame assembly of the two-wheeled vehicle. The main parts of the internal combustion (IC) engine include a cylinder head, a reciprocating piston on a cylinder block and a connecting rod which connects the piston to a crankshaft which rotates due to the corresponding reciprocating motion of the piston due to - slider crank mechanism. The internal combustion (IC) engine converts thermal energy obtained from burning of a fuel with an oxidizer (air) into mechanical energy, which can be employed to provide motive force for movement of an automobile. -
[0003] Generally, the internal combustion (IC) engine has to be cranked for it to start. For cranking the engine, a mechanical force is to be provided by the user or through a source of electrical energy. Typically, a kick-start mechanism or an electric start mechanism is provided for cranking the engine. In case of electrical system, an auxiliary power source drives an electrical machine for cranking the engine.
|0004| In addition to cranking system, the vehicle is provided with an ignition system for combustion of air-fuel mixture in a combustion chamber of the internal combustion (IC) engine. Generally, a spark plug is used for providing timely combustion of air-fuel mixture. Therefore, the ignition system plays an important role in the combustion process, which is essential for generating desired power and torque output from the internal combustion (IC) engine.

BRIEF DESCRIPTION OF THE DRAWINGS
[00051 The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference like features arid components.
[0006| Fig. 1(a) illustrates a left side view of an exemplary two-wheeled vehicle, in accordance with an embodiment of present subject matter.
|0007] Fig. 1(b) illustrates a left side of an exemplary internal combustion engine, in accordance with the embodiment of Fig. 1 (a).
[0008| Fig. 2 depicts a schematic view of an ignition system, in accordance with the embodiment of Fig. 1 (b).
[0009| Fig. 3 illustrates a method of operation of the ignition system, in accordance with the embodiment of Fig. I (a).
[00010| Fig. 4(a) depicts exemplary waveforms for ignition timing plotted against time, in accordance with another embodiment of the present subject matter.
[00011| Fig. 4(b) depicts exemplary waveforms for ignition timing plotted against time, in accordance with another embodiment of the present subject matter.
DETAILED DESCRIPTION
[00012J Various features and embodiments of the present subject matter here will be discernible from the following further description thereof, set out hereunder. According to an embodiment, an internal combustion engine (IC) described here operates in four cycles. Such an Internal combustion (IC) engine is installed in a step through type two wheeled vehicle. It is contemplated that the concepts of the present invention may be applied to other types of vehicles such as straddle type vehicle having substantially vertical oriented cylinder axis within the spirit and scope of this invention. Further "front" and "rear", and "left" and "right" referred to in the ensuing description of the illustrated embodiment refer to front and rear, and left and right directions as seen from a rear portion of the Internal combustion (IC) engine and looking forward. Furthermore, a longitudinal axis unless

otherwise mentioned, refers to a front to rear axis relative to the Internal combustion (IC) engine, while a lateral axis unless otherwise mentioned, refers generally to a side to side, or left to right axis relative to the engine. The detailed explanation of the constitution of parts other than the present subject matter which constitutes an essentialpart has been omitted at suitable places.
[00013| Generally, it is cumbersome for the user to start the vehicle using kick-start mechanism, which requires exertion of force on a kick-rod of the kick-start mechanism. Therefore, an electrical machine functioning as a motor for starting the internal combustion (IC) engine is provided, which is referred to as electric starting system. Such electric starting systems are also implemented in small capacity vehicles such as scooter or motorcycles. Generally, a battery is provided on the vehicle for driving the electrical machine as motor. Also, another electrical machine is also provided in the vehicle that is used as a generator, which is-a magneto. The generator is functional during the operation of the internal combustion (IC) engine and the output of the generator is used to charge the battery and/or to drive vehicle loads. However, with the advent of technology, a single electrical machine has come to use that operates both as a starter and as a generator. Depending on application the magneto or the integrated starter-generator are used.
[00014) In general, a four-stroke cycle engine is an internal combustion (IC) engine that has four distinct piston strokes in one complete operation cycle. These four distinct piston strokes are: an intake stroke is when an air-fuel mixture is introduced to fill a combustion chamber as a piston moves from Top Dead Centre (TDC) to Bottom Dead Centre (BDC); a compression stroke is when the trapped air-fuel mixture is compressed inside the combustion chamber and the piston moves from Bottom Dead Centre (BDC) to Top Dead Centre (TDC); a power stroke in which hot expanding gases force the piston away from Top Dead Centre (TDC); and an exhaust stroke is when spent gases are expelled from the combustion chamber and released to the atmosphere. During these four strokes, the piston make two complete passes in the cylinder to complete one operating

cycle. An operating cycle requires two revolutions (720°) of the crankshaft. The four-stroke cycle engine is the most common type of internal combustion (!C) engine in the two-wheeled vehicle.
[00015] Generally, the internal combustion (IC) engine is provided with an ignition system with one or more spark plugs provided for generation of one or more sparks. Timing of spark generation is an essential aspect of the spark ignition systems as the ignition system is functioning during entire running state of the internal combustion (IC) engine. The ignition system is capable of affecting the performance, efficiency, fuel consumption, and exhaust emission of the internal combustion (IC) engine. Especially, in cases of starting the vehicle at conditions like cold start. Generally, the ignition system uses information coming from crankshaft speed sensor to produce high voltage accordingly across electrodes of the spark plug(s), which in turn generates spark for initiating combustion of air-fuel mixture process towards the end of the compression stroke of the internal combustion (IC) engine.
|000l6j To this end, the two-wheeler is a low cost vehicle and also having a compact layout. Such vehicles are provided with a carburetor for mixing the air from intake path and fuel from fuel tank, thereafter delivering the air-fuel mixture to the intake manifold of the internal combustion (IC) engine. During the internal combustion (IC) engine starting, the ignition timing will be close to the Top Dead Center (TDC) of a piston of the internal combustion (IC) engine to generate maximum power during the power stroke. Generally, with the increase in an engine speed, the ignition timing is advanced to complete combustion process before the start of the power stroke. So, there is no spark in general during the power stroke.
100017] In general, during starting of the internal combustion (IC) engine, especially during cold-start, friction will be high in combustion chamber and the air-fuel mixture condensation will also be high affecting smooth starting of the engine. Conventionally, a choke provided in the carburetor, which can be either manually or automatically controlled, is used to increase air-fuel mixture quantity

during starting so that the engine can warm up. However, this increases fuel consumption during starting. Moreover, a manual choke will require rider to operate the choke during engine starting, which is cumbersome. In some situations, it is also possible that user might not remember to use the choke. In addition, repeated starting attempts without application of choke further results in cold start emissions and fuel consumption. Use of an automatic choke control increases the cost of the system and also the carburetor design becomes complicated in the low-cost and the compact two-wheeled vehicles. Further, in cold start condition, the engine speed is unstable and ignition timing is varied erratically in a closed loop engine speed control due to which starting is not achieved quickly.
[00018| In some of the internal combustion (IC) engine to address the above-mentioned problem, ignition timing is at a higher advance angle for higher power due to combustion at the start of power stroke. Further, the change in ignition timing also provides better drivability. However, the higher advance angle for ignition timing causes vibration and noise in the internal combustion (IC) engine which further leads to deteriorated durability and reliability of in the internal combustion (IC) engine. Furthermore, such advancement in ignition timing also increases cost of the system and affects the compact layout of the internal combustion (IC) engine.
|00019] Thus, there is a need for an ignition system that can start, the engine quickly without increasing cost of the system and deteriorating durability and reliability of in the internal combustion (IC) engine. Moreover, the ignition control should enable retaining of the current engine design.
|00020| Hence, it is an object of the present subject matter to address the aforementioned and other problems in the prior art. Therefore, the present subject matter provides an ignition method and a system thereof for staring an internal combustion engine.
[000211 It is an aspect of the present subject matter that the ignition system generates maximum power in the internal combustion (IC) engine with maximum

combustion of fuel-air mixture at the start of the power stroke thereby providing improved durability and reliability of in the internal combustion (IQ engine.
[00022| In one embodiment, the ignition system and method begins with calculating the engine speed and comparing the engine speed with a first predetermined value of engine speed. On the basis of the comparison, delivering a first spark at a first angle of the crankshaft before the piston reaches top dead center in compression stroke takes place. Then, delivering of second spark occurs after the piston passes top dead center in the power stroke for maximum combustion of fuel-air mixture to generate maximum power in the internal combustion (IC) engine. The second spark in the power stroke come when the engine speed is lesser then the first predetermined value of engine speed. Subsequently, when the engine speed is more than the first predetermined value of engine speed and falls within a predetermined range of engine speed then delivering of second spark occurs before the piston passes top dead center in the compression stroke. Apart, from these two conditions there is only delivering of a first spark at a first angle of the crankshaft before the piston reaches top dead center in compression stroke. So, in present embodiment the ignition system provides flexibility to deliver or not to deliver second spark in the internal combustion (IC) engine in compression stroke or in power stroke based on the engine speed. Further, in present embodiment, the ignition system is providing the better start-ability, drive-ability, durability and reliability of in the internal combustion (IC) engine by retaining the current engine design. The current engine design includes single spark plug, single capacitor, single inductor and other parts. However, the claimed ignition method and system is not limited to only single spark plug, single capacitor and single inductor.
[00023| It is an aspect of the present subject matter that the engine speed is calculated from the engine speed signal acquired from a rotor coupled to the crankshaft.
|00024] It is an aspect of the present subject matter that the first predetermined value of engine speed is less than the predetermined range of engine speed.

[00025| It is advantage of the present subject matter that the ignition method eliminates stalling of the engine during starting by reducing retarding forced acting on the piston before reaching top dead center. Further, it also improves life of the parts thereof.
1000261 It is an effect of the present subject matter that the ignition method improves stability of the engine speed thereby enabling in improved starting of internal combustion (IC) engine.
|00027| It is an advantage of the present subject matter that the ignition system is cost effective as the ignition system uses crankshaft speed sensor like a pulser coil.
|00028| It is yet another advantage of the present subject matter that the ignition system is compact and is implementable in a compact vehicle like scooter, motorcycle, or a three-wheeler.
[00029] It is an additional aspect that the present subject matter retains the current engine design, as the system does not require additional sensors like heat sensor.
[00030| It is yet another, advantage of the present subject matter that the ignition system provides improved starting thereby providing ease of starting or improvement in start-ability and improved vehicle usage experience to user.
[00031| It is also another advantage that the ignition system generates maximum power in the internal combustion (IC) engine with maximum combustion of fuel-air mixture at the start of the power stroke thereby providing improved durability and reliability of in the internal combustion (IC) engine.
[00032] The present subject matter is applicable to both carburetor based and fuel injector based systems.
[000331 The aforesaid and other advantages of the present subject matter would be described in greater detail in conjunction with the figures in the following description.

(00034) Fig. 1(a) illustrates a left side view of a two-wheeled vehicle (100) typically called a motorcycle, in accordance with an embodiment of the present subject matter. A frontward direction is indicated by an arrow F, and a rearward direction indicated by an arrow R provided in the top center of first figure. The vehicle is extending from the front direction to the rear direction along the vehicle longitudinal axis (F-R). In an embodiment; the two-wheeled vehicle (100) of the present subject matter includes an internal combustion (IC) engine (125). The two-wheeled vehicle (100) further includes a front wheel (112), a rear wheel (122), a frame unit (105), a fuel tank (103) and seat (106). The frame unit (105) includes a head pipe (101), a main tube (102), a down tube (116), and a pair of rear tubes (104). The head pipe (101) supports a steering shaft (121) with two . brackets - upper bracket (not shown) and lower bracket (147) at each end for rotating the two-wheeled vehicle (100). Two telescopic front suspension (144) (only one shown) is attached to the lower bracket (147) on which is supported the front wheel (112). The upper portion of the front wheel (112) is covered by a front fender (119) mounted to the lower portion of a front fork of the telescopic front suspension (144). A headlamp assembly (139) is disposed in the front portion of the head tube (101). An exhaust assembly (not shown) is attached to the internal combustion engine (125) at a front end of the internal combustion engine (125) and extends rearwards from one side of the two wheeled vehicle in the opposite direction of the chain (in the present embodiment, the exhaust assembly is disposed towards the right side of the vehicle in the width direction). Down tube (116) is disposed in front of the IC engine (125) and stretches slantingly downward from head pipe (101). Main tube (102) is located above the internal combustion engine (125) and stretches rearward from head pipe (101) and connects to the rear of the internal combustion engine (125). The pair of rear tubes (104) is joined near to the middle of the main tube (102) and stretches rearward. The pair of rear tubes (104), which are joined to the main tube (102) and stretching rearward to support a seat assembly (106) disposed above these pair of rear tubes. Generally, two rear wheel suspensions (113) (only one shown) are arranged between rear swing arm. A tail lamp assembly (108) is disposed on the

rear end of the seat assembly (106). A grab rail (107) is also provided on the rear of the seat assembly (106). Rear wheel (122) is arranged below seat assembly (106) and rotates by the driving force of the internal combustion engine (125) transmitted through a chain drive (114) from the internal combustion engine (125). A rear fender (109) is disposed above the rear wheel (122) and attached to the pair of rear tubes (104). The internal combustion engine (125) includes an air intake system (not shown), an air fuel supply system (not shown) that are coupled to an intake side of the internal combustion engine (125) and are disposed on the internal combustion engine (125). Also, an exhaust system (not shown) is coupled to exhaust side of the internal combustion engine (125) and the exhaust system (not shown) extends towards one lateral side of the two-wheeled vehicle (100). Hereinafter, the term two-wheeled vehicle (100) is used interchangeably as the vehicle (100)'
(00035| Fig. 1 (b) depicts a left side view of an exemplary internal combustion engine, in accordance with the embodiment depicted in Fig. 1 (a). The internal combustion engine (125) includes a crankcase (125A) comprising at least two portions including plurality of apertures and mounting portion for rotatably supporting various components including a crankshaft (125B). The crankshaft (125B) is rotatably supported by the crankcase (125A) and the crankshaft (125B) is connected to a piston (not shown) having a reciprocating motion about a cylinder portion (CP) therein. The reciprocating motion of the piston (not shown) is converted into a rotating motion of the crankshaft (125B) through four piston strokes. These four distinct piston strokes are: an intake stroke is when an air-fuel mixture is introduced to fill a combustion chamber as a piston moves from Top Dead Centre (TDC) to Bottom Dead Centre (BDC); a compression stroke is when the trapped air-fuel mixture is compressed inside the combustion chamber and the piston moves from Bottom Dead Centre (BDC) to Top Dead Centre (TDC); a power stroke in which hot expanding gases force the piston away from Top Dead Centre (TDC); and an exhaust stroke is when spent gases are expelled from the combustion chamber and released to the atmosphere. During these four strokes, the piston (not-shown) make two complete passes in the cylinder portion (CP) to

complete one operating cycle. An operating cycle requires two revolutions (720°) of the crankshaft (125B). The four-stroke cycle engine is the most common type of internal combustion engine (125) in the two-wheeled vehicle (100).
[000361 Further, the cylinder portion (CP) includes a cylinder body (125CA) and a cylinder head (125CB) that are supported by the crankcase (125A). The internal combustion engine (125) is connected svvingably or through a revolute joint (not shown) to the frame unit (105) through an aperture portion (125F) provided on the crankcase (125A). Further, the internal combustion engine (125) includes an air-fuel supply means (125D) that includes a carburetor (not shown) or a fuel injector (not shown). Furthermore, an ignition system (not shown) means including a spark plug (not shown) is provided for generation of one or more sparks for combustion of air-fuel mixture in the internal combustion engine (125)
|00037| Further, the crankshaft (125B) is mounted with an electrical machine (125E). In one embodiment, the electrical machine (125E) is connected to the crankshaft through gear or a belt. In a preferred embodiment, the electrical machine (125E) is a magneto (125E). Hereinafter, the terms electrical machine (125E) and magneto (125E) are interchangeably used. The magneto (125E) includes a rotor (not shown) and a stator (not shown). The rotor (not shown) is connected to the crankshaft (125B). The rotor (not shown) includes magnetic members and the stator (not shown) is provided with plurality of windings (not shown). A starter motor enables rotation of the crankshaft (125B) for cranking the internal combustion engine (125) and an ignition system (200) (shown in Fig. 2) enables delivering of spark.
1000381 Fig. 2 depicts a schematic view of an ignition system for the internal combustion engine (125) of the two-wheeled vehicle (100), in accordance with the embodiment of Fig. 1 (b). The ignition system (200) includes a magneto (125E) coupled to the crankshaft (125B) for generating electricity based on mechanical energy available at the crankshaft (125B) of the internal combustion engine (125). In another embodiment, an integrated starter generator (ISG) is coupled to the crankshaft (125B) of the internal combustion engine (125). The rotating magnetic

field produced due to rotation of the crankshaft (125B) generates alternating current (AC) voltage across coils (205) wound to the stator. The voltage from the coils it rectified and regulated by a regulator and rectifier (RR) unit (210) for the auxiliary power source (215), which is a battery (215) in the present embodiment. In another embodiment, the auxiliary power source can be a fuel cell or a hydrogen cell. The battery (215) and the output of RR unit (210) are capable of driving various direct current (DC) loads (220) of the two-wheeled vehicle (100). Further, the ignition system (200) includes an ignition control unit (ICU) (225), wherein either the battery (215) or the RR unit (210) drives the ignition control unit (225). Further, a fuse (230) is provided to protect wires and other components against a short circuit condition of the battery (215). Also, the two-wheeled vehicle (100) may include AC loads (235) that are driven by the RR Unit (210), wherein regulated AC voltage is supplied to the AC loads (235).
[00039| Further, the rotor of the magneto (125E) includes a ferromagnetic pip (240) provided on the outer periphery of the rotor. The pip (240) works in conjunction with a pulser coil (245), wherein the pip (240) and the pulser coil (245) enable detection of the position of the rotor of the magneto (125E) being analogous to position of the crankshaft (125B). Furthermore, the ignition system (200) includes an ignition coil (250) including a primary winding and a secondary winding. The ignition coil (250) uses energy stored in a capacitor or an inductor to generate a spark. The ignition control unit (225) is capable of actuating the primary winding that further generates high voltage across a spark plug (255) connected to the secondary. In one embodiment, a suppressor resistor (260) limits a spark current for reducing any electromagnetic interference. The stroke of the internal combustion engine (125) or the piston position is determined by the ignition control unit (225) from the pulser coil (245) signal
[00040| Fig. 3 depicts the method of operation of the ignition system (200), in accordance with the embodiment as depicted in Fig. 1(A). The two-wheeled vehicle (100) includes a key for activating ignition of the internal combustion engine (125). The key can be a physical key or a wireless key that is detected by

the two-wheeled vehicle (100). Further, the two-wheeled vehicle (100) includes an ignition switch (not shown). In one embodiment, the two-wheeled vehicle (100) is also provided with an electric start switch (ESS) (not shown). The electric start switch enables starting of the internal combustion engine (125). Upon receiving electric start input from the user, the ignition system (200) enables cranking of the internal combustion engine (125).
|000411 The ignition control unit (225) receives signal from the pulser coil (245). The rotor of the magneto (125E) is provided with the magnetic pip (240). The four-cycles of the IC engine (125) results in two complete rotations of the crankshaft (125B). Therefore, the magnetic pip (240) working in conjunction with the pulser coil (245) provides the relative position of the piston. The piston has a reciprocating motion, moving between a top dead center (TDC) and a bottom dead center (BDC) within the combustion chamber. The pulser coil (245) provides signal to the ignition control unit (225) for delivering ignition.
[00042| So, once the ignition switch gets ON, the process begins through step (S305), where the ignition control unit (225) receives signal from pulser coil (245). At step (S310), the ignition control unit (225) calculates an engine speed from signal received from the pulser coil (245). The engine speed is analogous to the rotations per minute (RPM) of the crankshaft (125B). Hereinafter, the terms engine speed, engine RPM, crankshaft speed, or crankshaft RPM are interchangeably used. Further, the ignition control unit (225) compares the calculated engine speed with a first predetermined value of engine speed, at step (S315). Once the ignition control unit (225) detects that the engine speed is lesser than the First predetermined value of engine speed, at step (S320), the ignition control unit (225) enables delivering of first spark from the ignition coil (250) at a first angle of the crankshaft (125B) which is delivered during the compression stroke and delivering of second spark from the ignition coil (250) at a second angle of the crankshaft (125B) which is delivered in beginning of the power stroke. In one embodiment, the first angle is also termed as a base angle. In terms of the four-stroke cycle, at step (S320), the first spark from the ignition coil (250)

comes before top dead center (TDC) at the end of the compression stroke and the second spark from the ignition coil (250) comes after top dead center (TDC) at the beginning of the power stroke. This ensures maximum combustion of fuel-air mixture inside the combustion chamber to generate maximum power in the internal combustion (1C) engine. Due to maximum combustion of fuel-air mixture inside the combustion chamber, cold start-ability and cold recovery of the internal combustion (1C) engine also got improved.
|00043| Furthermore, at step (S315), upon detection of the engine speed being greater than the first predetermined value of engine speed, the ignition control unit (225) moves to step (S325). At step (S325), the ignition control unit (225) compares the engine speed with the first predetermined value of engine speed and if the engine speed is more than the first predetermined value of engine speed and falls within a predetermined range of engine speed then the second spark during compression stroke occurs. In present embodiment, the predetermined range of engine speed is higher than the first predetermined value of engine speed. Upon detection of the engine speed being more than the first predetermined value of engine speed and not falling within a predetermined range of engine speed then the ignition control unit (225) modifies the angle of crankshaft at which the ignition coil (250) only delivers first spark in compression stroke. But once the higher engine speed falls within the predetermined range of engine speed then the ignition coil (250) delivers first and second spark in compression stroke, as shown at step (S345). In a preferred embodiment, the delivering of the ignition coil (250) is advanced upon detection of the engine speed more than the first predetermined value of engine speed. In other words, only one spark occurs in compression stroke during the four-stroke cycle when the engine speed is more than the first predetermined value of engine speed and not falling within the predetermined range of engine speed. However, at step (S345), two sparks occur in compression stroke i.e. the first spark and the second spark coming from the ignition coil (250) before top dead center (TDC) at the end of the compression stroke. This enables occurrence of combustion of air-fuel mixture at a position of the piston so as to increase the engine speed. Due to dual spark in the compression stroke at the high

engine speed, there is a reduction in the internal combustion (IC) engine (125) vibrations and noise which improves the drive-ability of the vehicle (100). Further, the first predetermined value of engine speed and the predetermined range of engine speed vary in accordance with variations in the internal combustion (IC) engine (125) design and specifications. In present embodiment, the first predetermined value of engine speed is 800 rpm and the predetermined range of engine speed lies between 2900-7300 rpm.
|00044] At shown in step (S325), upon detection of the engine speed being more than the predetermined value of engine speed and not falling within the predetermined range of engine speed, then step (S330) takes place, at step (S330) the ignition control unit (225) through the ignition coil (250) delivers only one spark during the compression stroke. Since at step (S330), the ignition control unit " (225) gives a single spark with an aim to reduce vibrations and noise for the internal combustion (IC) engine (125). Further, the ignition control unit (225) enables delivery of spark or sparks from the ignition coil (250) based on various engine parameters including throttle position, engine speed, or load.
100045] Fig 4(a) and Fig 4(b) depicts exemplary waveforms for ignition timing plotted against time, in accordance with an embodiment of the present subject matter. The ignition method with two sparks provision improves combustion of air-fuel mixture in the combustion chamber. The upper-most waveform in both the figures Fig 4(a) and Fig 4(b) is the pulser coil (245) waveform to indicate the position of top dead center (TDC) and Bottom dead center (BDC). In the pulser coil (245) waveform top dead center (TDC) is shown by a highest rise in waveform. Further, the bottom-most waveform in both the figures Fig 4(a) and Fig 4(b) is a secondary voltage waveform which represents the first spark and second spark through two different dips in waveform.
[00046| In one embodiment as shown in Fig 4(a), the waveforms are showing the provision of the first spark before top dead center (TDC) at the end of the compression stroke and the second spark after top dead center (TDC) at the beginning of the power stroke. For example, the waveform shown in Fig 4(a) is

drawn at the first predetermined value of engine speed is 800 RPM. The base angle for delivering the ignition coil (250) is set to 5 degrees before TDC. Upon detecting the engine speed being below 800 RPM, the first spark is produced at 5 degrees before top dead center (TDC) then the second spark is produced at 5 degrees after top dead center (TDC). So the first spark is delivered towards the end of compression stroke and the second spark is delivered in the beginning of power stroke, thereby causing maximum combustion of air-fuel mixture in the combustion chamber. This results in the improved cold start-ability and cold recovery of the internal combustion (1C) engine (125).
[00047] In one embodiment as shown in Fig 4(b), the waveforms are showing the provision of the first spark and the second spark before top dead center (TDC) at the end of the compression stroke. For example, the waveform shown in Fig 4(b) is drawn at the predetermined range of engine speed lies between 2900-7300 RPM. Upon detecting the engine speed is falling between 2900-7300 RPM, then the ignition control unit (225) enables said ignition coil (250) to deliver the first spark and the second spark in the compression stroke of the internal combustion (IC) engine (125). The presence of dual spark in compression stroke only for the predetermined range of engine speed provides maximum combustion of air-fuel mixture in the combustion chamber. This results in reduction of the engine noise and vibrations and improves the drive-ability of the vehicle (100).
|00048| Further, if the engine speed is found more than 2900-7300 RPM by the ignition control unit (225), then only one spark or the first spark is delivered in the compression stroke. Furthermore, the present subject matter is applicable to electronic spark ignition including Transistor Controlled Ignition (TCI), Capacitive Discharge Ignition (CDI), and Inductive Discharge Ignition (1D1) with single or multiple spark plugs.
|00049] Many modifications and variations of the present subject matter are possible in the light of above disclosure. Therefore, within the scope of claims of the present subject matter, the present disclosure may be practiced other than as specifically described.

We claim:
1. An ignition system (200) for an internal combustion (IC) engine (125) of a
vehicle (100).comprising:
an ignition coil (250) to generate a spark through energy stored in a capacitor or an inductor based on signal received from an ignition control unit (225); and
the ignition control unit (225) is configured to receive engine speed signal from a pulser coil (245); wherein,
the ignition control unit (225) enables the ignition coil (250) to deliver a first spark in a compression stroke of the internal combustion (IC) engine (125) and a second spark in a power stroke of the internal combustion (IC) engine (125) upon detection of an . engine speed is lesser than a first predetermined value of engine speed.
2. The ignition system (200) of an internal combustion (IC) engine (125) of the vehicle (100) as claimed in claim I, wherein a magneto (125B) comprises a magnetic pip (240) to work in conjunction with the pulser coil (245);
3. The ignition system (200) of an internal combustion (IC) engine (125) of the vehicle (100) as claimed in claim 1, wherein the ignition control unit (225) detects that the engine speed is more than the first predetermined value of engine speed and falls within a predetermined range of the engine speed, thereby the ignition control unit (225) enables the ignition coil (250) to deliver the first spark and the second spark in the compression stroke of the internal combustion (IC) engine (125).
4. The ignition system (200) of an internal combustion (IC) engine (125) of the vehicle (100) as claimed in claim I, wherein the ignition control unit (225) detects that the engine speed is more than the first predetermined value of engine speed and does not fall within the predetermined range of

the engine speed, thereby the ignition controi unit (225) enables the ignition coil (250) to deliver only the first spark in the compression stroke of the internal combustion (IC) engine (125).
5. The ignition system (200) of an internal combustion (IC) engine (125) of the vehicle (100) as claimed in claim I, wherein the predetermined range of engine speed is higher than the first predetermined value of engine speed.
6. The ignition system (200) of an internal combustion (IC) engine (125) of the vehicle (100) as claimed in claim I, wherein the ignition coil (250) uses only a single capacitor or single a inductor to generate a spark by means of energy stored in the single capacitor or the single inductor.
7. The ignition system (200) of an internal combustion (IC) engine (125) of the vehicle (100) as claimed in claim 1, wherein the first predetermined value of engine speed and the predetermined range of engine speed vary in accordance with variations in the internal combustion (IC) engine (125) design and specifications.
8. The ignition system (200) of an internal combustion (IC) engine (125) of the vehicle (100) as claimed in claim I, wherein the first predetermined value of engine speed is 800 rpm and the predetermined range of engine speed lies between 2900- 7300 rpm
9. A method for improving an ignition system (200) of an internal combustion (IC) engine (125) of a vehicle (lOO)comprising:
detecting a starting signal for starting of an ignition control unit
(225);
sending an engine speed signal from a pulser coil (245) to the
ignition control unit (225);
comparing the engine speed with a first predetermined value of
engine speed;
delivering a first spark in a compression stroke of the internal
combustion (IC) engine (125) and a second spark in a power stroke

of the internal combustion (IC) engine (125) by an ignition coil (250) upon detection of the engine speed is lesser than the first predetermined value of engine speed; and
delivering the first spark and the second spark in the compression stroke of the internal combustion (IC) engine (125) by the ignition coil (250) upon detection of the engine speed is more than the first predetermined value of engine speed and fall within a predetermined range of engine speed.
10. The method for improving the ignition system (200) of the internal combustion (IC) engine (125) of the vehicle (100) as claimed in claim 9, wherein the ignition coil (250) uses only a single capacitor or a single inductor to generate a spark in a combustion chamber of the internal combustion (IC) engine (125) by means of energy stored in the single capacitor or the single inductor. -
11. The method for improving the ignition system (200) of the internal combustion (IC) engine (125) of the vehicle (100) as claimed in claim 9, wherein the ignition coil (250) delivers the first spark in the compression stroke of the internal combustion (IC) engine (125) upon detection of the engine speed is more than the first predetermined value of engine speed and not falling within the predetermined range of engine speed.'