FIELD OF INVENTION

The subject matter described herein, in general, relates to a switch assembly and in particular relates to a switch assembly for terminating an ignition process in an engine.

BACKGROUND

Internal combustion (IC) engine in light vehicles, such as a car or a motorcycle, typically include a fuel ignition system to accomplish a fuel ignition process. These vehicles include a vehicle starter system to initiate operations of the engine. For the purpose, the vehicle starter system has a battery powered starter motor, which cranks the engine till the fuel ignition process becomes self-sustaining.

Typically, the vehicle starter system is provided with a start switch to activate the starter motor. An ignition switch provided in the vehicles also activates the starter motor. Specifically, an ON state of both the ignition switch and the start switch signals the fuel ignition system to allow the fuel ignition process. An OFF state of either of these switches disallows the fuel ignition process.

In addition, some vehicles are also provided with a kill-switch as an additional feature to activate the fuel ignition process. Specifically, an ON state of the kill-switch signals the fuel ignition system to terminate the fuel ignition process irrespective of the slate of the ignition switch and the start switch. Whereas, an OFF state of the kill switch causes the ignition switch and the start switch to activate the fuel ignition process as aforesaid. The kill-switch may be used for purposes including emergency stopping, long duration parking, preventing vehicle theft, etc.

As the vehicle starter system operates independent of the state of the kill-switch, it is possible to initiate the starter motor by the start switch even when the kill-switch is in the ON state. This causes the battery-powered starter motor to run even when the fuel ignition process is disallowed due to the ON state of the kill-switch. This results in futile cranking of the engine and wastage of battery power.

There can be also a situation where the kill-switch is either inadvertently switched ON or is unknowingly left in the ON state by a user. In such a case, the user may keep trying to crank the engine through the vehicle starter system. This would again lead to the futile cranking of the engine without producing any positive result. Such a situation may also cause the user to doubt the vehicle's performance and may create an unwarranted dilemma.

To overcome similar issues, double-pole-double-throw (DPDT) switches have been employed in heavy vehicles to provide a dual switching feature for controlling the operations of the engine-starter motor combination. For the purpose, two separate pair of contact terminals exist for separately implementing a kill-switch circuit and a starter system circuit. These switches not only terminate the fuel ignition process within the engine, but also disable the operation of the starter motor. However, implementation of a DPDT switch is not feasible in light vehicles due to its high cost and large size.

SUMMARY

The subject matter described herein is directed to a switch assembly for terminating ignition of an engine. The switch assembly includes a starter relay, which is connected to a power source, for example, a battery, and a kill-switch. The switch assembly further includes a cut off sensor connected to the kill-switch for sensing a state of the kill-switch. The kill-switch, in an ON state, connects the cut off sensor to a ground terminal and disables ignition of the engine. Moreover, while being in the ON state, the kill-switch disconnects the starter relay from the ground terminal to disable operation of a starter motor, which is also connected to the power source.

The switch assembly as described herein implements a dual kill feature for implementation in various fuel ignition systems including alternating current (AC) signal based fuel ignition systems. In addition, the kill-switch of the switch assembly is compact in size and simple in design.

These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF DRAWINGS

The above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description, appended claims, and accompanying drawings where:

Fig. 1 illustrates a block diagram representation of a switch assembly implementing a kill-switch for an engine, according to an embodiment of the present subject matter.

Fig. 2a is a top view of a two-wheeler assembly implementing the switch assembly of Fig. I, according to an embodiment of the present subject matter.

Fig. 2b is an isometric view of the two-wheeler assembly of Fig. 2a, according to an embodiment of the present subject matter.

DETAILED DESCRIPTION

The disclosed subject matter relates to a switch assembly incorporating a kill-switch for terminating a fuel ignition process in an engine of a vehicle.

Kill-switches in conventional vehicles are used for disabling the operation of a starter motor of the vehicle in addition to terminating fuel ignition. This dual functionality in a conventional kill-switch is accomplished by employing a relay in addition to a primary relay already present in existing kill-switch circuits. The additional relay has one normally open (NO) & one normally closed (NC) connection. However, such an implementation not only proves costly, but also complex and cumbersome to install, given the space constraints of a typical kill-switch circuit.

Another way of implementing this dual functionality in an existing vehicle is through disconnecting power supplies to a fuel ignition system and a starter circuit of the vehicle through a switch having a single contact mechanism. However, this implementation is not realizable in vehicles having an alternating current (AC) signal based ignition system. In addition, the kill-switch required to control power supply is generally of a high contact rating, thereby incurring a high manufacturing cost.

The present subject matter describes a switch assembly for use in light vehicles, such as cars, scooters, and motorcycle. The switch assembly, when implemented in a vehicle, abruptly shuts down all operations of the vehicle, whenever required, for example, while idling at a traffic signal. For the purpose, the switch assembly comprises a kill-switch, which can be placed in an ON state by a user, for example, a rider of the vehicle. In its ON state, the kill-switch shuts down the engine and prevents any further ignition inside the engine. In addition, the starter motor is also rendered non-operational as long as the kill-switch is in the ON state, thereby making the vehicle completely idle.

The kill-switch of the present switch assembly is compact, light weighted, and specially designed for use in cars, scooters, motorcycles, etc. In addition, the present kill-switch is compatible with AC signal based fuel ignition systems. Moreover, the kill-switch of the present switch assembly has a low contact rating, therefore its manufacturing cost is also low.

For the purposes of explanation, the switch assembly is explained herein in context of a two-wheeled vehicle. However, it will be appreciated that the present switch assembly may also be employed for terminating the fuel ignition process in the engine of four-wheeled vehicles and other heavy vehicles, and non-terrestrial vehicles as well.

Figure 1 depicts a block diagram representation of an exemplary switch assembly 100 for an IC engine, according to an embodiment of the invention. As depicted in Fig 1, each block of the switch assembly 100 represents a component involved in the operation of the switch assembly 100. The switch assembly 100 may also be interchangeably referred to as a kill-switch assembly 100. For the purpose of explanation, the switch assembly 100 may be considered as including three separate circuits: a starter circuit, a controller circuit, and an ignition cut-off circuit.

In an implementation, the starter circuit includes a power source 102, a starter relay 104, and a starter motor 106. The power source 102 may be interchangeably referred to as battery 102. When the starter circuit is closed, power from the battery 102 is supplied to the starter motor 106 to crank the IC engine. As known in the existing art, the starter motor 106 is operably coupled to a piston of the IC engine. Accordingly, the activation of the starter motor 106 makes the piston undergo a reciprocating motion. As the IC engine enters into an ignition phase of its operation, the piston starts reciprocating under the influence of combustion of fuel and the starter motor 106 gets deactivated automatically.

Further, the controller circuit controls the starter circuit and, in one implementation, includes an ignition switch 108, a start switch 110, the starter relay 104, and a kill-switch 112. The controller circuit is connected to the power source 102 for its operation and is designed in a way such that the starter circuit is closed only when the controller circuit is closed. This functionality is implemented through the starter relay 104, which is a shared component between the starter circuit and the controller circuit.

Similarly, the ignition cut-off circuit includes a cut off sensor 114, an engine control unit 116, the ignition switch 108, and the kill-switch 112. The ignition switch 108 and the kill-switch 112 are shared components between the controller circuit and the ignition cut-off circuit. The ignition cut-off circuit is connected to the power source 102 for its operation and functions to disallow a fuel ignition process in the engine whenever the cut off sensor 114 is grounded via either the ignition switch 108 or the kill-switch 112.

Further, the engine may have additional circuitry to charge the power source 102. Such circuitry may help, as known in the art, in harnessing the electrical energy generated by a dynamo or magneto connected to the engine, Further, the power source 102 is connected at a power input terminal I of the starter relay 104. A terminal J of the starter relay 104 is connected to the starter motor 106.

The starter relay 104 is a contactor-type relay having terminals G, H, the terminal I and the terminal J. In operation, the terminals I and J are part of the starter circuit and the terminals G and H are part of the controller circuit. In operation, the starter relay 104 functions in a way such that when a connection between the terminal G and the terminal H is energized, i.e., when the controller circuit is closed, the connection between the terminal I and the terminal J is enabled. Such a connection activates the starter motor 106 to crank and subsequently start the engine.

In the controller circuit, the power source 102 is connected to a terminal D of the ignition switch 108. The ignition switch 108 has a terminal C connected to a terminal E of the start switch 110. The start switch 110 has a terminal F, which connects to the terminal G of the starter relay 104. The terminal G is internally connected to the terminal H of the starter relay 104. The terminal H is further connected to a terminal K of the kill-switch 112. The kill-switch 112 has a terminal L, which is connected to a ground terminal 113.

In operation, the ignition switch 108, the start switch 110, and the kill-switch 112 may be turned ON or OFF in order to fulfill functional requirements of the engine. For example, turning the ignition switch 108 ON indicates a decision to allow the fuel ignition process to take place, while turning the ignition switch 108 OFF indicates a decision to turn off the fuel ignition process. Similarly, turning the start switch 110 ON indicates the need to crank the engine, while turning the kill-switch 112 ON indicates the need to terminate the fuel ignition process of the engine, immediately. In another implementation, the ignition switch 108 and the start switch 110 may be combined and implemented as a single switch, as will be easily understood by a person skilled in the art. A decision to turn ON or OFF the aforementioned switches may be taken by a user or by an on-board computer present within the vehicle.

The controller circuit operates to control the operation of the starter motor 106 in a way such that the starter motor 106 is activated only when both the ignition switch 108 and the start switch 110 are in the ON state, and the kill-switch 112 is in the OFF state. If any of these switches is in a different state, the controller circuit remains open, thereby disabling the operation of the starter motor 106. In one implementation, the ignition switch 108 may be turned ON or OFF by the user through means such as an ignition key.

The terminals C and D of the ignition switch 108 are part of the controller circuit and terminals A and B of the ignition switch 108 are part of the ignition cut-off circuit. When the ignition switch 108 is turned ON by the user, the terminals C and D are connected and the terminals A and B are disconnected. When the ignition switch 108 is turned OFF, the terminals C and I) are disconnected and the terminals A and B are connected. The terminal A of the ignition switch 108 is connected to the cut off sensor 114, whereas the terminal B is connected to the ground terminal 113.

Typically, the ignition switch 108 is turned ON to allow the fuel ignition process and is kept in the ON state during the operation of the engine. When the user desires to stop the engine, the ignition switch 108 is turned OFF, thereby connecting the cut off sensor 114 to the ground terminal 113 to terminate the fuel ignition process.

As mentioned before, the ignition switch 108 has the terminal C connected to the terminal E of the start switch 110. The start switch 110 may be a user activated switch, which switches the connection between the terminals E and F. When the start switch 110 is turned ON, the connection between the terminals E and F is established and when the start switch 110 is OFF, this connection is broken. At the user end, the start switch 110 is turned ON by the user when the starter motor 106 is desired to be operated for the purpose of commencing the operation of the engine.

Further, as aforementioned, the start switch 110 has the terminal F connected to the terminal G of the starter relay 104. The starter relay 104 has the terminal H connected to the terminal K of the kill-switch 112. In one implementation, the kill-switch 112 may be a user activated two-way switch, such as a single pole double throw (SPDT) switch. The terminal L of the kill-switch 112 is a common terminal of the SPDT configuration of the kill-switch 112 and is connected to the ground terminal 113, As known in the existing art, the common terminal is generally referred to as a pole.

In accordance with the state of the kill-switch 112 as set by the user, the terminal L may either be connected to the terminal K or the terminal M of the kill-switch 112. Accordingly, when the state of the kill-switch 112 is set as OFF by the user to indicate that an engine kill operation is not required, the terminals K and L are connected.

This type of connection between the terminal K and the terminal L leads to a connection of the controller circuit with the ground terminal 113, thereby completing the controller circuit. In other words, the kill-switch 112 controls a ground signal supply to the controller circuit. Specifically, the starter relay 104 is connected to the ground signal supply through the kill-switch 112 in the OFF state of the kill-switch 112. As mentioned before, the starter relay 104 acts as a component of the controller circuit. Accordingly, the kill-switch 112 controls the ground signal supply to the starter relay 104, and thereby to the controller circuit.

Under normal circumstances or by default, the kill-switch 112 is in the OFF state. When the user turns the kill-switch 112 into the ON state, the terminals L and M get connected, and this leads to the connection of the cut off sensor 114 with the ground terminal 113, This further leads to disconnection of the controller circuit from the ground terminal 113, thereby opening the controller circuit. Accordingly, the turning ON of the kill-switch 112 by the user ensures that the controller circuit remains open, thereby leading to an open state of the starter circuit.

In the ignition cut-off circuit, the cut off sensor 114 is directly connected at one end to the engine control unit 116, while the other end is connected to the terminal A of the ignition switch 108. From this other end, the cut off sensor 114 is also connected to the terminal M of the kill-switch U2.

In operation, by controlling the states of either the ignition switch 108 or the kill-switch 112, the cut off sensor 114 may be grounded, i.e., connected to the ground terminal 113. The cut off sensor 114 may be grounded either by connecting the terminals A and B in the ignition switch 108 or by connecting the terminals L and M of the kill-switch 112. For this purpose, either the ignition switch 108 may be turned OFF or the kill-switch 112 may be turned ON.

The grounded state of the cut off sensor 114 is sensed by the engine control unit 116 to terminate the fuel ignition process in the engine. Moreover, as long as the cut off sensor 114 is grounded, the engine control unit 116 disallows any fuel ignition process in the engine.

In various implementations of the present subject matter, the engine control unit 116 may be a transistorized coil ignition (TCI) unit, a capacitor discharge ignition (CDI) unit, or an electronic control unit (ECU) to control the fuel ignition system responsible for carrying out the ignition of fuel in the engine. The engine control unit 116 may be powered by the power source 102, or by any other power source present in the engine, through a separate circuit. In an implementation, the engine control unit 116 may include a mechanical or pneumatic system based sensor,

Fig. 2a is a top view of a two-wheeled vehicle assembly 200 implementing the switch assembly 100 of Fig 1, according to an embodiment of the present subject matter. As depicted by Fig 2a, the two wheeled vehicle assembly 200 includes a utility box 210 and the kill-switch 112. As known in the existing art, the utility box 210 is a storage area for various types of material goods. In order to deter any attempts of theft, this utility box 210 is provided with a cover within the two wheeled vehicle assembly 200 to restrict unwanted access.

In one embodiment of the present subject matter, the kill-switch 112 may be disposed within such utility box 210 of the two-wheeled vehicle assembly 200. Without limiting the scope of present subject, there may be more than one kill-switch 112 within the two-wheeled vehicle assembly 200. These kill-switches 112 may be provided in other types of restricted locations apart from the utility box 210, such as a hidden recess provided within the two-wheeled vehicle assembly 200. Such an arrangement can be used to avoid theft of the vehicle by leaving the kill-switch 112 in the ON state when the vehicle is parked. In such a case, an unauthorized person will not be able to start the vehicle unless the kill-switch 112 is switched OFF.

Fig. 2b is an isometric view of the two-wheeled vehicle assembly 200 of Fig 2a, according to another embodiment of the present subject matter. As depicted in Fig 2b, the two wheeled vehicle assembly 200 includes a handlebar arrangement 215. In an embodiment, the kill-switch 112 may be disposed at a convenient user accessible location such as the handlebar arrangement 215 to support the kill-switch 112.

In one implementation of the present subject matter, the switch assembly 100 may also be implemented as a safety feature in a way that the kill-switch 112 is activated automatically when the user loses control of the vehicle or is dismounted in case of an accident, leading to an immediate shut down of the engine. In yet another embodiment of the present subject matter, an actuator in the form of a remote controlled device may be provided to control the kill-switch 112.

The previously described versions of the subject matter and its equivalent thereof have many advantages, including those which are described below.

The switch assembly 100 of the present subject matter employs the kill-switch 112 with a dual kill feature and is compatible with various fuel ignition systems like an AC signal based fuel ignition system. The dual kill feature corresponds to switching ON or OFF the fuel ignition process and disabling an operation of the starter motor 106, both actions being executed simultaneously, Further, as the present kill-switch 112 controls the ground signal instead of a power supply signal to the starter relay 104, a switch contact rating required for the present kill-switch U2 is less. Accordingly, the kill-switch 112 has a low contact area and a low manufacturing cost. Furthermore, the ground signal control by the kill switch 112 protects the battery 102 of the present switch assembly 100 even in the instances of a short circuit. Moreover, such type of control suppresses a development of leakage current flow within the switch assembly 100.

Thus, the kill-switch 112 is compact, light weighted, and specially designed for light vehicles like cars, scooters and motorcycles. Accordingly, the kill-switch 112 of the present switch assembly 100 occupies lesser space and provides an ease of operation.

Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein

We Claim:

1. A switch assembly (100) for an engine, the switch assembly (100) comprising:

a starter relay (104) connected to a power source (102);

a kill-switch (112) connected to the starter relay (104): and

a cut off sensor (114) connected to the kill-switch (112) to sense a state of the kill-switch (112);

characterised in that.

the kill-switch (112), in an ON state, connects the cut off sensor (114) to a ground terminal (113) for disabling fuel ignition in the engine, and

wherein the kill-switch (112), in the ON state, disconnects the starter relay (104) from the ground terminal (113) for disabling an operation of a starter motor (106).

2. The switch assembly (100) as claimed in claim 1, wherein the kill-switch (111), in an OFF state, connects the starter relay (104) to the ground terminal (113) for enabling the operation of the starter motor (106).

3. The switch assembly (100) as claimed in claim 1, wherein the kill-switch (112), in an OFF state, disconnects the cut off sensor (114) from the ground terminal (113) for enabling the fuel ignition in the engine.

4. The switch assembly (100) as claimed in claim 1, further comprising an ignition switch (108) connected to the cut off sensor (114) and to the ground terminal (113), wherein the cut off sensor (114) senses a state of the ignition switch (108).

5. The switch assembly (100) as claimed in claim 4, wherein the ignition switch (108), in an OFF state, connects the cut off sensor (114) to the ground terminal (113) for disabling the fuel ignition in the engine.

6. The switch assembly (100) as claimed in claim 4, wherein the ignition switch (108) is connected to the starter relay (104) through a start switch (110) for actuating the starter motor (106).

7. The switch assembly (100) as claimed in claim 4, wherein the cut off sensor (114) is configured to communicate the state of the kill-switch (112) and the state of the ignition switch (108) to an engine control unit (116) for controlling the fuel ignition in the engine.

8. The switch assembly (100) as claimed in claim 1, wherein the kill-switch (112) is provided within a utility box (210) of a two wheeled vehicle assembly (200).

9. The switch assembly (100) as claimed in claim 1, wherein the kill-switch (112) is
provided on a handlebar arrangement (215) of a two wheeled vehicle assembly (200).

10. A vehicle comprising the switch assembly (100) as claimed in any of the preceding claims.