DESC:FIELD OF THE INVENTION
The present invention is in the technical field of automotive vehicles with two speed axles. More particularly, the present invention relates to the auto actuation or self-ratio shift mechanism associated with two speed axle between low and high speed ranges.

DESCRIPTION OF THE PRIOR ART
Multiple speed axles, such as two speed axles, are employed in drive assembly of motor vehicles such as automobiles, and can provide two different drive ratios to the wheels, and give the driver an option to choose between different speed ratio, to adapt to changing Route profiles, load and speed conditions.
Two speed axles is a unique product which provides an additional option of selecting two ratios, causing the increased speed in one ratio and provides the increased torque on demand in another ratio. The axle would be beneficial to the end users/fleet owners as this will lead to the increased the fuel efficiency and reduced turnaround/Transit/Transportation time. Such two speed axle assembly employs a sun gear and an associated planetary system with shifting mechanism to shift the axle ratio`s resulting in different vehicle speeds . This shifting mechanism employed may cause an undesirable gear retcheting during shift from one mode to another if not operated properly.
Traditionally the ratio shift is triggered through a switch located either on dash board/Gear handle or whichever the way convenient to the driver and the Vehicle Manufacturer. The ratio shift occurs through a shifter unit based on the operation of the ratio changeover switch by the driver. The shift from high to low completes through a mechanical engagement of the sun gear in the clutch plate.
Use of this manually operated multispeed axles require relatively skilled driver with the ability to properly operate the accelerator pedal during shift to synchronize ratio shift from either Low speed to High Speed or High speed to low speed which has direct impact on the shift smoothness.
Also in the traditional system the driver has to judge the requirement of the shift either from low to high or from high to low ratio. The judgment is again based on the experience of the driver and hence the performance of the fuel economy and transit time of the vehicle is dependent on the skills of the vehicle driver and the usage patterns by the Vehicle drivers.
US6258009 discloses an integrated system for automatically controlling the operation of both an automated manual transmission and a multiple speed axle assembly in a vehicle drive train assembly includes a transmission actuator for operating the transmission in any one of a plurality of transmission gear ratios. The system further includes an axle actuator for operating the axle assembly in any one of a plurality of axle gear ratios. An electronic controller is provided for operating the transmission in a desired one of the plurality of transmission gear ratios and for operating the axle assembly in a desired one of the plurality of axle gear ratios to provide a desired overall gear ratio for the vehicle. To accomplish this, the electronic controller is responsive to one or more input signals that represent operating parameters of the vehicle. When it is determined that a change in the overall gear ratio of the vehicle is necessary, the electronic controller initially causes the amount of torque that is being generated by the engine to be reduced to a relatively low level. When it is determined that the actual torque generated by the engine has been reduced to this relatively low level, the electronic controller generates a signal to the axle actuator to pre-select a shift to an appropriate speed reduction gear ratio in the axle assembly. Next, the clutch is operated to disengage the engine from the transmission. The rotational speed of the engine is then caused to be synchronized with a calculated anticipated rotational speed of the output shaft of the transmission after the shifting process within the axle assembly has been completed. When these rotational speeds are synchronized, the clutch is operated to re-engage the engine with the transmission. Lastly, the amount of torque that is being generated by the engine is increased to a normal level.
US6286379 pertains to a method of shifting multi-speed axles to drivably connect relatively rotating shafts in the driveline of a motor vehicle.
US4862363 discloses a vehicle two speed axle system can be voice-actuated by the vehicle operator. The two speed axle system includes a hydraulically actuated two speed axle unit having a solenoid-actuated control valve. A microphone is utilized to receive spoken commands from the operator which are recognized by a voice recognition and synthesis unit for controlling the system. A speaker is also provided for generating spoken messages representing conditions recognized by the system. The system includes a unique training program which is utilized initially to store voice template signals corresponding to the selected vocal instructions required to operate the system. The training program utilizes the voice synthesizer for prompting the operator through the training program.
US4774857 discloses a two speed axle assembly for automotive vehicles, providing positive shift engagement in shifting between direct and overdrive modes.
US6237712 discloses vehicles that have automatic transmissions and two speed axles, and electric circuits associated with shifting of such axles between high and low speed ranges.
There is, therefore a need to develop an improved two speed axle shifting mechanism capable of optimizing fuel efficiency and transit time and eliminate the possibility of concerns of Unfavourable ratio switch over by drivers during the vehicle driving and also eliminating the driver skill requirement associated with two speed axle usage.

OBJECTS OF THE INVENTION
One object of the invention is to overcome the disadvantages/drawbacks of the prior art.
A basic object of the present invention is to provide an improved two speed axle shifting mechanism for automotive vehicle.
Another object of the present invention is to provide an auto actuation/intelligent actuation/Smart Shift system that senses a pre-defined vehicle speed, engine Speed/RPM & current axle ratio for ratio shift for respective vehicle applications.
These and other advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings

SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
The present invention relates to a unique two speed actuation system capable of auto actuation/intelligent actuation/smart shift, for ratio shift from low speed to high speed or from high speed to low speed, based on pre-defined vehicle speed, engine Speed/RPM & current axle ratio with integrated timing for an optimized performance, by eliminating the skills and efforts required by the driver for the two speed axle ratio shift.
According to one aspect of the present invention, there is provided an improved actuation mechanism for use in a two speed axle shifting mechanism for automotive vehicle, said mechanism comprising:
means for receiving a vehicle speed and comparing the same with its pre-defined value(s) with respect to the current ratio of the two speed axle present in an intelligent actuation means to produce an output, said actuation means is present in said vehicle facilitating shifting of axle ratio to high or low according to the speed of the vehicle to meet drivability or torque requirements
characterised in that
said actuation means comprising a shifter means for shifting the desired axle ratio maintaining a speed of said vehicle followed by confirmation of said desired shift of ratio in axle and
said actuation means facilitates stopping and re-starting of an engine fuel supply solenoid according to said output.Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed block drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The following block drawing is illustrative of particular examples for enabling methods of the present invention, are descriptive of some of the methods, and are not intended to limit the scope of the invention. The block drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description.
Fig 1 is a block diagram of an Auto actuation/intelligent actuation/Smart Shift ratio shift mechanism of a two speed axle system
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.
Throughout the drawings, it should be noted that like reference numerals are used to depict the same or similar elements, features and structures.

DETAILED DESCRIPTION OF THE INVENTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.
Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.
By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.
It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.
Accordingly, the present invention provides an improved two speed axle shifting mechanism for automotive vehicle. The present invention has an unique two speed actuation system capable of auto actuation/intelligent actuation/smart shift, for ratio shift from low speed to high speed or from high speed to low speed in the two speed axle, based on pre-defined vehicle speed, engine Speed/RPM & current axle ratio with integrated timing for an optimized performance, by eliminating the skills and efforts required by the driver for the two speed axle ratio shift.
Referring to the fig.1, there is shown in the block diagram, an Auto actuation/intelligent actuation/Smart Shift system, takes the current vehicle speed, Current Engine Speed and current ratio in the two speed axle as inputs.
In one of the embodiments of the invention, the Auto actuation/intelligent actuation/Smart Shift system processes the inputs (Vehicle Speed Engine Speed & current axle ratio) and when the vehicle speed is less than the pre-defined speed the system provides the signal to stop and restart the fuel supply to engine by operating the engine fuel pump solenoid , then provide a signal to the Axle shifter solenoid to either start the Compressed air flow or to stop the compressed air flow in case of the pneumatic shift mechanism or provides a signal to electrical shifter to shift the ratio to the Low speed ratio as per the predefined limits. and confirm the shift.
In an another embodiment of the invention, the Auto actuation/intelligent actuation/Smart Shift system processes the inputs (Vehicle Speed Engine Speed & current axle ratio) and when the vehicle speed is beyond the pre-defined speed, system provides signals to stop and restart the fuel supply to engine by operating the engine fuel pump solenoid , then provide a signal to the Axle shifter solenoid to either start the compressed air flow or to stop the compressed air flow incase of the pneumatic shift mechanism or provides signals to electrical shifter to shift to high speed ratio confirm the Shift Completion.
The Auto actuation/intelligent actuation/Smart Shift will shift to high speed if the vehicle is beyond the pre-defined speed and the Axle is operating at the low speed ratio of the two speed axle, and will shift to low speed ratio is the vehicle speed is less then pre-defined vehicle speed and the vehicle is operating at high speed ratio of the two speed axle to meet drivability or torque requirements to negotiate the route profiles
Additional input of time integration is added with a provision to modify the time based on the vehicle models to support the reparative changeovers of ratios when the vehicle is moving a constant speed which is equivalent to the pre-defined vehicle speed.
Additional input of having a time gap is added between the mentioned outputs based on the inputs processing and can be changed to suit the requirements of the each vehicle model to provide an efficient and smooth shift overs of ratios either from low speed to high speed or from High speed to low speed in the 2 speed axle.

Advantages
Intelligent actuation system will shift the ratios to get optimized and uniform performance by eliminating the skills, focus and efforts required by the driver for the two speed axle ratio shift. The system will consider predefined vehicle speed with respective axle ratio and shift the axle ratio from high speed to low speed or low speed to high speed ratio in two speed axle even in the down grade without causing any concerns to the vehicle performance. Hence the system provides safer driving conditions compared to the conventional two speed axle fitted vehicles also providing good and consistance fuel efficiency for a given route profile. ,CLAIMS:WE CLAIM:
1. An improved actuation mechanism for use in a two speed axle shifting mechanism for automotive vehicle, said mechanism comprising:
means for receiving a vehicle speed and comparing the same with its pre-defined value(s) with respect to the current ratio of the two speed axle present in an intelligent actuation means to produce an output, said actuation means is present in said vehicle facilitating shifting of axle ratio to high or low according to the speed of the vehicle to meet drivability or torque requirements
characterised in that
said actuation means comprising a shifter means for shifting the desired axle ratio maintaining a speed of said vehicle followed by confirmation of said desired shift of ratio in axle and
said actuation means facilitates stopping and re-starting of an engine fuel supply solenoid according to said output.
2. The mechanism as claimed in claim 1, wherein said intelligent actuation means is adapted to stop and restart the acceleration based on the predefined timings as per the mechanism of said vehicle if said vehicle speed is less than said pre-defined value of speed and the two speed axle ratio is on high speed.
3. The mechanism as claimed in claim 1, wherein said fuel supply solenoid is adapted to stop and restart the fuel supply to engine as per the predefined timings of 1 milli second or so in the mechanism.
4. The mechanism as claimed in claim 1, wherein said intelligent actuation means is adapted to send signals to fuel supply solenoid to stop and restart the fuel supply to engine, if said vehicle speed is more than said pre-defined value of speed and the two speed axle ratio is on low speed.
5. The mechanism as claimed in claim 4, wherein said fuel pump solenoid stops and restart the fuel supply to engine as per the predefined timings of 1 milli second or so in the mechanism .
6. The mechanism as claimed in any of the preceding claims wherein a time integration input is provided to support the reparative changeover of said axle ratio, when the vehicle is moving with a constant speed.
7. The mechanism as claimed in claim 6, wherein said constant speed is equivalent to said pre-defined speed.
8. The mechanism as claimed in claim 1, wherein said shifter is selected from a group comprising electric shifter, pneumatic shifter and the like.
9. The mechanism as claimed in Claim 1, wherein the time gap is added between the outputs to have efficient and smooth shift overs to the suggested speed ratios in the two speed axle.