latesttechnology world

Saturday, 13 July 2013


                          PROJECT MODEL



1.     Hydraulic circuit
2.     Electronic circuit
3.     Mechanical components

            Hydraulic motion is selected for gear shifting owing to its large load acceptance and ease of adaptability in the car. Also the gear shift should be quick. The basic components design is explained in detail.

Load required to move the selector rod or to change the gear F=30 Kg
Pressure built in the compressor unit                                      P=10 bar
To find:

Cylinder dimensions D,L=?

1. Cylinder diameter D=?
    (10*105)*(P/4)*D2 = 30*9.81

D=0.0194 m = 20 mm

2. Cylinder length L =?
     Cylinder length L= Stroke Length+ Piston thickness+ Clearance
       L= 30+10+7 = 47 mm

Cylinder diameter= 20mm                          Cylinder length= 47mm

Selection of pump is based on following characteristics:
1. Select the actuator that is appropriate based on loads encountered.
2. Determine the flow rate requirements. This involves the calculation of the flow rate               necessary to drive the actuator to move the load through a specified distance within the given time.
3. Determine the pump speed and select the prime mover. This, together with the flow rate calculation, determines the pump size
4. Select the pump based on application
5. Select the system pressure. These involves in with the actuator size and magnitude of the resistive force produced by the external load on the system. Also involved here is the total amount of power to be delivered by the pump.
6. Select the reservoir and associated plumping, including piping, valving, hydraulic cylinders, motors and other miscellaneous components.
7. Calculate the overall cost of the system.
8. Consider factors such as noise levels, horse power loss, need for a heat exchanger due to heat generated, pump wear, scheduled maintenance service to provide a desired life of the total system.

The above characteristics are satisfied by the GEAR OIL PUMP and the following data are obtained from measurement,

Do =75 mm Di =50 mm W= 25 mm N=1440 rpm

1. Flow rate Q= (P/4)*(Do2-Di2)*W*N
                   = (P/4)*(0.0752-0.0502)*0.050*1440
                   = 0.0883 m3/S = 0.00147 m3/min = 1.47 Ltrs/min

2. Power required = Pressure*Flow rate= (10*105)*0.0883 = 88.3 kw


1. Reservoir Capacity= 2.5 to 3 Times of Pump flow
= 3*1.47
= 4.41 Ltrs
=4 Ltrs

2. Size of the copper tube =6 mm(for transmitting hydraulic fluid to valves
Hydraulic circuit diagram of the project

1. Reservoir.                                     7. Cylinder piston assembly
2. Pump.                                  8.  Limit Switch
3. Clutch                                  9. Gear Box
4. Engine                                 10. Gear selector rod
5. Inlet Solenoid Valve            11. Spring
6. Outlet Solenoid Valve        

The electronic circuit is used for governing the hydraulic operation. For this purpose we have used two solenoid valves (inlet and outlet) for each gear to be shifted. The supply voltage is from battery which is 12V. there will be six buttons 1, 2, 3, 4, R, N for gear shifting. Each actuates the gear corresponding when pressed.
The diagram below shows the electronic circuit for various operation of the gear shifter.
i. Engaging first gear

ii. Maintaining gear position
iii. Releasing gear-neutral position

iv. Gear changing


The main mechanical component for the project is the spring. The spring is used to counter balance the force exerted by the piston. Moreover it is useful in the return motion of the gear selector rod during gear disengagement. Presence of spring on the gear selector rod helps in the quick action that is required during the gear shift.


We have formula for deflection         Y = 8PD3n/Gd4
Y=deflection of spring
P=load acting on the spring
D=Diameter of spring
d= Diameter of spring coil
N=no of coils in the spring
G=modulus of elasticity of spring material

G=2*105 N/mm2
D=3.5 Cm
d=0.4 Cm
P=30 Kg
Y=1.5 Cm

No of coils in the spring,
= 1.5*2*105*0.44*100/(8*30*9.81*3.53)
= 8 coils

1.     Engine rotation
2.     Clutch engagement
3.     Pump rotation

Presently we have done this project as a table top working model. This consists of various parts which are listed below.

1)    FIAT Gearbox
2)    TOYOTA Power steering compressor
3)    Motor for driving the compressor
4)    Electro magnetic clutch
5)    Tank or reservoir for storing the hydraulic fluid
6)    Valves for controlling the flow of hydraulic fluid
7)    Limit switch to cut off the supply
8)    Hydraulic cylinder and piston assembly
9)    Copper tubes for transportation of fluid
10)                       Fluid Hoses
11)                       Base structure for holding the gearbox and motor arrangement

The current model is a simple one which is actuated by a stick switch governing the gear selection. This set up works good for two gears. In the future there are plans to incorporate the clutch action in the set up by using the electronic clutch.

¨     Leg room for passengers at front is increased more since the removal of gear rod.
¨     Ease of operation, by the use of feather touch buttons.
¨     Gear shift is sequential, so no problem of wrong gear selection.

This project is an innovative concept. It is a new dimension in the transmission system of a car. This is a simple and versatile pack that may be fitted to any cars existing with power steering. By implementing this smart gear shifter in cars, we can achieve more space, smooth operation, more user friendly, less effort to change the gear and no play. Also the project is a boon for physically challenged persons. The present condition of the project is promising for further developments. Lots of inputs are also got from the car specialists and academicians for its improvement. The concept can be transformed to a real time fitment on further development. We estimate a period of two years to see a car fitted with this mechanism.


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