1. INTRODUCTION:

A ramp or speed breaker for vehicles is generally constructed for reducing the speed of the ongoing vehicles. In the present work, a system is proposed for converting some of the kinetic energy of the vehicle into electrical energy. When a vehicle passes over the ramp, the ramp gets pressed because of the force (weight) exerted by the vehicle, which activates a generator that produces electricity. This kinetic energy of automobiles that pass over the ramp may effectively be used for power generation. It has been estimated that installing the prototype of this model in highway may generate about 10 kw of energy, which will be enough to power road signs, traffic lights and even street lights. The energy can also be stored into the batteries and can be used.

Advantages

1. The principle is simple.

2. Construction is easy.

3. It is free energy source.

4. The method of electricity generation is done without polluting the environment.

5. No fuel charge.

6. If fault occurs in the power generating unit then it will not affect the traffic movement.

Disadvantages

1. The initial cost of power ramp may be high.

2. It can cause discomfort for the riders of the vehicle.

3. It will reduce the traffic speed.

4. It cannot produce constant power supply.

Application:

1. To power road signs, traffic lights and street lighting.

2. It can be stored in batteries for future use.

2. EXPERIMENTAL SET UP:

Fig.1: Schematic diagram

Fig 2 : Photograph of the set-up

Fig.3 : Internal view of the set-up

Fig.4 : Photograph of glowing LED and power measurement

Description

The experimental setup consists of 0.6m long ramp. The ramp is hinged at the centre and can be pressed to move down when load is applied. Subsequently when the load releases the ramp it moves up because of the spring action. When ramp presses the primary shaft which is connected to sprocket through a crank shaft, it moves. The rotation of primary shaft causes the movement of secondary shaft. Primary and secondary shafts are connected together using a chain drive. A flywheel is also fitted over the secondary shaft for maintaining constant r.p.m. All these mechanism are fitted in a wooden box. The rotation of secondary shaft drives the D.C. generator at relatively high speed. The output of the DC generator is connected with LEDS. Specifications of the different parts are given below.

3. WORKING AND PROCEDURE:

When ramp gets loaded it operates the primary shaft and subsequently rotation of the secondary shaft starts. The rotation of the secondary shaft causes rotation of the shaft of D.C. generator (connected through gear mechanism). The D.C. generator is connected with the LEDs. The voltage produced and current supplied to the LEDs can be measured with the digital clamp meter. Known mild steel mass has been applied over the ramp using cam follower system with constant frequency. Application and removal of load from the ramp will cause the rotation of the D.C. generator which triggers the electricity into the leds. Application and removal of load over ramp is done continuously for one minute. The rpm of the generator shaft is measured. Similarly, the voltage and current drawn from leds are measured through clamp meter. Experiments have been conducted for different weights and frequencies. The frequency of application of loads is subsequently converted into the corresponding velocity of the vehicle which will press the ramp with same frequency. Power applied to the ramp has been calculated by using relationship

(Power)_input = Force x Velocity

Power generation by the D.C generator has been calculated by using following relationship

(Power)_output = Voltage x Current

Subsequently the efficiency of the system has been evaluated using following relationship

Efficiency = (Power)_output/(Power)_input

4. RESULTS AND DISCUSSIONS:

1. It is evident from the analysis of graph 1 that input power increases with increasing load or force over ramp. Similarly, analysis of graph 2 shows that velocity also increases the input power over the ramp. However, velocity of the vehicle cannot be increased at the ramp as it will cause discomfort and is not permissible.

Table 1: Input power applied to ramp by different loads at constant velocity

Mass in Kg	Force in N	Frequency (application of load/min)	Velocity in m/s	Input Power in w
1	9.81	33	0.55	5.434
2	19.62	33	0.55	10.86
5	49.05	33	0.55	27.17
10	98.1	33	0.55	54.34
15	147.1	33	0.55	81.52
20	196.2	33	0.55	108.6

Graph 1 : Power given to ramp at constant speed by different loads

Table 2 : Input power given to ramp by constant load at different velocities

Mass in Kg	Force in N	Frequency	Velocity in m/s	Power in w
2	19.62	33	0.55	10.79
2	19.62	66	1.1	21.58
2	19.62	100	1.66	32.56
2	19.62	133	2.216	43.47
2	19.62	166	2.76	54.15
2	19.62	200	3.33	65.33

Graph 2 : Power given to ramp by constant load in different speeds

Table 3 : Power produced by ramp

Mass Kg	Force N	R.P.M	Volt V	Current A	Output power V*I
1	9.81	9	0.3	0.01	0.003
2	19.62	10	0.53	0.011	0.005
5	49.05	12	0.69	0.012	0.008
10	98.1	15	0.8	0.105	0.012
15	147.15	20	1	0.017	0.017
20	196.2	30	1.05	0.02	0.021

Graph 3 : Applied force vs. r.p.m. produced by ramp at constant velocity

Graph 4: Input force vs. output R.P.M. of generator at constant velocity

2 As high velocity is not recommended over the ramp so further analysis has been done for increasing loads and maintaining constant velocity of 0.55 m/s. It can be concluded from graph 3 for increasing force over ramp increases the r.p.m. of the D.C. generator. Subsequently increasing r.p.m. increases the output power from ramp as shown in graph 4.

Table 4 : Efficiency of the power ramp

Input Power in w	Output Power in w	Efficiency in %
5.43474	0.003	0.0552004
10.86948	0.005	0.0460003
27.1737	0.008	0.0294402
54.3474	0.012	0.0220801
81.5211	0.017	0.0208534
108.6948	0.021	0.0193201

Graph 5 : Efficiency vs. output power of ramp

3 Increasing load increases the output power. However, it is evident from graph 5 that with increasing output power decreases the efficiency of the ramp. This shows that increment in the output power of the ramp requires more input power.

Graph 6 : Correlation for forecasting of output power for different input power

Using available data, correlation for the curve of output power vs. applied load has been drawn. The correlation between data has been presented in the following model between applied input power applied to ramp and output power from the ramp.

Y = 0.001 (X)^0.629

(P_output) = 0.0007 (P_input)^0.629

Further, the degree of confidence level of the found model is very high as the value of R² is 0.994.

4 Using presented model, forecasting has been made for the 10000 two wheelers of 100 kg, 5000 cars of 1000 kg, 5000 light duty trucks of 4000 kg and 5000 heavy duty truck of 10000 kg in the table 4 (assuming that power ramp has been installed at near toll plaza). This forecasting shows that installation of power ramp near the toll plaza where 25000 vehicles per day pass will generate almost 10 kw of electrical energy.

5. CONCLUSION:

It can be concluded from graphs that the output power solely depends over the rotational speed of the DC generator. Higher rpm of generator is possible by increasing the load over ramp or by increasing the velocity of vehicles. However, vehicles can not move in speed over the ramp so in the presented work, analyses have been made for 0.55 m/s velocity of vehicle.

The relationship between output power from the ramp and applied input power over ramp has been presented with the help of a model. The forecasting of output power has been simulated for actual vehicles using model. The presented model related the output power and applied load in the following manner.

(P_output) = 0.0007 (P_input)^0.629

The model is having high degree of confidence for the derived data as the value of R² = 0.99. Forecasting of output power has been made for 25,000 daily traffic movements over the ramp. Forecast shows that almost 10 kw of electrical energy can be produced by the power ramp. This energy will be enough to power the traffic lights and the batteries.

Table 4 : Forecast of expected output from power ramp

Mass Kg	Force N	Velocity m/s	Input Power	Forecast power	Vehicle type	No. of Vehicles	Total power
100	981	0.554	543.474	0.052532	Two wheelers	9000	472.7918
1000	9810	0.554	5434.74	0.223577	Cars	5000	1117.886
4000	39240	0.554	21738.96	0.534716	Light trucks	6000	3208.296
11000	107910	0.554	59782.14	1.01033	Heavy trucks	5000	5051.652
		Daily output power 9850.626 W