Report Due

We were at last able to rid ourselves of this burden that we have been carrying for almost a year, as today we submitted the project report. I am silently confident that we have produced a decent report seeing as we were extra careful in its preparation leading up to today. 

For now, our sights are firmly set on our final piece which is our presentation next week. 

This morning our group congregated  and had discussion regarding  this. We have worked out who will cover what in the presentation and now we are in the process of preparing slides next. 

I would hate for things to go downhill from here as we have done well up until now. 

I hope things should go according seeing as we just need pick those important points from the report to showcase our research. Bring on the final presentation!!

Report Writing

Now that we have completed the practical testing stages of the project, we must turn our attention to compiling the results and formally writing it up as our project report. The report itself is a vital piece of the pie and carries a weighting of 60% of the total marks. The remaining 30% is made up of background research and presentations. With this in mind, we must now put our heads into gear and complete this project report before we run out of time. 

Results

We are currently in process of analysing all the collected test data. From the results, it is evident that the voltage and current generated from the generator device is too insufficient to be utilized as a charging source. On the other hand, considering the experiment was carried out on a smaller scale generator, the results are promising and we have proof that the idea works and has the potential to produce a higher output if it is increased in size to a bigger scale.

From the findings of our research, we have come to the following conclusions:

- The generator does not generate a constant and continuous voltage on motorway driving condition due to good road profile on motorway. 

- The higher voltage output is required from the generator in order to produce higher charging voltage up to required battery voltage.

- The higher current output is found as a significant criteria for generator, since the higher current would provide a faster charging time for the higher capacity of energy storage.

On-board Vehicle Test

Today, we conducted on board vehicle testing. The Picoscope computer is placed inside the car, with all the connections already fitted to the generator (Figure - 1). The scope data was recorded inside the vehicle while the road tests were carried out. 

Figure - 1: On board vehicle testing using the computer Picoscope

The tests were carried out on several categories of road types with under various speeds: Unitec campus driveway (20-30 km/h), main road (50 km/h), residential road (50km/h) and motorway (100 km/h). The results of the experiment were as follows:

Chart - 1.0:  Test on motorway @ 100 km/h , voltage output is minimal

Figure -1.1: Test on motorway after 5 minutes, reaches 0.2 V

Chart - 2.0: Test on normal residential road @ 50km/h, peak voltage - 1.2 V

Chart - 2.1: Test on main road after 3 minutes of driving, peak voltage - 1.28 V 

Chart - 3.0: Test on campus driveway @ 30 km/h, peak voltage - 1.3 V

Chart - 3.1: Test on campus driveway @ 30 km/h, peak voltage - 2.0 V

The test results were not up to our expectations. Nevertheless, it is enough for us to make a comparison of the results with regards to the effect of different road profiles on the overall output voltage.

Prototype Fitment Design

Our first technology session back from the holidays,we decided to attempt fitting the proto-type to a vehicle. In the morning, we had a pre-arranged meeting with Prabhat to discuss our action plan and also to make arrangements to use the workshop and scope equipment to assist us with our practical work. Our meeting was very useful as prabhat pointed out some key obstacles that we might encounter during our investigation and made suggestions about how we could think of ways to overcome these issues. 

Figure - 1: Proposed fitment area

Key areas raised in the discussion included:

• Finding an appropriate mounting location
• Using an effective device mounting/fitting method
• The type of linkage to be used to firmly connect the permanent magnet of the device to the suspension system in such a way that allows for optimum suspension movement transfer to the device

Our objective today was to workout a method of mounting the generator device into the car and testing its output. We were able to identify possible fitment locations, though we found that most of the locations were not so suitable due to the limited space in the suspension area.

After further consideration, we decided to fit the generator inside the boot area, and to the top of the rear suspension. We noticed that mounting the device to the front suspension was improbable as the front wheels incorporate too much lateral wheel movements in order to steer the vehicle. The device is better located  at the rear suspension as the rear wheels are fixed. 

Figure - 3: Final fitment location for generator

Figure - 2: Rod end (rotor) fixed to suspension

               

Fitment Practical

A requirement of the project is that  the generator assembly to be mounted to the suspension system in order to utilise the vertical movements of the suspension. After careful consideration, we decided that the prototype assembly would be suitably mounted at the rear suspension of a vehicle instead of the front. This is due to the limited space availability at the front wheels due to the presence of steering components as well as steering movements. Initially, we planned to fit the stator assembly onto the lower part of the suspension, while the rotor would be connected to the vehicle chassis body as shown in Figure - 1.

Figure - 1: The first proposed fitment configuration

We used a steel rod to create a link between the generator and the rear lower arm suspension. Attached to the top rod end (inside boot), is permanent magnet which acts to excite the coil magnetic field. While the other end of the rod is firmly fixed to the suspension. This point will be the key to creating the oscillations for the device to function. The image below shows the location and how it is connected to the lower arm suspension. 

Figure - 2: Final fitment configuration

Third Prototype

We sat down and had a discussion with Prabhat about the output performance of the generator, and brainstormed possible ways in which we could increase the current output. 

The consensus was to go back to the basics of energy generation, and incorporate an iron core to the generator design. We decided to wrap the coil with an iron plate around its outer surface, which would theoretically help strengthen the magnetic field.

Another key point of interest was the air gap between the magnet and coil, which proved to be excessive. We believed that this air gap actually weakened the strength of the magnetic field and so we reduced the air gap by increasing the permanent magnet diameter by attaching a magnetic strip around the magnet circumference to fill the gap. On the downside, the modification has increased the overall weight of the magnet and so extra force is needed to stimulate the up and down rotor movement. 

Figure - 1: Generator fitted with iron plate 

The same tests were carried out for this as for prototypes 1 and 2. The results showed a significant increase in voltage and current, which allowed the capacitor to charge up quicker.

Figure - 2: Third prototype, Max. Voltage= 1.82 V @ 1Hz

We are satisfied with the current performance of the generator, and we believed the output will be sufficient for the generator to be installed and tested on vehicle.