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