2.1

Engineering tools

2.2

The course approach

Table 1 shows the schedule of the course in a Gantt chart. So far, the course topics and objectives are decided on, the design projects are decided on, the optical components to be used for the design projects are decided on, the CAL and CAD tool were decided on, and the textbooks are also decided on. The order of introducing the projects in the second offering of the course was decided to be CHMSL, STT, HB, LB keeping in mind the difficulty level in design of each lamp. The approach to cover the materials is as follows. Reflector optics was practiced for CHMSL design and refactor optics was practiced for STT design. This approach was decided based on the feedback from students during the first offering of the course. During the first offering, both the refractor optics and reflectors optics were taught to the students and then they were asked to use them in the CHMSL and STT projects as they wished. The results were not ideal since students were confused how to select which optics to use for which project, and some tried both of the optics to see which one is better, therefore some portion of their project time was wasted, leading to requests for extension of deadlines in each project.

Table 1.

Gantt Chart of the course on Automotive Lighting

Considering the prior experience, in the second offering of the course, the decision was to limit the confusion and design freedom of the students by teaching one optics per project. That is, reflector optics was taught for CHMSL project and then students were asked to deliver their CHMSL designs according to a set of constraints. Next, the refractor optics was taught for STT and then students were asked to deliver their STT designs according to another set of constraints. This isolation of topics and projects proved an effective method of teaching and practicing the topics. As in a hidden curriculum, the students eventually realized that they could have used any of these optics for any of the projects, however the approach to introduce them into the projects helped significantly in their confidence and learning outcomes. This progressive approach also helped the students to manage time better.

Further, to teach design for manufacturing such as plastic part design and the rules for draft angles and undercuts, the students were asked to design the CHMSL and STT lamps in full assembly rather than just the optics of each lamp. The lamp assembly for CHMSL and STT project includes the optics, housing, LED board, and the methods of locating each component to a reference, poke-yoke, mounting, harness holes and etc. This additional task was to add more learning opportunities for engineering students in order to learn considerations for volume manufacturing, and also practice CAD work over the time of the first two projects. In addition, such practices are helpful since students can function better in future when they join cross-functional teams with mechanical engineers, electrical engineers, and manufacturing engineers present, and can understand their view of the project to communicate effectively.

In the following sections, the projects, their constraints, their scoring items, and some design examples submitted by the students in the second offering are presented.

2.3

Project #1 CHMSL

2.4

Project #2 STT

Design a 4” round STT lamp. Toward this project, two types of refractive optics were introduced to the class. One of them was the Fresnel lens optics and the second was TIR optics. Students had freedom to choose any of the options. Also, obtaining the lit appearance of a lamp was taught to students in order to prepare them communicate with a potential client or with a marketing department. It was asked that the students provide the lit appearance of tail and stop functions of their legal designs. Some selected submissions are shown in the design example section.

2.5

Project #3 HB

The third project was arranged to transition from rear lighting to forward lighting. That means that students will need to use white LEDs rather than red colored LEDs. The HB is an easy lamp, therefore it provides opportunity to introduce more of the necessary skills for students. For example, the material dispersion was introduced in this section since the range of wavelengths was wide and over the full visible spectrum. The white LED light sources were introduced and the methods of making white LED were reviewed. Students were asked to investigate some of the manufacturers of automotive grade LEDs such as OSRAM, CREE, Nichia, LUMILEDs to familiarize themselves with the types and shapes of LEDs. Also, the high-power LEDs and their health risks were introduced. A sample high power LED with 1500 lumens was demonstrated in the classroom for students to get a sense of amount of light produced by such highpower LEDs.

Another concept that was introduced in this project was the ray files and how to incorporate them in the CAL in order to ensure realistic simulations. Ray files are the resources provided by the LED manufacturers as they spatially measure the real rays emitted by the LED. Therefore, instead of using an ideal rectangular or circular Lambertian emitting surface, the students learned to use the recommended, realistic rays for accurate simulations. The concepts of color temperature and color rendering index were also introduced in this project. Legal requirements of high beam were reviewed and different classes of lamps were studied. Students also were taught to obtain an estimate of the illuminated range of HB lamp on the road and they were required to report it for their own designs. The better range meant a better lamp. Chromatic ray tracing was also introduced in this part to accurately simulated emission spectrum of white LEDs.

The progressive introduction of materials in the second offering proved to be much more effective compared to the first offering. In the first offering, all the topics such as different types of optics, ray files, and other complex topics were taught first, and then students were asked to start on the projects. That approach caused confusion and also limited the time available for students to work on actual projects. In contrast, the progressive gradual introduction of more advanced skills helped students learn more efficiently and manage time better to deliver good designs in each project.

2.6

Project #4 LB

The final project of the course was to design a low beam lamp. Only the reflector was needed to be designed where advanced features of MacroFocal optics in Lucidshape were taught. The LB legal requirements is very complex and hard to achieve, especially in the time duration of only two weeks. As an example, the test points of a LB class LB3V are shown in Figure 1 with 26 points, zones, and gradients in total. Some test points are tightly located which makes it really challenging, even for an experienced engineer. It should be noted that a well analyzed LB could take weeks to be completed due to the difficulty of legal test points and tolerancing sensitivity. Therefore, the project #4 was only to obtain a nominal design. CAD work, ray files, or tolerancing were not included to ensure that students can achieve the satisfactory results within the available time.

Figure 1

– Test points of LB3V according to FMVSS 108.

The only option provided in the fourth project was that this was also the final project or the final exam of the students. Therefore, considering the amount of new skills and insights students had learned along the way, it was permitted that students could submit a revised version of their previous lamps to fix the issues were noted to them in their individual design review.

3.1

CHMSL Example Designs:

For this project, the students were required to ensure each part is solid, suitable for injection molding, with proper wall thickness and draft angles. The engineering drawings were also required. Note that these designs were completed in only two weeks, after only two weeks of training. This was the first time students design a complete product.

3.2

STT Design Examples

The STT project was a full lamp assembly just like CHMSL project. All the designs shown below are done by students in two weeks. All the designs meet the legal test points. Students were required to obtain lit appearance for tail and stop functions of their lamp. Different approaches are clear from the selected designs below. Some students used the Fresnel optics, some TIR optics and some combined the two.

3.3

HB Design Examples

In the HB project, students were only using the basic features of MacroFocal in order to design segmented reflectors for meeting the legal requirements. The reflectors and light patterns are shown below. The students were also taught how to obtain the bird’s eye view of the lamp when the HB is actually mounted on a vehicle and the road is illuminated by it. The greyscale bird’s eye view for a couple of submissions are shown as well.

3.4

LB Design Examples

For the LB project, the students used advanced features of MacroFocal in Lucidshape in order to create legal cut-off required in the standard documents. It was discussed in the class that meeting legal test points is just the beginning of the design and they should think about consumer preference. Therefore, some students designed LB lamps with wider road illumination to be legal and to help the driver see better. The light pattern to meet the test points and the driver view simulated in Lucidshape are shown below. The bird’s eye view of them are also shown.

3.5

Student Feedback

Students provide official feedback through anonymous evaluations at the end of each quarter. The evaluations are designed by office of assessment at Rose-Hulman Institute of Technology and are collected online in a learning management system. Some of the questions and feedback by students are provided below:

As pointed out by one student, the options for CAD tool turned out to be an issue. To improve the course in the future offerings, there are two new options: 1) only use Rhino, 2) use the new version of Lucidshape with integrated CATIA as the CAD tool. Regarding the issue on schedule, the circumstances with COVID-19 had caused one extra week of the classes to be eliminated in preparations for the pandemic and that one week had a negative effect on the course schedule. Another item that delayed parts of the course was the need to move online and record the lectures, during which occasional technical difficulties led to re-recording a few of the lectures and causing delays. In a normal schedule, such problems would not be an issue. The suggestion for team projects is interesting and would be investigated at a later time. Some of the feedback for improving the course really needs more time for the course, more than the available 10 weeks, which indicates the desire of students to learn more in courses like this.

3.6

Future developments

Future topics being considered to be added include: