Y.T：The group of products that make up the outside of an automobile is called "exterior parts". Starlite has been involved in front grilles, back door handles, roof rails, splash shields, undercovers, reinforcing parts, and more.

S.T：The basic functions of the exterior parts are to prevent unwanted objects from getting into the automobile and to make the design of the automobile more attractive. Starlite is required to develop safer automotive parts in a short period of time.

S.T：I will explain it in the cowl grille, the key unit that Starlite develops and designs. The cowl grille is the cover that joints the hood and windshield. It is a pretty simple looking product that is always blacked out in the initial design drawing of an automobile.

It sounds nice to hear that "all decisions and procedures are entrusted entirely to Starlite", but in fact, there are a wide variety of performance requirements we have to follow.

Y.T：First, it must cover the vehicle well from rain and wind as a "cowl", and also function as a "grille" to let air in.

Specifically, air for air conditioning is drawn in through the grille. Then, it blocks rainwater that runs down the windshield. If not blocked, the engine compartment will be soaked. On the other hand, heat and odors from the engine must be vented to the outside.

S.T：The parts surrounding the cowl grille, such as the metal cross member under the cowl grille, vary by vehicle type. Since cowl grilles are almost never the same, we make adjustments with automobile manufacturers and other suppliers each time. The basic function of keeping rainwater out of the engine compartment is updated according to each vehicle design.

Y.T：Windshield washer fluid is sprayed to remove dirt from the windshield, but if the volatile components contained in the fluid get into the engine compartment through the windshield, it could cause a fire.

S.T：The cowl grille has an open mesh to let air in for air conditioning. If rainwater that travels through the windshield enters the mesh, it will flow into the engine compartment, so a mechanism is needed to channel rainwater to the outside before it reaches the engine compartment. The water-draining ribs are designed on the underside of the cowl grille to channel water to the outside. We have also applied for a patent.

For the type of vehicle I was involved in, it became necessary to split the cowl grille into two pieces and assemble them in the middle. Water tends to leak from the joint area, so we placed the water-draining ribs mainly there. The maze structure predicts the flow of water and directs rainwater to the desired direction. I used to draw pictures while imagining as if I were water, and then reflect them in the drawing data.

Y.T：To direct rainwater to the desired direction, all kinds of approaches are made to the water-draining ribs, such as changing the shape, position, and size of the ribs. The difficult part is that the water-draining ribs must be designed to properly guide water even when an automobile is going uphill or swaying from side to side. That is very challenging.

S.T：We have recently incorporated designs to prepare for torrential rains too. For example, 100 millimeters of rain per hour.

S.T：First, it is harder to drain water, because water continues to flow in. It also needs to catch the splashes as a lot of water falls down. Although there is a blower that sends air to the air conditioning under the cowl grille, splashed water is easily sucked into the blower. Since not a drop of water is allowed to run through, the design must be quite meticulous.

Y.T：Another complex performance of the cowl grille is that under certain conditions it breaks down and absorbs energy.

Y.T：We have to make sure that exterior parts do not break down when driving normally, but in the unlikely event of a collision between the front of an automobile and a pedestrian, the pedestrian's head could strike the cowl grille area. When an accident like this happens, the cowl grille is designed to be destroyed in an ideal way and to absorb the impact energy.

S.T：As I explained earlier, the cowl grille is surrounded by hard parts. It is very hard to destroy the cowl grille in an ideal way, as the cowl grille is in contact with the windshield and the metal cross member, and each parts is not a simple configuration.

The cowl grille is strong enough to resist denting or crushing during normal driving. No matter where the head of a pedestrian hits, it has to be destroyed from basically the same place. It was not easy to achieve the results because we had never thought about that before.

S.T：The cowl grille is designed to bend easily to ensure that it crushes from the middle. We made "incisions" called notch, which is designed to bend from there.

We verified the position, depth, angle, and more of the notch. Just one degree of difference in angle makes a complete difference when it splits. Even if the right shape for the notch is determined, we also face the issue of whether an injection mold can be made for mass production.

Y.T：After conducting such theoretical verifications, we begin testing with the cowl grille installed on actual vehicles. We simulate a person's head hitting the hood of an automobile to see how it would affect a vehicle, not just the cowl grille alone. The final design of our cowl grille is determined after many rounds of adjusting to ensure that the Head Injury Criterion for pedestrian protection is met.

S.T：That is actually a good idea.

Y.T：We would like to develop products in a shorter period of time. For example, with the water-draining rib design, we need to perform a shower test after conducting theoretical verifications. We want to simulate it at some level, but it would take 5 hours to analyze 0.3 seconds of rainwater movement. We have just begun to explore various approaches, such as focusing analysis on key areas.

Y.T：The digital technology for such simulation is model-based development. It is still at the parts level now, but I believe, in the future, simulations will be advanced to provide system-level effects between the parts and surrounding parts, as well as vehicle performance.

If the results of the vehicle testing for the shape of the water-draining ribs selected in the meeting held in the morning are available by midday, both man-hours and development time can be significantly reduced. Of course it is important to think how to fill the gap between the analysis and the actual results, but I think it is significant to find the "first pin" of bowling, which is the key to the function, and to focus on that pin.

S.T：Faster development can also reduce costs. With a sense of speed, we will continue creating products for the next generation of automobiles.