A Toyota Engineer Opens Up About Putting Its Trucks Through Hell

The 2020 Tacoma and hydrogen-powered big rigs may not seem like they have much in common. One thing they share: Toyota beats them up in the desert.


Four years ago, Toyota had a thought: What if zero-emission, hydrogen-powered solutions were applied to heavy-duty trucking? So Project Portal was launched, aimed at proving a fully green big rig and trailer weighing 80,000 pounds could efficiently haul around California’s ports of Long Beach and Los Angeles. The first prototype semi was named Alpha and Toyota engineers toiled tirelessly to get it ready for a public debut, including many late nights in Arizona’s scorching desert during hot weather testing.

Here, Sheldon Brown, a chief engineer at Toyota who worked intimately on the project, tells us about the cheapest on-the-fly fix for a heavy-duty cooling problem, as well as about some of the night testing challenges faced by the team developing the facelifted 2020 Tacoma.

Q: Was it true one of your challenges on the Alpha vehicle was keeping the hydrogen powerplant cool enough?
A: To answer, let me back up a bit. During Alpha vehicle development, we knew this was a proof of concept vehicle, and it need not being perfect in all aspects; it’s allowed to be a little rough. One of the things we were working heavily on was how to quickly put together our cooling system. While it needed to function in different environmental conditions, we were trying to engineer to the bottom and the top of our limits, just to find functional solutions.

We started with extreme heat, which we got plenty of at our Toyota Proving Grounds in the desert outside of Phoenix, Arizona in the spring of 2016.

Q: What were temperatures like?
A: Absurd. The desert was running between 110 and 120 degrees. At this point, we had a one-off vehicle, with two bespoke motors and we had to build a hydrogen containment stack with all the vessels and the piping and everything. We’re literally using two Mirai sedan hydrogen fuel cell powerplants to run this. All of this was hidden under a Kenworth T680 that acted as our test mule.

As you know, these semi-trucks have giant fans, and you need about 50 hp each to run these fans to cool diesel engines. We’re all electric now, so we had to replace with electric fans and a new set of radiators, which took a while.

Q: When developing a new solution, are you worried about weight?
A: Not at that point. Those tractors weigh 18,000 pounds and pull 80,000 pounds. What we wanted to do was prove we could pull 80,000 pounds, total.

At the end of the day, whether you’re pulling that in the tractor or with the cargo trailer included isn’t that important. As you refine, you want to take the weight out of the tractor and put it back into the trailer. We wanted to run it in the actual Port of Los Angeles, so it was important that we had to be able to pull 40,000 pounds of cargo.

Q: What happened when you started testing?
A: We’re out there in the desert and we had a feeling our cooling would not be sufficient. Our target temp was about 100 degrees, with Los Angeles temperatures in mind. With the thermometer 20 degrees above that out in Arizona, the engine starts seizing. We could only do testing at night, which has its own challenges, and we’re on the fly, needing to do a bunch of other validations, too. So when the engine slows the powertrain starts to [lose] power because of cooling, you can’t do your other evaluations completely.

We knew we needed to augment the cooling, and we had no time to really think about long-term solutions. We took the windshield washer lines and rerouted them onto the radiators, and we [used] what you’d use to spray your windshield to hyper-cool the radiator to get a little extra bit out.

Q: Was it effective?
A: It was. The engine started running again and we were able to press on. In the desert, especially at night, a clean windshield is important, so I wouldn’t recommend this as a viable long-term solution. But it did work.

Q: You mentioned night development drives have challenges. Any others you can share?
A: I wasn’t involved in the heavy development of the current model Tacoma, but one of the challenges we did face was optimizing the new headlamps. How do we maximize efficiency from an LED light? During evaluation, you build a digital model and then have to test that in a light block phase, where you ensure that the light shown by the beams is actually what your digital model represents. We challenged the team to spend more time in the modeling phase.

Q: And they could skip light-blocking all together?
A: Precisely. They were able to get such good results digitally that we headed right to tooling. Once the computer models came back, built them with production tooling and tested in the middle of a desert night, with no moon so you can’t see three meters in front of you. Then we could understand where the light pattern is and trace it and check the lumens in each of our target categories.

The light block attempts to prototype the optics and show what you can do and our team is now able to get over that crutch of building a physical concept and do this from a digital standpoint. When we change optics, changing tooling is very expensive.

Q: How did the new lights end up?
A: Great. It was a big step forward in using computer modeling to predict what you’re going to do in production. With the new Tacoma lights, we use an LED with a reflector for the low beam and for the high beam. The Tacoma low beams now have an additional 38 meters of illumination, with 10 meters more on either side. They’re also 36 percent more efficient in terms of the amount of power used.

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