The Peterbilt 579 featured in the video up top is powered by the Cummins X15N natural gas engine. It's the engine maker's latest and greatest natural gas engine and just one of three engines in the company's new fuel-agnostic platform (the others will be powered by hydrogen and, yes, diesel).
[Related: Cummins readies new X15 diesel engine for 2027]
This CNG power plant features greater fuel efficiency than its predecessor, the ISX12N engine, and it's lighter than its X15 diesel counterpart. Peterbilt has fully integrated the X15N with its 579 powertrain to make this tractor model a viable option for long-haul trucking, with a range of up to 800 miles.
But how does driving a Peterbilt 579 with a natural gas engine compare to driving a diesel 579? "Well, the most important part is it sounds like a diesel," noted Overdrive sister publication CCJ's editor, Jason Cannon, from the driver's seat of the 579 during a quick drive he took alongside Peterbilt Marketing Manager Patrick Wallace. Check out the video up top for more, and the opening part of the talk in transcribed below for more about the 579's specs.
[Related: EPA 2027 diesel emissions regs: How high will truck prices go?]
Partial transcript follows:
Jason Cannon: Hey everybody. CCJ Chief Editor Jason Cannon here. I'm here with Patrick Wallace, marketing manager with Peterbilt, and our special guest is this Peterbilt right here. Patrick, there's something particularly special about this truck, because the Cummins logo on the hood is bigger than the Peterbilt logo on the hood. So tell us a little bit about what makes this truck unique.
Patrick Wallace: Well, this is a model 579 and it features Cummins' new X15 engine. And this is the latest and greatest natural gas engine that Cummins has released. It's the first engine on their new engine architecture platform. So they're doing a new fuel agnostic platform. And it's going to have hydrogen, diesel and natural gas. This is the first engine that comes out of that family, and it's a great improvement over the 12-liter.
There's better fuel economy. So about a 10% increase in fuel economy over that old engine. It's a great benefit. It's pretty light. You actually drop 500 pounds over a X15 diesel because you don't have to have as much aftertreatment here. You don't need any kind of urea injection or anything like that. So that's a good thing. And it also there's been big improvements with drivability. So this one's paired with an Endurant 12 speed transmission. And there's been specific drivability calibrations really to get, you know, the best feeling, the best maneuverability and drivability possible with a natural gas powertrain.
Jason Cannon: Now Patrick had said it was the latest in the greatest natural gas engine, but it's also the biggest. Let's pop the hood and take a look. When you pop the hood, I mean, it's red. It's a Cummins engine. It does look a little bit different, but for the most part, it just looks like a big Cummins engine. So Patrick, walk us through what makes this special other than, you know, some of the plumbing that you can see obviously at least in the natural gas.
Patrick Wallace: And so it's a big block. That's a nice thing. And customers will appreciate that. And this is all new. This is a whole new design. You can see this is well integrated as well. This has our air filter and everything like that that you'd find on a on a similar diesel. And I would say it's our best integration yet.
It's a very good packaging job to integrate. This is a fully integrated powertrain. It's definitely not an afterthought. it's something that we want to offer customers. We consider ourselves leaders in natural gas. We offer it in a variety of models as well. Also be in our 520 refuse truck and vocational applications as well.
Jason Cannon: What are we making here?
Patrick Wallace: So this truck has 400 horsepower. But the great thing about this new X15 is we can go anywhere from 400 to 500 horsepower and up to 1,850 torque. So this really will get you comparable to a lot of diesel applications.
Jason Cannon: What about the tanks? I mean, that's a unique configuration there. And I realize the more tanks you have the more range. And so you can kind of bake in. But what would you consider would be common on a spec like this. We're talking about a day cab. So obviously this truck wouldn't go very far.
Patrick Wallace: Actually this truck does go pretty far. It has a 175 diesel gallon equivalent tank. So it could go, you know, almost 800 miles or something like that. So if you look in our booth here at ACT Expo, we actually have a 579 ultraloft. And we want to show that to show customers that now it's an option to go long-haul with natural gas because we have the range.
Jason Cannon: What's the ideal natural gas customer? We hear a lot about electrification being, you know, limited range. Obviously you don't have a lot of range limitations with this, but, you know, you talk to a lot of people, you know, a lot of customers...
