After some self-described “false starts,” Cummins has officially launched its ISV5.0, a new commercial 5-L V8 diesel engine designed for North America to power pickup and delivery vehicles, other light- and medium-duty trucks, school buses, and RVs. Production of the engine, which had been in development for about 13 years, starts in the fourth quarter this year in Columbus, IN, at the Columbus Engine Plant.
The ISV5.0 has been designed to easily fit into the footprint taken up by a conventional V8 or V10 gasoline engine, and a nearly identical automotive version of the engine, the 5.0-L V8 Turbo Diesel, will be tasked with powering the 2015 Nissan Titan that is expected to be launched later this year. At press time, Cummins had not announced an OEM customer for the ISV5.0.
(The double-duty Cummins diesel was chosen by SAE editors as one of the “New technologies for 2014,” an article in the December 3, 2013, issue of Automotive Engineering. The digital edition of that issue can be viewed here.)
In addition to the ruggedness and power benefits inherent in diesel engines, “Diesel typically achieves 20-40% better fuel efficiency than a gas engine,” said Mike Taylor, Director, Customer Engineering and Business Development, Cummins.
Jim Katzenmeyer, Executive Engineer–V8 Program, Cummins, added that “the fuel savings offered by the ISV5.0 results in fewer greenhouse gas emissions.”
One hardware difference between the two engines will be the turbochargers, which must be different to address both the different certification requirements and duty cycles of commercial vs. automotive applications. Pickup trucks use chassis certification to verify emissions requirements, thus the engine and chassis are certified as one unit. In commercial vehicle markets, the engine undergoes dyno certification. The overall majority of the products that Cummins sells are engine dyno certified.
Other minor tweaks used to differentiate the engines' unique applications would include touches such as piston bowl design, or a little bit of difference in airflow on the intake manifold. Calibration is another technique, in terms of tuning the fueling timing map to meet emissions in certain applications and duty cycles.
The ISV5.0 will consist of a compacted graphite iron (CGI) cylinder block, forged steel crankshaft, high-strength aluminum alloy heads, and composite valve covers. These features, along with chain-driven dual overhead camshafts, also contribute to improved NVH characteristics of the engine.
“A lot of work went into designing a quiet engine,” said Katzenmeyer, part of which entailed the tight coupling between the cams and the belts.
The CGI block “has twice the tensile strength of a traditional block,” said Katzenmeyer, and Cummins’ use of the CGI block is a first for the company.
With the added strength to the engine comes dramatically reduced weight—by some accounts up to 50%—as the materials technology of the CGI allows for stronger, thinner walls, thus the use of less material.
Also, using “aluminum alloy cylinders heads vs. cast iron cylinder heads [traditionally used by Cummins] led to a significant reduction in weight of the engine,” said Katzenmeyer. “Other aluminum components include brackets, the intake manifold, and pistons.”
Put into context, overall the engine is about 400 lb (180 kg) lighter than the 6.7-L diesel for the Ram, according to Tyler LaSell, Assembly Business Leader, Cummins.
When asked by SAE Magazines if the CGI block would be used in other Cummins applications, Katzenmeyer said it’s certainly a possibility. “It’s a choice of does it make sense for a particular engine or for a particular market because it does have other attributes, such as the material being a little harder to machine. We have to understand all the trade-offs to evaluate for other projects.”
As casting is not a core competency for Cummins, the CGI block will be produced at the Tupy foundry in Brazil. A combination of carbide and ceramic tooling at the CEP facility will allow for the machining of the entire block and head on site. The company has been ramping up tooling in the facility to address machining challenges for about the past two years. While the facility once employed up to 4600 employees, it now has about 1600, said LaSell. That latter number is expected to grow as volumes increase. About 25% of ISV5.0 production will be automated.
In another first for Cummins, the 200-275 hp (149-205 kW) ISV5.0 engine will use a 2000-bar (29-ksi) Bosch High Pressure Common Rail (HPCR) fuel system—common on both engines—which features piezo fuel injectors that allow for “up to seven very precise injection events for any combustion cycle,” said Katzenmeyer.
Piezo technology is the main factor in the engine’s optimized in-cylinder combustion, leading to better fuel efficiency and reduced emissions, allowing “more injections per cycle and more accuracy,” said Katzenmeyer.
The multiple injection events are driven by integrated electronic controls. The HPCR fuel system, along with the variable geometry turbochargers, contributes to a peak torque of 560 lb·ft (759 N·m) and quick throttle response.
Maintenance-free ceramic glow plugs significantly reduce start time in extreme cold weather. The low electrical current draw reduces vehicle charging system requirements. The ceramic glow plugs are designed to last the life of the engine.
A two-stage fuel filter system for the ISV5.0 features the latest Cummins Filtration’s NanoNet media, which ensures that the sensitive HPCR fuel system is fully protected against fuel contamination. NanoNet's construction provides lower fuel-flow restriction, and traps greater than 99% of all particles as small as 4 micron.
Cummins Filtration also provided a high-efficiency coalescing filter for eliminating crankcase hydrocarbon emissions and oil mist, while Cummins Emission Solutions provided an aftertreatment system that features a DPF and SCR.
The ISV5.0 will be certified to the NOx and PM emissions levels required by the U.S. EPA. At launch, it will also meet GHG requirements through 2016, and 2015 Air Resources Board standards, including onboard diagnostics.Continue reading »