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Contributing Writer, GM-Trucks.com
General Motors reported this morning that the all-new Silverado equipped with the 3.0-Liter Duramax diesel engine has earned an EPA-estimated 33 MPG Highway in 2WD configurations. Here is a quick look at the numbers we have so far:
2WD Silverado Duramax = 33 MPG Highway, 23 City
4X4 Silverado Duramax = 29 MPG Highway, 21 City
Here are a couple of quick comparisons:
2019 Ford F-150 2WD Diesel = 30 Highway, 22 City
2019 Ford F-150 4WD Diesel = 28 Highway, 22 City
2019 Ram 1500 2WD Diesel = 27 Highway, 20 City
2019 Ram 1500 4WD Diesel = 27 Highway, 19 City
**2020 Chevrolet Colorado 2WD DIesel = 30 Highway, 20 City
**2020 Chevrolet Colorado 4WD DIesel = 28 Highway, 19 City
“We designed the all-new Silverado and the all-new 3.0L Duramax turbo-diesel to deliver both performance and efficiency,” said Tim Herrick, Silverado executive chief engineer. “The engine utilizes state-of-the-art technologies to optimize every drop of fuel, and takes advantage of architectural changes to make Silverado larger, lighter and more aerodynamic than before. The resulting combination offers all of the performance, refinement and capability customers want in a full-size truck, with highway fuel efficiency you would expect from a family sedan.”
The trade-off for fuel economy alone will worth calculating. In addition to the higher fuel cost compared to gasoline, for the LTZ and High Country, the 3.0L Diesel is a $2,495 option (identical to that of the 6.2L V-8). For the LT and RST, it is a $3,890 increase over a 2.7L Turbo engine. For those looking for diesel towing capability, the choice will be an easy one.
The EPA has not yet published full MPG and emissions information on the new Duramax at its site, www.fueleconomy.gov. Once data is posted we will do a more in-depth post on the comparison to some other Silverado models. First deliveries of the 2020 Silverado with the Duramax engine will be this coming fall.
Thom Cannel: Article & Photos
Zane Merva: Photos & Video
June 25th, 2019
By now you prospective 2020 Chevrolet Heavy Duty owners are over the Ho-Hum of our 2020 Silverado 3.0-liter story (we are totally Ho-Ho-Ho and Hmmm, can’t wait for a longer test!) and looking at the Alpha Dog, the 35,500-pound tow-rated Silverado Heavy Duty and its over 50 industry firsts including an updated diesel engine and all-new 6.6-liter gas engine. Let’s get to it.
Where to start? With its amazing trailer towing features that include 15-view camera and ability to memorize the features of five different trailers? How about the Durabed with its class-leading cargo volume and all-steel construction with a plethora of cargo tie-downs? Maybe you’re gobsmacked by the corner and bed steps with, now, plenty of toe room and 500-pound weigh-holding capacity? Is it the power tailgate that remotely lifts or lowers? An ability to hold first gear while towing maximum weight? Or, is it all of these?
Chevrolet states that Heavy Duty trucks are working vehicles, whether towing a gooseneck horse trailer or flatbed and whether gas or diesel-powered. They further tell us that, compared to light duty trucks where 84-percent are retail and 12-percent go to fleets, Heavy Duty buyers are 70-percent retail and 30-percent fleet. Further, Work Truck and Custom trucks make up the volume; LTZ and High Country capture an even larger share of the market for personal and dual use buyers, with mid-trim LT trucks straddling fleet and personal use. Hence the five available trim levels to suit the needs of every buyer.
There is no mistaking that the 2500HD and 3500HD is kin to the 1500, yet only roof sheet metal is common. Everything about the new HD trucks was designed to be functional from larger grille to lower side-height bed, to improved box and bed steps. It’s massively bold with strong character lines, huge fender wells and functional hood scoop. Both the 2500HD and 3500HD are distinctive and clearly Chevrolet.
For 2020, every frame is boxed and steel, there’s a model with built-in gooseneck cross-body reinforcements and bed holes, 4X4 models can option Autotrac two-speed electronic transfer case, the DEF tank is relocated inside the frame rails with the filler under the fuel door, plus a 10-segment DEF gauge measures content.
A statistic to toss off at your microbrewery; within the total HD segment, 54-percent are Crew Cab diesels while within fleets, 62-percent are gas-powered, with 34-percent of fleets buying Crew Cabs and diesel power. And if you’re wondering where the 2020 Silverado HD you’d like to scope out on your dealer’s lot is hiding, Crew Cabs began delivery last week with Regular Cab, Double Cab and Duallies hitting the streets this fall. Restrain yourselves.
Let’s now talk about the biggest reasons for owning a Heavy Duty Chevrolet (or GMC). It’s towing. And if you’ve noticed comments to our 15-camera article, there’s some passion about technology. Realistically, as many HD trucks are sold to new truck owners towing large RVs, anything that improves road safety is flat wonderful.
If you further read Chevy’s research that says 12-percent of pickup drivers have gotten into a fight with their significant other over trailer hookup, you’ll understand executive chief engineer Tim Herrick’s comment that “We save marriages.” Having driven every truck segment from light duty to tractor-trailers we feel you. So, when research says a majority of drivers are stressed by towing, please offer them a 2020 Silverado sales brochure and a tissue (and save a tissue for yourselves ‘cause you might be exaggerating your tow-cool).
So let’s dive deeper into the subject.
Everyone has a hitch camera these days, with overlaid guidelines to put you within a few inches, front-to-back, of the ball. Chevy goes further with a selectable view that looks own over the ball. Even those who haven’t set a hitch in years—or never—can get within a quarter-inch of perfect. And an APB or automatic parking brake engages automatically so that when you lift off the brake pedal you don’t roll off the ball.
Sticking with the non-pros and semi-pro haulers, there’s a checklist for your trailer, the ability to check the lights after connecting the trailer’s electrical system, a tow-haul reminder and VIN-specific labels for the trailer itself. If you option the smart trailer integration, which is designed to work with ASA Electronics iN∙Command® control system, you have control over trailer features like heat and air conditioning through the infotainment system or the myChevrolet mobile app. And nobody should turn down the ability to monitor trailer tire pressure and temperature. Blowouts are never convenient and most often low-pressure and highly temperature related, according to Michelin Tire Company.
We found the 15-view system difficult to get used to during the first five minutes, particularly when backing; our mirror habits are embedded. Yet, simulating tight turns where we could see along both the tight and far side, pulling forward into a tight box, or backing (after a few tries), we really came to appreciate what the system could do. Then, on the highway with an 18,000-pound box trailer behind us, mirrors just didn’t cut it compared to the high-tech camera system.
We were driving on twisting two-lane blacktop in mountain foothills. Using the entire camera tech set, particularly the ability to look out the back of the trailer, we could easily pick places to pull aside to let faster cars pass us. It took less than an hour to become a must-have feature. Later we towed a smaller skid-steer on a flatbed without the system and truly missed it despite using our slide-out mirrors fully extended.
This naturally leads to the two engines offered in the 2020 Heavy Duty, first the 6.6-liter V-8 purpose-built gas engine that delivers 22-percent more torque than its predecessor. Now it delivers 401 horsepower and 464 lb-ft of torque. It’s mated to a six-speed automatic transmission.
The 6.6L isn’t a just a 6-mm stroked 6.0L, rather it takes advantage of the Gen5 small block architecture and has a unique cast iron block with forged powdered-metal connecting rods and forged crankshaft. The most significant change is the addition of Direct Injection. It’s all new, an industry first for the heavy-duty market and new to GM trucks. Direct Injection allows a compression ratio of 10.8:1 Quoting Mike Kociba, a GM engineer and part of the Small Block team, “Our suite of changes allows us to hit class-leading gasoline engine torque, at 464 foot-pounds at a lower engine speed than the outgoing six-liter was optimized for. I'm proud of its 401 horsepower, which is SAE Certified; no games, it’s legitimate. Customers can have confidence they're going to tow whatever trailer they need.”
Don’t forget the larger cooling fan and newly designed water pump. The pump drives the fan through a one-inch shaft with unique bearing design to handle greatly increased thrust loads. Plus, the oil pump is now has variable output, so there’s less parasitic losses.
The 6.6L engine features an aluminum oil pan, nylon 6-6 air intake, and stainless steel exhaust manifolds unique for the Heavy Duty market. Like related light duty Gen 5 motors, this motor has variable dual-equal valve actuation, massive Gen5 valves and uses an actuator that’s mounted to the front cover to control intake and exhaust valves. The new block features inter-bore cooling, that is, coolant flows through Siamesed bores, notably in the upper bores where there’s a tendency to generate higher temperatures.
“Small engines with turbochargers allow them peak torque off idle,” Mike told us, “but for heavy duty we don't want that complexity. For the Heavy Duty segment we (General Motors) have durability requirements—Global Engine Durability—that are unique stringent. We know our customers and why we focus on durability. If they can't use their truck today, they might not get paid.”
When towing a heavy load, we loved the diesel’s engine braking capability. What about the gas engine? In Tow-Haul, up-speeds caused by downhill driving—together with intelligence based on throttle position—the powertrain produced seamless downshifts. It’s not quite the same as engine braking, but the trailer was “only” 12,000 pounds. Regardless, it was a comforting addition to stress-free towing.
The six-speed transmission used for 2020 Heavy Duty GM trucks is an updated 6L90 with an uprated torque converter and clutch pack. According to GM engineer Rich Mardeusz those changes were simple. When it came to the torque converter, things changed. “We looked at the components from a heavy-duty diesel torque converter and a high-output gas torque converter and then took the torque-carrying components from the diesel and married them to the spring and damping components from the gasoline torque converter. That’s what was needed to accommodate the approximate 22 percent across-the-board torque increase.” Those changes also damp out firing frequencies from the gasoline V-8 engine, making the powertrain smoother.
Since a majority of buyers opt for the diesel engine, let’s look at that. Also displacing 6.6-liters, the Duramax turbo-diesel makes 445 horsepower and 910 lb-ft of torque. It’s coupled to a 10-speed Allison transmission. There were minimal changes to the engine for 2020. They include a 28-inch fan for cooling; upgraded oil cooler—now 19 plates instead of 14 and the cylinder head gasket was improved.
Engine brake capacity is greater by 14-percent and while there’s a button for manual activation, while in Tow-Haul mode engine braking is automatically activated at certain RPMs. It’s Chevrolet keeping you safe.
Thus, under the new control system the powertrain will recognize any need for the engine brake and activate automatically. For instance in driving down hill and forgetting to shift, the higher RPM means automatic activation.
We did experience this with the18,000 pound box trailer and it is amazingly transparent and surprisingly quiet. You don’t have to downshift on modest hills, as the system will totally keep you at, or near your desired speed. Of course you may have to use a bit of smooth brake application if the grade is longer, or steeper. For really steep downhilling Plus-Minus buttons on the column-mounted shifter initiate gear changes. We’re not huge fans of the buttons as the steering wheel obscures their location and make it a bit fumbly to slide your thumb into position.
A really important feature for 2020, diesel models add an engine after-run feature. Should you tow up a grade and park for dinner without a cool-down, the truck will do it for you. Run time is limited by temperature and shutdown is equally automatic.
Because of the Allison/GM 10-speed transmission used for 2020, the powertrain required a complete recalibration. There are several positive results, according to David Ames, GM assistant chief engineer and Allison liaison. “Emissions have been improved and fine-tuned to maintain the best efficiency the transmission can offer to our customers.” It also has a fully warranted chain-driven engine-speed PTO available from the factory.
The new 10-speed’s torque converter has a lock-up clutch that is unique as it will lock up in first gear, even under max loads. So, if you're pulling 35,500 pounds, you can do a first gear launch and lock up right away, which helps get rid of heat. We asked David why this is important. “Normally in first gear you're under high torque and generating a lot of heat, which puts a lot of demand on the cooling system. Locking up gets rid of that heat. Also, the new transmission has a lower 4.5:1 first gear with four planetary gear sets and six clutches. We noticed the low gear and ten speeds on launches and while pulling the box trailer on the highway. Often in hilly driving you're downshifting to save brakes; with ten gears we held the right speed and best RPM, particularly with automatic engine braking.
We did drive a Silverado 3500HD dually at max capacity; 35,500 pounds on a closed course: our US Army CDL permit has lapsed. The claim of off-the-line torque is spot on. What was most interesting was the 3500’s ability to resist being pushed about on turns and we did several random serpentine loops to see if we could find any significant push? Nope. Later, with “only” 17,000 pounds behind us we finally found a bit of trailer push, which required a deeply rutted dirt road and an off camber turn. Nothing the truck couldn’t handle, even with a journalist behind the wheel.
Many of us wondered why the different transmissions for Heavy Duty trucks, why not just the Allison ten? We asked and, while suspecting that plant capacity utilization and raw costs have something to do with it, were told by Vincenzo Verino, the 3.0L Duramax global chief engineer “It’s really about what the transmission brings to the engine itself. With a wider torque band, the gas engine is well-matched to a six-speed, while the narrower torque band of the Duramax is better suited to a 10-speed.”
In the battle for Heavy Duty supremacy, big numbers are thrown around to convince potential buyers of worth and value. We found these slides from Chevrolet’s presentation compelling, showing Chevrolet doesn’t always have the biggest power numbers, yet can deliver more real world competency than competitors. Faster to 60 with better towing capability, we’ll take that over a bigger number any day. And Chevrolet says every diesel dually will tow more than 30,000 pounds the 2500HD with 6.6L gas engine has a tow capacity of 17,400 pounds, up 18-percent, that’s good regardless altitude.
There is much, much more to tell in future stories, like the no-cut removable fascia for winter snow plow installation and the covered fender-mounted engine heater outlet, use reports of the up-down power tailgate and the bed’s 12 fixed and 9 moveable tie-downs. There’s details on improved axles, locking rear differential, beefed-up prop shaft and 12-inch ring gear, stronger U-joints, class-exclusive SLA front suspension (“mandating a solid front axle for HD trucks isn’t a thing” according to the chief engineer Tim Herrick) and the list goes on.
We expect to write several more stories about the new trucks, each specific to how you’d use the truck and with even more details. We have only scratched the surface.
Thom Cannel: Article & Photos
Zane Merva: Photos
June 24th, 2019
This could be the shortest Chevrolet truck review in history.
If that's what you came for, you can stop reading right now. But if you're curious...
Why is the 3.0L Duramax so awesome? Because unless you’re building a custom lifestyle truck or simply using it for basic tasks you’ll be no doubt upgrade to more powerful engine when you buy your next Silverado or Sierra. That means either the famous 6.2-liter V-8 gas engine or this all-new 3.0L Duramax Turbo-diesel 3.0-liter diesel with its 277 HP, 460 torques and 9,300 pound towing capacity.
If your truck is a lifestyle statement—and we have zero problems with that—this may not apply to you. That is, unless you’re from Texas where a better engine is as necessary as church on Thursday, guns, and football. Our vote, as the upgrade cost is the same $2,495 as for the 6.2L gas engine, is the new 3.0-liter inline six-cylinder diesel. It has the same torque, better fuel economy (we expect) and even has a sweet engine exhaust sound.
Chevrolet invited GM-Trucks to Bend, Oregon to test the 2020 Silverado and it’s new diesel engine. Don’t worry if you just bought a 2019 Silverado—there are no huge differences for 2020; the truck was only released a few months ago. So, for 2020 Chevy adds adaptive cruise control and the amazing 15-view camera technology that includes “invisible trailer” from the Heavy Duty segment. We covered that.
For 2020 Chevrolet offers a diversity of engines. There are, in addition to the new diesel, the 310 horsepower / 348 lb-ft 2.7-liter DI turbocharged I-4 with an 8-speed transmission, and two legendary small block gas engines, the 5.3L and 6.2L.
In Model Year 2020 the 5.3L makes 355 horsepower (265 kW) and 383 lb-ft of torque (519 Nm) coupled to an 8-speed transmission, the 6.2L is SAE-certified to deliver 420 HP (313 kW) and 460 lb-ft of torque (623 Nm). It is paired with GM’s 10-speed transmission, which couples perfectly with GM’s DFM cylinder deactivation system. Hey, you don’t think you can run on two cylinders with an ordinary transmission, do you?
According to Chevrolet the new diesel motor will be available in LT, RST, LTZ and High Country trim levels. The 5.3L gas engine is standard in LTZ and High Country models and available on LT, RST and Trail Boss. The 6.2L gas gasser is available more trim levels for 2020. Both engines will be built at General Motors’ Tonawanda Engine Plant in Buffalo, New York.” Not mentioned is the carryover 4.3L engine aimed at fleet owners.
We arrived in Oregon to 80°F heat and blue skies, then were fed and watered, and set off on different tasks. We can’t talk about the HD trucks and their massive towing capacity for a couple of days. We were offered an incredibly deep-dive into the new engine, and a mileage competition featuring the new 3.0-liter diesel engine to start, however. Winning a comp is cool, but not realistic when you have a limited time with a vehicle in the first place. That said, other journalists did take the time to compete and Sunday’s winning mileage was in the 34-36 mpg range and then blown away by Monday’s 46 mpg. That, friends, is some serious hypermiling! However we still do not have official EPA certified mileage. That’s “To Come”.
If you haven’t read much about the 3.0, here’s a modestly deep dive into its guts. First, the whole engine is state-of-the-art, aluminum head and block with thin steel cylinder sleeves and seven main bearings for the crankshaft. Combustion processes were among the driving forces underpinning design theory, so the cylinder head is essentially flat and the bowl-shaped pistons have zero relief cuts for the valves. That was important for efficiency.
Simulation, and single-cylinder engine studies showed that having very vertical valves would not only allow a simpler bowl shape in the pistons, but that very shape would allow inlet-generated swirl to be maximized at every point. Swirl is produced and governed by dual intake runners feeding each cylinder. Oh, the ceramic glow plugs gave GM the highest compression ratio consistent with power and emissions, as well as allowing ignition to -22°F without a block heater. FYI, most of the engine development and engineering, as well as primary calibration took place in Turin, Italy. That’s GM’s center of diesel excellence.
To ensure a quiet engine, emissions that more than meet standards, and deliver fuel economy, GM finalized an injection pressure of 2,500 bar (36,500 psi) through solenoid injectors capable of up to ten injections per combustion cycle. Early injections are primarily used to build in-cylinder pressure smoothly to abate diesel clatter. Later injections can be used for power and to keep the catalyst working within specified temperatures (those injections, sometimes caused by a catalyst cooled by highway driving, do negatively affect fuel economy but maintain emissions specifications).
There’s a single close-coupled VGT turbo, for now, which indicates a possibility for later development of greater power and torque. Packaging to the “chemical factory” is as tight as could be manufactured.
What we really haven’t talked about is the decision for an I-6 engine, versus a V-type. Obviously, six cylinders are longer than three, or even four. This slightly under-square engine delivers two things that a V design does not: smoothness and less side force. A V-type engine necessarily produces some side thrust, which is one of the reasons that Ford’s new 3.0L is made of CGI or Compacted Graphite Iron. In contrast, by using a robust, deep skirt design, Chevrolet and other divisions have an all-aluminum block, saving weight. Some of the extra length is minimized by packaging chain driven shafts at the rear.
If you’ve never driven, or better yet heard an inline six, they’re smooth, likely the smoothest engine you’ve driven and with a unique sound. Both delivered by six evenly spaced exhaust pulses. The last I-6 engine GM produced was the gasoline Atlas LL8/Vortec 4200 used in Chevy Trailblazer, GMC Envoy, Buick Rainier, Olds Bravada, Isuzu Ascender and Saab 9-7X. ) Note that Detroit Diesel has produced an inline-6 since 1980 that displaces 11-14L.)
Before highway driving, we did a walk-around. The GM-exclusive Durabed is impressive, and hard-coated for scuff resistance. Chevrolet says it’s made up of several sections instead of 1-2 deep drawn pressings. This provides owners with more cargo volume. As Chevrolet (and GMC) will tell you, it’s made of several varieties of High Strength Steels, so they claim it’s more dent and penetration-resistant than Ford’s aluminum bed. Inside the bed are 12 fixed tie-down points and nine moveable points, which has been a big hit with owners. Plus there’s that available power up/down tailgate, a power outlet and task lighting. A somewhat unnoticed feature is relocating the bed lights to flank the CHMSL on the roof edge. A couple of other things that are important are the corner steps and bed steps. They’re made for size 13 steel-toed boots and hold up to 500 pounds.
We then drove the truck on the highway and on two-lane roads. Our first impression was of the powerful engine sound, followed by impressive torque. Electric motor type torque. Smooth power available at the lowest of engine speeds.
Engine noise isn’t intrusive but like the torque, off the line it lets you know it’s there. However, with an open hood you hardly know it’s a diesel, it is that quiet. Even a random enthusiast who had been researching the new 3.0L Duramax and stopped us at a boat launch had to ask if it was a Diesel. This is simply unlike the larger Duramax and any other light duty diesel on the market.
Something we’ll get into in our Heavy Duty story is the reason there’s a 10-speed transmission. If you think about the power band of a diesel engine, here delivering all of its 460 lb-ft of torque at just 1,500 rpm and holding strong to about 4,000 rpm, that’s significantly different than the power band of a gas engine. Thus, the 10-speed maximizes power and fuel economy—and every automaker has to deliver fuel economy, low CO2 and clean emissions.
We have much more to come. For instance, we need to see if tow ratings are realistic, if its EPA fuel economy beats Ford’s 30Highway/22City/25Combined and how well it lives up to the Find New Roads slogan in real world driving under every condition we can discover.
Contributing Writer, GM-Trucks.com
Chevrolet has just announced its prices and specs for its first-ever inline-six turbo-diesel offered in a Chevy full-size light-duty truck. The all-new 3.0-liter Duramax turbo-diesel will offer class-leading torque and horsepower according to Chevy. First up, pricing. The new Duramax option will be available on LT, RST, LTZ and High Country models. It is priced identically to the 6.2L V-8 option as a $2,495 premium over a 5.3L V-8 model or $3,890 over a 2.7L Turbo model.
Next up, specs. The Duramax 3.0-liter engine will generate 460 lb-ft of torque delivering 95 percent of peak torque at just 1,250 rpm. Peak torque is sustained from 1,500 rpm through 3,000 rpm, providing a powerfully smooth and satisfying driving experience. Being a diesel engine, power is low relative to bigger V8 gas engines, but pretty substantial for its displacement at 277 horsepower.
“From the moment the engine is started, to its idle, acceleration and highway cruising, the 3.0L Duramax performance will change perceptions of what a diesel engine can offer in refinement,” said Nicola Menarini, director for Diesel Truck Engine Program Execution. “With advanced technologies that draw on global diesel expertise, it’s a no-compromise choice for those who want the capability and driving range of a diesel in a light-duty truck.”
Design and Technology
Since the engine is an inline six, it is inherently balanced. There is no need for balance shafts and the engine only requires two cams. Chevy uses a cast aluminum alloy block that provides the strength required to support the high combustion pressures that occur within a diesel engine, while also offering a 25 percent mass savings over a cast iron engine block. Chevy says there are seven nodular iron main bearing caps that help ensure the block’s strength under those high combustion pressures, while also enabling accurate location of the rotating assembly. A deep-skirt block design, where the block casting extends below the crankshaft centerline, also contributes to the engine’s stiffness and refinement. It’s complemented by a stiffness-enhancing aluminum lower crankcase extension attached to the main bearing caps. Chevy went on to add that the rotating assembly consists of a forged steel crankshaft, forged steel connecting rods and hypereutectic aluminum pistons. The alloys in the respective castings for the rods and pistons make them lightweight and durable. Silicon is blended with the aluminum for heat resistance and tolerance within the piston cylinders, which enhances performance and makes the engine quiet. GM used a thick piston crown — the top of the piston — and also a reinforced top ring to add strength to support the high cylinder pressures enabled by turbocharging and the engine’s high 15.0:1 compression ratio. To ensure durability, Iron cylinder liners are employed. “In addition to reduced friction, the architecture enables smooth operation,” Menarini said. “The new Duramax 3.0L elevates the 2019 Silverado with one of the most refined and efficient diesel engines in the segment.”
Here is a quick rundown of some other features of this new engine:
OHC: Overhead camshafts offer a direct, efficient means of operating the valves, while four valves per cylinder activated by maintenance-free finger followers with hydraulic lash adjusters increase airflow in and out of the engine. This arrangement is integrated on the Duramax 3.0L’s lightweight aluminum cylinder head, which is topped with a lightweight composite cam cover that incorporates the crankcase ventilation and oil separation systems.
A pair of lightweight, assembled camshafts actuates 28.35 mm diameter (1.12-inch) intake and 24.55 mm diameter (0.97-inch) exhaust valves. The camshaft drivetrain is uniquely located at the rear (flywheel side) of the engine, for greater refinement and packaging considerations for the comparatively long inline-six. A crankshaft-driven chain drives the high-pressure direct-injection fuel pump, while a chain driven by the fuel pump drives both intake and exhaust camshafts. A smaller belt drives the variable flow oil pump from the crankshaft.
Variable geometry turbocharging enables the Duramax 3.0L engine to deliver class-leading horsepower with minimal effect on overall efficiency. The system uses closed loop controlled vanes position and sophisticated electronic controls to automatically adjust boost pressure to the desired value based on engine running conditions and instantaneous power demand. The liquid-cooled turbocharger features a low-friction ball-bearing shaft and is mounted close to the exhaust outlet of the engine for quicker spool-up of the turbine and quicker light-off of the exhaust catalyst. A water-to-air intercooling system produces a cooler higher density air charge for greater power. Maximum boost pressure is 43,5 psi (300 Kpa) absolute.
Low-pressure EGR: The Duramax 3.0L utilizes new low-pressure Exhaust Gas Recirculation to optimize performance and efficiency. The EGR system diverts some of the engine-out exhaust gas and mixes it back into the fresh intake air stream, which is drawn into the cylinder head for combustion. That lowers combustion temperatures and rates.
Traditionally, EGR systems in diesel applications recirculate exhaust gases between the two high-pressure points, the exhaust manifold(s) and intake manifold. However, it generally requires efficiency-robbing assistance from the turbocharger or other supporting elements to achieve the pressure differential required for sufficient EGR flow rates.
The new low-pressure system adds to the high-pressure system, supporting continual adjustment of exhaust backpressure for more efficient operation. It recirculates gases between the low-pressure points in the exhaust system (downstream of the particulate filter) and after the compressor inlet.
When the low-pressure EGR is activated by an electronically controlled valve, the engine burns exhaust gas that has already passed through the particulate filter. That increases the turbocharger’s efficiency, which helps overall vehicle efficiency without deteriorating the rate of particulate matter emitted by the engine.
A variable intake manifold offers dual air intake pathways for each cylinder. Electronically controlled flaps — one for each cylinder — shorten or lengthen the airflow to each cylinder. This optimizes the airflow into the engine and improves performance and responsiveness across the rpm band, particularly at lower engine speeds.
A variable-pressure oiling system with a continuously variable-displacement vane oil pump enhances efficiency by optimizing oil pressure as a function of engine speed and load. With it, the oil supply is matched to the engine requirements rather than the excessive supply of a conventional, fixed-displacement oil pump. The engine uses low-friction Diesel Dexos 0W20 oil.
Oil jets located in the block are employed for performance and temperature control. They target the inner core of the piston with an extra layer of cooling, friction-reducing oil. The jets reduce piston temperature, allowing the engine to produce more power and enhance long-term durability than engines without the technology.
Active Thermal Management helps the engine warm up quickly to achieve and maintain its optimal engine temperature for performance and efficiency over the entire engine operating range. The system uses a three-actuator rotary valve system to distribute coolant through the engine in a targeted manner. It sends heat where it’s needed to warm up the engine to reduce friction and heat the passenger cabin or cools when needed for high-power operation. The Duramax 3.0L also features split cooling between the block and head.
Common rail direct fuel injection of 2,500 bar (36,250 psi) helps generates class-leading horsepower and torque. The system’s pressure is generated by an engine-driven twin-piston pump sending fuel to solenoid-activated injectors with nine-hole nozzles that support precise metering of the fuel for a smooth idle and lower combustion noise. The fuel system is capable of multiple injections per combustion cycle — up to 10 times per injector — for more consistent and stable combustion performance that translates into smoothness and refinement, particularly at idle.
Electronic throttle valve: The Duramax 3.0L features an electronic throttle valve to regulate intake manifold pressure in order to optimize exhaust gas recirculation rates. It also contributes to a smooth engine shutdown via a more controlled method of airflow reduction.
Ceramic glow plugs used in the Duramax 3.0L heat up more quickly and hotter than conventional metal-based glow plugs, helping the engine start and heat up more quickly in cold weather. The Duramax 3.0L achieves unassisted and assisted starting temperatures of -22 F (-30 C) and -40 F (-40 C) respectively.
Stop/start technology helps optimize efficiency in city driving. The driver-selectable system shuts off the engine at stoplights and other stop-and-go situations. The engine automatically restarts when the driver takes their foot off the brake.
Chevy will offer just one transmission with the 3.0L Duramax, its 10L80 10-speed automatic transmission. The transmission features a centrifugal pendulum absorber torque converter that reduces vibrations to improve smoothness, reinforcing its performance, efficiency, and refinement. Exhaust braking is part of the design. This technology uses the diesel engine’s compression to help slow the vehicle, requiring fewer brake applications by the driver when in Tow Haul mode.
Due to some minor emission certification delays, the new diesel engine will be available in early 2020, rather than late 2019.
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