- Photo courtesy of GM

Photo courtesy of GM

The 2020 Chevrolet Silverado 1500’s available 3.0L Duramax inline-six turbo-diesel engine is the first-ever inline-six turbo-diesel offered in Chevrolet’s full-size light-duty trucks, according to General Motors.

Chevrolet engineers started with a clean-sheet design and developed an all-new engine. It is priced identically to the 6.2L V-8 as a $2,495 premium over a 5.3L V-8 model or $3,890 over a 2.7L Turbo model.

“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.”

Available on LT, RST, LTZ, and High Country models, the 3.0L Duramax diesel rounds out the new Silverado’s range of six propulsion choices.

It is rated at an SAE-certified 277 hp and 460 lb.-ft. of torque delivering 95% of peak torque at just 1,250 rpm. Peak torque is sustained from 1,500 rpm through 3,000 rpm.

The 3.0L Duramax is paired with GM’s 10L80 10-speed automatic transmission, featuring a centrifugal pendulum absorber torque converter that reduces vibrations to improve smoothness. This combination also offers exhaust braking, which uses the diesel engine’s compression to help slow the vehicle, requiring fewer brake applications by the driver when in Tow Haul mode.

The inline six-cylinder’s lightweight aluminum block and cylinder head reduce overall mass, and Active Thermal Management enhances efficiency and cold-weather warm-up. Ceramic glow plugs also help with shorter heat-up times and a quicker cold start, meaning the engine block heater is not needed until -22 degrees F.

Fleet drivers can gain additional confidence thanks to the exhaust brake available in tow-haul mode. The water charge air cooler, coupled with low-pressure EGR, reduces time to torque. The variable geometry turbocharger helps provide a greater balance of performance and efficiency, and an electronically variable intake manifold helps optimize performance across the rpm band.

Compared to a DOHC V-6, the inline-six architecture offers greater efficiency from the reduced friction of operating only two camshafts and their associated valvetrain components.

 - Photo courtesy of GM

Photo courtesy of GM

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.

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