Car & Driver
May 17, 2018
Source: General MotorsChevrolet will add a turbocharged four-cylinder engine to the 2019 Silverado pickup truck. The engine, built in Spring Hill, Tennessee, will be available in midline LT and RST trims and serves as the entry-level powertrain in those models. Today’s 4.3-liter V-6 will live on in lower-level Work Truck, Custom, and Custom Trail Boss trims.
Displacing 2.7 liters, the long-stroke forced-induction four is an all-new unit that General Motors said was designed specifically for truck applications. It packs a solid punch with 310 horsepower and 348 lb-ft of torque—just 35 lb-ft shy of the optional 5.3-liter V-8—that is available from as low as 1500 rpm and continues to 4000 revs. The engine is paired exclusively with an eight-speed automatic transmission.
The little engine moved the big Silverado with plenty of pep off the line while emitting no noticeable vibration while on the go, at idle, or on restarting from a stop by way of its automatic stop/start system. Additional efficiency measures include variable valve timing, an electric water pump, and a cylinder-deactivation system that seamlessly cuts fuel to cylinders two and three if conditions permit. The use of an aluminum block helps make for an engine that weighs approximately 80 pounds less than the 4.3-liter V-6.
April 17, 2018
The all-new 2.7L Turbo:
The all-new 2019 Chevrolet Silverado 1500 will be offered with an all-new, technologically advanced 2.7L Turbo that expands the range of available engines and builds upon additional choices to help customers find the Silverado that perfectly suits their needs.
Standard on LT and RST trims, the new engine delivers an SAE-certified 310 horsepower and 348 lb-ft of torque, for 22 percent more torque than the 4.3L V-6 it replaces. Developed specifically for truck applications, the new 2.7L Turbo inline four-cylinder engine delivers peak torque from 1,500 to 4,000 rpm.
The next-gen Silverado with the 2.7L Turbo delivers 0-60 mph performance in less than seven seconds and weighs 380 pounds less than the current Silverado with the 4.3L V-6. Compared with competitive full-size trucks, the Silverado 2.7L Turbo is expected to deliver comparable payload capability with greater torque than the 3.3L V-6 in the Ford F-150 XLT and the 3.6L V-6 in the Ram 1500 Big Horn.
“The new 2.7L Turbo is a technological marvel, with our most advanced valvetrain,” said Tom Sutter, chief engineer for the 2.7L Turbo. “With a broad, flat torque curve and quick throttle response, it punches above its weight, delivering surprising performance and efficiency.”
The cornerstone of the 2.7L Turbo is an innovative double overhead cam valvetrain that enables:
Chevrolet’s first use of Active Fuel Management (cylinder deactivation) on a four-cylinder engine.
High- and low-lift valve profiles.
Continuously variable valve timing.
Additional engine technologies supporting the engine’s performance and efficiency include:
Dual-volute turbocharger housing for improved throttle response and low-speed torque.
Chevrolet’s first application of Active Thermal Management, which uses targeted engine heating and cooling to improve engine performance in hot and cold ambient temperatures.
An integrated exhaust manifold that is part of the cylinder head assembly and recovers exhaust heat for faster engine and transmission warmup, with quicker turbo response.
Stop/start technology that automatically stops the engine in stop-and-go traffic for fuel efficiency.
An electric water pump that eliminates the drag of a conventional, engine-driven pump to enhance efficiency. It also enables continual cabin heating even when the engine is disabled by the stop/start feature.
Designed as a truck engine
The new 2.7L Turbo engine represents a clean-sheet design for Chevrolet and was developed from the outset as a truck engine.
To help generate the strong low-end torque customers expect in a truck, it was designed with a long piston stroke of 4.01 inches (102mm), which is the distance the piston travels up and down within the cylinder.
The long stroke enables improved combustion and thus a higher compression ratio. Typically, a long stroke can increase the load of the pistons against the cylinder walls, generating more friction. That’s alleviated in the 2.7L Turbo with an offset crankshaft. It is slightly off-center of the cylinders, allowing a more upright position for the connecting rods during their movement.
To support the high cylinder pressures that come with turbocharging, the crankshaft and connecting rods are made of forged steel and the pistons are made of a tough aluminum alloy with a cast iron ring groove insert.
All elements of the 2.7L Turbo were designed for the demands of turbocharged performance in a truck environment, and the engine was subjected to the same rigorous durability standards as the Silverado’s proven V-8 engines.
The 2.7L Turbo features an aluminum block and cylinder head for reduced mass.
Unique valvetrain offers more precise control
The 2.7L Turbo’s valvetrain is GM’s first to incorporate variable lift, duration and Active Fuel Management to optimize performance and efficiency across the rpm band. It is a key reason the engine’s peak torque is available at only 1,500 rpm.
The system’s electro-mechanical variable camshaft effectively allows the engine to operate with three different camshaft profiles, complementing the variable valve timing system to deliver optimized operating modes for different engine speeds and loads:
1. High valve lift for full power.
2. Low valve lift for balance of power and efficiency.
3. Active Fuel Management shuts down two of the cylinders in light load conditions to further conserve fuel.
“It’s like having different engines for low- and high-rpm performance,” said Sutter. “The camshaft profile and valve timing is completely different at low and high speeds, for excellent performance across the board.”
The camshaft design alters the lift of the intake and exhaust valves. As the engine load changes, electromagnetic actuators allow a movable shaft containing different cam lobes to shift imperceptibly between high-lift and low-lift profiles.
Lift is the distance the valve travels from its seat when opened, and duration is the amount of time the valve remains open. Higher lift and longer duration allow more air to flow into the combustion chamber, so the system’s high-lift lobe profile enhances performance at higher rpm, while the low-lift profile optimizes efficiency at low- and mid-range speeds.
Dual-volute turbocharger builds torque
The 2.7L Turbo engine employs an advanced dual-volute turbocharger that elevates the performance and efficiency advantages of a conventional turbo, with quicker response and enhanced low-rpm torque production.
Rather than a single spiral chamber (volute) feeding exhaust gas from the exhaust manifold to drive the turbine on the turbocharger, the dual volute design has a pair of separate chambers with two exhaust gas inlets and two nozzles to drive the turbine. The design allows the exhaust pulses of the engine to be leveraged for faster spool-up and subsequent boost production, particularly at low rpm, where the effect significantly enhances torque output and drivability.
It works in unison with the engine’s integrated exhaust manifold/turbocharger housing, which splits the exhaust channels from the cylinder head so the exhaust flows through two separate channels in the turbo housing, based on the engine’s exhaust pulses. When complemented by the precision of the engine’s valvetrain, that separation leverages exhaust scavenging techniques to optimize gas flow, which decreases exhaust gas temperatures, improves turbine efficiency and reduces turbo lag.
An electronically controlled wastegate and charge-air cooling system support the turbocharger and enhance its effectiveness. Compared to a conventional wastegate, the electronically controlled version offers more precise management of the engine’s boost pressure for smoother, more consistent performance.
With the charge-air cooler, the pressurized, heated air generated by the turbocharger is pumped through a heat exchanger before it enters the engine. That lowers the air charge temperature by about 130 degrees F (74 C), packing the combustion chambers with cooler, denser air that enhances power production. The system achieves more than 80 percent cooling efficiency with less than 2 psi (12 kPa) flow restriction at peak power, contributing to the engine’s available torque production at low rpm.
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.
Active Thermal Management helps the engine warm up faster and achieve its optimal engine temperature for performance and efficiency. The system uses a 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 cab, or cools when needed for high power operation.
An electric water pump — a first for Chevy trucks — supports the Active Thermal Management system and further enhances the engine’s performance and efficiency by eliminating the parasitic drag that comes with a conventional engine-driven water pump.
Direct fuel injection is used to optimize efficiency and performance. With direct injection, a higher compression ratio (10.0:1) is possible because of a cooling effect as the injected fuel vaporizes in the combustion chamber, reducing the charge temperature and improving resistance to spark knock. Direct injection also enables gas scavenging from the combustion chamber to the turbo for fast response.
Dual overhead camshafts contribute to the 2.7L Turbo’s smoothness and high output, with dual independent continuously variable valve timing working with the valvetrain to deliver optimal performance and efficiency. The dual independent system, which allows the intake and exhaust valves to be phased at different rates, promotes linear delivery of torque with near-peak levels over a broad rpm range, and high specific output (horsepower per liter of displacement) without sacrificing overall engine response or driveability.
An integrated exhaust manifold on the cylinder head assembly promotes faster engine warmup and quicker turbo response.
Oil jets located in the block are employed for performance and temperature control. They target the underside of the pistons and the surrounding cylinder walls 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.
Stop/start enhances fuel economy in city driving. The driver-selectable system shuts off the engine at stoplights and certain other stop-and-go situations, saving fuel. The engine automatically restarts when the driver takes their foot off the brake.
The all-new 2.7L Turbo is matched with a Hydra-Matic eight-speed automatic transmission featuring enhancements designed to improve shift quality, as well as a new centrifugal pendulum absorber torque converter that reduces vibrations to improve smoothness.
The all-new 2.7L Turbo will be built at the General Motors Spring Hill facility in Tennessee.
2019 Silverado Overview:
With eight trims paired with six engine/transmission combinations, even more customers will find a 2019 Silverado 1500 perfectly tailored to their needs for performance, efficiency, technology and value.
“A major focus of the next-generation Silverado is expanding the range of choices,” said Tim Asoklis, chief engineer for the Silverado 1500. “With all-new engines and a broader model range, there’s a Silverado for everyone, whether you’re buying your first pickup or your tenth.”
The all-new 2019 Silverado 1500 propulsion lineup includes:
Over half of the models will be equipped with the most advanced V-8s in the brand’s history: updated versions of Chevrolet’s proven 5.3L and 6.2L engines equipped with industry-first Dynamic Fuel Management featuring 17 different modes of cylinder deactivation.
An all-new, advanced 2.7L Turbo engine that replaces the 4.3L V-6 as the standard engine on the high-volume Silverado LT and new Silverado RST, expected to offer 22 percent more torque, greater fuel efficiency and a stronger power-to-weight ratio than the current model.
Proven 4.3L V-6 and 5.3L V-8 engines deliver full-size truck capability and performance for the most affordable trucks in the Silverado lineup.
An all-new, Duramax 3.0L inline-six turbo diesel will be available in early 2019.
A Silverado — and an engine — for every need
Each engine/transmission combination is matched with exterior design and interior features to create distinct personalities for each Silverado trim, based on three broad customer profiles: High Value, High Volume and High Feature.
High Value — For customers seeking full-size truck capability and the highest level of affordability, the Work Truck (WT), Custom and Custom Trail Boss trims offer two proven engine and transmission combinations:
Standard: 4.3L V-6 with Active Fuel Management and a six-speed automatic transmission (SAE-certified at 285 hp/305 lb-ft).
Available: 5.3L V-8 with Active Fuel Management and a six-speed automatic transmission (SAE-certified at 355 hp/383 lb-ft).
High Volume — For customers shopping in the heart of the truck market, the LT, RST and LT Trail Boss trims balance technology, efficiency and performance:
Standard for LT and RST: All-new 2.7L Turbo with Active Fuel Management and stop/start technology paired with an eight-speed automatic transmission (SAE-certified at 310 hp/348 lb-ft).
Standard on LT Trail Boss and available on LT and RST: An updated 5.3L V-8 with Dynamic Fuel Management and stop/start technology with an eight-speed automatic transmission (SAE certified at 355 hp/383 lb-ft).
Available on LT and RST: The all-new Duramax 3.0L Turbo-Diesel with stop/start technology paired with a 10-speed automatic transmission will be available in early 2019.
High Feature — For customers shopping for a premium truck, the LTZ and High Country trims offer the highest levels of performance and technology, including:
Standard: Updated 5.3L V-8 with Dynamic Fuel Management and stop/start technology paired with an eight-speed automatic transmission (SAE certified at 355 hp/383 lb-ft).
Available: Updated 6.2L V-8 with Dynamic Fuel Management and stop/start technology paired with a 10-speed automatic transmission (SAE certified at 420 hp/460 lb-ft).
Available: The all-new Duramax 3.0L inline-six Turbo-Diesel with stop/start technology paired with a 10-speed automatic transmission will be available in early 2019.
Improved Driving Experience
The performance of each engine/transmission combination benefits from a truck that is lighter and more aerodynamic than the previous model.
“With less weight and less wind resistance, we improved the driving dynamics without sacrificing fuel efficiency,” said Asoklis. “The next-gen Silverado is a bigger truck, but the chassis feels more responsive and acceleration is more pronounced. I would argue it’s the best-driving truck we have ever built.”
The 2019 Silverado is larger than before, including a wheelbase that is up to 3.9 inches (100mm) longer, yet overall length is only 1.6 inches (41mm) longer, enabling both more cargo volume and more interior room for all cab lengths. Remarkably, it’s also lighter, weighing up to 450 pounds (204 kg) less than the current Silverado when comparing crew cab V-8 models, due to extensive use of mixed materials and advanced manufacturing.
To improve the aerodynamic efficiency of the next-gen Silverado, the front grille features functional air curtains, similar to those introduced on the sixth-generation Camaro, that reduce wind drag by routing air around the front wheel wells. The powerful side profile also enhances aerodynamics, with an integrated spoiler at the rear edge of the cab that directs air onto the contoured tailgate, reducing wind drag from the bed. Most models also feature active aero shutters integrated in the front grille that close to reduce wind drag and open to provide improved engine cooling when needed. Changes like these result in a 7 percent increase in total aerodynamic efficiency.
From the family of the Most Dependable, Longest Lasting full-size pickups on the road*
For the new Silverado, Chevy set the lofty goal of improving on the legacy of the Most Dependable, Longest Lasting full-size pickups on the road. To do so, the next-gen truck will be subjected to more than 475,000 validation tests and accumulate a staggering seven million miles of real-world testing before the first 2019 Silverado 1500 is delivered to customers.
That includes a battery of tests for the Silverado engines and transmissions that will simulate a range of customer needs:
Each type of engine was first subjected to a “torture test” in a dynamometer test cell, running for months nonstop to simulate a lifetime of maximum hot and cold cycles.
Each Silverado variant is certified to the SAE J2807 standard for towing and payload capacity. Certification requires a full battery of grueling tests such as the Davis Dam test, in which the truck must carry its maximum gross combined vehicle weight up a 7 percent grade in 110-degrees F (43 degrees C) heat, with no reduction in performance, including air-conditioning.
Chevrolet engineers prove every Silverado engine and transmission design for lubrication capability on tilt stands, originally developed for Corvette, that tilt at an angle of up to 53 degrees and can simulate angles at a rate of up to 40 degrees a second — the equivalent of up to 1.4g.
Silverado production commences with crew-cab V-8 models starting in the third quarter. In the fourth quarter, production will expand to include regular- and double-cab models, as well as V-6 and 2.7L Turbo engines. The new Duramax 3.0L inline-six turbo diesel will be available in early 2019.
EPA fuel economy estimates and towing/payload capacities are not yet available, and will be announced closer to launch.