![The 2.7-liter turbocharged gasoline engine with active fuel management pumps out 310 hp and 348 lb.-ft. of torque.](https://img.forconstructionpros.com/files/base/acbm/fcp/image/2019/09/2019_2_7L_I_4_Turbo_Chevrolet_Silverado.5d7651d2eeed1.png?auto=format%2Ccompress&fit=crop&h=288&q=70&w=512)
The three best-selling vehicles in the United States are full-size pickups:
· Ford F-Series
· Chevrolet Silverado
· Ram Truck
This makes dominance of the ½-ton pickup truck category a true battleground for the manufacturers. Increased fuel economy ranks near the top of customer demands. Unlike their larger ¾-ton relatives that are primarily used for towing applications, the ½-ton pickups are often used for commuting. This places a greater emphasis on the cost of operation.
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According to Consumer Reports 2019 Automotive Fuel Economy Survey Report, 88% of American adults agree that automakers should continue to improve fuel economy. Drivers of large SUVs and pickup trucks are almost twice as likely (55%) as drivers of small or mid-size vehicles (30%) to select fuel economy as a desired improvement. Seventy three percent of people driving a large SUV or pickup truck express an interest in getting a vehicle that is more fuel efficient regardless of their assessments of their current vehicles fuel efficiency.[CT1]
There is a contradiction between the truck manufactures’ efforts to increase fuel economy and the perception by consumers. According to the report, only 34% of Americans agree that automakers care about lowering fuel costs for their customers.
The reality is that the competitive landscape demands that full-size pickup truck manufactures address pressures to increase fuel economy. They have stepped to the plate with several new product offerings. These include diesel engines, advanced controls for gasoline engines, hybrids, eight- and ten-speed transmissions, start/stop technology and more.
Even a few years ago it would have been hard to imagine a full-size pickup achieving 30 mpg. Now there are several options that exceed this mark. The diesel engine is the most significant technology driving these impressive fuel economy gains in the full-size pickup market.
Clean Diesel Technology Conserves Fuel
Diesel engines are typically more efficient and provide more low-end torque than similar-size gasoline engines. Diesel fuel also contains 10 to 15% more energy than gasoline does. These two factors mean a diesel-powered vehicle can travel 25 to 35% further on a gallon of fuel than its gasoline-powered counterpart.
Think of a traditional internal combustion engine as a large air pump. The pump that moves the air more efficiently will get the work done with less effort. A higher compression ratio allows the engine to extract more mechanical energy from a certain quantity of fuel.
The Ford F-150 with the 3.0-liter Power Stroke diesel engine is targeted to return an EPA-estimated rating of 30 mpg highway.Ford Motor Company
There are trade-offs associated with compression ratios that also have to be taken into account with the gasoline engine. The compression ratio is limited by the octane rating. As the compression ratio increases, so must the octane rating to prevent pre-ignition. That’s why higher performance engines often require more costly premium fuel with higher octane ratings.
In the past, a downside to the diesel engine was the ‘dirty’ image and cold-weather start ability issues. Pre-emission control diesel engines tended to produce black smoke at startup and when pulling heavy loads. Since there is no spark plug, diesel engines rely on the heat of compression to ignite the fuel. When it is cold out, this fuel condenses on the cylinder walls, making it more difficult to start.
The negative perceptions surrounding the diesel engine still persist, even though the reality is quite different. This may partially be due to the fact that diesel engines typically have long lifespans and many of the older technology diesel trucks are still on the road.
Modern diesel engines with Selective Catalytic Reduction (SCR) technology have cleaned up the tailpipe emissions. More than one truck manufacturer has held a white cloth over the tailpipe of a running diesel to prove that diesel smoke is a relic of the past. Sophisticated electronic controls and a steady improvement in glow plug technology. have pretty much eliminated cold-weather start ability issues. Just make sure the tank is filled with winter blend fuel so it doesn’t gel when the temperature drops.
Half-ton Pickups Convert to Diesel
The Chevrolet Silverado’s 3.0L Duramax inline-six turbo-diesel engine offers segment-leading torque and horsepower, in addition to a focus on fuel economy and capability.General Motors
Ford introduced the 3.0-liter Power Stroke diesel F-150 for the 2018 model year. At that time, it led half-ton fuel economy with an EPA-estimate rating of 30 mpg highway, 22 mpg city and 25 mpg combined. This was accomplished without sacrificing capability. The 3.0-liter Power Stroke pumps out 250 hp and, more importantly, 440-lb.-ft. of torque. The torque helps the F-150 achieve 11,400 lbs. of towing capability
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General Motors developed a 3.0L DuraMax turbo-diesel for its 2020 Chevrolet Silverado 1500 full-size pickup line. It delivers an EPA-estimated 33 mpg highway and 23 city in rear-wheel-drive models. EPA-estimated fuel economy for four-wheel drive models is 29 mpg highway/23 city.
It targets performance with 277 hp and 460-lb. ft. of torque in addition to focusing on fuel efficiency. This engine is capable of delivering 95% of peak torque at just 1,250 rpm. It then offers a flat torque curve that sustains peak torque from 1,500 to 3,000 rpm.
The third generation Ram Truck EcoDiesel pumps out a class leading 480 lb. ft. of torque at 1,600 rpm and 260 hp at 3,600 rpm. Compared to the previous generation EcoDiesel, the new powerplant produces 14% more torque and 8% more horsepower.Ram Trucks
The third generation EcoDiesel is not a warmed-over version of the previous offering. It is a fresh design with over 80% new components. This includes revolutionary technologies such as a low friction Diamond Like Coating (DLC) on the piston pin and piston side skirts to reduce friction and a 0.3 mm piston pin offset to reduce piston noise caused by piston slap. Piston slap is a major contributor to that classic ‘diesel’ sound many of us have grown accustomed to over the years.
The third generation EcoDiesel pumps out a class leading 480 lb. ft. of torque at 1,600 rpm and 260 hp at 3,600 rpm. Compared to the previous generation EcoDiesel, the new powerplant produces 14% more torque and 8% more horsepower. Ram’s half-ton EcoDiesel is rated at 32 mpg highway, 22 mpg city for 4x2 models; 29 mpg highway, 21 mpg city for 4x4 models..
Gasoline Engine Option Focused on Saving Fuel
The 2.7-liter Ford EcoBoost engine with standard Auto Start-Stop provides best-in-class gas mileage, mid-range V8-like towing capability of 8,500 lbs., payload of 2,250 lbs., 325 hp and 375 lb.-ft. of torque.Ford Motor Company
Ford has expanded upon its EcoBoost philosophy to increase the efficiency of the company’s gasoline engines. EcoBoost engines combine turbocharging, direct fuel injection and twin independent variable camshaft timing (Ti-VCT) for power and efficiency. This allows smaller-displacement engines to pump out more power than some larger displacement engines, increasing the overall efficiency.
For the 2018 model year, Ford put its second-generation 2.7-liter EcoBoost gasoline engine, mated to a 10-speed SelectShift automatic transmission into its F-150. This resulted in an EPA estimated rating of 20 mpg city, 26 mpg highway and 22 mpg combined. Despite its small displacement, this engine pumps out 325 hp at 5,000 rpm and 400 ft.-lb. of torque at 2,750 rpm. For customers who need more performance out of their gasoline powerplant and still want to maximize fuel efficiency, Ford also offers a 3.5-liter EcoBoost and a 3.5-liter high-output EcoBoost.
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Chevrolet offers five gasoline engine choices as an alternative to its new diesel engine offering. For those seeking to maximize fuel efficiency, there is a 2.7-liter Turbo with Active Fuel Management which pumps out 310 hp and 348 lb.-ft. of torque. Then there is a 4.3-liter EcoTec3 V6 with Active Fuel Management, a 5.3-liter EcoTec3 V8 with Dynamic Fuel Management, a 5.3-liter EcoTec3 V8 with Active Fuel Management and a 6.2-liter V8 with Dynamic Fuel Management.
Active Fuel Management represents traditional approach to engine cylinder deactivation where a set number of cylinders deactivates based on the load and driving conditions. Depending upon the engine configuration, an engine alternates between eight- and four-cylinder modes, six- and three-cylinder modes or four- and two-cylinder modes.
General motors recently rolled out a more advanced cylinder deactivation system called Dynamic Fuel Management. It temporarily shuts off between one and seven cylinders in a variety of different configurations depending upon needs of the customer and the load that the pickup is experiencing. Dynamic Fuel Management works by controlling engine oil flow via special valve lifters on each cylinder that activate or deactivate each cylinder via a software algorithm. The system operates in concert with the throttle system and provides only the power required, thus dramatically improving efficiency.
Ram Truck has taken half-ton pickup gasoline powertrain technology in a new direction - hybridization. But this technology is much different from past hybrid systems from the various manufacturer.
Ram Trucks' eTorque hybrid system increases the launch performance as well as fuel efficiency. It adds up to 90 lbs.-ft. of launch torque to the 3.6-liter V6 gasoline engine.Ram Trucks
eTorque increases the pickups’ launch performance as well as fuel efficiency. It adds up to 90 lbs.-ft. of launch torque to the 3.6-liter V6 and up to 130 lbs.-ft. to the 5.7-liter HEMI V8. The eTorque system results in a 2 mpg city and 2 mpg combined fuel economy benefit.
With the engine running, eTorque’s motor generator unit feeds 48-volt current to a 430-watt-hour lithium-ion Nickel Manganese Cobalt-Graphite battery. The battery pack includes a 3-kW DC-to-DC converter to maintain the battery’s state of charge and convert 48 volts to 12 volts to power the Ram 1500’s accessories and charge its conventional 12-volt lead-acid battery.
The V6 and V8 engines with eTorque retain a conventional 12-volt starter motor, used for cold starts and first start of the day due to its greater efficiency in extreme temperatures.
In addition to spinning the engine for restarts, the eTorque recaptures energy during deceleration and braking to feed charge to the battery pack. eTorque also enhances the vehicle’s driving experience by adding torque to the crankshaft during gear changes to minimize noise, vibration and harshness.
The eTorque motor generator is slightly different between the 3.6-liter Pentastar V6 and 5.7-liter HEMI V8 applications. The Pentastar eTorque unit is liquid cooled and mounted on the front of the engine. The HEMI V8 eTorque unit is air cooled and mounted toward the top of the engine in the traditional alternator location.
Start/stop Improves City Driving Fuel Economy
Stop/start technology helps optimize efficiency in city driving. The engine automatically restarts when the driver takes their foot off the brake. All of the Big Three offer start/stop technology on their 2019 pickup offerings. These systems are most effective in stop and go traffic.
Some of these systems are automatic and some can be switched off at the preference of the driver. For those that don’t like the system, it usually turns on every time the vehicle is started, therefore it must be disabled every time the vehicle is started. Driving a pickup with start/stop for the first time can be a little unnerving as you hear nothing but silence at the stop light and the engine rpms drop to zero. Taking your foot off the brake immediately brings the engine back to life.
Ford has made start/stop standard across the F-150 lineup. In its applications, Auto Start-Stop deactivates when it wouldn’t be needed, such as when you’re towing a trailer or running in four-wheel drive.
Multi-speed transmissions hit the sweet spot
Transmissions have been adding gears over the past several years. Most pickup trucks moved to six-speed transmissions. Then Ram Trucks adopted the use of electronic eight-speed transmissions. Most recently, Ford and General Motors worked together to develop a 10-speed gearbox.
By having more gear ratios, it is possible to keep an engine near its ideal operating speed most of the time. The transmission’s wider overall ratio enables a lower numerical top gear ratio, an attribute that reduces engine speed on the highway and results in increased fuel economy.