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Advanced Engine Technologies

Also called multiple displacement, displacement on demand, active fuel management, and variable cylinder management

This technology "turns off" some of the engine's cylinders when they are not needed. It essentially turns off the valves to some cylinders so that fuel and air aren't pumped into them. This temporarily turns an 8- or 6-cylinder engine into a 4- or 3-cylinder engine, saving fuel.

Potential Efficiency Improvement: Up to 5%1
Savings Over Vehicle Lifetime: *

Turbochargers are compressors that force additional air into the engine's cylinders, allowing more fuel to be injected as well. The additional air and fuel create more power. This allows automakers to use smaller engines without sacrificing performance.

Additional Information: How Turbochargers Work

Potential Efficiency Improvement: Up to 8%1
Savings Over Vehicle Lifetime: *

Includes variable valve actuation, variable-cam timing, cam phasing, variable valve timing and lift electronic control (VTEC®, VANOS®, VVT-i®), etc.

Valves control the flow of fresh air into the cylinders and the flow of exhaust out of them. When and how long the valves open (timing) and how much the valves move (lift) both affect engine efficiency.

Traditional engine designs use fixed timing and lift settings. The best timing and lift settings vary with engine speed. So, fixed settings are a compromise between the optimum for high and low engine speeds. Variable valve timing and lift, however, can alter timing and lift to the optimal settings for the engine speed and power.

Potential Efficiency Improvement: 3%–4%1
Savings Over Vehicle Lifetime: *

Also called direct fuel injection, spark ignition direct injection (SIDI)

In conventional gasoline engines, fuel is injected into the intake port and mixed with air while the air-fuel mixture is drawn into the cylinder. In direct injection systems, fuel is injected directly into the cylinder, which makes the fuel-air mixture somewhat cooler. Cooler air allows higher compression ratios and/or more efficient spark timing. This can increase performance and lower fuel use.

Potential Efficiency Improvement: 1%1
Savings Over Vehicle Lifetime: *

* Fuel cost savings are estimated assuming an average vehicle lifetime of 166,000 miles,2 a fuel price of , and an average fuel economy of 25.2 MPG.3 All estimates are rounded to the nearest hundred dollars.

View Data Sources…
  1. National Academy of Sciences. 2015. Cost, Effectiveness and Deployment of Fuel Economy Technologies for Light-Duty Vehicles. The National Academies Press, Washington, D.C. To be conservative, most values have been rounded down to the nearest percent.
  2. Average MPG for 2017 vehicles based on Light-Duty Automotive Technology,Carbon Dioxide Emissions, and Fuel Economy Trends: 1975 Through 2017.Adobe Acrobat Icon. EPA, 2017. Table 2.1.
  3. Average of car and truck lifetime mileage estimates (rounded to the nearest thousand miles) based on 2006 NHTSA study cited in Transportation Energy Data Book, Edition 36.2. Oak Ridge National Laboratory. Table 3.13.

This website is administered by Oak Ridge National Laboratory for the U.S. DOE and the U.S. EPA.