• Variable Valve Timing & Lift (VVT&L)
• Cylinder Deactivation
• Turbocharging & Supercharging
• Direct Fuel Injection (w/ turbocharging or supercharging)
• Integrated Starter/Generator (ISG)

Variable Valve Timing & Lift (VVT&L)
Also called variable valve actuation (VVT), variable-cam timing and variable valve timing and lift electronic control (VTEC®)

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

Optimum timing and lift settings are different for high and low engine speeds. Traditional designs, however, use fixed timing and lift settings, which are a compromise between the optimum for high and low speeds. VVT&L systems automatically alter timing and lift to the optimum settings for the engine speed.

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Cylinder Deactivation
Also called multiple displacement, displacement on demand (DOD), and variable cylinder management

This technology merely deactives some of the engine's cylinders when they are not needed. This temporarily turns a 8- or 6-cylinder engine into a 4- or 3-cylinder engine. This technology is not used on 4-cylinder engines since it would cause a noticeable decrease in engine smoothness.

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Turbocharging & Supercharging

Turbochargers and superchargers are fans that force compressed air into an engine’s cylinders. A turbocharger fan is powered by exhaust from the engine, while a supercharger fan is powered by the engine itself.

Both technologies allow more compressed air and fuel to be injected into the cylinders, generating extra power from each explosion. A turbocharged or supercharged engine produces more power than the same engine without the charging, allowing manufacturers to user smaller engines without sacrificing performance.

Additional Information:

• How Turbochargers Work

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Direct Fuel Injection (with Turbocharging/Supercharging)
Also called fuel stratified injection or direct injection stratified charge

In conventional multi-port fuel injection systems, fuel is injected into the port and mixed with air before the air-fuel mixture is pumped into the cylinder. In direct injection systems, fuel is injected directly into the cylinder so that the timing and shape of the fuel mist can be precisely controlled. This allows higher compression ratios and more efficient fuel intake, which deliver higher performance with lower fuel consumption.

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Integrated Starter/Generator (ISG)

These systems automatically turn the engine off when the vehicle comes to a stop and restart it instantaneously when the accelerator is pressed so that fuel isn't wasted for idling. In addition, regenerative braking is often used to convert mechanical energy lost in braking into electricity, which is stored in a battery and used to power the automatic starter.

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* Fuel cost savings are estimated assuming an average vehicle lifetime of 185,000 miles, a fuel price of $2.44, and an average fuel economy of 21 MPG. All estimates are rounded to the nearest hundred dollars.

**Some documents on this page are provided as Adobe Portable Document Format (PDF) files. Any PDF file can be downloaded, viewed on screen, and printed using the Adobe Acrobat Reader software. This free software can be downloaded from the Adobe Web site. Installation and setup instructions are provided on this site.

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