Fuel Efficient Technologies

You may have heard that starting an engine requires more fuel than letting a car idle. It turns out this isn’t true. Enter the Start/Stop Engine. First introduced in the 1980’s this idea has gained traction in recent years. Here’s how it works. When car comes to a stop the engine computer cuts the spark and shuts down the engine. Then, when the driver lifts his foot off of the break or engages the clutch, the car automatically restarts. (Car and Driver, April 2011) Technology #1: The Start/Stop Engine ILLUSTRATION BY CHRIS PHILPOT. Car and Driver 2009

Technology #2 …Variable valve timing: In older cars the valve timing was done on a fixed basis. This meant that the car could operate most efficiently only at one fixed speed. Variable timing fixes this problem by allowing the components of the valve train system to work at different rates. At lower speeds the smaller parts of the system control the firing of the piston, causing the valve to open less and thus saving fuel. At higher speeds the larger part of the system is activated and allows for the greater fuel flow necessary for the increased speed. A video explaining this in more detail can be seen at

Traditional transmissions rely on gears. This can be inefficient when a car is at an in-between speed (say on a hill) and the engine can’t decide which gear is best (therefore switching back and forth between gears. Continuously variable transmissions don’t rely on gears. Instead they use a pulley system situated along a central mechanism which allows the car to adjust to the exact speed at which it is traveling. This increases fuel efficiency be eliminating gear changes. Technology #3: Continuously Variable Transmission

Technology #4: Active Shutter Grill In older cars the front grill has vents that allow air to flow into the engine. This air is used to help keep the engine cool. However, manufacturers realized that more air is entering the engine than is necessary to keep the engine cool. As the air flowing in increased drag (decreasing fuel efficiency), the car makers figured out that they could design grills that close some of their vents at higher speeds, thus reducing drag and increasing fuel efficiency. (Greencarreports.com, October 8 th 2012). Newer versions of the Ford Escape have an active shutter grill.

Technology #5: Direct Fuel Injection How direct fuel injection works Gasoline engines work by sucking a mixture of gasoline and air into a cylinder, compressing it with a piston, and igniting it with a spark; the resulting explosion drives the piston downwards, producing power. Traditional (indirect) fuel injection systems pre-mix the gasoline and air in a chamber just outside the cylinder called the intake manifold. In a direct-injection system, the air and gasoline are not pre-mixed; air comes in via the intake manifold, while the gasoline is injected directly into the cylinder. Advantages of direct fuel injection Combined with ultra-precise computer management, direct injection allows more accurate control over fuel metering (the amount of fuel injected) and injection timing (exactly when the fuel is introduced into the cylinder). The location of the injector also allows for a more optimal spray pattern that breaks the gasoline up into smaller droplets. The result is more complete combustion -- in other words, more of the gasoline is burned, which translates to more power and less pollution from each drop of gasoline. (Aaron Gold, about.com guide) The 2013 Chevy Malibu Eco uses direct injection, delivering fuel at high pressure directly into the combustion chambers. (General Motors photo)

Technology #6: Multistage Oil Pump A regular oil pump has chambers for suction and a discharge chamber. But this one from automotive supplier Aisin, just introduced in some Toyota products, has two discharge chambers--one slightly smaller than normal, and another even smaller--so you can tailor pressure to when you actually need it, and divide the discharge in half. There's full pressure from both chambers at idle, some from both at medium speed with higher loads, and full pressure from just the main chamber with light load conditions. At high rpm, when a pump would provide more pressure than needed, the oil flow comes from both chambers but is reduced by bleeding pressure through the relief valve. So it essentially reduces the total amount of work the pump has to, well, pump out. (Popular Mechanics, October 1, 2009)

Works Cited: 1.) Engine Start Stop Systems on Non-Hybrid Vehicles; Car and Driver, April 2011, K.C. Colwell/Author, Chris Philpot/illustrator 2.) Active Shutter Grille Vents: How they Improve MPG ; Green Car Reports, October 2012, Nikki Gordon-Bloomfield 3.) Direct Fuel Injection, What it is & How it Works ; About.com, Aaron Gold 4.) Six Fuel Saving Technologies to Help Hit 35 MPG Soon; Popular Mechanics, October 2009, Paul Weissler