Michael Mathe
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GDI Technology Offers Improved Power And Efficiency, Along With A New Set Of Challenges For Motor Oil

Fuel economy and performance are probably the two most emphasized features of vehicles today. Even powerful pickup trucks are touting their respective MPGs alongside horsepower in an appeal to both the macho and penny-pinching sides of prospective truck buyers. Better fuel economy and better performance - is it possible to have both?

The answer is, "yes," with Corporate Average Fuel Economy (CAFE) standards driving the need, and gasoline direct injection (GDI) technology as a leading solution.

Automakers are being pressured by the federal government's CAFE mandates to produce vehicles that meet higher fuel economy standards and decrease emissions. In October 2012, the National Highway Traffic Safety Administration and Environmental Protection Agency released final standards regulating CAFE and greenhouse gas emissions for light-duty vehicles (passenger cars and trucks) manufactured in model years 2017 through 2025. This legislation projects average required fleet-wide fuel economy ranging from 40.3 to 41.0 mpg in model year 2021 and from 48.7 to 49.7 mpg in model year 2025. The 2025 "split" estimates the average required car mpg from 55.3 to 56.2 mpg and light trucks from 39.3 to 40.3 mpg.

One promising source for better fuel economy and performance is seen in the resurgence of GDI engines. The major difference between GDIs and conventional port-injected engines is how and where the gasoline is introduced prior to combustion. In conventional port-injected fuel systems, the fuel/air mixture occurs in the intake manifold; in GDI engines, gasoline is injected directly into the combustion chamber under very high pressures. Like similarly injected diesel engines, this results in greater power, torque and operating efficiency. Because of the specialized fuel delivery components required for gasoline direct injection, GDI engines remain more expensive to build than port-injected systems. Even so, most major car manufacturers are now, or soon will be, producing vehicles employing GDI technology. IHS Automotive, a global industry forecasting company, predicts North American GDI engine installation to rise from approximately 3 million units in 2012 to more than 8 million units by 2016. There are several reasons for the increasing production:

1. Today's injector systems are computer-controlled and capable of delivering extremely accurate and rapid distribution of atomized gasoline. The fuel can be sprayed directly at the hottest part of the combustion chamber, which is near the spark, improving efficiency. Standard gasoline engines end up with the fuel-air mixture widely dispersed in the chamber, resulting in less efficient operation.

2. Because fuel in GDI engines is injected directly into the cylinder instead of the intake port, as in traditional gasoline engines, it remains cooler and can be compressed more densely to produce greater power.

3. Since the fuel supply is more precisely controlled, combustion can occur at leaner air-to-fuel ratios. GDI engines use a mixture of 40 parts (or more) air to one part fuel during light loading, while traditional gasoline engines use a mixture of 14.7 parts air to one part fuel. The 40:1 ratio means less fuel is burned during combustion, resulting in better fuel economy.

4. When atomized fuel is injected into cyl-inders at high pressure, the combustion chamber temperature decreases. This temporary in-cylinder cooling increases the efficiency of the air-fuel mixture charge.

GDI engines also work well with turbo-chargers, and by combining the two tech¬nologies automakers can build smaller-displacement engines with performance specs comparable to - or better than - larger engines.

GDI engines are not faultless, however. Because fuel is injected directly into the combustion chamber, intake valves don't get "washed" with gasoline as they do in port-injected engines. This can result in carbon build-up. To fight these deposits, GDI engines rely primarily on injection timing calibration and exhaust gas recirculation (EGR), allowing combustion gases to "wash" the intake valves. These technologies have limitations though, and can come up short. Because they are located in the combustion chamber, the fuel injectors are also exposed to greater temperatures and pressures. This environment makes them more susceptible to deposits that impede the spray pattern, reducing engine efficiency.

In addition to using high-quality gas, regular use of robust fuel additives is a good practice for keeping fuel systems clean. AMSOIL P.i. Performance Improver Gasoline Additive (API) contains powerful detergents that clean deposits that can form in combustion chambers and on fuel injectors. By doing so, P.i. improves fuel economy and reduces emissions. P.i. is the top choice to keep GDI and port-fuel-injected engines deposit-free and running at peak efficiency.

GDI technology is a major component of achieving both better fuel economy and increased performance. How far the technology goes is yet to be determined. Meanwhile, AMSOIL P.i. Performance Improver gasoline additive makes it easy to help keep engines clean and operating at peak performance. Published, AMSOIL Magazine 2/13. LLC is a large nationwide Dealer of AMSOIL Synthetic Lubricants and is now expanding into your area and surrounding states. If you have a business or are an individual with several vehicles, AMSOIL has several options available that may allow you to Purchase AMSOIL Products at Wholesale Prices. We can show you how to save money and extend equipment life with AMSOIL Synthetic Motor Oils, Lubricants, Filters and Fuel Additives. Please visit the AMSOIL Online Store for more information and to purchase AMSOIL Products.

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