Super-Mileage Fuel Injection Team

Welcome

Welcome to the Umass Super-Mileage Fuel Injection Team (SMVFIT) homepage. Our team is a group of five undergraduate electrical, computer systems, and mechanical engineering students. We will be working throughout the next two semesters with a larger team of mechanical engineering students on the SAE Super-Mileage Competition Vehicle. Our work on this project falls within the guidelines and academic review of the ECE Senior Design Project (SDP). For a brief abstract of our project, please read below. Alternatively, you can find a more detailed description in the SDP Documents section of the site.

Why Electronic Fuel Injection?

Before computers became small, fast, and inexpensive enough to properly manage the metering of fuel into an engine, mechanical devices were devised to accomplish the task. These devices are known as carburetors. Carburetors, while effective, are an inefficient means with which to control the air/fuel (A/F) ratio of intake gases. The amount of fuel dispensed into the intake air stream is dependent strictly on a few mechanical variables such as fuel line pressure, motor RPM, fuel jet flow rate, and intake gas pressure. A fuel dispensing system designed around a carburetor cannot take into account variables such as measured A/F ratio, exhaust gas temperature, throttle position, and mass-air flow. Certain advances had been made in carburetor technology into the early 1980s including electronic jet control (a precursor to electronic fuel injection), but the real revolution was the introduction of electronically controlled valves with fast opening and closing times as well as good fuel atomization.

Electronic Fuel Injection (EFI) works on two major principles. The first is the ability to measure the mass of the air flowing through the intake manifold. The second is the ability to measure the exhaust gas oxygen content. Using sensors for the observation of these variables, a properly programmed EFI system can inject a nearly stoichiometric mix of fuel and air into the motor's cylinder and thus obtain the best combustion and fuel economy characteristics. The system is timed by a cam position sensor and is fine tuned with data from a variety of other sensors including exhaust gas temperature, throttle position, and valve position.

The goal of the system is to obtain a stoichiometric mix of air and fuel such that the chemical reaction of the combustion process leaves neither oxygen or fuel in the exhaust. For more project background and up to date project progress, please check out the Project Updates and SDP Documents sections of the site. For information on the Super-Mileage Competition, Rules, and history, please check out some of our links to SAE's competition site. To get a primer on the operation of a 4-cycle motor, check out the links below to HowStuffWorks.com. Enjoy the site and feel free to contact any of us through Meet the Team.

How Car Engines Work Have you ever opened the hood of your car and wondered what was going on in there? A car engine can look like a big confusing jumble of metal, tubes and wires to the uninitiated. You might want to know what's going on simply out of curiosity. Or perhaps you are buying a new car, and you hear things like "3.0 liter V-6" and "dual overhead cams" and "tuned port fuel injection." What does this. . .	How Fuel Injection Systems WorkIn trying to keep up with emissions and fuel efficiency laws, the fuel system used in modern cars has changed a lot over the years. The 1990 Subaru Justy was the last car sold in the United States to have a carburetor; the following model year, the Justy had fuel injection. But fuel injection has been around since the 1950s, and electronic fuel injection was used widely on European cars starting. . .
How does a carburetor work? If you have read the page entitled How a Gasoline Engine Works (now newly illustrated with cool 3-D graphics, by the way!), you know that the idea behind an engine is to burn gasoline to create pressure, and then to turn the pressure into motion. A remarkably tiny amount of gasoline is needed during each combustion cycle. Something on the order of 10 milligrams of gasoline per combustion stroke is all it takes!	How does the oxygen sensor in a car work? Every new car, and most cars produced after 1980, have an oxygen sensor . The sensor is part of the emissions control system and feeds data to the engine management computer . The goal of the sensor is to help the engine run as efficiently as possible and also to produce as few emissions as possible.
How Camshafts Work If you have read the article How Car Engines Work, you know about the valves that let the air/fuel mixture into the engine and the exhaust out of the engine. The camshaft uses lobes (called cams ) that push against the valves to open them as the camshaft rotates; springs on the valves return them to their closed position. This is a critical job, and can have a great impact on an engine's performance. . .	How Automobile Ignition Systems Work The internal combustion engine is an amazing machine that has evolved for more than 100 years. It continues to evolve as automakers manage to squeeze out a little more efficiency, or a little less pollution, with each passing year. The result is an incredibly complicated, surprisingly reliable machine.

Super-Mileage Fuel Injection Team

Super-Mileage Fuel Injection

Super-Mileage Competition

Manufacturer Links

Welcome

Why Electronic Fuel Injection?