Diesel Fuel Injection Research Paper Example

Diesel Fuel Injection Research Paper Example Diesel Fuel Injection Paper Diesel Fuel Injection Paper One big difference between a diesel engine and a gas engine is in the injection process. Most car engines use port injection or a carburetor. A port injection system injects fuel just prior to the intake stroke (outside the cylinder). A carburetor mixes air and fuel long before the air enters the cylinder. In a car engine, therefore, all of the fuel is loaded into the cylinder during the intake stroke and then compressed. The compression of the fuel/air mixture limits the compression ratio of the engine if it compresses the air too much, the fuel/air mixture spontaneously ignites and causes knocking. Because it causes excessive heat, knocking can damage the engine. Diesel engines use direct fuel injection the diesel fuel is injected directly into the cylinder. The injector on a diesel engine is its most complex component and has been the subject of a great deal of experimentation in any particular engine, it may be located in a variety of places. The injector has to be able to withstand the temperature and pressure inside the cylinder and still deliver the fuel in a fine mist. Getting the mist circulated in the cylinder so that it is evenly distributed is also a problem, so some diesel engines employ special induction valves, pre-combustion chambers or other devices to swirl the air in the combustion chamber or otherwise improve the ignition and combustion process. |[pic] | |Photo courtesy DaimlerChrysler | |Atego six-cylinder diesel engine | Some diesel engines contain a glow plug. When a diesel engine is cold, the compression process may not raise the air to a high enough temperature to ignite the fuel. The glow plug is an electrically heated wire (think of the hot wires you see in a toaster) that heats the combustion chambers and raises the air temperature when the engine is cold so that the engine can start. According to Cley Brotherton, a Journeyman heavy equipment technician: All functions in a modern engine are controlled by the ECM communicating with an elaborate set of sensors measuring everything from R. P. M. o engine coolant and oil temperatures and even engine position (i. e. T. D. C. ). Glow plugs are rarely used today on larger engines. The ECM senses ambient air temperature and retards the timing of the engine in cold weather so the injector sprays the fuel at a later time. The air in the cylinder is compressed more, creating more heat, which aids in starting. Smaller engines and engines that do not have s uch advanced computer control use glow plugs to solve the cold-starting problem. Of course, mechanics arent the only difference between diesel engines and gasoline engines. Theres also the issue of the fuel itself. Diesel Engines vs. Gasoline Engines In theory, diesel engines and gasoline engines are quite similar. They are both internal combustion engines designed to convert the chemical energy available in fuel into mechanical energy. This mechanical energy moves pistons up and down inside cylinders. The pistons are connected to a crankshaft, and the up-and-down motion of the pistons, known as linear motion, creates the rotary motion needed to turn the wheels of a car forward. Both diesel engines and gasoline engines covert fuel into energy through a series of small explosions or combustions. The major difference between diesel and gasoline is the way these explosions happen. In a gasoline engine, fuel is mixed with air, compressed by pistons and ignited by sparks from spark plugs. In a diesel engine, however, the air is compressed first, and then the fuel is injected. Because air heats up when its compressed, the fuel ignites. The following animation shows the diesel cycle in action. You can compare it to the animation of the gasoline engine to see the differences: The diesel engine uses a four-stroke combustion cycle just like a gasoline engine. The four strokes are: Intake stroke The intake valve opens up, letting in air and moving the piston down. Compression stroke The piston moves back up and compresses the air. Combustion stroke As the piston reaches the top, fuel is injected at just the right moment and ignited, forcing the piston back down. Exhaust stroke The piston moves back to the top, pushing out the exhaust created from the combustion out of the exhaust valve. Remember that the diesel engine has no spark plug, that it intakes air and compresses it, and that it then njects the fuel directly into the combustion chamber (direct injection). It is the heat of the compressed air that lights the fuel in a diesel engine. In the next section, well examine the diesel injection process. |Compression | |When working on his calculations, Rudolf Diesel theorized that higher compression leads | |to higher efficiency and more power. This happens because when the piston squeezes air | |with the cylinder, the air becomes conce ntrated. Diesel fuel has a high energy content, | |so the likelihood of diesel reacting with the concentrated air is greater. Another way | |to think of it is when air molecules are packed so close together, fuel has a better | |chance of reacting with as many oxygen molecules as possible. Rudolf turned out to be | |right a gasoline engine compresses at a ratio of 8:1 to 12:1, while a diesel engine | |compresses at a ratio of 14:1 to as high as 25:1. | http://auto. howstuffworks. com/diesel2. htm

Business System Assessment Essay

Business System Assessment Essay Business System Assessment Essay This is a free sample essay on Business System Assessment: The information methods that can be used in analyzing requirements are the documentation, interview, observation, questionnaire, and the measuring methods. Each method can be an effective way to gather requirements but some can be better then others depending on what kind of business your company does. The documentation method can be an effective method of analyzing requirements if the company already has good documentation. The interview method is a good method to use for companies that are smaller and everyone is in one office. I feel that a face-to-face interview is more personable and more effective then doing an interview over the phone. The observation method is a good method because it allows you to see how the current processes are done. If the questionnaires ask the right questions and are effective in tracking certain aspects of the business, then this is an effective method. I have never used the measuring method but the book says that it can be a good method for gathering statistical information from the existing system. A process map is a graphical representation of the activities which make up the process It is a diagram which shows each step of the process, each input and output, and which uses agreed symbols to represent different process elements. It is similar in many ways to a flowchart of the process and, in common with a flowchart, the process map represents the logic necessary to achieve the desired result. The methods that should be used in process mapping are ones that you are comfortable with and ones that you have used before and have been successful in using. I dont know that the reading or lecture for this week actually went over actual mapping methods, but one method that was mentioned was the value chain principle. The mapping tools that should be used in documenting analysis are joint applications development/design (JAD) or rapid applications development (RAD) tools. These tools can be used to speed up the analysis and design of a system. Object oriented analysis (OOA), spiral, iterative or a combination of these tools are all good tools to use. These tools should be used along with the System Development Life Cycle (SDLC). An analyst would know if the methods and tools mentioned above are effective because hopefully he/she has enough experience and has used these tools and methods before. The analyst would first need to determine if the company already has a standard methodology that they use as a standard. If they do have an established methodology already, the analyst should try to use that method and get permission from the company before using a different method. Hopefully the method already established by the client is an effective method. The prototyping tools used by the analyst can be used to confirm if the requirements are effective. This can be done by either the measuring method or by using diagramming tools. By utilizing either of these methods, an output would be generated to measure the effectiveness of the enterprise-level system analysis. ______________ is a professional essay writing service which can provide high school, college and university students with 100% original custom written essays, research papers, term papers, dissertations, courseworks, homeworks, book reviews, book reports, lab reports, projects, presentations and other assignments of top quality. More than 700 professional Ph.D. and Master’s academic writers. Feel free to order a custom written essay on Business System Assessment from our professional essay writing service.