外文翻译---发动机零件及其工作原理模具设计与制造-模具设计(编辑修改稿)

外文翻译---发动机零件及其工作原理模具设计与制造-模具设计(编辑修改稿)内容摘要：

e Cycle The fourstroke cycle is described here using a single cylinder engine (). Automobile engines actually have multiple cylinders. The movement of the piston from the top of its travel to the bottom of its travel is called a stroke. Each cycle required to burnthe airfuelmixture has four strokes. Hence the name, fourstroke cycle. 共 9 页 第 5 页 The Valve Is Operated by a Lobe The FourStroke Cycle During the intake stroke, the piston is pulled down by the turning crankshaft, creating a vacuum above it. Because the intake valve is open while the piston is moving down, the airfuel mixture is drawn into the cylinder through the intake valve port. The mixture is supplied to the cylinder by the fuel system. Gasoline is especially bustible when one part of it is atomized with about 15 parts of air. Atomization makes the mixture like fog. The piston moves back up in the cylinder on the pression stroke, pressing the airfuel, making it far more bustible. As the piston approaches the top of its travel, a spark plug ignites the mixture. During the power stroke the burning fuel expands rapidly, forcing the piston to move back down in the cylinder. The exhaust valve opens as the piston approaches the bottom of its is so that burning gases can escape before the piston begins to move upward in the cylinder once again. 共 9 页 第 6 页 During the exhaust stroke the piston moves back up, forcing any remaining exhaust gas from the cylinder through the open exhaust valve. As the crankshaft continues to rotate, the piston goes back down in the cylinder as the fourstroke cycle repeats itself. Mould Design and Manufacturing CAD and CAM are widely applied in mould design and mould making. [1]CAD allowsyouto draw a model on screen, then view it from every angle using 3D animation and, finally, to testit by introducing various parameters into the digital simulation models (pressure, temperature,impact, etc.). CAM, on the other hand, allows you to control the manufacturing quality. Theadvantages of these puter technologies are legion: shorter design times (modifications can bemade at the speed of the puter), lower cost, faster manufacturing, etc. This new approach also allows shorter production runs, and to make lastminute changes to the mould for a particular , also, these new processes can be used to make plex parts. ComputerAided Design (CAD) of Mould Traditionally, the creation of drawings of mould tools has been a timeconsuming task thatis not part of the creative process. Drawings are an organizational necessity rather than a desiredpart of the process. ComputerAided Design (CAD) means using the puter and peripheral devices to simplify and enhance the design process. CAD systems offer an efficient means of design, and can be used to create inspection programs when use。