A building contractor has asked us to design a small, gasoline-engine powered air compressor to use for driving his air-hammers on remote job sites. A preliminary design concept is shown in the accompanying figure. A single-cylinder, 2-stroke engine with flywheel is coupled to a gearset to reduce the engine speed and boost its torque appropriately. The ratio for this gearset is to be determined. The 2.5 HP gasoline engine is governed at 3200 rpm. The gearset’s output shaft drives the crankshaft of a single-cylinder Schramm (poppet valve) piston compressor through a keyed coupling.

    Each group will have a different assigned pump rpm and cylinder displacement according to the attached chart. Throughout the term you will design various parts of this assembly. There are many elements to this relatively simple machine. We will only have time to address a small fraction of the total collection of parts. Some of the elements which need our careful design attention are:

• the keyed coupling

• the shaft

• the shaft bearings

• the gearset

• the cylinder headbolts

• the valve springs

    We will find that the designing of these parts is interdependent. Changes to one element may reflect through the system and require compensating changes in other parts. We will address the design of various parts as we develop and discuss the necessary theoretical aspects of the course topics.

    Some of the force analysis can be done with the program engine v. 5.2.1 supplied. Other analysis can best be done using a program such as TKSolver or MathCad, or with a spreadsheet. Note that it is required that a computer be used to solve this problem and TKSolver is recommended. We will provide master TK files to use as setups.

    We will attack this design project in six (6) phases as defined below. Each phase will be allowed one week of effort beginning in week 2 of the course. This will ultimately be a group project, but until the groups are formed (at phase 2) you will each work independently on phase 1 and then combine your efforts on the later phases. We will assign the groups.

    Five weekly progress reports will be required in a format defined in the Progress Report Specifications handout supplied. A final Project Report will also be expected whose format will adhere to the separate Project Report Specifications handout supplied.