1、外文翻译 外文翻译原文： The Reciprocating Engine My Internet research eventually led me to the American Stirling Company While cruising their website for engine kits I ran across， an ad that said they wanted a technical writer who would trade some writing of instructional material and plans for engine kits I s
2、hot them a quick email I am a technical writer in my day job， and I write instructional material for computer software Now that I was designing my own Stirling engines， I thought I would be a perfect match for them!Well， I didn t end up working for them， but after a few conversations with the owner
3、of the company I was on a mission to complete my quest for a hand built LTD Stirling engine， and I was going to write a book about it at the same time Brent Van Arsdell of The American Stirling Company was very helpful He gave me some very good advice about how to increase the efficiency of my engin
4、e designs He knew a lot a bout friction He knew how to calculate its impact， and how to overcome some of the problems it can cause He didn t really need a technical writer any more，but he did offer me some great encouragement on my efforts to design an efficient hand built engine He suggested that i
5、f I could build a Stirling engine that met these criteria， it would make a great selling book Here is what my designs had to do： The engine had to run from the heat of a warm hand The engine had to be made from common materials that would be easy for anyone to obtain It had to be affordable to build
6、 It had to be built without the aid of a machine shop I could only use the kinds of tools that most folks already have in their garage I stumbled across the website of an engineer in France who was working on a similar project The only problem was the website was entirely in French!I had a brief ema
7、il exchange with the author and asked him if his website was available i n English He replied。“ Sorry no It is hard enough to explain in French! But I gleaned a lot of helpful hints from his pictures and from his text， thanks in part to tools like the Google Translator My previous design attempt had
8、 been troubled by friction and by pressure leaks With gems of wisdom from Brent and some neat tricks on the French site 1 was able to create a design that reduced the number of friction points and eliminated the pressure leaks My first original Stirling engine was born!The first design was a recipro
9、cating engine That means the flywheel does not spin continuously in the same direction， but rocks back and forth as it runs It is efficient enough to run from the heat of my hand And remember， I constructed the engine you see here (and several others) while recovering from back surgery I was under D
10、r. S orders to not bend over， don t lift anything more than 10 pounds， and don t pick up anything off of the floor Those restrictions presented some interesting challenges Especially when tiny parts would jump off the table and land on the floor I took over half the dining room table for this projec
11、t， which is where most of my assembly work was done There were just a few times I felt it was better to move into the shop for a construction step All of my tools and materials fit in a medium sized storage tub for those times when the table was needed for more mundane thinks， Like eating You may re
12、call that before I ventured near the LTD engine designs， I started by first building a pop can Stirling engine Building a pop can Stirling engine is a great way to start， and I highly recommend it The most popular set of plans on the Internet are posted by the Stephen F Austin State University in Ea
13、st Texas You may be able to find the plans if you search the web for SFA Stirling Engine Project. The pop can engine is easy to build and is a very forgiving design It will teach you how the Stirling cycle works while giving you lots of success My early efforts with the pop can engine and my first a
14、ttempt at an LTD design taught me several important lessons that went into the design of the three engines here： Friction is the enemy The more moving parts you have， the more friction you have Pressure leaks have a high impact on LTD designs The point where the displacer shaft enters the pressure c
15、hamber in a traditional Stirling engine creates friction and a leak Both contribute to a loss of power Precision is required， especially at the sliding points like pistons and the displacer pushrod gland Balance is critical An out of balance flywheel consumes more energy than it provides， and balanc
16、ing them is not as easy as one first thinks Best of all， I learned the Stirling cycle I learned friction is the enemy Every point where 2 moving parts touch is a friction point Even though my friction appeared to be non existent， it wasn t The piston arrangement on the Coffee Cup Engine worked， but
17、it had some friction And the displacer pushrod made noise as it passed in and out of the pressure， chamber gland I knew noise comes from vibration， and vibration comes from friction Some of the first flywheels I made would spin freely on their bearings for 4 or 5 seconds and appeared to be working w
18、ell I didn t realize how much friction was present until I created my first flywheel on averticalaxle and gave it a spin I could get it to coast for about 2 minutes!In the micro horsepower world of model Stirling engines it takes only a small amount of friction to have a huge impact on performance I
19、 learned pressure leaks will rob you of precious power A tiny pressure leak will help a Stirling engine equalizeto match the changing barometric pressure， or help it bleed off a little excess pressure as the average temperature rises in the engine But with that advantage comes a loss of power My lit
20、tle engine needed all the power it could muster， especially for the lower temperature differentials I wanted it to run on Some miniscule pressure leaks seemed impossible to avoid， such as where a moving shaft must pass through the wall of the pressure chamber I eventually found a way to use magnets
21、to replace that pushrod so now my pressure chamber is completely sealed I learned that balance is a difficult science A typical design has a rotating flywheel that lifts the displacer up and down You add a little weight to one side of the flywheel in order to compensate for the weight of the displac
22、er You place the weight opposite of the load so that when the displacer is moving up， the counterbalance is moving down This makes the displacer motion almost effortless I have used this technique to successfully reduce vibration and wobble， but I have never been able to completely eliminate it I ne
23、eded to create a design that did not require the flywheel to lift anything If it wasn t lifting anything， balance would not be a problem So now the challenge is to apply these lessons to the building of an LTD engine Lower temperature differential means this engine will have less power than the pop can engine This means it will have to have more precision， less friction， and a straightforward application of the Stirling cycle And I have to do this without the aid of a machine shop!
