Engine output increase of twostroke combustion with exhaust. Mota software, 2 stroke engine simulation software, 2 stroke exhaust design. For further investigate of the operation of twostroke engines with tuned exhaust pipes it is most appropriate to analyze actual test data. Everything you need to know about the twostroke cylinder. Method 1 and method 2 two and three stage diffuser. Twostroke waveaction engine simulation motion software.
Two strokes use the same principles, but the intake side is not tuned. Mota and its related set of programs have been developed to simulate the performance of highoutput single cylinder two stroke engines. There are many ways to boost the power, one of which is by installing a tuned pipe. Two stroke performance tuning chapter 3 porting and cylinder scavenging today, when we take a look down the cylinder of a two stroke engine, we find its walls literally filled with ports to handle the induction, transfer and exhaust phases of gas flow through the engine. How twostroke expansion chambers work, and why you should care.
So whether you have a 50cc road bike, a 500cc motocrosser or a classic racer, we will design the perfect exhaust system for you. New feature of racingsm software, the 2stroke exhaust segment splitter. Two stroke performance tuning chapter 3 porting and cylinder scavenging today, when we take a look down the cylinder of a twostroke engine, we find its walls literally filled with ports to handle the induction, transfer and exhaust phases of gas flow through the engine. Free 2 stroke exhaust expansion chamber calculator youtube. For this we can go to the tfx website where they demonstrate their testing and data analysis software, or read the paper referenced below titled exhaust gas flow behavior in a twostroke engine. The lubricant is mixed with fuel and injected directly into the combustion chamber. This small java applet uses design rules according to, and, to size a tuned pipe for a 2 stroke piston engine.
For this we can go to the tfx website where they demonstrate their testing and data analysis software, or read the paper referenced below titled exhaust gas flow behavior in a two stroke engine. For port work, one company that will help you is 2strokeporting. Assign fixed relationships between transfers and exhaust port. Fourstroke engines as well as turbine engines are not suitable. My professional 2 stroke expansion chamber design software is more sophisticated than other programs that only use a few basic formulas. In a twostroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust or scavenging functions occurring at the same time. We can see one undesirable side effect of the intake system on our 2strokes, however, which is spitting back of some of the fuel mixture at lower rpms. The ports found within a twostroke cylinder in combination with the exhaust system have the greatest influence on power, torque, and the rpm at which maximum power is created out of the various engine subsystems found within a twostroke engine. The difference between the pressure in the cylinder and the pressure at the cylinder end of the exhaust duct determines whether gas flows from the cylinder into the exhaust duct or into the cylinder from the exhaust duct. Two stroke exhaust pattern if i were doing this the first thing i would do is model the entire design as a single solid body no wall thickness, no separate components.
Acceptable piston stroke is 28mm to 81mm in version 27 and 29. Engineering acousticssonic supercharging of 2 stroke engines. Specificaly written for gokarts engines, but will do any 2 stroke. He will do one of two things,hang up, or if he is a good one,start explaining the complex nature of fluid dynamics, sonic wave pressures and the effects temperature on the speed and timing it takes to hit an open exhaust port at 6500 rpmsthis being said. Exhaust pipe design with cone layout software by paul crowe if you have ever tried to layout a conic section on sheet metal, cutting just the right piece, that when rolled over and joined on edge, you have a cone with the exact shape, size and angled openings desired, you know its not easy. Advanced two stroke tuned exhaust system the challenge the society of automotive engineers clean snowmobile challenge 2002 sae csc 2002 is an engineering design competition for college and university student members of the society of automotive engineers sae. Jan 23, 2019 2 stroke exhaust expansion chamber calculator using 3 methods. Oct 21, 2017 6 excel spreadsheets for designing an expansion chamber, a heads squish band, a boost bottle, a balanced crank, correct fueloil ratio, and correct port dura. The official home page of our 2 stroke wizard tuned pipe. No previous knowledge of the two stroke cycle engine is required just input the required data and then run mota to set in motion this powerful process. Simulation strategy and analysis of a twocylinder two stroke. We also have a simple 2stroke expansion chamber design program. Simulation strategy and analysis of a twocylinder two.
Small values of kh are best suited to grand prix engines with narrow power bands, larger. Once i have that completed i would understand the geometry that i need and have an envelopescaffold defining the geometry. Jul 25, 2007 exhaust pipe design with cone layout software by paul crowe if you have ever tried to layout a conic section on sheet metal, cutting just the right piece, that when rolled over and joined on edge, you have a cone with the exact shape, size and angled openings desired, you know its not easy. So whether you have a 50cc road bike, a 500cc motocrosser or a classic racer. It is also very good for expansion chamber designs. Minimum to maximum acceptable exhaust pulse widths are.
Nov 02, 2019 for further investigate of the operation of two stroke engines with tuned exhaust pipes it is most appropriate to analyze actual test data. As the forces in a two stroke pipe design have become more wellunderstood, designers have been able to create engines that take more advantage of them and in fact require an expansion chamber to run at all. The port duration should not exceed the recommended value. This software covers the 3 stage diffuser type expansion chamber exhaust as per equations provided in his book entitled design and simulation of twostroke engines published in 1996. New version of 2t exhaust calculator it is a freeware 2 stroke expansion chamber exhaust calculator program download at. Split your calculated 2 stroke exhaust up to 42 sections with regular length or even more with irregular lengths. Two stroke cylinder porting tips watch this before you start cutting. When the exhaust port shape is decided from time area targets etc. Good evening folks, i have been trying to make a two stroke exhaust, and would like to use solidworks to curve all the conic sections, because doing this. The one i have been using is call mota, from ian williams tuning. Crankcasescavenge twostroke engines have always been fitted with a large expansion chamber immediately outside the exhaust ports, but this is by no means essential, as such engines will operate very satisfactorily with a plain exhaust pipe.
The simulation of a two stroke two cylinder engine requires the simulation of the complete geometry with both cylinders and the complete exhaust port see figure 1. If you are aiming for these qualities, modifying your 2stroke engine is a great strategy. Torqsoft twostroke exhaust bend template programme. Engineering acousticssonic supercharging of 2 stroke. In designing a twostroke engine, you want to extract the combustion gases as quickly as possible and then plug the exhaust. After printing the paper template, the template can be glued to either cardboard or even a stiffer material such as wood. The complete engine geometry together with these two exhaust systems is simulated using an engine simulation software package virtual 4stroke and the experimentallyrecorded exhaust pressure diagrams and performance characteristics of power, torque, etc.
The revisions were to be so extensive on the authors the basic design of twostroke engines that what was to be a second edition evolved into a new book. Racingsm software 2stroke exhaust calculator lufo youtube. However, you shouldnt just pick any business that you can find anywhere. Note also how the secondorder reflected positive pressure wave in the intake tract light blue reaches the back of the intake valve just before ivo, and works together with properlytimed. It will simulate one of the cylinders of a multicylinder twostroke engine provided that the cylinders are identical in layout and dimensions and each cylinder has a seperate exhaust and induction system.
Two stroke design software the following are spreadsheets for different aspects of 2 stroke designmodification. Calculates port heights from durations, or durations from port heights. Those of us who have grown up in the japanese two stroke. The way a two stroke motor works causes them to be f. The exhaust blowdown target is a statistical value for the tuning degree decided by the bmep target braked mean efficient pressure.
Any donations greatly appreciated, please use paypal link. This software covers the 3 stage diffuser type expansion chamber exhaust as per equations provided in his book entitled design and simulation of two stroke engines published in 1996. Click here to download a spreadsheet that will let you figure out your engines exhaust pulse width. North american twostrokes general twostroke discussion. The calculations are assuming a speed of sound in the exhaust gas, which is not known exactly. Advanced twostroke tuned exhaust system the challenge the society of automotive engineers clean snowmobile challenge 2002 sae csc 2002 is an engineering design competition for college and university student members of the society of automotive engineers sae. The template also provides a reference if port work needs to be matched later.
They are so simple and fun that ive always enjoyed tinkering with them. Twostrokes use the same principles, but the intake side is not tuned. Great tool for those who are building exquisite format exhausts, one of the largest benefits of this module is that it can be used with any exhaust formula results. On the other hand, while the twostroke engine does not commonly require large.
But because of the limited worldwide activity in two stroke engine development, program sales were limited and further development was curtailed. A complete twostroke pipe has properly tuned header, convergent, belly, divergent and stinger sectionsa difficult process. A simple 3 stage two stroke exhaust calculator based on formulas of g. Twostroke engines often have a high powertoweight ratio, power being available in a narrow range of rotational speeds called the power. There are a few software programs available for 2 stroke simulations. Performance fabrications is dedicated to manufacturing the finest bespoke hand crafted exhaust systems available.
In this engine the suction stroke and exhaust strokes are eliminated and ports are used instead of valves. But because of the limited worldwide activity in twostroke engine development, program sales were limited and further development was curtailed. Jan 19, 2008 he will do one of two things,hang up, or if he is a good one,start explaining the complex nature of fluid dynamics, sonic wave pressures and the effects temperature on the speed and timing it takes to hit an open exhaust port at 6500 rpmsthis being said. In contrast, a twostroke engines valve timing may be altered simply by reshaping the holes in its cylinders, and its power output markedly changed by utilizing inertia and resonant effects in its intake and exhaust tracts. Those of us who have grown up in the japanese twostroke. We use computer design software to maximize power and torque at any elevation.
Port work involves matching all the mating surfaces and gaskets from the carb boot thru to the exhaust flange. New feature of racingsm software, the 2 stroke exhaust segment splitter. Split your calculated 2stroke exhaust up to 42 sections with regular length or even more with irregular lengths. In a two stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust or scavenging functions occurring at the same time. A complete two stroke pipe has properly tuned header, convergent, belly, divergent and stinger sectionsa difficult process. You can also save and load the data by using the provided functions. Two stroke engine and exhaust design software page 2. This coefficient kh is called the horn coefficient, with typical values between one and two. You should only rely on the experience of the very best. In this engine, the cylinders are coupled a two into one exhaust system. Technical the wankel engine does not have a separate lubrication chamber. The exhaust stroke is the 4th stroke in a 4 cycle engine. We shall send you a pdf document with the templates for manufacturing your exhaust. The exhaust port is smoothed, sanded, then polished, and the exhaust flange matched.
With the torqsoft exhaust bend template programme, a 2d representation of the bend is drawn and then saved in an pdf file for immediate printing or saved to your computer for future use. This is one of the reasons why the ignition timing needs to be reduced with higher crank speed in a 2stroke engine. How twostroke expansion chambers work, and why you should. In designing a two stroke engine, you want to extract the combustion gases as quickly as possible and then plug the exhaust. Note in figure two, how the cylinder pressure black and exhaust port red pressures go strongly negative from approximately mid exhaust stroke to tdc. Engine output increase of twostroke combustion with. The intent of the competition is to provide universities with an.
Millions of fluid and thermodynamic calculations are made by mota representing the conditions inside your two stroke engine throughout its complete operating cycle. Our goal is to achieve the biggest power gains as possible, while maintaining reliability on your 2stroke engine. As the forces in a twostroke pipe design have become more wellunderstood, designers have been able to create engines that take more advantage of them and in fact require an expansion chamber to run at all. Our goal is to achieve the biggest power gains as possible, while maintaining reliability on your 2 stroke engine. Two stroke engine porting, head mods and pipes two stroke tuning advice from the experts at bimotion. Mota and its related set of programs have been developed to simulate the performance of highoutput single cylinder twostroke engines. Two stroke engines often have a high powertoweight ratio, power being available in a narrow range of rotational speeds called the power. How to bend a conetwo stroke pipe model solidworks forums.
The simulation of a twostroke twocylinder engine requires the simulation of the complete geometry with both cylinders and the complete exhaust port see figure 1. It will simulate one of the cylinders of a multicylinder two stroke engine provided that the cylinders are identical in layout and dimensions and each cylinder has a seperate exhaust and induction system. North american two strokes general two stroke discussion two stroke engine and exhaust design software this is the place to talk about anything related to two stroke road race bikes. North american twostrokes general twostroke discussion two stroke engine and exhaust design software this is the place to talk about anything related to twostroke road race bikes. Two stroke engine and exhaust design software north. Free 2 stroke expansion chamber calculator software update. As a result, poor lubrication, reduced quality of exhaust, less durable. Improve the performance of your two stroke engine with a torqsoft designed exhaust system. Feb 16, 2017 two stroke cylinder porting tips watch this before you start cutting. Improve the performance of your twostroke engine with a torqsoft designed exhaust system. I found most other software work on outdated blair and jennings formulas. Follow the link to my software site and go to the 2t exhaust calc menu item and download either the stand alone program or a installer package.
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