Because it will produce a high amount of heat than the engine is designed to handle. It will cause the piston rings to wear off rapidly, means more wear and tear to the engine. And also single cylinder engines are difficult to turbocharge because the intake valve is closed when the exhaustive valve is open.
- Best Turbo 4 Cylinder
- Old Single Cylinder Motors
- Single Cylinder Turbo Diesel Engine
- Single Cylinder Turbo Kit
- Single Stroke Engine
My invention is a method for turbocharging single cylinder internal combustion engines. This technology makes small engines cleaner, more powerful, lighter, more fuel efficient, and lower cost. With new emissions standards coming online, companies are having difficulties keeping the costs of their engines down. This is especially a problem for developing nations where single cylinder four stroke engines power small vehicles, farm equipment, and generators. Turbocharged engines have better fuel economy, cost efficiency, and power density than an equivalently sized, naturally aspirated engine. Most multi-cylinder diesel engines are turbocharged for these reasons. However, due to the timing mismatch between the exhaust stroke, when the turbocharger is powered, and the intake stroke, when the engine intakes air, turbocharging is not used in commercial single cylinder engines. Single cylinder engines are ubiquitous in developing world off grid power applications such as tractors, small vehicles, generators, and water pumps due to their low cost. Turbocharging these engines could give users a lower cost and more fuel-efficient engine. The proposed solution is to add an air capacitor, in the form of a large volume intake manifold, in between the turbocharger compressor and the engine intake to smooth out the flow.
The theoretical feasibility of the air capacitor was analyzed, focusing on fill time, optimal volume, density gain that the system can achieve, and thermal effects due to adiabatic compression of the intake air. Computational techniques were used to determine that the system is feasible. It was found that the system is feasible from a cost perspective, since adding a turbocharger is expected to be approximately 20% of the cost of adding a second cylinder (doubling the power). This means that even in the worst-case heat transfer scenario, turbocharging is half the cost of adding a second cylinder per unit power gained.
- From studying everything that has gone on with the TBM and Meridian and with knowledge of the high performance piston fleet, I get the feeling that the lower fatal accident rate in the turboprops has to be attributable to better training. Better reliability could be a factor and the enhanced performance capabilities of these airplanes may have also made a contribution to safer operation.
- While it is certainly possible, it is not really sensible to fit a turbo charger to a single cylinder engine. The power pulses driving the turbine are just too far apart (one each two revolutions). To stop the turbine constantly speeding up slowing down - with pretty unspectacular intake pressures - will take sophisticated knowledge of pressure.
- Turbocharging technology for single cylinder engines is applicable to a variety of current and prospective single cylinder diesel engine markets, including tractors, generators, water pumps, rickshaws, motorcycles, lawn mowers, and landscaping equipment.
An initial prototype was built and an experiment was conducted where it was found that peak power output increases with manifold size, increasing by as much as twenty nine percent with the largest sized manifold (approximately seven times engine volume). This is a significant increase in power and shows that turbocharging a four-stroke, single cylinder internal combustion engine is technologically and financially feasible.
An optimization model was built using Matlab, Simulink, and Ricardo Wave (an engine modeling software). The model optimizes the air capacitor and engine parameters around fuel economy, power, emissions, and air flow using a simulated annealing optimization algorithm. From this analysis I found that I can reduce emissions by 2-5%, improve fuel economy by 3-5% and increase power by 30-35% at the same time.
Using this information, a more advanced prototype and experiment were developed. Through the experiment it was found that the air capacitor turbocharging system can improve emissions, fuel economy, power, and transient response characteristics. This project will have a real world impact; it will give farmers a tool to make them more productive, reduce emissions from small diesel engines, and lower the cost of small devices that are powered by small diesel engines.
Awards
- 2017 Top 100 Entries
Voting
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ABOUT THE ENTRANT
- Michael Buchman
- individual
- Student
- As a child I was interested in tinkering, building, experimenting and spending lots of time playing with Legos, Meccano, model trains, and science kits. Along the way, I figured out that I was one of the lucky few that could turn my hobby into a career. I decided to focus my research on creating new technologies that have real world applications and a positive impact. This led me to accepting a position in the Global Engineering and Research Laboratory (GEAR Lab) under professor Winter. This is a new laboratory that specializes in combining rigorous engineering theory with user centered product design to create technological solutions to problems in emerging markets.
- Matlab, Simulink, and Ricardo Wave
- patented
Does a large turbo car make a terrible streetcar?
Contributed by: Enginebasics.com
So you have decided to turbocharge your car or upgrade your existing turbo, but are stuck on what size of turbo would be right for you. It would be nice if turbocharging was like many other decisions where bigger is better, but not so. While 90% of the internet would tell you to pick the smallest turbocharger that meets your horsepower goals I would like to offer a different point of view after we go over the pro’s and con’s of each.
Best Turbo 4 Cylinder
Small turbochargers
Pro’s
- Spool faster providing more torque lower in the power band.
- Easier install due to smaller dimensions.
- Cheaper
Old Single Cylinder Motors
Con’s
- Torque falls in the upper RPM of the power band.
- Smaller turbine wheels cause more exhaust manifold pressure (EMAP) causing more cylinder reversion of exhaust gasses, raising cylinder temperatures causing the motor to become more prone to detonation and pre-ignition.
- Don’t make as much power as larger turbochargers.
- Torque usually comes on rapidly over a small rpm band causing traction problems.
Large Turbochargers
Pro’s
- Usually maintain torque all the way to redline.
- Large turbine wheels allow good flow for better volumetric efficiency and less exhaust gas reversion, which helps in avoiding cylinder detonation and pre-ignition.
- More progressive torque curve that comes online in a more progressive manor.
Con’s.
Single Cylinder Turbo Diesel Engine
- Laggy. Meaning the time till the second boosted torque curve over the N/A torque curve takes time to obtain.
- Physically larger, therefor can be harder to install in a given space.
- Cost more than a smaller turbo.
Single Cylinder Turbo Kit
Now that we have talked a little about the pro’s and con’s of each let’s talk about why picking the smallest turbo for our power goals isn’t necessarily the end all advice to turbocharger sizing. Since we need a specific example to talk about let’s go with a mid size turbo and a mid size motor like a 3.0 Liter Toyota Supra motor (2jz). If we say our goal is say 650 wheel horsepower, then we would be looking for a turbo that can flow upwards of 60 lbs/min of air. Strong choices would be a Garrett GT35R or GTX35R, or a Precision 6262, or a Borg Warner S362. We go to the dyno and continue turning up the boost pressure till we hit our 650 HP goal. We eventually do meet our goal of 650whp but we had to run such high boost pressure to reach that goal, that race gas was required. Now this power can only be had if the owner is willing to grab his wallet for $9 dollar a gallon race gas in the tank. A bonus though of running such high boost and hitting high boost low in the RPM band was we made tons of torque too. We made 650 HP and 650 Torque. How exciting, but then our engine builder told us that making that much torque will most likely bend our stock rods and beat on our bearings a lot more. To fix this we need to be grabbing for our wallet once again and have the motor fully built with forged parts. Well the owner empties his wallet and hits the street. 1st gear the owner stabs the throttle and the turbo lights right up and so does the tires, so they shift to 2nd but the torque comes on so rapidly with the little turbo and so low in the rpm band that again the tires light right up again. They now back out of the peddle so the torque drops and traction can be found right around 5000 rpm where they are able to get back into the go peddle but are then unsatisfied as they can feel the engine torque falling off as the small turbo’s turbine wheel is too much of a restriction at high engine RPM. Also they think to themselves that if they wanted to wait till 5000 RPM to get into the go peddle they would have just bought a larger turbo.
Now let’s do the same scenario with a large turbo. The owner has the same goal of 650hp, but chooses to go with a larger turbo like a Garrett GTX40/88r or 6766 or Borg Warner S366. These turbo’s are all rated at 80+ lbs/min of airflow and will flow enough to make 800+ wheel HP. With the same goal of 650 whp the owner hits the dyno and is able to make 650 whp on pump gas do to the fact that not much boost pressure is required to get the large compressor and turbine wheel to flow enough air to make 650 HP. The owner is excited that he can make this power with cheap pump gas and enjoy that power daily. The dyno operator than says that power is 650 whp, but because they didn’t turn up the boost pressure very high and because the turbo didn’t spool up till later in the RPM where the motors volumetric efficiency was decreasing, the engine only made 575 ft/lbs of torque, but it was able to hold this torque almost all the way out to redline. The owner would have liked to make more torque, since more is better, but then the engine builder lets the owner know that since the motor didn’t make more than 600 ft/lbs or torque he would likely be fine running the stock rods and pistons, and that a built motor is not required. With this news the owner celebrates and leaves his wallet in his back pocket. Next the car takes to the street. In 1st gear the turbo is lazy so not much boost pressure is made, but the car is still very quick since traction is maintained and a 3.0L naturally aspirated motor is still very peppy. 2nd gear comes and the larger turbo spools a lot more linear and comes up much later in the RPM with less torque so that again, traction is maintained pretty well. The owner shifts to 3rd and traction is all there and so is the turbo. What is nice is the larger turbo pulls hard all the way to redline.
Single Stroke Engine
So which set-up is better? Well if money was infinite and traction was infinite than the smallest turbo to reach your HP goal wins hands down. Better response, more torque, and with infinite traction it would put car lengths on the larger turbo car till the larger turbo cars boost came in, and also would be much more responsive and fun to drive. BUT, in the real world where money matters, and traction is a big problem, which one is better??……there is no right answer. People always want more power it seems, and buying a new $1,500 dollar turbocharger in the never ending quest for more more more sounds expensive. So, this is some food for thought to those that say to buy the smallest turbo that satisfies your HP goals. An owner should think about a lot more than just reaching their HP goal.