Retrotechtacular: The Fell Locomotive

January 3, 2024 by Jenny List 20 Comments

If you were to visit a railway almost anywhere in the world, you would find that unless it was in some way running heritage trains, the locomotives would bear a similarity to each other. Electric traction is the norm, whether it comes from a trackside supply or from a diesel generator. In the middle of the last century, as the industry moved away from steam traction though, this was far from a certainty. Without much in the way of power electronics, it was a challenge to reliably and efficiently control a large traction motor, so there were competing traction schemes using mechanical gearboxes or hydraulic drives. One of these is the subject of an archive film released by the oil company Shell, and it’s a fascinating journey into a technology that might have been.

A model of a gearbox, in black and white. — The Fell differential gearbox.

All diesel locomotive designs struggle with the problem of transmitting the huge torque required to start a fully loaded train at low speeds, and because of the huge force required, it’s impossible to design a locomotive-sized conventional gearbox to do the job in the way it might be managed on a truck. Electric and hydraulic drives exploit the beneficial torque characteristics of electric and hydraulic motors, but the mechanical gearbox isn’t quite done for. The subject of the video is British Rail number 10100, otherwise commonly known as the Fell locomotive, and it was a one-off prototype that took to the rails at the start of the 1950s designed to test a very novel gearbox design.

At the heart of the Fell gearbox is a set of differential gears the same as you’d find in the axle of a car, and in the locomotive they are used to combine the output of more than one engine. The loco had four smaller-than-normal diesel traction motors that could be combined, but even then, it wasn’t done. To achieve variable torque, they employed superchargers driven by a set of even-smaller diesel engines, resulting in an ungainly multi-engined beast but with the desired characteristics for both starting heavy trains and for moving them at high speed. Continue reading “Retrotechtacular: The Fell Locomotive” →

Homebrew Optical Sensor Helps Your Diesel Pass The Smoke Test

June 27, 2022 by Dan Maloney 50 Comments

We’ve all heard of the smoke test, and we know that it’s the lowest possible bar for performance of an electronic device. If it doesn’t burst into flames when power is applied, you’re good to go for more functional testing. But the smoke test means something else for cars, especially those powered by diesel fuel. And passing diesel exhaust tests can become something of a chore.

To make passing these tests a little easier, [Janis Alnis] came up with this diesel exhaust monitor that measures the opacity of his car’s emissions. The sensor itself is quite simple, and mimics what commercial exhaust analyzers use: a LED and a photodiode at opposite ends of a tube of a specified length. Soot particles in exhaust passing through the tube will scatter light in a predictable way, and the numbers work out that a passing grade is anything greater than 53% transmission.

The sensor body is cobbled together from brass pipe fittings with glass windows epoxied into each end. Exhaust enters via a tee fitting attached to a hose and sampling tube, and exits through another tee. One window of the sensor has a cheap battery-powered flashlight as a light source, while the other end has a Texas Instruments OPT101 photodiode sensor. The sensor is connected to one of the analog inputs of an Arduino, which also runs a 128×64 pixel LCD display — inspired by this air quality meter — to show the current smokiness both graphically and as a percentage. The video below shows the sensor at work.

While there were some issues with soot buildup and water vapor condensation, using the sensor [Janis] discovered that a little bit of a warm-up drive got things hot enough to clear up his ride’s tendency to smoke a bit, allowing him to pass his inspection. Continue reading “Homebrew Optical Sensor Helps Your Diesel Pass The Smoke Test” →

Electric Vehicles, The Gasoline Problem, And Synthetic Fuels

October 18, 2021 by Dan Maloney 115 Comments

When you’re standing at the gas station filling up your car, watching those digits on the pump flip by can be a sobering experience. Fuel prices, especially the price of gasoline, have always been keenly watched, so it’s hard to imagine a time when gasoline was a low-value waste product. But kerosene, sold mainly for lighting, was once king of the petroleum industry, at least before the automobile came along, to the extent that the gasoline produced while refining kerosene was simply dumped into streams to get rid of it.

The modern mind perhaps shudders at the thought of an environmental crime of that magnitude, and we can’t imagine how anyone would think that was a good solution to the problem. And yet we now face much the same problem, as the increasing electrification of the world’s fleet of motor vehicles pushes down gasoline demand. To understand why this is a problem, we’ll start off by taking a look at how crude oil is formed, and how decreasing demand for gasoline may actually cause problems that we should think about before we get too far down the road.

Continue reading “Electric Vehicles, The Gasoline Problem, And Synthetic Fuels” →

The Rotary-X Engine Is A Revolution In Thermodynamics

February 15, 2021 by Kristina Panos 119 Comments

If you’re running an army, chances are good that you need a lot of portable power for everything from communications to weapons control systems. When it comes to your generators, every ounce counts. The smaller and lighter you can get them, the better.

Connecticut-based company LiquidPiston is developing a high-powered generator for the US Army that uses the company’s own rotary x-engine — a small, light, and powerful beast that sounds like a dream come true. It can run on gasoline, diesel, natural gas, kerosene, or jet fuel, and is scalable from 1 to 1,000 horsepower (PDF).

Co-founder and CEO Alex Schkolnik describes the design as a combination of the best parts of the Otto and Atkinson cycle engines, the Diesel, and the Wankel rotary while solving the big problems of the latter two. That sounds impressive, but it doesn’t mean much unless you understand how each of these engines work and what their various advantages and disadvantages are. So let’s take a look under the hood, shall we?

Continue reading “The Rotary-X Engine Is A Revolution In Thermodynamics” →

Hackaday Podcast 039: Elliot <3 Lightning Detectors, Ikea Dark Mode, The Smartest Watch, Solar Sailing The Sky, And VAWT Controversy

October 11, 2019 by Mike Szczys 1 Comment

Hackaday Editors Elliot Williams and Mike Szczys recap a week full of hacks from the solar sailing RC plane that has zero power storage, to geeking out about lightning detectors and hacking Ikea LED controllers to unlock real dimming to building backyard wind turbines. We look up an IoT egg tray with appreciation not for the concept but certainly for the engineering, and scratch our heads on why one-hacker-smartwatch-to-rule-them-all seems like something that should happen but so far has only been a fleeting concept.

Take a look at the links below if you want to follow along, and as always tell us what you think about this episode in the comments!

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

Continue reading “Hackaday Podcast 039: Elliot <3 Lightning Detectors, Ikea Dark Mode, The Smartest Watch, Solar Sailing The Sky, And VAWT Controversy” →

The Future Of Diesel Is On Shaky Ground

September 26, 2019 by Lewin Day 251 Comments

Diesel is a fuel that has had a mixed history, with varying levels of take-up by consumers around the world. In the world of transport, diesel engines have offered better fuel economy and torque than comparable gasoline engines. Particularly popular in Europe, diesel established a strong consumer base in both small commuter cars as well as heavy vehicles such as trucks and buses.

Despite this, the tide is turning, and for the average motorist, diesel’s days may be numbered. Why is this the case, and what are the potential alternatives vying for diesel’s crown?

Plenty of Pros, but Plenty of Cons

Diesel remains a fuel with a varied uptake around the world. It has enjoyed great popularity in Europe in small commuter cars.

Diesel is a hydrocarbon fuel with several advantages over gasoline. Its lack of volatility makes it workable to use in a compression-ignition mode, and diesel engines can be run with lean fuel-air ratios. It also has a higher volumetric energy density than gasoline, and thanks to low volatility, diesel engines can run at significantly higher compression ratios without risking detonation. These benefits allow diesel engines to produce significantly more torque than similarly sized gasoline engines, and they can offer fuel economy gains in excess of 15%.

Unfortunately, diesel also comes with its fair share of drawbacks. Diesel engines are typically poor when it comes to power to weight ratio, as their high compression ratio and torque output demands heavier materials in their construction. The major bugbear of the diesel engine, however, is its emissions. Despite greater fuel efficiency, carbon dioxide output from a diesel engine is often far worse than that of a comparable gas motor. Additionally, their lean-burning nature leads to production of high levels of oxides of nitrogen (NOx), which have major negative environmental effects. There’s also the problem of particulate pollution, which is responsible for respiratory harm in humans. Diesel automobiles rank significantly worse than gasoline vehicles in all these areas. It’s begun to cause figurative headaches for the industry, and literal headaches for the public. Continue reading “The Future Of Diesel Is On Shaky Ground” →

Fail Of The Week: Engine Flips Out

January 11, 2018 by Adam Fabio 66 Comments

A few weeks ago an incredible video of an engine exploding started making the rounds on Facebook. This particular engine was thankfully in a dyno room, rather than sitting a couple of feet away from a driver on a track. We’ve all seen engine carnage videos before, but this one stands out. This diesel engine literally rips itself apart, with the top half of the engine flipping and landing on one side of the room while the bottom half sits still spinning on the dyno frame.

Building performance engines is part science, part engineering, and part hacking. While F1 racing teams have millions of dollars of test and measurement equipment at their disposal, smaller shops have to operate on a much lower budget. In this case, the company makes their modifications, then tests things out in the dyno room. Usually, the tests work out fine. Sometimes though, things end spectacularly, as you can see with this diesel engine.

The engine in question belongs to Firepunk diesel, a racing team. It started life as a 6.7 liter Cummins diesel: the same engine you can find in Dodge Ram pickup trucks. This little engine wasn’t content to chug around town, though. The Firepunk team builds performance engines — drag racing and tractor pulling performance in this case. Little more than the engine block itself was original on this engine. Let’s take a deeper look.

Continue reading “Fail Of The Week: Engine Flips Out” →