Now we know how piston engines work, we can take a look into greener alternatives for fuel. Alternative fuels are not a new idea, Rudolph Diesel famously used peanut oil as well as mineral diesel in his early experiments. Henry Ford’s early cars were dual fuel - they could run on ethanol as well as petrol. In fact some conspiracy theorists believe Prohibition was actually an attempt to stop farmers in rural areas making and selling fuel without paying tax. Destroying the mash stills put a stop to that, although ironically ethanol is now making something of a comeback.
Mike Bassett, chief engineer for Research and Advanced Engineering from Mahle Powertrain, confirms, “We’re working with the oil companies to research biofuels, it’s definitely something we’re interested in. For example, we do a lot of work in Brazil with bioethanol.”
The picture is clouded by legislation. Bassett continues, “We’ve also built a CNG engine that has a very high specific output. However, the legislation isn’t helpful here as it focuses too much on exhaust emissions without considering the bigger CO2 picture. It’s the same for EVs – the legislation takes no account of the energy used to extract the lithium and manufacture the batteries. We’ve been trying to get this message across but when you get so many parties involved it becomes quite political and complex. I hope this will change, especially as if you take bioethanol as an example, it’s an ideal fuel for an engine. All you need to do is ensure the rubbers and plastics are able to withstand it and you can even take advantage of its properties by raising the compression ratio, enhancing efficiency.”
It does complicate the argument for EVs. What’s more is that the end of life recycling is very difficult, not just the dismantling of the vehicle but recycling the batteries themselves. Bassett says, “Recycling is a massive issue – there’s a reason why there’s so much work going on in that area. For me, the so called ‘second life’ usage is just delaying the inevitable, and it’s a nettle that has to be grasped at some point. Hopefully by the time we see large volumes of batteries that need recycling there will be a solution.” (Read the full interview here.)
So while battery technology improves, are there any quick fixes? Hydrogen is a possible solution, as well as powering a spark ignition engine when mixed with oxygen in a fuel cell it gives off electricity which can be used to charge a battery and power a vehicle along. There is currently an ambitious truck research project underway in California with this method of propulsion.
Some believe in following in Rudolph’s footsteps and there have been several efforts over the years to do this. Transesterifying vegetable oil makes biodiesel, which can be used in many conventional diesel engines.
Using straight vegetable oil (SVO) by adapting the engine is also an option, installing heater elements to reduce the oil’s viscosity. Companies are making a living selling a conversion kits, and one company, Elsbett, used to sell an engine specifically designed for the thicker SVO. This is an area where some feel more research is needed.
The UK government has announced a consultation period to examine the possibility of getting rid of diesel and petrol by 2035 or even 2030, have your say here.