Experimental with a diesel engine

[Ian]

Does anyone know of a project to put an auto diesel in an experimental plane or if this has been done successfully anywhere. The dedicated aero engines just seem to be too expensive for the market. 

Whenever I see a jetfuel tanker my mind wanders and starts going down the path of wouldn't it be nice if I could just use that fuel or diesel.

 

 

[facthunter]

You'd need fuel heaters for Diesel in some ops.  It's been tried for light aircraft but there is no wide uptake.   Nev

[Thruster88]

There was this one http://www.raptor-aircraft.com/models/dieselgtaudi30lv6tdi.html  however who wants that much grief, a Continental io-550 would have been a cheaper alternative as it panned out.

[facthunter]

Packard made a diesel radial in the 30's and some German aero engines were diesel. Used extensively on early Zeppelins. Nev

[gareth lacey]

Gaz aille french F/glass kit uses a small  diesil engine (Renault i think) i was in Coffs Harbour last week and had a look at a completed Gaz aille engine was very smooth running and uses about 10 lites per hr 

[Area-51]

PSA make engines for most everybody now; yes even your beloved thumping v6 diesel ford tonka wagon... hangon, thats the same motor with the volvo stamp, no now its bmw, what? No? its also a Landrover??? ... now i'm just confused, you want me to believe its Peugeot or Citroen??? look now it says its Mazda...

 

So PSA make millions of diesel motors every year in small and large wrappers... if you want a lightweight high speed alloy block diesel for aircraft you use PSA turbo charged Citroen Berlingo common rail.... start and end discussion here.

[Thruster88]

4 minutes ago, Area-51 said:

 if you want a lightweight high speed alloy block diesel for aircraft you use PSA turbo charged Citroen Berlingo common rail.... start and end discussion here.

I am sure it is a fantastic engine, the problems may start when the required reduction drive is mated with the engine, perhaps some harmonic vibration that cracks the crankshaft. In an aircraft like a Thruster no problem, in the RV it would be no way for me. The engine in an aircraft is often referred to as the power plant, all the systems have to work, the power plant is only as good as the weakest link.

[Old Koreelah]

4 hours ago, Ian said:

Does anyone know of a project to put an auto diesel in an experimental plane or if this has been done successfully anywhere. The dedicated aero engines just seem to be too expensive for the market.

Whenever I see a jetfuel tanker my mind wanders and starts going down the path of wouldn't it be nice if I could just use that fuel or diesel

Ian this topic was very well covered in the Jodel forum a decade or more ago. Some members were installing diesels in their homebuilt Jodels. As Area 51 said above, PSA have made millions of very reliable light diesels. Chas Kenney in NZ has installed one:

 

http://www.aviationbanter.com/showthread.php?t=11469

 

 

PM me and I’ll send you his email.

[onetrack]

The problem with diesels in light aircraft is the level of the power pulses is much higher than a petrol engine. As diesel is a relatively slow-burning fuel (this is how you get vastly increased torque from a diesel engine), the piston is being propelled for a far longer period of time on the downstroke, than with a petrol engine. The high compression also adds to an increased level of propeller pulse. It is absolutely critical that a torsional pulse absorption coupler is used with a diesel engine in a light aircraft.

 

Guiberson and Packard ( both from around the late 1920's) produced diesel radials that were satisfactory, but neither could be classed as regular production diesels due to low production numbers and continuing development.

The Packard diesel died in 1931 when its chief engineer/designer was killed in an air crash in April 1930. Packard ceased any further work on the Packard diesel from 1931, as the chief engineer was the main driver of the project.

 

The manufacturing rights of the Guiberson diesel were transferred to the Buda Engine Co in 1940 - and Buda built the Guiberson specifically for powering military tanks and aircraft during WW2. However, it appears very few Guiberson diesels made it into aircraft - the majority of Guiberson diesel production went into tanks.

When the War ended, the manufacture of Guiberson radial diesels stopped and it appears no attempt was ever again made to fit them to aircraft. I believe high octane fuel availability after WW2 killed them off. The production numbers for Guiberson radial diesel engines are unknown, but it appears only a few hundred were built.

 

http://www.enginehistory.org/Piston/Diesels/Ch3.pdf

 

Caterpillar were engaged by the U.S. Govt during 1942 to redesign the Wright Cyclone R-1820 into a diesel engine - specifically for use in military tanks. Cat were very successful in doing this, and the engine was renamed the Caterpillar RD-1820. However, after only about 200 RD-1820 engines had been produced, the U.S. Govt canned the deal, on the basis that plenty of petrol aircraft radials were now available - and Cat were required to concentrate on the production of vital crawler tractors and motor graders and gensets.

 

http://www.theshermantank.com/wp-content/uploads/2015/12/TM9-1756A-Model-RD-1820-Caterpillar.pdf

 

The Junkers Jumo engines were by far the greatest commercial success story of the aircraft diesel engine - but they were all very large and heavy engines. WW2 effectively put a stop to Junkers Jumo diesel production, as the Nazis concentrated on the petrol aircraft engines, which could produce more power for less weight.

 

The Subaru Boxer diesel is currently being modified and produced in the U.K. for aircraft use, by a company named CKT Engineering. But it's a heavy beast - 230kgs - so that puts it right out of the ultralight ballpark.

 

http://www.cktaeroengines.com/ckt-240td-engine/

 

Edited May 22, 2022 by onetrack

[Ian]

There's a good body of knowledge in this area.

I was aware of the Guiberson however I didn't realise that Caterpillar redesigned the R-1820 which is interesting.

 

Thanks for the mention of Chaz, I found a link to his plane. The drive to innovate appears to be alive and well in NZ.

http://nzcivair.blogspot.com/2015/07/charlie-kennys-jodel-d-150x-zk-ccd-has.html

 

On 22/05/2022 at 10:46 PM, onetrack said:

The Subaru Boxer diesel is currently being modified and produced in the U.K. for aircraft use, by a company named CKT Engineering. But it's a heavy beast - 230kgs - so that puts it right out of the ultralight ballpark.

 

http://www.cktaeroengines.com/ckt-240td-engine/

The subaru engine appears to use a simple offset gearbox. However as many can attest reduction gearboxes are hard work. With an opposed engine like this they might have been tempted by a planetary gearbox however they're difficult to get right as well.

[Old Koreelah]

Simple belt drives seem to be viable. As well as being lighter, they also help soak up power pulses.

[onetrack]

I've often wondered about utilising the smallest and latest Honda diesel - the 1.6L, iDTEC engine. This U.K. built engine first appeared in 2013, and its design was centred around light weight, low friction losses, and responsiveness that equated a petrol engine. I have never found an actual weight for this engine, apart from a constant parroting that it's "47kg lighter than the 2.2L iDTEC engine". This means it must be around 110-120 kgs in weight.

 

The 1.6L iDTEC engine was reworked in late 2017 and weight was reduced slightly again, and thermal efficiency was again improved. The major change was from alloy pistons to lightweight, low friction steel pistons - which also allowed for a weight saving of 280g in a new, stiffer cylinder head design, to match the steel pistons. A new, stiffer block with more ribs was announced. The engine is an open deck, alloy block and alloy head engine, 4 valve heads, high pressure common rail injection, and a variable vane turbocharger. Plateau honing of the bores combined with numerous other refinements means the 1.6L iDTEC engine has friction losses on a par with a similar size petrol engine.

 

The engine produces 120PS at 4000RPM, and I reckon it's a candidate for a light aircraft engine. All the Honda engines I've come across, or had anything to do with, are exceptionally reliable and long-lived engines. 

 

https://tridenthonda.co.uk/posts/2018-01-24-2018-civic-i-dtec-diesel

[Bosi72]

On 22/05/2022 at 5:11 PM, Ian said:

Does anyone know of a project to put an auto diesel in an experimental plane or if this has been done successfully anywhere. The dedicated aero engines just seem to be too expensive for the market. 

Whenever I see a jetfuel tanker my mind wanders and starts going down the path of wouldn't it be nice if I could just use that fuel or diesel.

 

 

 

 

10 years old video of a Cessna 172 with VW 1.9 Tdi.  Have a look at his other videos. 

 

 

 

[turboplanner]

We covered the diesel subject in another thread a while back, and went into a lot of detail.

JetA-1 is not diesel, it's kerosene.

We used Power kerosene in tractors up until around the 1950s when it was superseded by the more efficient indirect injection diesels.

Diesel initially had some potential for aircraft with torque curve ideal for constant load applications - so long life.

It burned less fuel per hour than a petrol engine.

There was less excise than petrol, so it became popular in 4WD off road and cravaning.

It was refined to a reasonably clean standard in Australia, albeit with a lot of wax.

 

Those days are gone.

As a byproduct of mandatory emission levels and changed market demand, petrol powered cars became more economical than diesel.

As diesel took over market leadership in both cars and light commercial, government applied full excise charges and it lost its price advantage.

Australia no longer refines it and we seem to be getting the dirtiest diesel in the world.

The Diesel Particulate Filter (DPF) is in the process of killing off the diesel sector in the car market and non-essential SUV market. I commented a while back about having to buy a cheap aftermarket DPF for a Subaru at $1200.00, (down from the Dealer genuine part of around $2,500) and from memory it took several days to change over.

Accelerating the DPF disadvantage, are the new families of petrol engined cars with lightweight aluminium engines able to cruise at around 4 litre/100 km with common rail petrol injection and multi injection/firing electronics which allow the torque curve to be tailored.

At the heavy end of the 4WD market Nissan Patrol was the first vehicle to return from diesel to petrol with a V8 petrol engine and financial pack which was claimed to give the same total cost of operation over 5 years as the diesel powered version. I hven't heard how that panned out, but haven't heard any squealing either.

 

The direction the auto industry is going is away from diesel, towards petrol with even better fuel economy and lower emissions, so if you were to start building a recreational aircraft today, within 5 years, if you wanted an automotive engine, petrol would be where you'd find it.

 

A handy side-benefit is if you have to refuel a petrol aircraft at a lonely airfield after you've spilt fuel all over your clothes, you don't stink for the rest of the trip.

 

 

[Old Koreelah]

Anyone starting a project would love a crystal ball, because of how rapidly the fuel landscape changes during a build.

Glad I stopped work on my diesel aeroplane over a decade ago. 

 

[onetrack]

You could never get any petrol engine to produce the sheer torque of a diesel engine, full stop. If you could, tractors and locomotives would return to petrol power.

Try asking the caravanners how they go with petrol power. The ones convinced that big V8 petrol engines are the go, grimace when they talk about fuel consumption.

If you try to get the torque from a petrol engine that a diesel produces, fuel consumption rockets.

With both petrol and diesel nearly the same cost per litre today, diesel is a no-brainer.

My workshop neighbour, a truckie, runs a Nissan Patrol 6cyl 4.8L petrol, and he regularly repeats the old joke, about how it can "pass anything but a service station".

 

I agree that diesel stinks. But with changes in the formulation of petrol, I now find that petrol stinks as much as diesel, today. So, not really a major bone of contention.

 

There are differences in formulation between Jet A-1 and diesel. Jet A-1 is referred to as a kerosene-type fuel, and diesel is referred to as a distillate fuel oil. They come from different distillation processes - but this doesn't mean that a diesel won't run satisfactorily on Jet A-1. 

The main differences are that Jet A-1 does not have a minimum cetane rating - whereas diesel does, as it's refined to meet ASTM D975 - which standard was set in 1931 - but which standard has been modified several times since its initial formulation.

 

The biggest change to diesel in recent years is in the reduction in sulphur content. Australian fuel specifications now specifies (since 2009) ultra-low sulphur diesel - 10ppm - and a reduction in sulphur means problems with lubricity, so the oil companies/refiners now add lubricity improvers to counter the major reduction in the lubricity of diesel.

 

Jet A-1 is still relatively high sulphur content, so you have increased lubricity with the added sulphur. Jet A-1 has anti-freeze additives, so it will still flow at -40°C. 

The problem with modern diesels is that fuel parameters are now much narrower than with the older diesels, and ECU's on modern diesels will shut down fuel supply if the fuel doesn't reach the ECU's programmed parameters.

 

The wax problem (filter plugging in cold conditions) we had with diesel was related to the diesel obtained from Bass Strait crude in the 80's and 90's, which contained high levels of wax.

It became recognised as a source of cold weather problems, and was dealt with by the late 90's. A reduction in the level of use of crude from Bass Strait, in crude blends, with blends of lighter crude from other parts of the world, was the solution.

 

We must be careful of comparing Australian diesel to American diesel. American diesel is refined to different specifications to Australian diesel, and comes in several grades. 

We have only one grade of diesel, and our fuel specifications are based on European fuel specifications, not U.S. specifications.

American diesel also largely utilises American crude. We have fuel produced from crudes from all over the world, and the crudes are blended to produce the specified end product.

 

In addition, Australian fuels are now largely produced by refineries in Japan, South Korea and Singapore - who produce both diesel and petrol specifically refined to meet Australian Fuel Standard Regulations 2019.

 

DPF's are largely a failed and costly technology, IMO. The horror stories of DPF problems surface in every motoring discussion. Even Toyota are not immune, with a class action pending over the dreadful DPF problems of the 2015-2019 Hiluxes.

 

The greatest single problem with diesels today is they're becoming more and more high-tech all the time, with multiple levels of electronic controls, common rail injection running at extremely high pressures, and closer and closer tolerances - with the likes of injection equipment tolerances being reduced to half what they were 20 years ago.

On the other hand, electronic control of injection has led to vast improvements in diesel performance, with multiple injection stages reducing diesel knock and improving economy, DLC (Diamond-Like Coating) now providing vastly improved engine component life (particularly in highly-stressed items such as injectors), and low-friction engine designs are now making diesel engines very responsive.

 

But DPF's are sending diesels backwards, in that DPF's increase fuel consumption (they require fuel to be injected into the DPF to burn off the carbon, add major costs to operating a diesel, and increase the fire hazard potential of diesels.

The bottom line is DPF's are not required for aviation diesels, so that's an item you would immediately remove from any diesel engine used in aviation.

Edited May 26, 2022 by onetrack

[Yenn]

There seems to be confusion about the definition of diesel and petrol engines.

Diesel is not a fuel as it is used in engines. It is an operating system, properly known as compression ignition, whereas petrol is spark ignition.

Diesels engines, compression ignition engines can run on Diesel fuel or distilate as it may me called and also on Jet A1, or kerosine.

Petrol engines, spark ignition used in aircraft will run on distillate, but they will self destruct in very short time. As proved by several RV10s that were misfuelled with jet A1.

What is the difference between direct and indirect injection diesel engines. I have used both and worked on both and in my opinion direct injection is superior, except maybe for noise at idle.

Another thing about diesel is that you can't advance the throttle, because there isn't one. Power control in diesel is by fuel amount per stroke, there is full air flow. Power control in petrol is by controlling air flow with the throttle as well as some kind of fuel quantity control.

[onetrack]

It's interesting that the U.S. Military is very big on "multi-fuel" engines. They want engines that will run on a wide range of fuels, so that their forces don't get caught out with the wrong fuels for an operation.

 

The U.S. military fuel standard is JP-8 - which is essentially aviation fuel. JP-8 is used as a backup to diesel in multiple applications. It is used for powering aircraft, powering tanks, used in heaters and stoves, and even used as a coolant.

 

JP-8, as a kerosene-based fuel, does not have the energy content of regular diesel, and diesel engines run on it suffer from a power reduction of around 10-15%.

There also have been issues with premature fuel injection equipment wear in some military equipment - but the injection equipment problems are mostly confined to vehicles with rotary fuel injection pumps - such as the Stanadyne injection pump found on the 6.2L and 6.5L Chev V8 diesels, fitted to the Humvees.

Because rotary fuel injection pumps use only one pump plunger for all cylinders (instead of individual injection pumps, as in inline Bosch/CAV/Lucas-Delphi/Zexel/Kiki Diesel/Nippon-Denso injection pumps), they are always prone to increased wear rates. Injection pump lubrication additives are a must for these style of injection pumps.

 

Edited May 26, 2022 by onetrack

[Thruster88]

Interesting article about one of the early car based diesels the theilert 1.7, based on a Mercedes I think. Even with all the resources of a large company there were many problems and a lycoming version of the Diamond Da42 had to be developed. 

 

https://www.aviationconsumer.com/aircraftreviews/diamond-da42-l360-lycoming-reborn/

[turboplanner]

2 hours ago, Yenn said:

What is the difference between direct and indirect injection diesel engines. I have used both and worked on both and in my opinion direct injection is superior, except maybe for noise at idle.

Indirect injection fired in a swirl chamber and needed glow plugs to start the engine. They followed the previous commer knocker era where you could hear the vehicle five miles away at night. I specified them on buses and coaches from around 1971 to 1976 where their quietness was a sales feature.                                      As the fuel crisis began to hit and the cost of fuel rose, direct injection started to be used because of its lower fuel consumption, and it's stayed because of its ability to meet contionually tightening emission laws.

[turboplanner]

Don't forget, the application in this case doesn't required high torque because there isn't a startability or gradability task like a light commercial towing a trailer or a truck. The application requires constant-load components, but the task is to generate horsepower and that can be done by rpm.

Also the time scale for the engines I was talking about is 2022 models rather than picking up old 2005 etc engines from wreckers.

 

[onetrack]

Indirect injection (IDI) was the primary diesel design up until the late 1950's, when direct injection (DI) designs became more favoured. The IDI system utilises a precombustion chamber to commence the fuel burn.

Many heavy industrial diesel engine designs dropped IDI in favour of DI in the late 1950's and early 1960's, because the early IDI designs could not meet the efficiency requirements of the newer, high speed (2000-2500RPM) diesels being produced in that era.

Older IDI designs became smoky and lost efficiency at high RPM's, and DI offered lower thermal losses, so DI became more prevalent. Caterpillar stuck with IDI until the late 1970's, when tighter diesel emissions laws made DI a better choice.

 

However, a number of Japanese and European manufacturers have stuck with IDI designs, thanks to improved design abilities created by computerisation, and improved real-time combustion studies.

IDI still does have some advantages, both in lower manufacturing cost and the ability to utilise lower injection pressures - but as a general guide, the current ruling diesel designs are DI, electronically-controlled piezo injectors, and extremely high pressure common-rail fuel injection systems.

 

A couple of the problems associated with CR fuel injection are - the heat generated by pressurising the fuel to exceptionally high pressures (30,000psi or 206Mpa) has to be removed via fuel cooling - and any water in diesel fuel in a CR system causes catastrophic damage to delicate, high precision, fine tolerance injectors, the high pressure pump, and associated valves.

Another problem is common rails bursting with the extremely high pressure, thus posing a major personnel and fire hazard. So much so, that some manufacturers encase the high pressure rail inside another protective layer of heavy tubing.

 

Edited May 26, 2022 by onetrack

[440032]

AUSTRO engines are EASA certified and fitted to Diamond aircraft. Based on a regular Mercedes automobile engine. Jet A or diesel auto fuel.

[Ian]

One thing that's surprising is that the power/weight ration of the Guiberson engine 0.781 kW/kg  is better than the Austro Engine 0.67 kW/kg.

The BSFC of the Guiberson was 232 g/kWh however I couldn't find any specific mentions of the BFSC of the Austro engine however based upon the figures in the wikipedia article are 221 g/kWh and 200 g/kWh at full power and cruise respectively if my calcs are correct.

The Junkers Jumo 204 two stoke diesel operated at 211 g/kWh which is pretty good for a two stroke of WW2 vintage with a power/weight of 0.74 kW/kg.

It makes you wonder how these these engines would run with a modern common rail injection system.

 

You can compare that to 275 g/kWh for an O-235. Also remember that this is in grams with heavy fuels being about 12% denser than AVgas.

ie 0.262 L/kWh for the Junker vs  0.370 L/kWh for the Lycoming.

 

Effectively this means about a for every litre of diesel fuel you'd burn 1.4 litres of AVgas at the same power output. Food for thought especially if you run on biodiesel.

 

 

[turboplanner]

9 hours ago, Ian said:

Food for thought especially if you run on biodiesel.

 

I haven't seen anything on biodiesel since the reports on a Victorian farmer who had set up a collection deal with fish and chip shops and was running his tractor with biodiesel. The downside was that he had to warm everything up including the solid fat in the tank each morning to start the engine - very much like the procedure and operation of the Lanz Bulldog tractors.

This was in the "Fuel Crisis" "Peak Oil" crisis period and before that magically went away and the "Emission Armageddon"

Have you found anything recently on biodiesel?