Special control units

'I'm sorry, my German isn't very good, so I would prefer to write in English.'

My hobby is building flying machines. The newest one will be equipped with a car engine, a VW PD 1.9 DTI. Currently, I'm working on the mechanical components (building a reduction gearbox to decrease the propeller speed). The next step will be the electronics. The standard engine control unit is far too complex for what's needed in flight. I'm looking for information or assistance regarding data for this engine, specifically the start and duration of injection at different RPM and load ranges, in relation to turbo pressure, air temperature, and air volume, so that I can build a special, very simple control unit containing only the essential functions for the engine, necessary to drive the propeller.


tomflyer

Hi,

Do you want to build your own control computer for a PD engine? I guess that this is far more complex than simply adapting the original unit to your needs by removing sensors (and replacing their inputs with appropriate signals) and making connections to other systems (such as the immobilizer).

By the way... do you think this machine is powerful enough for your needs? The power-to-weight ratio is not as good with a TDI engine (compared to gasoline engines of the same power).

Greetings,

Jan.

In my opinion, Jan is right.
The TDI is a very heavy engine. Please tell us what kind of flying machine you have. A supercharged engine is the best type of engine for reaching a high altitude. But isn't a small Smart CDI engine a better choice?

Tom, you might consider using an engine with a distributor pump, such as an 110hp AFN or ASV.
It is possible to convert these engines to operate purely mechanically (but with considerable effort).

take a look at and http://www.thielert.com/.
They have a flight-diesel engine certified to JAR-E.

@jan

of course, a TDI is much heavier than a gasoline engine, but the fuel consumption is much lower. so you can compare the engine weight with less fuel http://www.centurion-engines.com/.



CU Gremlin.

Hello fellow Diesel enthusiasts,

Thank you for all the responses. My plane is a BD-4 experimental aircraft, already built up to the firewall, and I'm waiting for a suitable diesel engine. I have quite a bit of leeway regarding weight and power. The plane can be equipped with engines ranging from 118 to 350 HP. Initially, since I'm in Sweden, I was planning to install a Volvo D5 common rail engine, which is all aluminum, including the block. It weighs 183 kg and produces 163 HP, a marvelous engine. However, the five cylinders plus the high-pressure pump at the front make the engine very long, resulting in the PSRU (propeller speed reduction unit, weighing approximately 25-30 kg) being positioned too far forward. This fact can only be compensated by placing lead (dead weight) at the back of the plane as a counterbalance to restore the essential center of gravity. That's why I believe a VW engine is more suitable. I've already made some sketches that show how the entire driving unit (engine and PSRU) can be placed under the original cowling designed for a Lycoming engine. The drawbacks are: a relatively heavy engine, although it is lighter than the Volvo (the VW block is made of cast iron, not aluminum), and slightly less power, 130 HP versus 163. However, I think the advantages outweigh the disadvantages. Presumably, the power of the VW engine could be temporarily increased to 150 HP for takeoff. The VW is also much shorter than the Volvo, so the weight imbalance in the back can be reduced or even eliminated. Furthermore, the VW PD represents the latest generation of diesel technology, whereas the Volvo uses a common rail system. If you consider that a Lycoming or Continental engine today doesn't differ much from its 50-year-old counterparts (except for its price), you probably understand my efforts. Gremlin has recommended the Thielert engine. They, of course, have possibilities and resources far beyond anything I have. Thielert completely removes the brand new original (Mercedes) engine and, with numerous modifications, rebuilds it into an aviation engine. The ready-built and certified flight engine, called Centurion 1.7, is rated to 135 HP and suitable for both the private and commercial markets. However, its selling price is extremely high, which is typical for the aviation market. As someone who is part of the homebuilding community with limited resources but a lot of enthusiasm, Thielert is not a solution for me. My current plane, which uses a VW diesel engine, is the third aircraft I have built. For us homebuilders, it is very important to keep costs down. Therefore, my approach is to use a mass-produced car engine, utilizing the latest technology and an acceptable purchase price, and operate within the experimental category. Gremlin even proposes using a VW engine with a distributor pump, rated at 90 HP. In reality, these older types of diesel engines don't run as smoothly as those with electronic injection, resulting in significant torsional vibrations. These vibrations are hardly noticeable in a car, but can be extremely dangerous in flight. In a car, the entire body, weighing around 1000 kg, acts as a linear flywheel, damping resonances. However, in the air, this is replaced by the inertia of the propeller (a few kilograms) and the impact of the air. On the other hand, I've already purchased a VW PD engine that has only run a few thousand kilometers in a Passat. I don't even intend to open the engine itself, but the steering box cannot be used as is. It wouldn't have surprised me to build another box containing only the essential functions. However, Jan, also known as 'Jan6K,' a computer expert, is advising me to keep the original box and to disconnect all the cables.
(for instance ABS, EGR, immobilizer, and so on), which are not needed in the air. Matthias, also known as 'MatthiasTDI96,' completely agrees with him. Jan recommends for:

'Adapting the original box to your needs by simply removing sensors (and replacing their inputs with appropriate signals) and making connections to other systems (such as the immobilizer).'

Since I don't have a replacement control unit yet, the one I'll purchase later will need to be reprogrammed, specifically regarding the immobilizer functions. I'm increasingly inclined to use an original control unit. The idea itself seems very practical and realistic, and I would appreciate some information about it. Is there anyone of you who...?
Can I offer some assistance in this matter?

Regards.
Tom.

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