Micro diesel engine

For smallholder farmers in developing countries, a first step away from rain fed agriculture only is small scale and manual irrigation which may include some sort of manual pumping device like a treadle pump. A next step, which is often seen by
farmers as a leap forward, is mechanized irrigation by means of an engine pumpset. Especially for smallholder farmers, the available pumpsets on the market do not necessarily meet the requirements related to field size and water quantities. In practice, this means that for those smallholder farmers the available pumpsets are:
– Too big and too heavy;
– Unnecessarily fuel-inefficient;
– Using petrol instead of the cheaper and often preferred diesel fuel or kerosene fuel;
– Too expensive (resulting in non-affordability);
Those drawbacks often hamper the shift for those farmers to mechanized irrigation, withholding them the possibilities to improve their farm revenue and make the step out of extreme poverty. It is for this specific reason that PRACTICA started working on developing a small, fuel efficient and affordable diesel irrigation pumpset that could enable those farmers to make the shift to mechanized irrigation.


The micro diesel development

PRACTICA has worked on developing a small, low-cost and simple diesel engine by using the existing 18cc Lohmann two-stroke diesel engine, which was designed and produced in the 1950′s.
Work included transformation of the engine into a stationary engine and extensive laboratory testing.
The work on development of a micro diesel pumpset based on the Lohmann engine was discontinued in December 2009 based on poor test results

irrigation India.jpgmotorized irrigation in Bihar, India

nl-prototype-250x400.jpgthe Dutch micro diesel prototype

Major findings of the micro diesel work

The work on the micro diesel is summarized in the final report ‘The Lohmann experience; A concluding document about the development of a micro diesel engine based on the Lohmann homogeneous charge compression ignition engine’, which is available for download below.

The experience gained during the work has resulted in the conclusion that the Lohmann engine is not a suitable engine to function as a low-cost, simple and fuel-efficient engine for water pumping for irrigation purpose, as:

1.    The actual power output of both the 18cc micro diesel engine and the original Lohmann engine is lower than expected and lower than claimed in literature from the 1950’s. With lower power output, the 18cc diesel engine is not the best choice for the purpose of powering a pump suitable for irrigating 0,5 – 1 ha land at static water levels up to 7m;
2.    The fuel consumption of the 18cc diesel engine is higher than expected and higher than claimed in the literature from the 1950’s. With the actual fuel consumption as measured in the range from 900 – 1100 g/kWh (compared to the claimed value of 563 g/kWh, the engine is not an attractive alternative to other small engines with specific fuel consumption in the range of 500 g/kWh.
3.    Visual emissions during the engine testing were higher than comparable small 2-stroke engines and it is expected to be very difficult to make the engine clean enough to meet the standards that apply;
4.    Serious problems are expected with stationary running of the engine, due to the homogeneous charge compression ignition principle that needs constant adjustment of the compression with changing load, throttle, engine temperature or ambient temperature.

lohmann exploded view 2.jpgLohmann engine

chart leistung.jpgoriginal Lohmann performance curve

test setup 2.jpgengine testing of prototype

Reports and drawings

All the work has been finalized and is available in the form of reports, test results and drawings. PRACTICA encourages other parties to use this information to support the goal to make small, low-cost and fuel efficient motor pumpsets available for marginalized farmers.
The materials presented here can be used freely as long as PRACTICA is mentioned as the source of the material. Please send us your feedback through our contact form.

Micro diesel final report ‘the Lohmann experience’ in PDF format (5,8 MB)

Micro diesel drawings in PDF format (1,9 MB)

Micro diesel prototype testing May 2008 xls format (1,9 MB)

Original Lohman testing 2008 xls format (0,2 MB)

Earlier prototype test report in PDF format (0,4 MB)

3d micro diesel.jpg3D model of the micro diesel