The different methods for the generation of hydrogen are well known, as well as their applications, advantages and complications for their use. Every day it is essential to replace fossil fuels, so it is necessary to improve and take advantage of the different devices that we already have. The alkaline electrolyser is one of the best options, due to the simplicity of its components and its simple assembling; it is a relatively inexpensive device for the production of hydrogen. In this article, three different alkaline electrolyser stacks are presented, ECH-001 model. The difference between them lies in the fact that the configuration of the electrode changes with the number of drill holes. This has the purpose of optimizing the maximum productivity of the oxyhydrogen gas (OH2G) with respect to input power and the performance with different operation parameters, like the number of serial plates, geometry and the distance between them. The performance curves of parallel and serial arrangements are shown. The performance of a DEKTM diesel engine (monocylinder of 406 cc) with and without OH2G was evaluated, with flows of one, two and three sL min-1. Tests for CO, CO2, HC and NOx emissions were measured using the exhaust gas analyzer and varying the engine speed. The results show that the electrolyser assembly with four holes electrodes achieved the best performance with an OH2G productivity of 2 sL min-1 when using; 7 serial plates at the anode (which is called arrangement 1, 5–10), 3 mm gap and a 5% solution of NaOH. The results also shows a 14% reduction in fuel consumption, 22% reduction in HC, 23% reduction in CO, 7% reduction in CO2 and 15.5% NOx reduction with 2 sL min-1 of OH2G all this for 2500 rpm. The obtained results show a great advantage for the use of dual combustion with the diesel-hydrogen combination. Display omitted •APQP methodology for small-scale Alkaline electrolyser was established.•Alkaline electrolyser was designed with different electrode configuration.•Reduction diesel consumption of 14% in dual combustion diesel-hydrogen.•Reduction of HC, CO, CO2 and NOx emission when 2 L/min of OH2 gas was fed.