Determining of optimum composition of water-fuel mixture for a spark-ignition internal combustion engine with electronic control

Abstract

The relevance of the study is stipulated by the necessity for determining of optimum composition of water-fuel mixture (WFM) for a spark-ignition internal combustion engine with electronic control. The objective of the study is the determining of the optimum composition of water-fuel mixture (WFM) during the operation of a VAZ-21114 engine which allows for the best quantitative performance specifications. For this purpose, an experimental test fixture was developed, consisting of a KI-2139 electrical brake bench with a pendulum arm machine and an “AVTOTEST-02.03” 5-component gas analyzer, with equipment for bench testing in accordance with the requirements of GOST 14846-81 “Automotive engines. Bench test methods”. As a result, for the first time, optimum quantitative WFM composition was obtained for operation of VAZ-21114 spark-ignition engine with electronic control providing for the best quantitative performance specifications. The analysis of the obtained data demonstrates lowering of the concentration of toxic exhaust gas (EG) components of the engine, specific effective (ge ) and hourly (Gm ) fuel consumption rate, as well as the EG temperature (Toe ) during its operation by the external rpm vs. load curve within the utilization range of WFM with 0 to 12% water content. At water content growth in the WFM from 12 to 20%, a growth of carbon monoxide (CO) and unburnt hydrocarbons (CH) in the EG is observed, as well as a growth of ge and Gm . The minimum quantitative values of the parameters CO, CH, NOx, Toe, ge and Gm were: 6.0 and 1.65% of CO at water content in WFM of 10 and 13%, respectively; 173 and 142.5 ppm of CH at 10% water content in WFM; 113 and 215 ppm of NOx and Toe 650 and 730 К at up to 20% water content in WFM; ge 330 and 303 g/kWh at 12.5 and 11.5% water content in WFM, respectively, Gm 6.5 kg/h at 11.5% water content in WFM. The maximum quantitative value of the effective engine power Ne of 44.2 kW was obtained with WTM with 20% water content. The obtained results demonstrate that, for the operation of a spark-ignition type VAZ-21114 engine with electronic control, the WTM should contain 9…12% water as an optimum providing for achievement of the best quantitative performance values.