Browsing by Author "Hassan, Ghulam"

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Design of research oriented cylinder head for a heavy duty engine
(2017-10-30) Hassan, Ghulam
Insinööritieteiden korkeakoulu | Master's thesis
The swirl flow is considered beneficial to enhance air-fuel mixing in CI engines during compression stroke as the piston reaches TDC, and helps in faster burn during combustion phase. Contrary to that, with the advancement of highly pressurized fuel injection systems and optimized types of IC engines like dual fuel engine demands for low swirl or preferably no swirl intake configuration is prevailing. The swirl structure induces by intake port differs from other flow structures like tumble; swirl not only survives during compression stroke but also throughout the expansion stroke. Therefore, swirl influences spray evolution and evaporation process during combustion and affect heat release due to the crumbling of the large-scale structure into small scale by adding more turbulence. This thesis work is aimed at designing, performing steady-state CFD analysis, and exercising additive manufacturing technique for a new single-cylinder research-oriented cylinder head with no induced swirl flow. The study also incorporates inclusive evaluation of flow structures produced by existing model of cylinder head through computational fluid analysis by employing Star-CCM+ software and experimental validation; then conjunction with that inquisition a new directed port model is devised. In addition, new ports position is designed, analyzed, and final model is selected based on admissible results. The new exhaust ports, cooling channels, and the main body of the cylinder head with appropriate thickness values are also designed. Additive manufacturing is a customized fabrication process to produce cost-effective products. AM has completely revolutionized current manufacturing techniques with a diverse selection of methods for different materials. Selective laser sintering is one of the powders based AM techniques with a range of available materials as polymers and metals used to contrive good quality densely structured light parts with flexible, interlocking and functional features. Therefore, SLS technique is adopted for new cylinder head manufacturing for later experimentally check of swirl flow.
High-pressure direct injection of methanol and pilot diesel: A non-premixed dual-fuel engine concept
(2020-10-01) Dong, Yabin; Kaario, Ossi; Hassan, Ghulam; Ranta, Olli; Larmi, Martti; Johansson, Bengt
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
In order to reduce the climate impacts, methanol produced from carbon-neutral methods plays an important role. Due to its oxygen content and high latent heat, methanol combustion can achieve low soot and NOx emissions. In the present study, direct injection (DI) of methanol is investigated in a non-premixed dual-fuel (DF) setup with diesel pilot. The present DF engine study is carried out via a specially-designed new cylinder head operating with a centrally located methanol injector and with an off-centered diesel pilot injector. The target is to inject methanol close to top dead center (TDC) in a similar fashion as in standard diesel combustion enabling robust operation with high efficiency. The ignition of the DI methanol is achieved with an almost simultaneously injected diesel pilot. The experiments were conducted in a single-cylinder heavy-duty research engine at a constant engine speed of 1500 rpm with a compression ratio of 16.5. The indicated mean effective pressure (IMEP) varied between 4.2 and 13.8 bar while the methanol substitution ratio was swept between 45 and 95%. In addition, the diesel pilot and methanol injection timings were varied for optimum efficiency and emissions. The introduced non-premixed DF concept using methanol as the main fuel showed robust ignition characteristics, stable combustion, and low CO and HC emissions. The results indicate that increasing both the load and the methanol substitution ratio can increase the thermal efficiency and the stability of combustion (lower COV) together with decreased CO and HC emissions.