STUDI NUMERIK KARAKTERISASI ALIRAN YANG BERSILANGAN (CROSS FLOW) DISEKITAR CIRCULAR CYLINDER PADA STAGGED ARRAY DI DALAM CYLINDER BANK

Heat exchanger adalah alat yang sering digunakan dalam industri terutama untuk proses pendinginan dan pengkondisian udara/air conditioning. Dalam penelitian ini dilakukan studi numerik untuk mendapatkan karakterisasi aliran yang bersilangan (cross flow) didalam cylinder bank yang terdiri dari 18 circular cylinder yang tersusun pada 7 staged array. Penelitian ini menggunakan studi numeric secara 2D unsteady dengan menggunakan variasi bilangan Reynolds sebesar 7960 dan 47700 dengan menggunakan model viscous standar K-Omega SST, sehingga akan diperoleh data Coeffisien Pressure (Cp).

Comparative analysis of balancing of V6 engines with common- and split-pin crankshafts

An analysis of balancing of V6 engines equipped with split-pin crankshafts with any cylinder bank angle based on the mathematical relations derived in the paper was carried out. A comparison of the quality of their balancing with engines equipped with common-pin crankshafts was also carried out. The bank angle ranges beneficial for balancing of moments of inertia forces in reciprocating motion were determined. A mathematical relation on the optimum value of the main counterweights in the function of the cylinder bank angle was derived as well. The advantages of the split-pin crankshafts from the point of view of balancing were also indicated also.

Analysis of balancing of four stroke V6 engines

Analysis of balance of V6 engines with a common-pin crankshaft depending on a cylinder bank angle and the crank radius to connecting rod length ratios l based on the relations derived is presented in the paper. The bank angles providing the lowest moment of inertia forces in reciprocating motion for selected l values were determined. The position of the plane of the main counterweights in order to maximum balance of the moment of the first order inertia forces and degree of its balancing in the function of the cylinder bank angle were also defined in the paper. The position of the balancing shaft with respect to the crankshaft to fully balance the moments of the first order inertia forces was also determined. Apart from the quality of balancing, also other criteria for the selection of the cylinder bank angle of vehicle engines were indicated in the paper.

Fuel and ignition control methodologies for engines with articulated connecting rods

In this work fuel and ignition control techniques are developed for articulated rod, largebore, two-stroke, natural-gas-fuelled engines. A Cooper-Bessemer GMV-4TF engine is utilized for the experimental investigation. Due to the articulation of the connecting rods, the even bank cylinders have different piston position and port opening profiles and different compression ratios than the odd bank cylinders. Additionally, due to the mechanical design of the engine, ignition and top dead centre (TDC) for the cylinders are not evenly spaced. The non-symmetric timing and articulated geometry result in different gas flow characteristics for each cylinder bank. These differences result in increased NOX emissions of the even cylinder bank compared with those of the odd bank. Results of engine testing have demonstrated that this difference can be compensated for through bank specific fuel and ignition control. Two separate control techniques were utilized for compensation. The first resulted in decreased fuel consumption at a constant NOX level, and the second produced reductions in NOX emissions at a constant fuel consumption.

Simulation of the Airflow Characteristics of a Two-Stroke Natural Gas Engine With an Articulated Crank

The topic of this paper is the simulation of the airflow characteristics of a large bore two stroke natural gas fueled engine. The modeling was performed with the program WAVE, a computer code developed for engine cycle simulations. The engine studied was a four cylinder Cooper GMV engine. This engine has an articulated crankshaft connecting even and odd bank cylinders. Due to the articulation, the even bank cylinders have different piston profiles, port profiles, and compression ratios than the odd bank cylinders. Due to the non-symmetric timing and articulated geometry of the odd and even banks, the gas flow processes are not the same for each cylinder bank. The different manifold and port pressure profiles result in different amounts of trapped mass in the odd and even banks. The even bank is predicted to have a smaller amount of trapped mass and slightly lower trapping and scavenging efficiencies. Finally, the model predicts that the even bank cylinders attain higher maximum temperatures, which would produce increased NOx.