Automotive Systems Principles - Assignment Example

Automotive Systems Principles Name Institutional Affiliation Date Section 1 Part 1(a) Internal Gas Flows-800 Design of the apparatus The apparatus for this experiment is as shown below. The data to be collected include; The seat angles valves with angle 30 45 and 60˚ The depth of the adaptor The diameter of the adaptor The overall diameter of the valve Connect the apparatus as shown in the figure below. Means of interpreting results The results in this experiment will be interpreted using both numerical analysis and with the aid of graphs. Both the numerical analysis and the graphical analysis are done in the calculation section of this paper. Calculations and presentation The findings of the experiment are both numerically and graphically represented as shown below. The calculation of the mean gas velocity across the annulus formed by the valve head and valve seat at an arbitrary valve (7mm) at the engine stages illustrated in the diagram of figure 2 below. In the first tube, the seat angle valve is 60˚ while w = 1.32, in the second tube, the seat angle valve is 45˚ while w = 3.65and finally, in the last tube, the seat angle valve is 30˚ while w = 6.25. The seat angle parameters are as shown in the figure below. The data of the engine under experimental conditions is as follows; The depth of the adaptor = 90.5mm The diameter of the adaptor = 83.5mm The overall diameter of the valve = 32.0mm Given the following gas flow equation; V (m/s) = L.N/30000(D/d) ² i. 1500 RP/M Revolutions per second N = 1500/60 = 25 rps V (m/s) = 90.5 x 10-3 x 25/[30000(83.5/32)²] m/s, therefore the velocity in m/s is given as, V = 4.43 x 10-7 m/s ii. 2500 RP/M Revolutions per second N =2500/60 rps = 41.67 rps V (m/s) = 90.5 x 10-3 x 41.67/[30000(83.5/32)²] m/s therefore the velocity in m/s is given as, V = 1.85 x 10-5 m/s iii. 3500 RP/M Revolutions per second N =3500/60 rps = 58.33 rps V (m/s) = 90.5 x 10-3 x 58.33/[30000(83.5/32)²] m/s therefore the velocity in m/s is given as, V = 2.585 x 10-5 m/s iv. 4000 RP/M Revolutions per second N =4000/60 rps = 66.67 rps V (m/s) = 90.5 x 10-3 x 66.67/[30000(83.5/32)²] m/s therefore the velocity in m/s is given as, V = 2.95 x 10-5 m/s The results can be graphically represented as shown below. The graphical representation of the shape and position of the flow area is as shown below. Conclusion The following conclusion can be made from the experiment above. From the calculations done in the above section the results can be tabulated as shown below. N Speed in Revolutions per minute (rpm) N Speed in Revolutions per second (rps) Velocity in meters per second (m/s) 1500 25 4.43 x 10-7 m/s 2500 41.67 1.85 x 10-5 m/s 3500 58.33 2.585 x 10-5 m/s 4000 66.67 2.95 x 10-5 m/s From the above table it can be seen that as the speed in revolutions per minute of the engine increases, the velocity also increases. This implies that an increase in revolutions made per minute has a effect in the amount of torque registered by the engine. This means that for the engine designers to have a good torque, the speed of the engine has to be designed at the optimum in order to register a good velocity which in the end translates to positive torque. Optimizing the torque of vehicle angine is a very critical factor that designers consider since it significantly influences the vehicle’s acceleratory performance (Ahmadi, 2007). In the case of automobile engines, volumetric efficiency (VE) is the main component that significantly affects the torque output. volumetric efficiency as a major determinant factor is the ratio of the actual induced air divided by the piston’s swept volume. volumetric efficiency as a factor in torque determination is linked to other factors like the exhaust process timing, the induction process timing, the resonance conditions occuring in the maniflod of the engine, the mean speed observed for the fluid flow and the losses arising as a result of the fluid flow The seat angle valves are two by two way pistons that are pneumatically actuated valves that are used for gases, steam, liquids and steam among other aggressive fluids. In some cases the vacuum services may apply. It has a unique and superior design for its piston for retracting the plug very far away from the path of flow. This ensures that the capacity of flow is optimized. It has a dual packing in its design with wide diameter and self aligning stem to ensure that the cycle life is optimum. It functions along with other important accessories like solenoid valves, limit switches and stroke limiters. As the seat angle valve increases, the value w decreases as shown in the diagram above. Part 1 (b) Literature Review The optimization of an internal combustion engine induction tract requires a design made specifically for maximum torque. In order to achieve this, a flat torque curve should be targeted over an extended RPM range of an engine as shown in the diagram below. Power plants that are rotary in nature like internal combustion engines have one major characteristic regarding the torque output. They have several points through which the output of the torque attains global or local maximum. Optimizing the torque of vehicle angine is a very critical factor that designers consider since it significantly influences the vehicle’s acceleratory performance. In the case of automobile engines, volumetric efficiency (VE) is the main component that significantly affects the torque output. volumetric efficiency as a major determinant factor is the ratio of the actual induced air divided by the piston’s swept volume. volumetric efficiency as a factor in torque determination is linked to other factors like the exhaust process timing, the induction process timing, the resonance conditions occuring in the maniflod of the engine, the mean speed observed for the fluid flow and the losses arising as a result of the fluid flow (Erjavec, 2010).. Computational and empirical studies clearly indicate the relationship that exists between the the manifold’s duct geometry and the high performance volumetric efficiency resonance peaks. This results to the tuning of the engine manifold by the designers so as to achieve maximum volumetric efficiency at specified speed of the engine by critically choosing a suitable geometry of the manifold’s duct. The only challenge with the tuning of the engine is engine’s drivabiliy since such engine types demonstrate operating bands that are narrow in terms of peak performance. This research attempts to achieve a drivable performance engine by making use of the flat torque curve. Such a performance can be attained by varying the geometry of the manifold in a dynamic manner in a bid to achieve a state of engine drivability without ideally resulting to rise in the displacment of the engine so as to account and cater for the torque regimes that are low. The flat torque curve along with the new variable valve timing engine systems are very vital for the reduction of the exhaust emmisions, increasing the torque gains as well as increasing the fuel economy. In the case of motorcycle engines, an overally simpler construction that has an intake that is variable can be adopted to suit such a need. There are numerous engine models that are in existence to help in the prediction of the volumetric efficiency curves and its relationship with the length of the runner not to mention other different manifold geometry. Some of the models have mass springs that are simply basic, some have wave simulatios that are single dimension in nature. All these models come with their benefits as well as disadvantages. The models that have mass springs have limitations when it comes to the fact that its is a simple equation that can only estimate the peak of volumetric efficiency without any information regarding their operaitng points. This therefore means that such a model cannot be employed in the calculations as oposed to accuracy since at high speeds, it can show tremendous error especially at greater speeds. When new engines are developed by various engine makers, there are some critical issues that they give a significant weight. Some of them include fuel consumption by the engine as well as the possibility of boosting the performance of the engine. In order for the engine developers to improve the performance of the engine, a very critical consideration is the increase of the combustion efficiency of the engine within the cylinder chamber. This calls for a critical analysis of the mass flow rate and the swirl strength. In the contemporary engine development, swirl strengh is increased by applying a system of port de-activate to the manifold intake. This is done within the cylinder chamber both in low speed range and medium speed range. The swirl helps in in improving the fuel’s mixing effect together with the air within the cylinder chamber. With the application of the system of port de-activate, the volumetric efficiency of the system worsens because of the decrease in the mass flow rate. When a multi or single objective GA is employed in determining the design parameter’s optimal solution, certain exhaust and intake factors like intake geometry of the manifold, timing of the exhaust valve and intake valve, the length of the intake pipe, among others are very critical and should be considered (Vaughan, 2010). The gas reciprocating engine exchange system effectiveness greatly influences the emmision of pollutants and noise and the performance of the engine. The idea of predicting, controlling and understanding both the discharge and charge processes is not a simple task. This is due to the fact that the dynamics of these processes are not linear or steady but are imperative within the system in achieving a high engine performance. There is tremendous development in as far as research is concerned in order to propose the methods that can be applied in order to optimise both the exhaust and intake design systems. Most techniques used currently are capable of evaluating the internal combustion engines performance. These techniques are based on the principle of gas dynamics that are one dimensional in nature. They are also based on strong commercial codes that help in similating and modeling very accurate engine. There are however, a lot of issues surrounding one domensional dynamical approach since it has several limitations. This is due to the fact that the process of developing a system like the gas exchange system that influence the emmisssions and performance of the engines entails myriad parameters as oposed to the single and linear effects that are witnessed in the one dimensional system (Vaughan & Delagrammatikas, 2010).Such parameters include secondary and primary dimensions of the inlet pipe and outlet pipe, the volume of the resonator and the intake plenum, the lift profile of the exhaust valve and intake valve as well as the the geometry of the manifold exhaust and timing. These may result to several effects when it comes to the emission of the engine exhaust and the porformance of a given automobile engine. References Top of Form Bottom of Form Top of Form Bottom of Form Top of Form Bottom of Form Top of Form Bottom of Form Top of Form Bottom of Form Top of Form Bottom of Form AHMADI, M. (2007). Intake, exhaust and valve timing design using single and multi- objective genetic algorithm. Warrendale, Pa, SAE International. ERJAVEC, J. (2010). Automotive technology: a systems approach. Australia, Delmar Cengage Learning. PAI D.B., SINGH H.S., & MUHAMMED P.V.F. (2011). Simulation based approach for optimization of intake manifold. SAE Technical Papers. SAFARI, M., GHAMARI, M., & NASIRITOSI, A. (2003). Intake manifold optimization by using 3-D CFD analysis. Madison, Wis, SAE International. VAUGHAN A., & DELAGRAMMATIKAS G.J. (2010). Variable runner length intake manifold design: An interim progress report. SAE Technical Papers. VAUGHAN, A. (2010). A high performance, continuously variable engine intake manifold. Thesis (M.E.)--Cooper Union for the Advancement of Science and Art, Albert Nerken School of Engineering, Graduate Division, 2010. Read More