Analysis of BMW's Super Eta Engine: A Focus on Connecting Rod Innovations

Analysis, Pages 11 (2526 words)

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Abstract

The main topic for this analysis report is discussion of the engine of BMW product with a type of Super Eta. The purpose of the research and content for this report is to discuss the ways in which BMW manufactures super eta engines. More specific in this report leads to the use of shorter original Eta rods connected to the position above the connecting rod that is applied in the production process for BMW's super eta engine with the 2.5I series. The engine developer wants to know about the changes that occur whether it has an impact on the operation of the super eta engine or not.

The selection made by BMW in determining the type of connecting rod to be applied is important because even though it does not seem to need much attention, connecting rod itself can affect the output power that the engine can produce when operated and has a considerable influence on the length and short duration of the engine used.

to operate as long as it is used by vehicle users. In addition, this research report has the purpose of comparing the impact that occurred after the shorter original connecting rods were used on the super eta engine because previously the 2.5-rod type for connecting rod had better results and was favored by BMW users in general.

Introduction

Before further discussing the results obtained by engine developer, engine developer explain about the functions and main roles of piston handlebars or connecting rods. In machines, connecting rods themselves have very heavy responsibilities, connecting rods must be able to withstand the pressure that comes from the piston.

Also able to withstand the load received during the stretching process, from the results of the suction and bending steps in conjunction with the piston rod, piston handlebars and connecting rod is changing from a straight motion into a rotating motion. In addition, engine developer want to discuss other functions of piston rod components, piston handlebars, and connecting rods.

Connecting the piston to the crankshaft which ultimately receives the stress from the piston, because of the combustion that occurs in the engine and continues again to the crankshaft.

Some summaries of the general functions possessed by piston rods include:

Serves as a link between the piston and the crankshaft.
Functioning in making a straight motion that occurs on the piston becomes a rotating motion on the crankshaft.
Serves to move the force produced by the piston against the crankshaft and increase the rotating power that occurs on the crankshaft.

In the case of production for piston rods or connecting rods, usually piston rods are made with a cap that has a flat shape even though there are also caps that are made unevenly. There are several advantages of the production of piston rods with a lid that is installed separately because the piston rod and lid can be removed to be moved to the position at the top of the cylinder. However, there is also a weakness when the piston rod is separated from the cover, which is usually the stress on the component such as the bolt or nut between the connecting rods and the cover itself.

In those components installed on the crankshaft and also bearings located at the position of the big end of the piston rod section or connecting rods, there are metal main bearings which are inserted and installed firmly, the bearing is round and serves as a lock such as serration, bolt, and dowel. In the case of the piston installation, there are several techniques used especially those applied to piston rods or connecting rods which function as binders from the pen through bolts and in the relationship between the pen and piston rod circlip is used in order to strengthen the position of the pen in the piston itself. The technique of piston mounting with a position called the term full-floating is commonly used on diesel engines while the type of semi-floating technique that is applied by binding using bolts as a connector and also pressed is usually used on engines with gasoline and other modern engines.

Using the kinematic and kinetic analysis of Super Eta, in this research report the length of connecting rods has a variety of sizes, but the authors use data from reports containing certainty about policy in general, the authors want to explain that the size of the original eta connecting rods has a length of 130 mm. This has an impact on the gudgeon pin journal pads as well as on the walls of the engine cylinders. This also has a greater impact on the acceleration of the piston. This is different when compared to piston rods or connecting rods with a length of more than 130 mm because of the impact of pressure and the resulting load becomes smaller.

The reality is the main difference regarding connecting rods in the process of accelerating pistons which is capable of being carried out on the load received by the components of the gudgeon pin and its bearing even though the differences that occur can be ignored. Based on the results of the study, it can be concluded that the difference in the length of the connecting rods does not increase the level of speed which results in wear on the components that are interconnected when the engine is operating. So that in the end, the engine developer can also conclude that the use of original eta connecting rods in the BMW 2.5i series is acceptable and also favored by car users in general despite the reasons for the limitations regarding the availability of several components and relatively high prices.

Even so, the engine developer also want to explain the results obtained regarding the significant differences found especially regarding piston acceleration that is produced between the connection with the connecting rods and the gudgeon pin components and their bearings.

In addition, engine developer want to explain the effect of using the original connecting rods, namely that in reality there is an adverse effect on the engine that is operating due to the result of increased piston wear and other connected components such as piston rods or connecting rods and crankshafts. If this continues, it can be estimated that the worst thing that might happen is the failure of the engine while operating. In the end, the author would like to provide recommendations on this research report which explains that MBW products with 2.5i series have acceptable connecting rods even though the availability of some parts or components is limited but this can be ignored.

With the rapid development of industrial companies in the world, there is also an influence on the rapid decline of fuel oil so that in the end each country makes a plan, one of which is to produce efficient car engines in terms of fuel use. Savings regarding fuel in the world have started since the 1980s and along the lines

In this research report, also analyzes the load that can be received and the resistance of each of the main components of the engine, especially those that are directly related to the connecting rods or piston handlebars. Not to forget also, the authors pay close attention to the acceleration that pistons can produce with different types of lengths of connecting rods. The results of the research or the data obtained from the two connecting rods must then be compared to highlight significant differences and other impacts.

Then in the end with the differences obtained, the engine developer also evaluates the results that occur to conclude quantitatively or in a calculation based on the numbers obtained to explain the possibility of significant negative impacts from the use of each of these connecting rods with different lengths. The above can be really done by considering the kinematics obtained related to the kinetic of mechanical systems.

In the end, the author made a calculation simulation using a computer to build profile modeling from these connecting rods to later make it easier when comparing and drawing conclusions from comparisons of findings found by engine developer.

Result and Data Analysis

In this research report, the system analysis was conducted by engine developer because each calculation regarding connecting rod mostly uses model-based representations based on each component. This is the picture of the assembly of the crank components, pistons and connecting rods along with detailed explanations especially those related to a piston with piston rods or connecting rods mounted on the crankshaft.

Two values, θ (theta) and Φ (phi) have been added to track the angular displacement of both the connecting road and crank throw.

It was stipulated that all analysis was to be taken at the maximum designed revolution rate, 7000 RPM. For all calculation purposes this was converted into radians per second, and interpreted as the angular velocity of the crankshaft AB, denoted ωab:

7000 rev/min = 7000 rev/min x 2π radian/rev x 1 min/60 sec

ωab = 733.0383 rad/s

This means that the system undergoes a single cycle after a specific time, denoted as ‘T’, where T is:

T= 1 / frequency= 1/ (7000/60) rev/s

T =0.008571428 sec/rev

Simplifications of the model:

No x displacement of the piston
Rigid bodies
Energy mass, momentum all conserved
Frictionless piston movements
No energy loss due to heat at joints
No forces due to combustion
Assume θ = ωab*t

Using our previous assumption that there is no movement of the piston in the x-direction, we can put all of Vc’s i components equal to zero, put Φ in terms of θ and use our assumption that θ = ωab*t. To get the angular acceleration of link BC (the connecting rod), the derivative of ωbc was taken. Noting that the piston moves only up and down, we can consider the J components of Vc to be the velocity of the piston, then sub in the equation for ωbc. A similar expression for the acceleration of the piston can be obtained by differentiating Vc.

Discussion

A brief discussion about the main material used in the production process of a piston is to use steel materials but previously through the process of quality improvement, including 34 CR MO 4 or it can be called the term cast iron. Unlike the car engine, the piston handlebars are manufactured for titanium-based racing motorbikes for the reason that titanium itself does have a lightweight but strength and durability to withstand high compression pressures. But in contrast to the types of small motors, the piston rod produced is usually based on a combination of aluminum with the main goal of reducing the weight of the piston handlebars produced.

Continuing the previous discussion about other functions of piston rod components, piston handlebars, and connecting rods which served to connect the piston to the crankshaft which eventually received stress from the piston because of the combustion that occurred in the engine and continued later to the crankshaft. At the end of the connecting rods that are connected directly to the pin contained in the piston, it is usually referred to as small end, while the end of the connecting rods which are connected to the crankshaft are commonly referred to as the big end. When the engine is operating, inside big end there is a high-speed rotation so that this process has an impact on the temperature produced by the engine, a change in temperature which also rapidly rises. Because this is certain to occur in the process of operating a machine then to avoid the high-temperature rise, a metal can be created that can be used in the big end. This metal can function properly, but previously it needs to get lubrication from engine oil with a work process, which is part of the oil on the engine connected to the piston to lubricate the piston with the aim of cooling the piston during engine operation.

In addition to the connecting rods, it must be able to withstand the pressure coming from the piston. connecting rod must also be able to withstand the load received during the stretching process from the results of the suction and bending steps in conjunction with the piston rod, piston handlebars and connecting rods themselves when the process of changing from a straight motion into a rotating motion. In the end, in order not to need a large amount of motion during the process, the product of the piston rod must have a lightweight or load but still be strong. This can be made possible by producing connecting rods with shapes like the letters H or I. In the process, the small end of the piston rod must be able to be connected to the piston by using a piston pen so that the other end of the piston rod can be connected and operate when the engine starts by utilizing the function of the bearing paired on the crankshaft.

Discusses the connection between connecting rods and pistons during the process of moving the force from combustion results obtained when the engine operates with the crankshaft. The author also wants to explain some of the main parts contained in the connecting rods, as follows:

The small end part which functions as a load restraint on the piston with the bearing shape.
Shank components are components that exist in connecting rods and are installed in positions between small end and big end. Shank itself has a shape like I-beam but has a strong resistance and has a rigid nature.
The components of the crankshaft journal bore and stamp are components of the connecting rods that are in the position of the big end of the connecting rods themselves. This crankshaft component is paired to coat the crankshaft bearing journal after connecting it firmly between the connecting rods and the crankshaft.
The bolt and nut rod component functions to lock the rod and cap on the crankshaft component parts. The usual bolt and nut rod components are located at the position at the end of the connecting rods.
The big end bearing components in connecting rods are usually located at the position of the crack end. In its operation, the crankshaft processes the bearing part of the connecting rods which carry loads generated when the engine is running, after that the connecting rods also move the force from the combustion process to the crankshaft component and finally make changes in movement from up and down to movement spinning.

In connecting rods there are parts such as hardened wrought iron, this is done with the aim of removing the stress produced by the connecting rods. connecting rods are made and have a tapered shape in the design. This is done with the intention that in its scarcity, the connecting rods are able to provide additional in terms of the contact area received between pins and bores so as to produce strength but have stronger durability to withstand the effects that occur from the piston with components from the assembly rod.

Conclusion

The analysis confirms that BMW's choice of connecting rod length in the Super Eta engine strikes a balance between mechanical efficiency and component durability. Despite limited availability and higher costs of certain configurations, the chosen design meets the demands of modern engine performance and fuel efficiency standards.