Design and Development of Combined Mechanical and Pneumatic Valve Spring Remover

: A combined mechanical and pneumatic valve spring remover is used to remove or install valve springs from an engine while the cylinder head is mounted on the engine or supported on a workbench (off the head). The designed tool was adjustable and mounted over the cylinder head by a stud. It can operate manually to depress the spring or by using an air compressor for a pneumatic actuator. The model of the tools is done by SOLIDWORK 2021 and we selected the stainless steel AISI grade-304(12) material. Tools were made following the calculations that have been done on valve springs. From the data calculation, the force required to depress the valve spring is 1350 N but the tools were designed to produce 1962.5 N by considering some friction loss. The analysis of the pneumatic system done by ANSYS software shows acceptable results like, Von Mises stress (20.036 MPa), maximum principal stress (26.426 MPa), and the total deformation becomes 1.6029×10-3. The prototype was built, and the test was carried out in time efficiently during the removal or installation of the valve spring on Engine YaMZ-238. The test result shows that to remove 4 springs, the designed tool is very effective to use by optimizing the difference in time savings of an average of 1 minute and 17 seconds when removing the spring valve, and 1 minute and 26 seconds when installing the valve, even when we use it mechanically. The developed valve spring remover has several advantages over the standard C-clamp tools, such as greater precision and accuracy in removing valve springs, reduced labor and time required for the task, and Increased safety with minimal human force.


INTRODUCTION
Automotive service requires a wide range of excellent work.The work done must meet the needs of the customers in terms of time, money, and effort.Working in a commercial automotive shop or automotive service centre needs tools and equipment that are very useful.If we have performed any kind of repair on our vehicle's cylinder head or camshaft that involves taking-off or replacing the valve springs, we will know that compressing these springs is not that easy to pull off.There are several faulty methods out there that many people use to do this, which have resulted in damaging their valve springs.Most mechanics might have struggled with this too.

Cylinder Head
The cylinder head is a crucial part of an engine, limiting the combustion chamber and protecting the top of the engine block.Its structure is strong and rigid, and undergoes deep thermal cycle shock testing for durability.The cylinder head serves various functions, including the combustion chamber, valve mechanism placement, spark plug installation, inlet and exhaust installation, and water jacket coating.The valve train is essential for proper engine operation, and proper matching of valves, retainers, keepers, springs, and rocker arms ensures long-lasting operation and optimal performance [1].

Cylinder Head Valve Spring
A Cylinder head valve spring is a crucial component in an internal-combustion engine, holding closed valves in the cylinder head.Its primary function is to build engine compression and maintain specific pressure on all moving parts.Valve springs function nearly 70,000 times in an hour and trillion times in their life, ensuring consistent application of spring pressure to prevent valve bounce, which can lead to engine failure, power loss, and even valve breakage.Continuous use wears every part, making valve springs essential for maintaining engine performance [2].Valve springs come in single and dual designs, with the former supporting the valve independently and the latter having a smaller spring.The right spring pressure is crucial for fast retraction, valve float prevention, and cam wear [3].

Function of Valve Spring Remover
Valve spring remover tools enable mechanics to replace or change stem seals while a vehicle cylinder head is still in the engine.They compress the valve spring, allowing mechanics to remove keepers on a retainer and groove on the top of the valve stem.The main function of a valve spring remover is to control the entire valve train by applying the right amount of spring pressure to prevent valve bouncing [4].

RELATED WORKS
Automotive workshops often struggle with the valve removal process during engine rebuilding due to inadequate valve spring removers.Existing tools are prone to issues such as lock keys falling

Design Modelling and Construction
The newly developed valve spring remover can efficiently and safely compress valve springs on any overhead valve engine and camshaft block valves, whether the cylinder head is attached to the engine block or not, and even when the engine is still in the vehicle.

A Brief History of Pneumatics
Pneumatics involves using compressed air to transmit energy and force.An everyday example is inflating a balloon and letting it propel around a room.A pneumatic cylinder converts this pressure energy into motion.A double-acting cylinder uses compressed air alternately applied to the rear and front ports to move the piston back and forth.Airflow is controlled by a directional control valve, which directs the compressed air to the appropriate port for the desired movement

Design of Pneumatic Cylinder
Based on our selection of materials conducted in methodology our selected material for pneumatic cylinder wall is stainless steel AISI grade-304 (12).

Minimum Bore Diameter:
To calculate the force exerted by an air cylinder, use the formula: The theoretical force accounts for the required force plus friction and any spring force: The bore of a pneumatic cylinder is the circular chamber where pressurized air acts to generate force.The term "bore diameter" refers to the diameter of this chamber, often simply called the "bore," and is denoted as D for the inner diameter of the cylinder.The calculated diameter of the cylinder is 43.08 mm is theoretical size.For our design the factor safety with let take D= 50mm

Thickness of Pneumatic Cylinder
The thickness without corrosion allowance for each component of a piping system based on the appropriate design code calculations and code allowable stress that consider pressure, mechanical and structural loadings [11].Where P is internal pressure, D is the pipe diameter (54 mm), σ is the allowable stress (137.895MPa), E is the material quality factor (0.85), Y is the wall thickness coefficient (0.2), and C is the corrosion allowance (1 mm/year).Were as our simple formula is: ) + 1 = 1.342In the design calculation, the Young's modulus for stainless steel is 210 GPA.The cylinder force, with a safety factor applied, is 1350 N. The total stroke length is 100 mm (0.1 m).A factor K=0.7K = 0.7K=0.7 is used, with K=0.8K = 0.8K=0.8chosen to accommodate maintenance and potential adjustments, such as an increase in the stroke length.The moment of inertia and the maximum permissible stress to avoid buckling is dependent on the type of end fixing of the cylinder.Hence diameter of the piston rod required, d = 16mm.Finally, for other calculations and in a case of construction, the diameter of the piston rod used will be 16mm, safety.Copyright The Author(s) 2024.This is an Open Access Article distributed under the CC BY license.(http://creativecommons.org/licenses/by/4.0/)20 By substituting the above value into those equations, we have, hence diameter of piston required D = 47 mm.Finally, for other calculations and construction, the diameter of the piston is taken to be 50mm.

Design of Mechanical Part of Special Service Tools 3.3.1. Design of Stand and Base
The design of stand of tools typically aligns axial loads with the column's axis, but some applications may subject columns to off-center loading, causing more severe bending stress.The distance between the column's axis and the eccentric load line of action is known as eccentricity, indicated by e.For example, if a load P is applied to a column at a distance e from the axis, the column will be subjected to an eccentric load, with the load's line of action being at e. [12].The constant thickness is denoted as t. and (b = t, B = 2t, H =1.7t, h = 0.3t) Area of cross section A = Bh + Hb= A= 2.3t.hence centroid is:  By using newton Raphson method the above polynomial equation the value of t = 9.719mm so we can take the value of t 10mm

The Moment of Inertia of Stand
The following steps should be followed to find the moment of inertia of the T section.Therefore, the value of beam deflection will be Approximately 32.5 micrometer so there is no deflection on the boom.

Designing of Lead Screw and Nut
Lead screws are components used to transmit power or force.They consist of a cylindrical screw with a helical thread that engages with a matching nut.When the screw rotates, it moves axially within the nut, which remains stationary [13].
Direct Stress: The axial load (force) is W, compressive in nature and the area which carries the force is the core cross section of diameter d1 Hence, compressive stress Additionally, the compressive stress is increased by 30% to account for other stresses.
The materials selected for the screw and nut are steel and cast iron, respectively, with properties taken from B.D. Shiwalkar's Design Data Book (Page 94, Table IX  The permissible shear stress for nut is 21 N/mm2 and design value of shear stress for nut is 3.981 N/mm 2 .Here, design value of shear stress is less than the permissible shear stress i.e. n < τ allowable for nuts so the design of nuts is safe.

Construction and Working Principle of CVSR
The combined pneumatic and mechanical valve spring remover features several main components, including a stand, extension rod, pneumatic part, screw part, and pressure pieces.The pneumatic section comprises a cylinder, piston, piston rod, and bush seal, which are essential for operating the pneumatic actuator.The stand, made up of a base, bolt, nut, cylinder holder, and threaded bolt, is adjustable and designed with a T-cross section to handle axial loads and bending stresses, supporting and securing the tool on the engine.Additionally, the tool includes a lead screw and handle for mechanical operation and pressure pieces for compression.The pressure piece features a cylindrical hollow magnet housed in a non-ferromagnetic case, allowing for the replacement of the magnetic disc to accommodate different valve tip diameters.The tool's operation involves fastening it to the cylinder head with bolts and nuts.The spring is compressed either pneumatically or mechanically, with the pressure disc unit pressing against the spring retainer.This process moves the retainer away from the cotter piece, which is then removed by a magnet.After compression, the piston is lifted, facilitating the removal of the spring from the cylinder head.

RESULT AND DISCUSSION
The all the components and parts of the double acting double-end hydraulic cylinder were carefully developed and modelled using SOLIDWORKS workspace.The simulation results for both the stress analysis and deformation will be represented in this section.

Finite Element Analysis (FEA) of the Pneumatic Cylinder
A 3D model of pneumatic cylinder with the following specifications was designed using stainless steel AISI grade-304 (12).When the cylinder subjected to an internal pressure of 10 bar, the maximum stress experienced at the ends will be way less than the yield strength of the material.

Meshing and Boundary Condition
The meshing technique is used to divide the model into a number of small parts for better analytical accuracy.In both cases, meshing was carried out at an element size of 1mm for the cylinder barrel in direct contact with the pressure.The meshing results of cylinder barrel designs are as shown in When longitudinal stress is given in equation 5.2.
Note that typical maximum allowable stress for stainless steel is below 80 MPa.Therefore, our design is safe.When

Strain Analysis:
The equivalent elastic strain of 1.0421e-004 and maximum principal elastic strain of 1.1163e-004 show the elastic deformation of the material.These strains are within the elastic limit, indicating that the cylinder barrel should return to its original shape once the internal pressure is relieved, because, the material remains within its elastic range.The directional deformation values (0.0014553 mm for the cylinder end cap and 0.000686 mm for the cylinder head cap) are relatively small, indicating that the structural deformations due to the applied pressure are within acceptable limits for typical engineering applications.

Stress Analysis:
The higher equivalent stress of 23.856 MPa suggests that the cylinder end cap is experiencing more significant stress concentrations compared to the cylinder head cap.Engineers should carefully evaluate stress concentrations to ensure they are within allowable limits to avoid structural failure or plastic deformation.The lower equivalent stress of 6.0646 MPa indicates that the cylinder head cap is experiencing lower stress levels compared to the end cap.

Prototype Fabrication
Most of the components are made of materials that exist in this university and some of the materials are purchased from the local market.We used different methods to manufacture this tools, the materials are machined using a milling machine, as well as a turning machine and welded based on the design contained in 2D drawings.Furthermore, it was assembled into a combined Valve Spring remover which is ready for testing.

Test Variables and Test Design
The test variable is in the form of data when using the release of all valves.Direct testing on Engine YaMZ-238.The engine which intended for heavy vehicles "Minsk Automobile Plant (MAZ)" and "Ural 4320".both with standard tools and the new design Combined Valve Spring Compressor (CVSC).The test was carried out many times with different people who already had the skills to carry out general overhaul and top overhaul services.

Result of Test on Head Engine
This result is the experimental result of disassembling and assembling the valve spring without removing the engine head only by doing the protection of valve floating.In this study, it was assessed directly using a stopwatch.Four participants performed the task, and the average time from these four trials was calculated for both the assembly and disassembly processes.

Removing and Replacing a Valve Spring With off Cylinder Head
To remove a valve spring, first, with the cylinder head removed, use the handle at the bottom of the valve spring compressor to open the jaws wide enough to fit over the valve.Adjust the tool if necessary so it aligns with the edges of the spring.

Figure 3 - 1 :
Figure 3-1: Solid Work Model of Cylinder Barrel and Its Cup

Figure 3 - 7
Figure 3-3: piston rod 3.2.3.1.Design of the Piston In a double-acting pneumatic cylinder, pressure applies to both sides of the rod, and the force produced is determined by the piston's full area and the rod's cross-sectional area. =  ( − ) 3.7

= 3 𝑡𝑟𝑒𝑎𝑑𝑠
For standard square thread the depth or thickness of the thread, total height of nut (h) = n x p = 3 x 4mm = 12 mm Shear induced in the nut thread (τn ):

Figure 4 - 6
Figure 4-6 Stand with Support Tail IGS Form Model

Figure 4 - 1 :
Figure 4-1: Mesh Result of Pneumatic Cylinder Barrel Change in diameter, ℇ ×d = 2.7625×10 -3 mm.Longitudinal strain, (Ɛl), Change in length, ℇ ×L = 1.687×10 -3 m Let's analyze the results from the ANSYS analysis of the pneumatic cylinder barrel with a 2 mm thick wall subjected to 1 MPa internal pressure, focusing on the key parameters: total deformation, equivalent (Von Mises) stress, maximum principal stress, equivalent elastic strain, and maximum principal elastic strain.

Figure 5 - 2
Figure 5-2 Prototype Model during Working in Engine Head Is on

Table 5 -
2: Table of Result for Disassembling of Valve Spring