MBD Simulation on IC Engine Valve Train
Objective:
To create a 3Dmodel for IC Engine Valve Train and assemble and performed a motion analysis and also to study contact force between parts.
Components used in IC Engine valve train:
Cam:
A camshaft is a device to convert rotational motion into reciprocating motion. which actuate the intake and exhaust valves of the cylinders. The cams and the camshaft are usually formed as a unit, with the cams set at angles so as to open and close the valves in a prescribed sequence as the cams rotate. A separate camshaft for each row of cylinders is driven by gears or chains from the crankshaft.. One of the most widely used applications of camshafts is the opening and closing of fuel valves in virtually all piston-driven internal combustion engines.
Push rod:
Push rod is a rod that pushes up rocker arm by actuated by a cam to open or close a valve of an internal combustion engine.
Rocker Arm:
Rocker arm is an oscillating lever that conveys radial movement from the cam lobe into linear movement at the poppet valve to open it. One end is raised and lowered by a rotating lobe of the camshaft while the other end acts on the valve. When the camshaft lobe raises the outside of the arm, the inside presses down on the valve stem, opening the valve. When the outside of the arm is permitted to return due to the camshafts rotation, the inside rises, allowing the valve spring to close the valve.Some overhead cam engines employ short rocker arms in which the cam lobe pushes down on the rocker arm to open the valve. On this type of rocker arm, the fulcrum is at the end rather than the middle, while the cam acts on the middle of the arm. The opposite end opens the valve.
Valve:
Valve is a device to close and open a passage. In motor vehicle engines, two engine valves are used for each cylinder-an inlet (or intake) valve and an exhaust valve. Fuel is allowed to the cylinder by the inlet valve. When closed, the valve seals the combustion space tightly.
Valve Mount:
Valve Mount use to support the valve to move in correct direction and spring is attached to the valve mount,
Assembly of IC Engine Valve Train:
Input Parameters.
| Sl.No | CAM Lift (mm) | Speed (RPM) | Material |
| 1 | 3.5 | 1500 | Cast Carbon Steel |
| 2 | 6 | 1500 |
Cast Carbon Steel |
Calculation fo Cam Lift (mm):
Case 1: Cam lift at 3.5mm
R1 = 12.5mm (dia - 25mm)
R2 = 5mm (dia - 10)
CAM LIFT = (L - R1) + R2
3.5 = (L - 12.5) + 5
3.5-5 = L-12.5
-1.5+12.5 = L
L = 11
Case 1: Cam lift at 6mm
R1 = 12.5mm (dia - 25mm)
R2 = 5mm (dia - 10)
CAM LIFT = (L - R1) + R2
6 = (L - 12.5) + 5
6-5 = L-12.5
1+12.5 = L
L = 13.5
Procedure:
- Creating required 3D model for IC Engine Valve Train.
- Creating 2 seperate cam's with 3.5mm lift and 6mm lift.
- Assembiling the 3D model by using constraints.
- In this input motor is fixed to cam and it rotes at the constant speed of 1500rpm in two cases.
- Linear spring is added between surface of valve and valve mount with spring constant of 10 N/mm and free length of 45mm.
- In this we are using motion study properties, 7200 frames per second and using Precise contact
- Fixing the contact type as solid bodies for IC Engine valve Train and assigning material as Cast Carbon Steel, and calculat the motion analysis.
Output:
Calculating the motion analysis of Contact force between Cam and Push Rod, Pushrod and Rocker Arm, Rocker Arm and Valve for both x direction and magnitude.
Case1: Cam lift at 3.5mm
Liner Displacement of Valve lift at 3.5mm
Contact force b/w Cam and Push rod at 3.5mm
Contact force b/w Push rod and Racker Arm at 3.5mm
Contact force b/w Racker Arm and Valve at 3.5mm
Magnitude)
Contact force b/w Racker Arm and Valve at 3.5mm (X direction)
https://drive.google.com/file/d/12WM6h2aRWSNUsPhQbl7JdKDkhfC_dyGz/view?usp=drivesdk
Case 2:Cam lift at 6mm
Liner Displacement of Valve lift at 6mm
Contact force b/w Cam and Push rod at 6mm
Contact force b/w Push rod and Racker Arm at 6mm
Contact force b/w Racker Arm and Valve at 6mm (Magnitude)
Contact force b/w Racker Arm and Valve at 6mm (X direction)