MBD Simulation on IC Engine Valve Train
AIM : MBD simulation on IC Valve Train.
OBJECTIVE OF THE PROJECT:
Our main objective is to design a 3D model for various parts of the vlave train, simulate it and plot the graph. Also to run the simulation in different cam lift which are:
1. 3.6 mm cam lift for 1500 rpm and material cast carbon steel.
2. 6 mm cam lift for 1500 rpm and material cast carbon steel.
CAM LIFT FORMULA:
ABOUT IC ENGINE VALVE TRAIN :
A valve train is a mechanical system that controls operation of the intake and exhaust valves in an IC engine.The intake valves control the flow of air/fuel mixture (or air alone for direct-injected engines) into the combustion chamber, while the exhaust valves control the flow of spent exhaust gasses out of the combusion chamber once combustion is completed.
It consist of the following components:
1. Valve - Valve is the component which is used to inject the air fuel mixture in the combustion chamber. There are two vlave one for inlet of fuel and other for exit of the combustion product. The designed 3D model of valve is given below:
2. Valve mounting - It is the component which in which valvr is connected. It is connected rigidly and had a spring attached to its surface.The 3D modelis given below:
3. Rocker Arm - The valves are actuated by a rocker arm. Overhead valve engines use rocker arms, which are actuated by a pushrod and pivot on a shaft or individual ball studs in order to actuate the valves.. The 3D model is giveen below:
4. Pushrod - Pushrods are long, slender metal rods that are used in overhead valve engines to transfer motion from the camshaft (located in the engine block) to the valves (located in the cylinder head). The bottom end of a pushrod is attached to the cam and uppper end is attached to the rocker arm. The camshaft lobe moves the lifter upwards, which moves the pushrod. The top end of the lifter pushes on the rocker arm, which opens the valve.. The 3D model of the puch rod is :
5. Cam : It is the rotating element which pushes the pushrod. Cam provide the appropriate lift for the valves. They are attached to the camshaft which is connected to the crankshaft, they are connected with a timing belt to each other. The 3D model of the cam is:
Assembly of the component:
Case 1:
for the cam lift of 3.5 mm:
Cam design
Animation of the valve train for 3.5 mm cam lift:
OUTPUTS:
1.Linear displacement of valve:
2. contact force between cam and Push Rod:
3. contact force between Push Rod and rocker arm :
4. contact force between rockerarm and valve:
5. contact force between rockerarm and valve measured in X direction:
Case 1:
for the cam lift of 6 mm:
Cam design:
Animation of the valve train for 6 mm cam lift:
OUTPUTS:
1.Linear displacement of valve:
2. contact force between cam and Push Rod:
3. contact force between Push Rod and rocker arm :
3. contact force between rocker arm and valve :
5. contact force between rockerarm and valve measured in X direction:
RESULTS:
The contact force in X direction is the friction force that arises due to the rockrarm sliding over the surface of the valve. The change in the direction of force is because the rocker arm slides over the surface towards the origin giving the positive force and then slides away from origin in opposite direction giving the negative value. The magnitude gives the net net contact force that is acting between the rocker arm and the valve.
CONCLUSION :
- I have designed the components of the IC egine valve train successfully .
- I have obtained the plots for various conditon successfully.