MBD Simulation on IC Engine Valve Train

Aim: Motion analysis of Piston Valve Train using Solidworks Multi Body Dynamics.

Theory: A valve train or valve train is a mechanical system that controls operation of the intake and exhaust valves in an internal combustion 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 combustion chamber once combustion is completed.

It consists of five components:

1. Cam
2. Push Rod
3. Rocker Arm
4. Valve
5. Valve Mount

1.Cam: The cam drives the upper portion of the engine with lobes or cam lobes to open and close the valves.

2.Push Rod: A rod in an overhead-valve engine that is part of the linkage used to open and close the valves.

3.Rocker Arm: A rocker arm (in the context of an internal combustion engine of automotive, marine, motorcycle and reciprocating aviation types) is an oscillating lever that conveys radial movement from the cam lobe into linear movement at the poppet valve to open it.

4.Valve: Valves form an integral component of an internal combustion engine and every cylinder in an engine atleast has two of them, i.e. an intake (intake of fuel-air mixture) and an exhaust valve (exhaust gases). A multi-valve engine can have three, four and sometimes five valves.

5.Valve Mount: Acts a spring for the Valve.

Assembly of the Piston Valve Train

Drawing of Cam for case 1 and case 2

Case 1

Case 2

Procedure:

1. At first we will make part modelling of all the 5 parts in Solidworks and the unit should be MMGS.
2. Then we will open Solidworks assembly to start assembling the five components in solidworks assembly.
3. In this the material we will be using will be Cast Carbon Steel.
4. Now Since we have completed the assembly and defining the material we will go for motion analysis and for that we will go in add in and click on Solidworks motion.
5. Now we will define the motor at Cam axis as 1500 rpm in clockwise direction.
6. For the case 1 we will keep the distance from origin to the smaller circle axis as 11mm and for case 2 as 13.5mm.
7. Now we will define contact between Cam and Push Rod then Push Rod and Rocker Arm and then between Rocker Arm and Valve.
8. Now we will apply Spring between Valve and Valve Mount with stiffness of 10N/mm and distance as 35mm.
9. Now Since our defining of Parts is done we can change the motion analysis to 9000 frame per second.
10. Now we can hit on calculate and then can go for results and plots after calculation is done.

Results and Plots:

Case 1)

Case 2)

The formula for calculation of the distance(L) is:

`L=R1-R2+(cl)`

where cl is cam lift

all units are in mm

Observation:

With Increase in Cam lift, linear displacement of valve also increased.Thus, Valve lift is dependent on design of Cam.

Contact force between the Rocker Arm and valve with respect to the X direction force gives the contact force only in X direction.But in X direction force has both negative and positive when the Valve is moving upwards and downwards.

Google drive Link for the Parts and Assembly:

https://drive.google.com/file/d/1ijurd0hq0IOdkAYRHxQp80bPpAO0kO1w/view?usp=sharing

https://drive.google.com/file/d/1ix6jT3TjkFqKja5zAfUploaOl7RnbF9P/view?usp=sharing

https://drive.google.com/file/d/1oxYG4D6pTE2fV5Tqvtg5ETZDLA38CMuE/view?usp=sharing

https://drive.google.com/file/d/1XebXHG34u9N-D4o51NRriaEtaJIUroMo/view?usp=sharing

https://drive.google.com/file/d/1QnlJ0ZIP0KSZwMTeTj9Vxrg8k7SaisVL/view?usp=sharing

https://drive.google.com/file/d/1RMtHUVhbQO06l3SfOhOdzgZn55NLIeTv/view?usp=sharing

Animation:

Case 1:

Case 2: