Design of Variable Valve Actuation System for an engine

Project Title

Design of Variable Valve Actuation System for an engine

Project Area of Specialization Mechanical EngineeringProject Summary

The internal combustion engine continues to be the preferred power source for automotive applications. This can be attributed to the desirable properties of fossil fuels such as high power density, high energy density and the ease of refueling. The internal combustion engine has evolved over the last few years due to the need for better fuel efficiency and performance. Recent issues like depleting oil reserves, increasing fuel prices, stricter emission standards and the increased use of alternative fuels have all motivated the development of unorthodox engine mechanisms. The main focus of the project is on developing a variable valve actuation system for a camless engine to increase efficiency, fuel economy and providing viable design to be potentially manufactured on a large scale. Camless engines are not manufactured on a large scale due to the complexity and cost of the mechatronics involved.We aim to provide innovative solutions to afore mentioned problems.Use of this technology has become more common in recent years as an effective technique for improving fuel economy and exhaust emissions as well as engine output, and it is growing in importance as a promising technique for reducing CO2 in response to environmental problems in particular.There are 1 Billion automobiles in the world with 4 major global corporations and more than 60 auto brands around the globe. Our idea will facilitate the whole automobile industry.Camless valve trains have long been investigated by several companies, including Renault, BMW, Fiat, Valeo, General Motors, Lotus Engineering, Ford and Koenigsegg's sister company FreeValve. Some of these systems are commercially available, although not yet in engines in production road vehicles.

Project Objectives

Developing a variable valve actuation system for an engine to increase efficiency, fuel economy, emission performance and providing viable design to be potentially manufactured on a large scale .

The project is implemented using the already available engine and design it's valve actuation system into a desired camless actuation system . We aim to design the assembly on 3D modelling software and analyze the engine , valve train and all the concerned components. Our primary motive is to analyze the efficiency and working of the chosen engine on different criterias and RPMs . Our project will facilitate the automobile manufacturers in implementing the technology . We will enlist all the advantages and disadvantages of the said engine and provide a working model of the engine which is economical and industry applicable . 

The purpose of this project is to completely remove the dependency of camshafts and their pre-determined timing profile lobes. We expect increases in fuel efficiency, power, and reliability with pneumatic valve actuators, which uses the force from compressed air to open and close the valves.

Project Implementation Method

In a camless engine, charge gases and exhaust gases are introduced and expelled from the engine in the conventional method, via valves opening and closing at a pre-ordained time using camshaft. Instead of using rotating cams that are driven from the engine’s crank to actuate the valves, a camless engine uses air pressure above and below a piston that is connected to the valves to operate it .There are also some examples that use electromagnets to operate the valves, although these aren't common. We will use electro-pneumatic valves to control the lift , timing and duration of the intake and exhaust valves . The pneumatic actuation system has either single acting or double acting cylinders . The actuation system is controlled electronically using arduino . The air is provided using the reservoir already compressed in the car . Our project will require extensive testing and use of different sensors and softwares with lengthy calculations to make our design valid . This project will only consider making a functional control system for the EPVA as well as running a few combustion runs. Installing the system in a vehicle or optimization the fuel economy will not be a part of this thesis. The thesis will not go into testing different combustion and operating modes to seek out potential efficiency gains, only create a control system for the valves, so that any user can operate them without having to reprogram the control system.

Benefits of the Project

Because camless engines have no camshaft, they may have fewer moving parts. In these systems, the camshaft rollers and pushrods have been replaced by an electro-pneumatic system which uses the existing fuel pumps, thus reducing development risks of the new system by employing existing technology.Direction changing on older B&W MC engines was engaged by changing the direction of the cam roller, whereas with the new camless engine, it is controlled by a computer. This eliminates the risk of mechanical failures that could damage the engine if there was a malfunction while changing directions. Additionally, because there is no chain connection between the crank shaft and the camshaft, the engine is lighter with fewer points of failure. The absence of a camshaft also means that the parasitic load on the engine is lower, which is particularly useful in large marine engines, as it can equate to a large amount of power savings. With a camless engine, fuel injection and exhaust timing are directly controlled by an engine control unit and can be constantly changed and adjusted without stopping the engine. This allows for the engine to run at a lower RPM, a feature useful in ships as it allows better low speed maneuvering while docking. Additionally, when a ship is maneuvering, the computer controlled fuel injection and valve timing allows for faster RPM control, hence faster stopping in emergency situations.Because these new engines can diagnose themselves and run efficiently without an operator changing settings, these engines require a smaller crew to maintain them at sea. This crew reduction equates to cheaper shipping and more global trade. Upon start-up, the exhaust stream from both exhaust valves can be directed into the exhaust system, which greatly reduces the time it takes to warm up the catalytic converter. In practice, this means that pre-catalytic treatment of the exhaust stream is not required. Note however, that during the time it takes the catalytic converter to heat up, the turbocharger is deprived of drive pressure (exhaust gas), which will certainly increase turbo lag.

Technical Details of Final Deliverable

The project revolves around getting the engine data from an online catalogue . We will design the valve train no camshaft. This will require calculations of valve train dyamics and design of intake and exhaust manifold . We will design the engine and penumatic actuator on solidworks . Then comes the analysis part. We will use CFD analysis and FEM analysis to make our design suitable for production . We will choose the relevant sensors and material to design a prototype which is replica of a real camless engine . The programming will be done using Mathworks’ MATLAB and Simulink

The first thing to build and get working is the electrical part where all combined electrical components have the motor controlling the power going to the LEDs and solenoids depending on the speed of the motor. Every 2 rotations of the shaft has a sequence of events that occur that basically supplies power to solenoid 1, shuts off the power to solenoid 1, supplies power to solenoid 2, and shuts off the power to solenoid 2. These sequence of events repeatedly occurs every 2 rotations of the crankshaft.

Second, to dynamically trigger events that occur based on speed and position of the shaft, a timing variable must be stored into a variable in the code. We found a timing library on the Arduino website and tied that library into our code. The timing library makes use of the internal clock setting on the Arduino microcontroller and counts milliseconds. We will manipulate the position and time variables to display Revolutions Per Minute (RPM) which is fed real-time on the computer.

Next, incorporating the solenoids in the circuit is a bit tricky. The voltages and current paths must be divided and have a specific path so that we don't destroy the electrical components. The solenoids and DC motor require a 12-volt supply which should come from an external power supply and power to the LEDs and encoder must not exceed 5-volts. Note that the 5-volt supply should come from a computer via Arduino 5-volt power supply. The solution here is to use a MOSFET as a switch . In the circuit below, we should be using a 1 Mega-Ohm resistor (Rgs) and a 5 Watt / 24V Zener diode (Flywheel Diode). The Lamp is essentially replaced with the solenoid.

Final Deliverable of the Project HW/SW integrated systemCore Industry ManufacturingOther Industries Energy , Transportation Core Technology OthersOther Technologies 3D/4D PrintingSustainable Development Goals Industry, Innovation and InfrastructureRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	40480
pneumatic piston cylinder	Equipment	2	2500	5000
air valve solenoid	Equipment	2	500	1000
Housing / mounting case for all mechanical components	Equipment	1	6000	6000
DC motor	Equipment	1	60	60
Crankshaft	Equipment	1	17000	17000
Valves	Equipment	4	500	2000
Arduino microcontroller board (Arduino Uno)	Equipment	1	800	800
Arduino Uno Shield	Equipment	1	120	120
Optical Encoder	Equipment	1	2000	2000
Motor controller with dial/knob	Equipment	1	1500	1500
Workshop Expenditure	Miscellaneous	1	3000	3000
Printing and Stationery	Miscellaneous	1	2000	2000