This document summarizes advances in internal combustion engines. It discusses major areas of advancement including engine design, material selection, timing controls, and fuel injection and combustion. It provides examples of various engine designs, materials used, and technologies like variable valve timing, cylinder deactivation, direct injection, supercharging, and turbocharging. It also briefly discusses six-stroke engine designs that aim to improve power and efficiency over traditional four-stroke engines.

1. ADVANCES IN IC
ENGINES
SANKAR RAM T. , MIDHUN ANTONY JOSEPH
Jyothi engineering college, Cheruthuruthy, Thrissur.

2. Introduction to IC engines
 Invented in early 1680
 First attempt by Christian Huygens
 Converts heat energy produced by burning of
fuel to mechanical output.
 Basically consists of a piston-cylinder
arrangement.
 The expansion of air due to the heat produced
moves the piston inside the cylinder.

3. Classification of IC engines
 Two main classifications:
 Based on combustion
 Spark Ignition [SI engines] (Eg: Petrol Engine)
 Compression Ignition [CI engines] (Eg: Diesel
Engine)
 Based on Number of strokes
 Two stroke
 Four Stroke
 Six Stroke

4. Major areas of advancement
 The vision behind evolving of IC engine was to
extract maximum power from the fuel while
reducing emissions and pollution from the
engine.
 The main areas of advancement are:
 Engine Design
 Material Selection
 Timing Controls
 Fuel Injection And Combustion
 The advances moves almost parallel and most
companies have their own versions of the
advances discussed here.

5. Engine Design
 The early designs involved a single cylinder.
This caused a large amount of fluctuations in
power output.
 So more number of cylinders were added to
reduce output fluctuations and size of engine
 There are four types of engine designs used.
 Inline
 V Type
 Flat Type
 Radial Engines

6. Engine Design
Inline Engine
V Type Engine
Flat Engine
Radial Engine

7. Material selection
 When selecting materials for engine, following
factors are considered
 Weight of material
 Melting point
 Coefficient of expansion
 Heat transmission power
 Vibration and sound damping
 The main metals used in engine manufacture
are
 Grey Cast Iron
 Aluminium
 Magnesium

8. Use of Sodium in engines
 A part of engine is hollowed and is filled with
sodium
 When temperature of the part becomes 1600C
sodium melts
 This molten state has better heat transfer that
solid metal
 Sodium is mainly used in:
 Sodium Valves (Exhaust Valves)
 Piston Skirts

9. Timing controls
 The Efficiency of engine is decided by the
timing of its sequential operation.
 Timing of inlet and exhaust valves
 Timing of the spark in SI engines
 Timing of fuel injection in CI engines
 Sequential operation of each cylinders in multi cylinder engine
 In normal cases these timings are a design
parameter set at time of manufacture.
 The goal of timing control is to change the
timings of engine while its working.

10. Variable Valve Timing (VVT)
 At low rpm, the timing is adjusted for maximum
efficiency.
 At high rpm, time the valve remains opened is
reduced while increasing the opening size.
 This helps to pump more charge to cylinder
without creating backpressure or scavenching.
 An electronic system uses a microcontroller to
adjust the solenoid valve.

11. Variable Valve Timing (VVT)
 In a mechanical system, the input from crank
is given to a gear which is locked to the cam
using a pin.
 When adjustment is needed, the pin is
removed magnetically and a stepper motor
adjusts the cam.
 Used in many cars in various names
BMW Valvetronic, VANOS
Fiat Twin Cam VIS
General Motors VVT, DCVCP
Honda VTEC, i-VTEC

12. Variable Valve Timing (VVT)

13. Active Valve Train
 In active valve train, there will be two cams
designed for specific road conditions.
 When the microprocessor detects a rough
terrain, the cam used will be the one for more
power.
 But during cruising, the cam is switched to a
low power, high efficient cam using a cam
tapper.
 Introduced first by Lotus Motors and later
developed by Nissan Motors.

14. Cylinder Deactivation
 Cylinder deactivation is a derived form of
active cam switching.
 In this method, while cruising a part of
cylinders are switched off by switching to a
cam without lobes.
 This method is successful because of
following
 Lesser fuel consumption
 Less heat generation
 Less power lost in managing other cylinders
 This is mostly employed in V Type Engines.

15. Cylinder Deactivation
 The cylinder is deactivated by
 Keeping the inlet valve closed so that there is no
fuel flow
 Keeping the exhaust valve open so there is no
work done in compression.
 Some Companies using cylinder deactivation
are
 General Motors V8-6-4 (Cadillac)
 General Motors Active Fuel Management
 DaimlerChrysler Active Cylinder Control (ACC) (for Mercedes-
Benz)
 Honda Variable Cylinder Management (VCM)

16. Fuels and Fuel Injection
 The fuels and its input to the engine highly
influences the emissions from the engines.
 In SI engines a air-fuel mixture called charge
is introduced to the cylinder before
compression
 In CI engines the fuel is injected after the
compression stroke to the cylinder. This helps
in attaining higher compression ratios.
 In SI engines it is not possible because there
is a chance that the fuel may burn before
hand.

17. Direct Injection
 With direct injection, the advantages of CI
engines can be obtained in SI engines also.
 In direct injection, first the air is filled in the
cylinder. Then half way through the
compression stroke, a small amount of fuel is
injected to the cylinder to create a lean
mixture.
 At the end of compression, just before the
spark the rest of fuel is injected to the head of
spark plug.
 The burning of fuel occurs in a stratified

18. Direct Injection
 Direct injection has many advantages such as
 No need of carburetor
 Easy design of manifold
 Better compression is achievable
 No case of knocking in engines
 Lower NOx emissions
 Due to stratified combustion leaner mixture can
be used which reduces the fuel consumption.

19. Direct Injection

20. Superchargers
 Consists of a compressor coupled to the
engine using a belt.
 The output is directly connected to the engine.
 As the engine rotates, the air is sucked in and
compressed which is then fed to the cylinders.
 Increases the amount of oxygen given to
engine thus helps in better burning.
 Is a must in aircrafts flying at high altitudes
were air is less dense.

21. Turbochargers
 Is a derived form of supercharger
 Consists of a turbine and a compressor
coupled in a shaft.
 Instead of using the power from engine to turn
the compressor, the exhaust is used to turn the
turbine which rotates the compressor.
 Turbochargers can only act at high velocity
exhaust so they need some time to start up in
cold start. This time is called as turbo lag.

22. Six Stroke Engines
 The invention of six stroke engines was for the
following reasons:
 Less weight to power ratio
 Less scavenching
 Less moving parts
 More power and fuel economy
 Obtain freedom in designing
 Better cooling
 Six stroke engines are developed in two
different ways

23. Air/Water injection to Cylinder
 In this method air or water is injected to the
cylinder at the end of exhaust stroke.
 The fluid absorbs the heat and expands
providing another power stroke. An exhaust
stroke is provided to removed the fluid from
cylinder.
 Three recognized names in this section are:
 Bajulaz six stroke engine (Preheating of air)
 Velozeta six stroke engine (Injection of air)
 Crower six stroke engine (Injection of water)

24. Opposed Piston Engines
 This model uses two pistons working in and
cylinder.
 The pistons are used to open and close ports
just like a two stroke engine.
 The working of opposed pistons provide better
compression.
 The pistons have either a change in speed or
have a phase shift between them.
 Some engines in this section are:
 Beare Head Engine
 M4+2 engine

25. References
 en.wikipedia.org
 www.greencar.com
 www.mitsubishi-motors.com
 www.bmw.com/com/en/insights
 Elements of IC Engines, Rogowsky, Tata
McGraw hill
 Internal Combustion Engines, Mathur &
Metha, Vol I&II Pergamon Press