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:
 Bajulazsix 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:
 BeareHead 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