Atkinson cycle (Atkinson cycle Engines)

Atkinson Engines Invented in 1882 by British engineer James Atkinson. in this try to cover the brief history, its comparison with otto cycle operated engines . & some little-bit its modern models.

2. BRIEF HISTORY OF ATKINSON CYCLE
Invented in 1882 by
British engineer James
Atkinson
Patents for the existing Otto
cycle engine presented a need
for a new crankshaft design
TheAtkinsoncycleisdesignedto
provideefficiencyattheexpense
ofpowerdensity,andisusedin
somemodernhybridelectric
applications.Alsocalledthe
Bartaenginein(1884).

3. ATKINSON-CYCLEENGINES
Operates on a four-stroke cycle
Intake
Compression
Combustion
exhaust
Its Combustion stroke is longer than compression
stroke allowing more expansion of combustion
gases.
These are all strokes complete in one revolution
of crankshaft.

4. THERMODYNAMICS OFATKINSON-CYCLE
ENGINE
The ideal Atkinson cycle consists of following
operations:
1-2Isentropicorreversibleadiabaticcompression
2-3Isochoricheat addition (Qin)
3-4 Isentropic expansion
4-1 Isobaric heat rej(Qout)

5. ATKINSONENGINEV/S OTTOENGINE
Atkinson and Otto engines are very similar.
Atkinson uses slightly different timing for valve
opening and closing events
In particular, the intake valve stays open as the
compression stroke begins.
This difference results in increased fuel
efficiency, but decreased peak power

6. ATKINSONENGINEV/S OTTOENGINE
From a mechanical standpoint, the only thing
that needs to change between an Otto cycle and
an Atkinson cycle is the camshaft(s)
The power of the engine can be supplemented by
anelectric motor during times when more power
is needed.

7. ATKINSONCYCLEV/S OTTOCYCLE
the Atkinson cycle has an efficiency advantage
over the Otto cycle.
Atkinson cycle has a larger expansion ratio than
compression ratio.
The power output would be lower in Atkinson
cycle engine as compared to a similar sized Otto
cycle en

8. COMPARISON OFOTTOANDATKINSONCYCLES

9. ADVANTAGE ANDDISADVANTAGE OFATKINSON
CYCLEENGINE
The main advantage of the Atkinson cycle is that
it is much more efficient than the Otto cycle.
But the Biggest disadvantage is reduction in
power density (power/unit volume) arising from
the reduction in air intake
However Atkinson cycle engine can be
supplemented with electric motor to provide more
power if needed
Electric motors can be used in combination or
independent of Atkinson cycle engines to provide
the desired power output most efficiently

10. USESOFATKINSONCYCLEENGINE
Today Atkinson cycle engine used in many cars
such as
Toyota Priushybrid electric
Ford Escape/Mercury Mariner/Mazda Tribute
hybrid electric
Toyota Camry hybrid electric
Honda Accord Plug-in Hybrid
Lexus CT 200h

11. ATKINSON-CYCLEENGINESTODAY

12. TODAYATKINSONCYCLEENGINE