The Otto cycle has less compression ratio (7:1 to 10:1) but in diesel cycle the compression ratio is high (11:1 to 22:1). In Otto cycle as well as in diesel cycle heat rejection takes place at constant volume. The efficiency of
Otto cycle is less
as compared with the Diesel cycle.
Is diesel engine an Otto cycle?
The Diesel cycle is
a combustion process of a reciprocating internal combustion engine
. … This is in contrast to igniting the fuel-air mixture with a spark plug as in the Otto cycle (four-stroke/petrol) engine.
What is the difference between the Otto cycle and the Diesel cycle explain why the higher efficiency of the Otto cycle compared to the Diesel cycle for the same compression ratio is not a result of practical importance?
6 Diesel Cycle
Although for a given compression ratio the Otto cycle has higher efficiency, because
the Diesel engine can be operated to higher compression ratio
, the engine can actually have higher efficiency than an Otto cycle when both are operated at compression ratios that might be achieved in practice.
Which is more efficient diesel engine or Otto engine?
In practice,
Diesels
are more efficient than Otto engines, because the latter must operate at lower compression ratios to avoid knocking (Section 3.6).
What is Otto cycle used for?
The Otto Cycle, describes
how heat engines turn gasoline into motion
. Like other thermodynamic cycles, this cycle turns chemical energy into thermal energy and then into motion. The Otto cycle describes how internal combustion engines (that use gasoline) work, like automobiles and lawn mowers.
What is Diesel cycle efficiency?
A typical diesel automotive engine operates at
around 30% to 35% of thermal efficiency
. About 65-70% is rejected as waste heat without being converted into useful work, i.e. work delivered to wheels. In general, engines using the Diesel cycle are usually more efficient, than engines using the Otto cycle.
What is K in Otto cycle?
Thermal Efficiency Derivation
A typical value for an air/fuel mixture is
k = 1.35
.
Which fuel is used in Otto cycle?
The Otto cycle engine uses a spark to ignite a mixture of air and – traditionally
– gasoline
2
compressed by the piston within the engine cylinder. This spark ignition causes an explosive release of heat energy which increases the gas pressure in the cylinder, forcing the piston outwards as the gas tries to expand.
What is ideal Otto cycle?
In the ideal Otto cycle the fuel-air mixture is introduced during the induction stroke and compressed to a much lower compression ratio (around
8:1
) and is then ignited by a spark. The combustion results in a sudden jump in pressure while the volume remains essentially constant.
Which cycle is used in diesel engine?
The diesel engine is an intermittent-combustion piston-cylinder device. It operates on either a
two-stroke or four-stroke cycle
(see figure); however, unlike the spark-ignition gasoline engine, the diesel engine induces only air into the combustion chamber on its intake stroke.
Is a diesel engine a heat engine?
A diesel engine is
a type of internal combustion heat engine
, powered by diesel. These engines run small electric generators called diesel generators, often in remote areas as well as the engines of cars and trucks (both large and small).
What is the biggest engine in the world?
The Wärtsilä RT-flex96C
is a turbocharged, two-stroke reciprocating diesel engine designed to power large container ships and is the world’s largest engine.
Why diesel engine has higher thermal efficiency?
High Oxygen to Fuel Ratio
The second reason that diesel engines have a higher thermal efficiency than gasoline engines is that of the oxygen to fuel ratio. The greater the amount of air in an air-to-fuel ratio, the cleaner the fuel burns and the more energy it produces.
What is Otto cycle with diagram?
The idealized diagrams of a four-stroke Otto cycle Both diagrams: the intake (A) stroke is performed by an isobaric expansion, followed by an adiabatic compression (B) stroke. … The cycle is closed by the exhaust (D) stroke, characterized by isochoric cooling and isobaric compression processes.
What is Otto cycle process?
The four-stroke Otto cycle is made up of the following four internally reversible processes:
1–2, isentropic compression; 2–3, constant-volume heat addition; 3–4, isentropic expansion; and 4–1, constant-volume heat rejection
.
What are the 4 strokes of the Otto cycle?
3.0 SOURCES OF IGNITION:
While the original Otto cycle engine used gasoline as a fuel source, diesel engines use the same 4-cycle operation through mixing
a fuel/air mixture, fuel compression, downward combustion and exhaust
.
