What is a stratified charge combustion chamber?
The term “stratified charge” refers to the working fluids and fuel vapors entering the cylinder. In simple terms a stratified charge engine creates a richer mixture of fuel near the spark and a leaner mixture throughout the rest of the combustion chamber.
What are the benefits of stratified charge engine?
The benefits of stratified charge include1 (1) reduced pumping losses due to unthrottled part-load operation, (2) decreased heat loss to cylinder walls and (3) an increase in compression ratio due to lower end gas temperatures associated with stratified combustion.
Which technique can be the charge stratification be achieved?
Explanation: The charge stratification can be achieved by injection as well as carburation. Charge stratification means providing different fuel-air mixture strengths at various places in the combustion chamber.
What does the term stratified charge mean?
: an internal-combustion engine in whose cylinders the combustion of fuel in a layer of rich fuel-air mixture promotes ignition in a greater volume of lean mixture.
What are the types of stratified charge engine?
As with the diesel engine there are two basic methods of achieving stratified charge combustion, namely the pre- or divided chamber method (Fig. 2) and the open-chamber method (Fig. 3).
What is supercharging MCQs?
This set of IC Engines Multiple Choice Questions & Answers (MCQs) focuses on “Supercharging”. Explanation: Detonation and pre-ignition are increased by an increase in supercharging pressure. 3. The supercharged petrol engines have a lower fuel consumption than naturally aspirated engines.
How does a lean burn engine work?
Lean-burn refers to the burning of fuel with an excess of air in an internal combustion engine. The excess of air in a lean-burn engine emits far less hydrocarbons. High air–fuel ratios can also be used to reduce losses caused by other engine power management systems such as throttling losses.
Why do engines downsize?
In the automotive industry, engine downsizing is the practice of utilizing smaller combustion engines over larger ones of the same power capacity when manufacturing vehicles. Reducing the number of cylinders also reduces the amount of friction in the engine, increasing the efficiency. …
What kind of engine is a stratified charge engine?
Unsourced material may be challenged and removed. A stratified charge engine describes a certain type of internal combustion engine, usually spark ignition (SI) engine that can be used in trucks, automobiles, portable and stationary equipment.
What happens to the lean charge in a stratified charge engine?
Combustion management. It can be seen from this method of charge stratification that the lean charge is ‘burnt’ and the engine utilising this form of stratification is no longer subject to ‘ knock’ or uncontrolled combustion. The fuel being burnt in the lean charge is therefore not ‘knock’ or octane restricted.
How does a homogeneous charge system affect combustion?
In a homogeneous charge system, the air/fuel ratio is kept very close to stoichiometric, meaning it contains the exact amount of air necessary for complete combustion of the fuel. This gives stable combustion, but it places an upper limit on the engine’s efficiency: any attempt to improve fuel economy by running…
Can a charge engine be stratified without a spark plug?
Charge stratification can also be achieved where there is no ‘in cylinder’ stratification: the inlet mixture can be so lean that it is unable to be ignited by the limited energy provided by a conventional spark plug.