Diesel engines generally achieve greater fuel efficiency than petrol (gasoline) engines. Passenger car diesel engines have energy efficiency of up to 41% but more typically 30%, and petrol engines of up to 37.3%, but more typically 20%.
Which engine has highest efficiency?
The electric engine is most efficient. Electric motors are very efficient at converting electricity into work. Physicists throw around abstract numbers like 90%, whereas when discussing combustion engines, they use numbers less than 40%.
Which engine has more mechanical efficiency?
Real diesel engines are of course considered to be more efficient that Otto cycle engines; one reason being that diesel engines typically operate at higher compression ratio and the expansion ratio from even the later stages of heat release can still be considerably higher than that of most real Otto cycle engines.
Which is more efficient SI or CI engine?
Thermal efficiency: Due to lower compression ratio, maximum value of thermal efficiency is lower in an S.I engine compared to that of C.I. 7… Weight : S.I engines are generally lighter in weight due to their lower peak pressures as compare to C.I engines that are generally heavier, due to higher peak pressure.
At what RPM is an engine most efficient?
In general, the economical band for petrol vehicles is between 1,500 and 2,500 rpm (for diesels it is between 1,300 rpm and 2,000 rpm), and these bands are the same for the vast majority of vehicles, Sale says. “The exception to the rules are vehicles which have either a very high or a very low power to weight ratio.
Is 1.6 or 2.0 engine better?
In short, they indicate the 1.6 turbo is a much better engine than the 2.0 which is both slower and more gas hungry. On the other hand, they prefer the traditional transmission that is packaged with the 2.0 to the dual clutch 7 speed matched with the turbo.
Which is faster 2 stroke or 4 stroke?
Typically, a 2-stroke engine creates more torque at a higher RPM, while a 4-stroke engine creates a higher torque at a lower RPM. … Because 2-stroke engines are designed to run at a higher RPM, they also tend to wear out faster; a 4-stroke engine is generally more durable.
Why are two stroke engines banned?
Vehicular air pollution is common in growing metropolitan areas throughout the world. … To eliminate their impact on air quality, the government of Bangladesh promulgated an order banning all two-stroke engines from the roads in Dhaka starting on December 31, 2002.
Which is more fuel efficient 2 stroke or 4 stroke?
Four stroke is more fuel efficient than two stroke because 2 stroke engine doesn’t burn entire fuel. … In a 2 stroke petrol engine, due to open ports the fuel efficacy is very low as compared to 4 stroke engines.
Which fuel is used in SI engine?
In SI engines, acetylene and gasoline are either injected into the intake manifold or directly into the cylinder and the mixture is ignited by spark plug at the end of the compression stroke. In diesel engines, acetylene is either inducted along with intake air or injected directly into the cylinder and compressed.
What is a good compression ratio?
Compression ratios usually range from 8:1 to 10:1. A higher compression ratio — say, from 12:1 to 14:1 — means higher combustion efficiency. Higher compression ratios and combustion efficiency mean more power with less fuel, and fewer exhaust gases.
Why diesel engines are called CI engines?
In diesel engines, the mixture of air and fuel is ignited by the heat of compression, owing to the high compression ratio. … Diesel engines are called CI engines because in the diesel engines the combustion of the fuel takes place due to the heat generated by the compression of the air. CI means compression ignition.
At what speed is a car most efficient?
The Energy Saving Trust says that the most efficient speed you can travel in a car in terms of achieving the best fuel economy is 55-65mph. Any faster, though, and the fuel efficiency decreases rapidly. For example, driving at 85mph uses 40% more fuel than at 70mph (oh, and it’s illegal too).
Why is 55 mph the most efficient speed?
The most efficient speed for electric cars is closer to 15-20 mph versus 55 mph for ordinary cars. This is because the losses at low speeds for ordinary cars has to do with the construction and inefficiency of the gas ICE. Directly to the question at hand – they also give the sources of losses over the range of speeds.
Is it better to accelerate quickly or slowly?
Accelerating quickly requires more energy than accelerating slowly. There is a super-linear releationship between rate of acceleration and rate of fuel consumption (more fuel consumed per meter/second^2 at higher rates of of acceleration).