Mileage is an indication of an automobile's fuel efficiency, typically expressed in terms of amount of distance the vehicle can travel with one litre or gallon of fuel (km/L or mpg), or the amount of fuel required to travel 100km (L/100km).
Mileage can be generalized into two classes -- the mileage observed from driving on the road (observed mileage), and the standard mileage measured during the vehicle certification. The standard mileage is used not only by consumers as a basis of comparison for fuel economy while purchasing a vehicle, but also by certain governments in measuring the Corporate Average Fuel Economy of automobile manufacturers. Hence, to make standard mileage as reliable and objective a basis of comparison for fuel efficiency between vehicles, measuring it follows a strict set of rules.
The standard mileage differs between nations, but below described devices and methodologies are uniform across all countries.
At the same time, they are also used to certify emission levels of harmful exhausts, such as THC, CO, NOx, and PM.
Standard mileage is defined by measuring the mileage of a vehicle through a mode specified by government-approved institutions. The measuring is done in a constant-temperature environment, by placing the vehicle on a chassis dynamometer to simulate the load received by the vehicle during an actual drive with one driver. The driver follows the instructions from the pre-programmed driver aid, during which the concentration levels of emitted CO, CO2, HC, NOx, and other particulate matters. According to their emission amount per unit distance traveled (g/km), the standard mileage for the vehicle is calculated through carbon balancing.
On the chassis dynamometer, the driver performs acceleration, deceleration, and gear changes as per the driver aid's instructions, resulting in average speed of 34.1km/h, maximum speed of 91.2km/h, travel time of 1874 seconds, and travel distance of 17.84km, as can be seen on the figure above.
As such, the standard mileage is derived with government-specified criteria from certified evaluation institutions (National Institute of Environmental Research, Korea Institute of Energy Research, Institute of Automobile Performance Research, and Institute of Automobile Component Research, in case of Korea). Hence, the difference between standard and observed mileages are from applying the aforementioned measurement criteria.
he significance of CVS75 mode (certified evaluation data)
In measuring fuel efficiency,
① With a new vehicle having 100%, it is said a typical vehicle has 95% combustion efficiency.
Through maintenance and inspection, the combustion efficiency of the testing vehicle is brought to 95%.
② What is 95% combustion efficiency?
Calculated via carbon balancing derived from exhaust emission amount per unit distance traveled (g/km)
a) Travel time 1,874 seconds
b) Travel distance 17.84km
c) While changing speed and gears on the chassis dynamometer,
d) Follow the driver aid's instructions with maximum speed of 91.2km/h, and average speed of 34.1km/h.
While obeying each clause, 95% of the fuel is consumed and the other 5% is turned into exhaust gas and emitted through the exhaust pipe. According to such, there does not exist a vehicle with combustion efficiency higher than 92~95% in the world, meaning 5~8% of all vehicle fuel is turned and emitted as exhaust gas, something the automobile researchers all over the world are working to bring down as close to 0% as possible.
It has been confirmed with test data that with Green Saver installed, the fuel efficiency becomes 95%+3.2%=98.2%. 1% increase in combustion efficiency in test data is known to have a 7~10% fuel reduction rate in real-world application. Similarly, for the difference between standard and observed mileage, it is applied that1% in certified data makes 7~10 times the difference in observed mileage.
According to the Lambda Law the optimal oxygen-to-fuel ratio in an automobile engine (also known as the theoretical mileage ratio) is 14.75:1.
With Green Saver, the theoretical mileage ratio averages to 20:1.
5.25/14.75=0.35 --> 35% increase in oxygen. Since the amount of oxygen has increased by 35%, the amount of fuel has been reduced by 35%.
Typically, gasoline's theoretical mileage ratio is 14.7:1, meaning for a complete combustion of 1g of gasoline, 14.5g ~ 15.0g of air is required. 15:1 in terms of weight, 8,500:1 in volume. Green Save increases this ratio to 22~23:1, increasing the amount of air required for combustion, allowing combustion and reduced fuel consumption. Usage of Green Saver for such effects requires below inspections.
① Check the air cleaner's condition (Since the amount of air (oxygen) sucked into the combustion engine is
increased, the air cleaner must be in adequate condition. If the air cleaner has been contaminated, it must
be replaced to maximize air suction).
② Remove the connecting piece of the air cleaner and the tube attached to the throttle body (suction
system), open the throttle valve shaft, and thoroughly clean the carbon contaminant sediment off of the
carburetor and injector (gasoline vehicles only).
Due to the large amount of air (oxygen) requirement, Green Saver necessitates clean air cleaner and
Much like a regular vehicle, a powerful igniter is needed for complete combustion.
With Green Saver, the fuel particles become fine and minute, then sprayed into the internal combustion system. To provide a powerful ignition to the minute fuel particles, the ignition plug and wiring must be in sufficient condition, for complete combustion and hence, reduced fuel and exhaust emission, as well as increased output.
Complete combustion requires an adequate ignition. As a requirement for complete combustion, the ignition plug and wiring must be replaced on a regular basis.
Green Saver requires standard fuel pump pressure.
A certain amount of pressure is required for the fuel particles to be broken down to minute size. Without sufficient pressure, the resulting mileage and output could be drop after installation of Green Saver. Hence, the fuel pump and filter must be inspected and if needed, replaced. Fuel filter is not of common knowledge, as it is rarely mentioned.
The importance of fuel filter
☞ A fuel filter filters out any moisture or extraneous substance from the fuel to prevent the injector from clogging, as well as contribute to a steady output. A clogged fuel filter hinders acceleration, causing incomplete combustion and the catalyst burns out from overheating.
A diesel vehicle, in particular, needs special attention against such phenomenon. Malfunction from moisture requires costly repairs, and can cause the fuel filter to freeze in winter, either forbidding ignition or shutting the engine down while on the road.
A clogged fuel filter and/or inadequate fuel pump keeps Green Saver from performing its full potential. To maximize Green Saver's effects, the fuel filter and pump must be inspected and replaced and ensure sufficient fuel pressure.
1) Check your engine oil change date. Replace your air cleaner.
(Air cleaner is replaced along with engine oil. If your engine oil change is overdue, replace your air
cleaner as well)
2) Using proper cleaning agent, thoroughly clean the carburetor and injector of their carbon contaminants
and other sediments. This will improve the fusing rate for fuel and oxygen, aiding Green Saver's
3) Check the ignition plug and cable replacement date.
The ignition plug and cable are typically replaced on every 20,000~25,000km. Complete combustion
requires a powerful ignition. As the ignition plug and cable are closely related to Green Saver's
performance, have them replaced if they are overdue.
4) Check the fuel filter replacement date.
As the fuel filter keeps moisture and impurities out, installing Green Saver could have an adverse effect on
the vehicle's mileage and output if the fuel filter is clogged or damaged. Please ensure the quality and
status of your fuel filter.
Fuel filter replacement is especially emphasized for diesel vehicles. Most drivers are oblivious to fuel filters
and are neglecting them. As it is directly related to Green Saver's performance, the inspection and
replacement dates for fuel filter on diesel vehicles must be double-checked -- a faulty fuel filter can cause
decreased mileage and output.
A fuel filter is typically replaced every two years, or 40,000km.