I am designing a GPS based acceleration meter for car. I'm planning to give user some scores based on his various acceleration practices. Not going to the electronics part of GPS, i want to know in what acceleration/braking range, fuel economy of any average 1000-1500cc car is maximum? Any chart including acceleration/deacceleration range vs fuel economy effect.
There are no charts that I am aware of, but you can calculate the theoretical maximum efficiency by considering the following":
- the RPM
- current speed
- assume a volumetric efficiency of 100%
- Assume an ideal air/fuel mixture of 14.7/1 (for petrol engines)
- the weight of the car
- assume the car is traveling on a 100% level surface
- total volume of cylinders
considering these things, you should be able to calculate the theoretical maximum efficiency of a car.
Tip: you don't need the GPS to tell you your accelleration if you plan on reading info from the OBD port because you can use the difference in speed between two requests for current speed combined with the delta of time to calculate acceleration.
I think you can't use a single average value for all cars. Here are some variables that could greatly influence your program :
- Gear engaged (The same acceleration won't use the same amount of fuel)
- Type of fuel (petrol, diesel)
- Car characteristics (weight, aerodynamysn)