Sorry,

I don't have the specific numbers for your vehicle but I can help explain an approach to figuring it out. But first, understand that going up or down a hill entails increasing or decreasing your potential energy. The only efficiency option is to minimize trying to accelerate when going up a hill as this puts the greatest load on the engine and can drive it into high power, inefficient modes:
Ultimately your vehicle has to generate enough energy to overcome drag:

• rolling - treated as a constant force
• air drag - a force that varies as the square of velocity
• "on" load - the energy needed if car is just "on"

If you can get a formula for your vehicle that shows these values, you can plot a curve that shows on a flat surface on a 'standard' day for a fixed engine efficiency, the MPG vs miles per hour:

The "red" line shows how much energy is needed to move the car, an NHW11 model Prius, based upon just the rolling and aerodynamic drag. The "blue" line shows how many miles per gallon we get assuming the engine runs at 31% efficiency. The "gray" line includes the "ON" load, the electric power consumed by the control computers and other electrical loads that are there all the time. This is the 'practical' line.

Now you will notice that there have been benchmarks that are above the "gray" line. This occurs because some cars have been "tuned" so the drag is lower, radiator blocks, and the engine more efficient. Also, some tests are on warmer days when the air and rolling resistance are less. So we can 'game' the system by tweaking our cars, driving them to maximize efficiency and choosing favorable weather conditions.

Ultimately the drag and vehicle overhead dictates how much energy is needed to move down the road. The sole source of this power is the engine as the batteries are just a means for efficient engine operation, not sustained motive power.

Now if you want to start with the NHW11 Prius formula, our coefficient of drag is .29 and the the .42 is the product of the the coefficient of drag times the maximum cross-section area. If you can get the equivalent values for the Honda Civic, you can determine what matches the ".42" value. Then you can also scale the rolling drag as a function of relative vehicle weight. These are first order approximations. Finally, you have to figure out the engine efficiency to the wheel (not just the shaft!). Although the Prius engine can achieve 38% efficiency on a test stand, it has to pass the power through the transmission and differential and there are losses.

Does this help?

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
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