Throttle input techniques to maximize efficiency

In your experience, is it more efficient to give short bursts of relatively higher throttle/kW output levels with coasting in between, or to "hold" the throttle longer at lower thottle/kW levels to maintain a certain speed?

I've been experimenting with trying to maximize my efficiency & range during my commute. It's ~18 miles one way, all surface streets and fairly level (few small ~5ft hills here and there), with speeds seldom exceeding 45mph. Pretty ideal conditions for the Volt and for experimentation with efficient driving. Under normal acceleration from a stop up to cruising speed, I'm generally keeping the throttle input at ~20kW or less.

One method I've used for maintaining cruising speed (let's say, of 35-40mph) has been to maintain a steady throttle input somewhere between 8-15kW, depending on conditions. Another method has been to use short 3-4 second bursts of 18-20kW throttle inputs to nudge the car back up to cruising speed after coasting (anywhere from 5-15 seconds, depending on conditions) and losing 2-4mph of speed. Under both experimental conditions, I'm maximizing use of coasting wherever possible.

I'm still on the fence as to which is more efficient, though I'm leaning towards the "burst" throttle method as being more efficient since I'm guessing that 20kW @ 3sec is less than, say 10kw for 6+ seconds. The main drawback of the burst method being that the ride is less smooth due to the oscillation of acceleration & coasting compared to the "constant" throttle method.

Any thoughts on your experiences?


Side note regarding efficiency: My Volt is still "learning" what the estimated range per charge would be as I've only had the car for a month now. For example this morning, it was estimating range of 51 miles after a full charge. I used 3.3kWh for my 17.7 mile commute (pretty average, my best so far has been 3.0kWh for the same trip), and the range estimator says I still have 38 miles left.