Cycle REx between peak efficiency and OFF

After doing a 35 mph benchmark with the REx, I learned it runs at a constant speed, 2400 rpm, and varies the throttle. Even if descending a grade, the engine continues to run burning idle level fuel rate.

Instead, REx operation should support a 1-2% SOC variation and run the engine only at peak efficiency or OFF. This will keep the engine out of inefficient power modes while keeping the SOC oscillating around the target.

My benchmarks show:

• 40 MPG @65 mph
  44 MPG @55 mph
  45 MPG @35 mph

Bob Wilson

Every time you start an engine, depending on how long you expect it to run, you get inefficiencies until things are up to temp which includes both the oil and the coolant. Starting and stopping an engine in short cycles, is not good for much of anything.

It is probably possible to code the REX logic, however learning how to do it would be an uphill battle. A practical solution is a proactive REX management with the "Hold" option. Most long trips include a prolonged highway portion. REX should used to save the battery for the slower parts of the trip.