Hi,

So far, my experiments show this works with the NHW11. It may also work with the NHW20. However, it is a little "exciting" the first few times and somewhat risky if you are not practiced.

PROBLEM

Until the coolant reaches 70 C, the engine of the NHW11 runs regardless. If you are stopped at a light or stop sign due to traffic, the idling engine can make a significant impact on your mileage. However, turning off the car induces a second, more wasteful engine STOP/START cycle.

SOLUTION

NOTE: be sure to practice this with no other traffic around!
NOTE 2: it seems to work only with the coolant below 40C

1. Hold the foot brake with your left foot, hard!
2. Shift into "R".
3. Pulse the accelerator. --> engine stops
4. Shift into "N".
5. Use right foot to hold brake, normally
6. When light changes, shift into "D", release brake, and drive off

SYNOPSIS

This works because the NHW11 turns off the engine when going in reverse. However, it appears you only have to be in "R" and hit the accelerator. It doesn't notice that the car is being held stationary by the power front disk brakes. So pulsing the accelerator causes it to shutdown the ICE. Then you slip into "N" to keep it from restarting the ICE.

Now this process can be a little exciting and the steps have to be follow precisely. It is especially important that the left foot hold the brake HARD as backing into a car behind you will result in further delays. However, it seems to work. This may also work with the NHW20 but I do not have a test vehicle.

Subsequent testing indicates that shutting off the engine is a brief event. When the coolant temperature is under 40C, it works reliably. However, above 40C, there is brief pause and the engine continues to run. Still, when the engine is very cool, anytime it can be shutdown at a stop is a good thing.

Bob Wilson

 

Bob,

doesn't your complicated/convoluted technique result in just as many WASTEFUL stop and start engine cycles as would be the case in simply "turning off" the car..??

And with no "danger" in the "turning off" case...??

 

It is a more efficient start/stop compared to the manual method:

• hit "start" on key, all ECUs have to come up
• MG1 spins ICE for 2-3 seconds
• apply gas, ignition and wait for ICE response

With the "N" trick:

• shift "D", all ECUs are already up
• MG1 spins ICE and uses a faster, ~250 ms., power up
• apply gas and ICE responds

My recommendation is to experiment with both approaches. My data suggests a manual start runs about a 5 MPG deficit even before the acceleration deficit. The "N" trick runs no deficit other than the normal acceleration cost.

Bob Wilson

 

Bob,

When I first read the title, I was expecting to read that your new method was to drive to work in reverse during rush hour in Huntsville.... That would have been exciting to watch.

 

INTRIGUING. Well, too many steps for me to handle.

 

Do the lights/head lights and accessory powered components turn off in both techniques or only with a true shutdown.....

Is there a chance that your data is flawed because MPG computation is suspended in reverse due to "forward proess" not being possible...??