Advanced tactics, help please

Pardon the paraphrasing of a cliché, but "brisk" is in the eye of the beholder. I'm not fond of such subjective terms. What is brisk to you may be moderate to someone else.

In any event, I've become convinced that for optimal pulsing, anything that the majority would describe as brisk is too aggressive. Hobbit suggests keeping "the engine under good load but at the lowest RPM we can manage without letting it unload." If your SG is X-gauge capable, you can use injector timing as he does, keeping injector timing during ICE-on conditions as low as possible but still above 5-6 ms.

Lacking an X-gauge, I suggest using RPM. At my typical pulsing speeds, RPM of 1200-1300 will track pretty closely with Hobbit's injector timing recommendations and will still accelerate the car. My fuel economy using these low ranges is better than with more aggressive pulsing. See this for an ongoing discussion of my journey to refine [FONT=&quot]–[/FONT] and define using factory instrumentation [FONT=&quot]–[/FONT] optimal acceleration criteria.

Either way, all it generally takes to reach this loaded-but-low-RPM state is just enough pedal pressure to light the ICE [FONT=&quot]– [/FONT]something likely considered gentle acceleration by anyone's standard.

 

Well, if you're used to a 1965 Chevelle, not much the Prius will do can be described as 'brisk.'

Doing significantly more or less than the posted speed limit, or the flow of traffic, is not safe. If you let the car slow down a bit going up hills, and let it speed up a bit going down, you'll get much better mileage than by maintaining a constant speed. On the freeway, generally, slower means better mileage, but you don't want to be a hazard. If there are times you can coast for a bit, that will help. A gentle foot on both pedals will use less gas.

 

Hi 65...,

Your doing very well. My comments may or may not work for you. We are in different enviorements.

My pulsing was 1800 to 2200 RPM, with NO battery contribution. Actually, the battery is being slightly charged during these pulses. Its not brisk. But, its faster than allot of afternoon grannies around here.


I was able to get away with P and G on a 45 mph road, by timing into the light where all the rabbits were stuck. As its four lane there (two lane up to the light), and many times the right lane was open, people behind me are patient. As we end up in front of the rabbits after the three lights in a row, at the end of a 5 mile stretch, many times.

Be careful with the Pules not to involve the battery. Over many pulses, the battery SOC will become low, and that will require the engine to run allot. Without allot of handy low slope long uphills around here, such charging is poor on the fuel economy. If the SOC is at two or three bars, run the engine a little bit rather than P and G, while moving along at 30 or more mph to get it back to 4 bars. You do not want to be in a situation of stop and go traffic with a 2 or 3 bar battery pack. It will eat gas.

I am supprised you are in the high 60's , doing 60 mph on the highway. Your definately not doing SHM at that speed. Its probably the higher temp there heating up the tires quicker.

I do SHM on the highway. In the summer, at 70 F temps, this is 53 mph, 1280 rpm, 75 mpg mile after mile after mile , on flat terrain...


A very effective tactic, but you may not be employing conciously, but probably are using, is the initial portion of the route. This may be more effective here due to the cooler temps, however. Run the car on a route with short stops (short lights, or stop signs) in the 30 to 40 mph range for 5 miles, before any higher speed driving. If you pop onto the highway, the car will run rich for those first 5 miles. There was one bridge in my old highway route at about 5 miles and it was like clockwork, the car would jump from 55 to 65 mpg there (it was uphill under the bridge).

With the Gen II , its best not to P and G until your into stage 4, with a 4 or more bar SOC. An exception to this might be long down hills during the warm up. This is because, you cannot be sure the engine is off when you go into a glide. With the engine running, the glide needs to be 40 mph for a long time (like down a hill) to get up above 60 mpg for the P and G operation. With the engine off during the glide, a 75 mpg p and g operation can readily happen.

 

I'm certainly not in the 60 mpg club..but I have started using a tactic lately that has boosted me from 51 to about 55 on average. It works especially well on a highway, of course traffic and safety considered,...I keep an eye on the vertically curved mpg indicator and when I am depressing the accelerator to keep up speed, I try to never let it go below 50. And when I am on a decline, I keep it as close to 100 as I can. Of course when going uphill, ya gotta do what you gotta do...but keeping it as high as possible on easy terrain seems to be a key.

 

My observations with SGII and Gen2 are(for various stages) follow. Sorry about the metrics but LHK is litres/100km.

IGN TPS LHK Comment
-9 15 5.0+ ICE warming up
5 13 0 ICE off and warmed up
14 17 2.5 ordinary running
15 18 3.0 ordinary running
19 19 3.5 ordinary running
20+ 20+ 5.0+ ordinary running

So keeping IGN and TPS <20 at the same time gives good consumption figures.

If you care to monitor LOD, keeping the value below 78 gives you acceptable consumption figures IMHO, better than 5.0 LHK(47 USmpg).

 

Increased tire pressure improves fuel economy. Try max sidewall pressure. My definition of "brisk acceleration" is when instantaneous mpg is half the speed.