Hi Rammstein:

___I did not know how far that went back … After a few seconds of thought, I believe the new 05 Ford Escape HEV uses a throttle by wire setup also. In our MDX, throttle-by-wire offers even higher fuel economy under cruise then without on the flats but I do not know why?

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net

 

The combination of high torque (I'm passed the 200 lb-ft now) and drive by wire makes going up hill very fun.

The ECU makes the car going at the exact speed you've set with the CC.

Sometimes big V6 and V8's can't follow me...

 

One way to tell if your gasoline ICE has cut off the fuel during a downhill in-gear coast is to tune your AM radio to an unoccupied frequency and turn the volume up. When the ignition is running, it produces a light static that you can hear on the radio. This static disappears when the engine cuts off the fuel and ignition during the coast.

The engine on my wife's '02 Odyssey cuts off during a coast in "D", but I can hear the ignition come back on and start idling the engine when I switch the transmission to "N" while coasting. I haven't driven it enough to figure out which is worst, the little bit of fuel used to idle the engine while freewheeling or the drag from the engine's compression braking reducing the rollout at the bottom of the hill and causing you to have to add power to maintain speed on a gradual downhill. I suspect an out-of-gear, engine idling coast is best in situations where you don't have to compression brake to reduce speed on the downhill.

Based on the radio test, my 92 Civic CX doesn't shut off fuel during an in-gear coast. But on long gentle coasts on rural roads where the speed won't get excessive without braking, I will manually shut off the engine and then clutch start it when I need power after the rollout at the bottom of the hill. My car doesn't have power steering, the power brake system's vacuum is good for 3 brake applications before I lose power braking, and I can clutch start the engine within a half second, so this is a perfectly safe driving practice in my car.

 

clutch start! wow that is pretty cool. I have thought about doing that a couple of times. Can you descibe exactly what you do? You turn off the engine and leave the key in acc position and then when you want to start again you put in the drive position but without turning it extra to engage the starter and then you clutch in? Doesn't that jerk the car and mess with your drive shafts?

 

I don't know if my car has fuel cut. Coasting out of gear with the engine idling and the tranny in neutral is definately better than leaving it in gear on my car. The mileage gauge shows better results in neutral and you have a higher speed at the bottom because you don't have engine braking.

A hybrid might be different esp if the batt is low.

Shutting the car down all together is curious. It has got to be the best but the car does not indicate so, because it was not on to record the decent. The car also warms up (in summer) so cutting it off is not comfortable and the air must run a little extra when it comes on to make up for the time lost while not cooling.

 

Hi Basjoos:

___In an Insight, we can swap our displays from English units to Metric. I believe the HCH has this capability as well. When you have “fuel cut” under the Metric display, your instantaneous display shows 0 L/100 Km no matter the speed you are traveling when “fuel cut” in engaged. Given “fuel cut” is a bit tricky at higher speeds without some regen in my Insight, for maximum mileage, I too use the key shutoff at 40 + mph. I believe Hot_Georgia_2004 uses the same technique as he has one monster climb out but on the way home, I thought I heard him mention he receives something like a 2 + mile free ride with the ICE shut down coasting into his drive. IMA starts are simply fantastic after such activity

___Hot_Georgia_2004, sorry in advance if I misquoted you above?

___Lakedude, you shut down the ICE but turn the key forward just one click to liven your HCH and the dash up, not start it. Well, don’t start it until necessary is all. With just one click forward instead of 2, your car as well as dash is live for you to see the wonderful detail of the free ride you just received if fuel cut is not in the cards at a particular speed or situation you happen to be traversing at the moment. I use the key off coast in traffic jams whenever there is a semi-sloped downhill as I can coast and take my foot off the clutch for a bit of a rest. I also use it on a particular fast downhill section into a toll booth at I55 and I294 near Chicago. When I use Autostop at 19 mph and below to coast to a standstill, I can also remove my left foot from the clutch and she will stay shutdown waiting for the IMA to light her up again after the shift back into first. It is just that while coasting in autostop, if I remove my foot from the clutch, she starts right back up again until I am fully stopped as explained above.

___There is also a downside to coasting w/ the ICE shutdown in colder weather in particular. Once you shut down the ICE, your coolant drops in temperature fast. This happens even in warmer weather as the airflow across the radiator is still performing its task even without the coolant pump moving even warmer fluid to the radiator core. The ICE just isn’t generating any heat is all. This in turn is a large negative to fuel economy given coolant temperatures are usually used by the ECU for warm up rich fuel ratios. A rich fuel mixture is deadly to a hypermiler unless using the lean-burn idle of an Insight to accelerate to 25 + mph or so.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net

 

2 Miles from home are a series of big downhills but I keep the ICE running as the speeds would get trecherous (Possible deer parts etc).
However on the way home I'll likely reboot in 2 specific areas @ 3:00AM.

I'll reboot about 1.5 miles from home, max speed (limit) is 35. After a VERY hard Left turn (Still dead ICE) I'll coast another 2K ft and Left into my subdivision. Not enough momentum to climb the hill so I'll restart while turning into the sub & pull 20MPG up to the 3rd mailbox then shut down again.
I'll roll another 1K ft right into the driveway, around the house, down the hill into the carport.
Note:
There are a few large hills on the way that would be dangerous to shut down the ICE but I still get a bonus by simply shifting to Neutral and letting it idle. (As long as SOC is full)

HCH CVT has a couple of quirks with the reboot technique:
1. When you first boot up the steering assist is not immediately reliable.
After a second or two you'll hear a relay "click" and the airbag light goes off, then you have reliable power assist.
2. I've limited the max speed for the ICE startup to be below 40MPH. Below 40, even though you are in Neutral there is a very light tug through the drive train.
If I am going over 40 that light tug becomes a jerk and above 50 it is a more severe surge.

Coasting and reboots gain about 5-7MPG in my case.

 

freak_lad,

Clutch starting a manual transmission car is easy to do and was done on a fairly regular basis in the days of 6V electric systems and less than fully reliable batteries. If you know you had a weak battery, you would park with your car facing downhill. Then when you came out to start the car and the engine wouldn't turn over, you would simply leave the key in the "run" position, release the brakes, and once the car was moving 10 to 15MPH, slowly release the clutch to turn the motor over and start it. The higher the gear you clutch start in and the faster you are moving, the less the of a jolt you get from releasing the clutch. At highway speeds in 5th gear you can hardly even notice it.

Another useful skill from the old days that has come in handy from time to time is the ability to shift gears in a manual transmission without using the clutch. You match engine RPM to transmission RPM and the gear pops right in. Its a tricky skill to learn, but easy to do once you've learned it. I've used it on several occasions where clutch cables have broken, clutch mechanisms have failed, and on one case where the clutch on an infrequently driven car had rusted together. Unfortunately, cars built since the 80's have a switch on the clutch pedal so you can't turn the starter over when the clutch released, making it inconveniant to start a car with a nonfunctioning clutch on flat ground. You have to either find and bypass the clutch switch or get someone to push start your car (and then hope you don't have to stop again on a flat road as you drive to a repair garage).


lakedude,

When shutting off my car on a downhill, I turn the key to "Acc" to stop the engine, then after a few seconds put it back to "run" to engage the engine electronics (and keep the speedometer/odometer working). Then all I do is put the car in gear (usually 5th) and release the clutch the restart the engine. The ventilation fan is still working so it doesn't get too hot in the car during the mile or two that I am coasting.

 

Minor correction, I don't have a HCH yet. I drive a 2000 Vette. I don't really want to get rid of the Vette but most of the time I drive it like you guys drive your hybrids so I figure what the heck. Why struggle to get 30MPG when I can hopefully get 50?

 

Hi Lakedude:

___IIRC, Automobile magazine had a 375 HP Vette on the autobahn that received 32 + mpg while driving over 80 mph! I remember reading the article and I thought that was incredible. About the only thing I can say is that if Automobile can get 32 from one at those speeds, 40 mpg is in the bag with a little work. At 40 mpg (if possible?), a hybrid looks rather sheepish by comparison.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net