Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

RobertSmalls · 11-02-2009, 09:55 PM

My fuel economy has thus far been below my expectations. This means I have work to do.

Despite the disappointing fuel economy, I'm absolutely thrilled with the car. It drives much differently from any other car I've driven. The car has turned a few heads, which means I really have to make it look pretty before I make it my daily driver.

This car is fun around town. Its low center of mass and long wheelbase make it quick in corners. The BSFC sweet spot is at 4000RPM, 70% throttle, which means spirited acceleration won't hurt the gas mileage, provided you follow it up with wise driving, like lean burn or EOC.

IMA makes hypermiling easier, faster, and more relaxing. Instead of DWB, you have regenerative braking. Instead of cursing every time someone cuts you off or you catch a light wrong, you just regen, and recover a good percentage of your kinetic energy, storing it for later use. If you find yourself at low RPMs, but you suddenly need to accelerate, no need to downshift. Just use the IMA assist. If you're at a red light with the engine off, you don't need to watch the red light with your foot on the clutch and your hand on the ignition. Shift out of neutral, and the Insight's engine is started before you're ready to let the clutch out.

On the interstate, the car feels stable and is so much quieter than the Subaru at 75mph. 75mph corresponds to 2600RPM, and 55mph is 1900RPM. That's great for fuel economy, but it means you have very little spare power available from the throttle pedal. You have to downshift to fourth or even third to hold your speed up certain hills. Want to pass someone? You'd better plan ahead. I love that.

Lean burn gave me around +8mpg, but you can't make more than, let's say, 15HP in lean burn. I engaged lean burn down hills and while drafting tractor trailers (from at least 1.5 trailer lengths away, don't worry), but on flat ground, I could only lean burn up to 68mph. I will increase the lean burn threshold by improving my aerodynamics to reduce the engine load at any given speed, and with a hot air intake. I intend to lean burn the entire way across the state of Ohio at 74mph at Thanksgiving.

Btw, here are some FE figures:

88.5mpg at the AMEC FE Run IV
68.3mpg @ ~65mph, being careful to hold lean burn
57.8mpg @ 70-74mph, on the way home from AMEC FE Run IV.
~61mpg on the way home from work today. Some traffic.

11-02-2009, 09:55 PM	#31 (permalink)
RobertSmalls Left Lane Ecodriver Join Date: Aug 2008 Location: Buffalo, NY, USA Posts: 2,257 Prius C - '12 Toyota Prius C Thanks: 79 Thanked 287 Times in 200 Posts	Go buy an Insight. My fuel economy has thus far been below my expectations. This means I have work to do. Despite the disappointing fuel economy, I'm absolutely thrilled with the car. It drives much differently from any other car I've driven. The car has turned a few heads, which means I really have to make it look pretty before I make it my daily driver. This car is fun around town. Its low center of mass and long wheelbase make it quick in corners. The BSFC sweet spot is at 4000RPM, 70% throttle, which means spirited acceleration won't hurt the gas mileage, provided you follow it up with wise driving, like lean burn or EOC. IMA makes hypermiling easier, faster, and more relaxing. Instead of DWB, you have regenerative braking. Instead of cursing every time someone cuts you off or you catch a light wrong, you just regen, and recover a good percentage of your kinetic energy, storing it for later use. If you find yourself at low RPMs, but you suddenly need to accelerate, no need to downshift. Just use the IMA assist. If you're at a red light with the engine off, you don't need to watch the red light with your foot on the clutch and your hand on the ignition. Shift out of neutral, and the Insight's engine is started before you're ready to let the clutch out. On the interstate, the car feels stable and is so much quieter than the Subaru at 75mph. 75mph corresponds to 2600RPM, and 55mph is 1900RPM. That's great for fuel economy, but it means you have very little spare power available from the throttle pedal. You have to downshift to fourth or even third to hold your speed up certain hills. Want to pass someone? You'd better plan ahead. I love that. Lean burn gave me around +8mpg, but you can't make more than, let's say, 15HP in lean burn. I engaged lean burn down hills and while drafting tractor trailers (from at least 1.5 trailer lengths away, don't worry), but on flat ground, I could only lean burn up to 68mph. I will increase the lean burn threshold by improving my aerodynamics to reduce the engine load at any given speed, and with a hot air intake. I intend to lean burn the entire way across the state of Ohio at 74mph at Thanksgiving. Btw, here are some FE figures: 88.5mpg at the AMEC FE Run IV 68.3mpg @ ~65mph, being careful to hold lean burn 57.8mpg @ 70-74mph, on the way home from AMEC FE Run IV. ~61mpg on the way home from work today. Some traffic.