Post by the light works on Apr 3, 2020 5:00:44 GMT
one of my biggest pet peeves is people who travel just below a speed that allows me to shift to a higher gear. and since I had to make a run to the parts house for the parts that should have been included in Brand X's installation... I had time to think about what is good for small cars and hybrids not being good for trucks. and specifically two scenarios:
1: lower speeds are more wasteful for conventional drivetrains despite being more efficient for hybrids. this goes clear back to a motorhead on the old board pointing out that an internal combustion engine is at its most efficient when it is running at maximum normal horsepower output - meaning the throttle is open, and the load on the engine is keeping it below redline. it also goes back to the fact that I know from having a partially clogged fuel filter, that my truck burns more fuel at 35 MPH in second gear than it burns climbing a hill at 55 MPH in 4th gear. so for this I would propose using various economical cars to establish efficient speeds for them (closed course, etc) and then have trucks drive the same course at the same speed and at higher speeds, and see if they lose efficiency through going slow.
2: steady speed vs surging or stop and go. we've all heard that we should go a stead speed, but how MUCH difference does it make, and how extreme can it end up.
for this I propose a closed course as well, with a measured distance, and up and downgrades. for each round of testing, I propose doing a surge and coast pattern - from gentle acceleration (without downshifting) and then coasting (tests both in and out of gear, since some people think coasting in neutral saves gas) then calculate an average speed for the course, and drive the course with the cruise control set at that speed, and see how it changes the fuel consumption. the most extreme would be full throttle acceleration and hard braking, to simulate urban freeway traffic.
1: lower speeds are more wasteful for conventional drivetrains despite being more efficient for hybrids. this goes clear back to a motorhead on the old board pointing out that an internal combustion engine is at its most efficient when it is running at maximum normal horsepower output - meaning the throttle is open, and the load on the engine is keeping it below redline. it also goes back to the fact that I know from having a partially clogged fuel filter, that my truck burns more fuel at 35 MPH in second gear than it burns climbing a hill at 55 MPH in 4th gear. so for this I would propose using various economical cars to establish efficient speeds for them (closed course, etc) and then have trucks drive the same course at the same speed and at higher speeds, and see if they lose efficiency through going slow.
2: steady speed vs surging or stop and go. we've all heard that we should go a stead speed, but how MUCH difference does it make, and how extreme can it end up.
for this I propose a closed course as well, with a measured distance, and up and downgrades. for each round of testing, I propose doing a surge and coast pattern - from gentle acceleration (without downshifting) and then coasting (tests both in and out of gear, since some people think coasting in neutral saves gas) then calculate an average speed for the course, and drive the course with the cruise control set at that speed, and see how it changes the fuel consumption. the most extreme would be full throttle acceleration and hard braking, to simulate urban freeway traffic.
