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Originally Posted by GreenHornet
This system improves fuel economy in a number of ways.
#1. Stop/Start capability which eliminates idling time prone to non hybrid cars.
#2. Used for low speed short distance driving whenever you can turn off the ICE and utilize an electric motor for propulsion you will be more efficient. A Gas engine at its best is 28% efficient vs an BLDC electric motor at over 90% efficiency. This type of motor has only 1 moving part compare that to an ICE. Then factor in the environmental aspect and pollution. There are other reasons why an electric motor makes more sense. ICE vehicles have there place but the vast majority of people living in and around Metro areas could absolutely do away with them completely.
#3. BLDC motors have the ability with the correct motor controller to utilize regenerative breaking. However without using ultracaps for harvesting this energy you will not gain very much back into your batteries. If ultracaps are used then you can capture upwards of 50% which then starts to get more attractive.
Honda could have downsized the engine even further to a .6L powerplant that they use in there Kei cars if they wanted to turbocharge the gas engine. Along with a little more capable lithium pack and E-motor you would have an extremely frugal Insight. Or better yet take an AC20 motor attach to manual transmission with 144V Curtis Controller and then use a very small like 200cc or less gas powered genset and you have a very fuel efficient set up for urban areas.
Adding a motor/generator to an existing engine if done correctly can make substantial improvements to fuel economy. There are a lot of factors however that play into it which also make it difficult for the average Joe to get correct. Car engineers have trouble getting it correct and they spend all day trying to figure it out and trying to find that winning combination. Can an average Joe do it? Yes it has been done with varied degrees of success.
Hybrid systems will be standard equipment with in the next 30 years due to emissions standards. They will have to find creative ways to downsize ICE without sacrificing power to help meet emissions standards. The E-motor is the best answer to this problem.
GH
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1) Other manufacturers have stop-start systems that don't require hybridizing the car; it's simply a matter of having a more robust starter.
2) Ultimately, that energy being used by the electric motor comes from the 28% efficient gasoline engine, but it needs the additional conversion of mechanical to electrical, storage in a battery, then back to mechanical energy, which is somewhat lossy. I'm not saying driving all-electric at low-speeds is a bad idea (quite the opposite), just that I'm skeptical of the viability of a belt drive motor that must still spin the engine's crankshaft as a very good way of doing it.
3) Regenerative braking that captures fewer percent of your kinetic energy than is added by additional mass to the vehicle is counterproductive. I'm not saying it does, but this is a factor.
A high-revving 0.6L would almost certainly deliver worse economy than the current 1.0L lean burn engine in the Insight. Below a certain point, downsizing an engine starts to have the opposite effect on economy, because you start needing to rev it up to make the same power. I'm not sure where boost falls into this, but if it's necessary to run rich when in boost (is it?) that would also be a factor. Cruising along at 70mph in 5th gear, the Insight has virtually no power to spare, it's nearly WoT, and when cruising at lower speeds, it leans out the AFR to is lean as 25:1 to keep the throttle plate almost completely open.
I'm not saying a smaller displacement motor couldn't work, just that you need to be mindful of avoiding revving it up.
I agree that hybrid systems will be standard, but they're probably going to be bolted onto downsized motors and allow for the engine to be decoupled from the drivetrain, rather than keeping the same displacement and needing to continue pumping air through the cylinders while the electric motor is providing power.