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Old 02-24-2019, 06:29 PM   #327 (permalink)
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Gaptooth (retired) - '00 Honda Insight
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Gen-1 Insights
90 day: 54.26 mpg (US)

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Originally Posted by Angel And The Wolf View Post
If super capacitors could be used in acceleration, a smaller engine could maintain vehicle speed.
Precisely the point of Honda's IMA.

The Insight's 1.0L engine is geared like a V8, and in top gear may top out between 65 and 85mph at WOT, depending on conditions (headwind, wet roads, air conditioning). Peak BSFC lines up almost perfectly with the engine's RPM and load at ~55mph - around 2000rpm. The motor assist allows the car to reasonably climb slight inclines and not lose speed in top gear, or for the air conditioner to cycle on and off and not slow you down, and for the car to still accelerate to cruising speed in a reasonable time without leaving that most efficient range. If you downsized any further with the same specific output, with the target of not raising RPM at all, you simply could not maintain speed.

I imagine a newer engine might be able to downsize 5-10%, but point is that Honda and Toyota figured out 20 years ago that assist can make driving a car with the smallest practical output usable on American (or wherever) roads.
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