Quote:
Originally Posted by Baltothewolf
I have to admit I disagree with the engine vibration cancel idea. I have driven so, so many insights that have the IMA completely bypassed, and even a car with an alternator that had the ENTIRE IMA system removed except the electric motor and they all feel the same as cars with IMA.
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IMA Motor and Engine Vibration - Insight Central: Honda Insight Forum
Quote:
Originally Posted by Hybrid-Battery-Repair
If you have a MIMA, you can see it pulsing at idle. The gauges, as usual, lie to you and hide it.
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Quote:
Originally Posted by Mike Dabrowski 2000
As I see it,
The crank position sensor lets the ECM know where the crank is at all times. The IMA motor is always in the same relative position to the crank, as it is a synchronous motor.
The vibration is predictable within the revolution, and the vibration continues every rotation, so it is not a random event.
The crank position sensor lets the system know the rotational position, but also by measuring the time between crank position sensor pulses, vibration amplitude can be derived.
The system fires the IMA regen or assist pulse and looks for a more consistent flywheel speed as feedback to determine the IMA pulse amplitude that smooths the vibration best.
A look at the current sensor signal with a scope at idle will show the pulses clearly. Once the RPM gets over 1500rpm, the flywheel can damp the vibrations without help, so the amplitude of the balancing pulses decreases and eventually stops as rpm increases.
If the AC is on at idle, the pulses need to be bigger to damp vibrations as the AC load is trying to slow the flywheel down, and less energy is stored between power pulses, therefore more crank position sensor speed variations are seen, so more damping is applied until the speed variations are minimized.
The MIMA current sensor measurement is done frequently enough to catch the rapidly pulsing current and it shows it as alternating assist and regen flashing LEDS.
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The Insight has a balanced crankshaft and flywheel, unlike most other inline 3 engines.
Quote:
Originally Posted by jamesqf
I wish you'd explain why you think this would be a benefit, when you have only a relatively small battery. You could only go a mile or two on electric, and doing so would add many charge/discharge cycles. Seems far better to simply use the IMA system as designed. (With of course the addition of MIMA.)
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I'd argue that it could be a tool for hypermilers, but it's completely understandable why Honda didn't do this. They did, however, enable EV-only mode on the Gen2 HCH. Rather than moving the IMA motor, they engineered in a system to shut all of the valves in the engine and let the IMA drag it along down the road. Why, I couldn't say. Maybe so they had feature parity with the Prius?