QUOTE(touristking @ Jun 21 2024, 11:32 AM)
I know their differences. And their drawbacks. Honda's switch to engine above ~100 kph and become less powerful than the 1.5T. Didn't realize Toyota's switch mainly to engine at lowly 60 kph
That is becoz Toyota HSD system powered the wheel using both electrical motor and engine using the complex planetary gear aka power splitting gear/device when necessary at most speed except for low speed when it tries to use the motor as much as possible as it is mostly a parallel hybrids except again at higher speed. Once it hit mid-range, both motor and engine powering the wheel at most times with the planetary gear juggling the power going into the transaxle...superbly efficient setup. Unfortunately for Honda, Toyota owned the right, meaning Honda has to find another way to powered its hybrid thus the experimental IMA, iDCD and finally the iMMD where finally Honda did it right that it can finally matched up HSD albeit with its own weakness and strength.
Honda iMMD is a serial hybrids that mostly runs on motor at below 100km/h with engine powering the motor. It is only a 90-100km/h onwards (depending on the how we tekan minyak), it clutched in the engine to run it the transaxle directly....direct to drive. Otherwise it will still be the motor powering the wheel at most times.
There is always an argument that Honda iMMD is a more complex setup but in reality HSD is a much more complex setup with it's planetary gear system that include a CPU to manipulate 2 sources of energy to power the wheel at the same time (micro juggling between the motor and engine power source). However it's complexity is right on the gear system itself leaving the rest with a simpler minimal gear setup.
iMMD has to run clutches (gear sets) for the engine direct drive setup, more parts to replace and maintain. It is actually a simpler setup but require more mechanical parts to divert the engine power back into the system for direct drive capabilities thus reducing in mechanical reliability vs the efficient HSD setup.
I like the iMMD system more than HSD coz it actually gives more EV experiences at low to mid end drive, when it runs low, the engine charge up the battery and it still runs mostly on EV mode while HSD at least on Toyota Cross only runs pure EV on low drive and will switch to combined power once it runs low. As mentioned, it comes at the cost of more mechanical parts, gears, etc meaning more risk of failure, definitely more wear and tear in future. With reliability issues at stake, HSD still trumped if you combine reliability with efficiency. iMMD is no way less efficient, it produced low mileage savings that are on par with HSD, they just have more room to improve on reliability due to usage of more gears and other parts to produce this result. On long term reliability, I don't think any manufacturer can matched the much researched and proven HSD system coz a decade down the road, I am not sure if I regret getting the iMMD or not if and when any of the clutches and gears start wear and tear and need repair and replacement.
Amazing when both setup uses similar 2 motors system (1 traction, 1 generator) but went entirely different ways to achieve the same result.
On less powerful than turbo, sure lar, Atkinson engine is fuel efficiency but no power wan but cannot fight Otto engine on power much less when you include turbo into the equation. See what happened to Cross 1.8 atkinson engine, already the standard Cross 1.8 NA engine underpowered (western get 2.0, also consider a bit lackluster by them), With Atkinson running at highway, 1.8 really no energy. At least CRV has 2.0 atkinson and rely on the motor for better torque acceleration but then it is a heavier and bigger car. The advantage I can see over the HSD is under 100km/h, the torque comes mostly from the motor, so it might have stronger torque up to mid end.
My 2 cents only....my own understanding but might be wrong interpretation on the power flow especially on Toyota HSD system. The planetary gear system algorithm for power flow is a black box, at least for me, other parts super direct and easy to maintain. iMMD although have more parts are a simpler setup to understand.
This post has been edited by Cavino: Jun 21 2024, 01:36 PM