2010 Toyota Prius – Click above for high-res ikon gallery
2009 has not been a beatific assemblage for Toyota. After effort its prototypal full-year expiration in heptad decades, it visaged its biggest-ever country request over inadvertent speed caused by story mats and/or enrich curb software. Now, as the assemblage draws to a close, a newborn possibleness difficulty has sprung up. This instance around, the supply is attendant to the braking grouping on the stylish Prius, which debuted primeval this year.
The problem, which has been reportable to National Highway Traffic Safety Administration (NHTSA) by individual dozen drivers, relates to a expiration of swiftness when transitioning from regenerative braking to exertion braking. At this time, NHTSA has not unsealed a flooded enquiry but it is monitoring the situation.
This is actually quite a complicated issue, and it highlights digit of the reasons ground it takes automakers so daylong to alter cars to market. Read on after the move for whatever communicating on what strength be happening.
Gallery: 2010 Toyota Prius
[Source: The city Bureau]
Hybrids and EVs actually hit digit assorted braking mechanisms. In constituent to the tralatitious hydraulic exertion braking grouping that’s been utilised most of the instance century, they also state regenerative braking to modify kinetic forcefulness backwards to electrical forcefulness to calculate the battery. A difficulty arises, however, in that there is exclusive digit curb mechanism: the brushwood pedal. As a result, electronics and Byzantine mechanics are utilised to combining the turn of braking from the digit systems to wage gain swiftness progressive to the turn of push the utility applies to the pedal.
This would every be dustlike if the activity of both systems was completely predictable. In that housing both could be shapely mathematically, and the estimated force from apiece could be calculated. Unfortunately, the exertion brushwood in portion crapper show momentous unregularity caused by wear, humidity, temperature and numerous added factors. Control and activity engineers pay tens of thousands of man-hours investigating and nonindustrial the systems in an endeavor to secure that they bear predictably and consistently over the chronicle of the container and low assorted operative conditions.
The difficulty reportedly existence old in the newborn Prius relates to an manifest expiration of swiftness when the brushwood transformation from regen to exertion braking. Having worked on the controls for kindred braking systems in a preceding chronicle as an engineer, I crapper feature from undergo that this is not an exceptional problem. Typically, it occurs when the exertion brushwood are producing inferior force than the help predicts.
A sort of things could drive this. The most base is the brushwood linings, which could hit inferior exertion than expected. In this case, the curb formula should be healthy to see and compensate. The difficulty could also be attendant to the push sensors in the hydraulic organisation that are conception of the closed-loop control. Sensors crapper hit incorrect signals or move over instance and temperature. Again, there are mechanisms to precise for this but they’re not perfect. Not existence old with the specifics of the Prius system, we crapper exclusive put most what has denaturized in the newborn version.
There’s added existence supported on the aggregation in the reports. Apparently, at diminutive whatever of the owners old the detected expiration of swiftness after touch a strike or pothole. When we reviewed the Prius, we noted that its newly-revised support falsehood seemed to appendage large agency imperfections well, but it was a taste over-damped on diminutive intense inputs. This could drive the ring to retrograde bond with the agency in this case, and thusly move to show slip. The brushwood grouping could be sleuthing this explosive process in rotate swiftness (as anti to container deceleration) and responding by proactively reaction brushwood force in an endeavor to preclude close rotate hair and the requirement for full-blown ABS control.
If (and we pronounce IF) this is existence finished likewise aggressively, it could vindicate what drivers are feeling. We never old some much activity when we crowd the Prius, but we wouldn’t conception it discover low the correct conditions. If you possess a third-generation Prius and hit old anything same this, permit us — and, more importantly, NHTSA and your Toyota moneyman — know. It haw not be a actual problem, but if it is, Toyota module requirement as some accumulation points as doable in visit to right study and mend it.
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