Author Topic: 20mph engine surge (Read 1147 times)

sportse · « **on:** May 31, 2022, 10:39:03 AM »

Someone mentioned on another thread that their car seemed to be 'slipping a gear' around 20mph, with an increase in engine speed but nothing much happening to the car speed.

My own EX hasn't done this, but I have experienced it on a crosstar EX loan car so it may perhaps be a software issue that only affects some cars,

Kremmen · « **Reply #1 on:** May 31, 2022, 10:41:39 AM »

No problem here either and I'm surrounded by 20mph limits.

ColinB · « **Reply #2 on:** May 31, 2022, 01:11:40 PM »

Quote from: sportse on May 31, 2022, 10:39:03 AM

... an increase in engine speed but nothing much happening to the car speed.

That sounds like a perfectly normal result of the hybrid system. Remember that the ICE is acting as a generator, and it will run at it's most efficient speed which will not be directly related to road speed in the same way that a conventional ICE-powered car would. If the battery's low and the car decides it needs recharging, it's quite likely to be perceived as "screaming loudly" or "surging" even if the car's moving slowly.

sportse · « **Reply #3 on:** May 31, 2022, 01:22:38 PM »

In my EX over 15k miles it has never happened, but in a loan crosstar with 2k miles its happened several times.

There's no connection between the engine and road at low speeds, it feels exactly like a slipping gear but can't be.

Maybe just due to build quality variations, some battery packs asking for more electricity at lower speeds?

Likely nothing to worry about, with the Jazz it's best to ignore the noises the generator makes.

With music on, you can't hear the generator - it's only when it's quiet you can hear the surge.

guest9814 · « **Reply #4 on:** June 04, 2022, 01:47:23 PM »

Quote from: sportse on May 31, 2022, 10:39:03 AM

Someone mentioned on another thread that their car seemed to be 'slipping a gear' around 20mph, with an increase in engine speed but nothing much happening to the car speed.

My own EX hasn't done this, but I have experienced it on a crosstar EX loan car so it may perhaps be a software issue that only affects some cars,

It's normal because at that speed ICE used as generator, if hybrid battery discharged to its limit 25-30% ICE starts to charge battery, if the same time driver need to accelerate his car on a road that rises at a slight angle, the generator needs to generate more energy for movement and at the same time give a charge to the battery.

About that the Crosstar was much nippier, maybe in Crosstar ECON not turned on ?