Author Topic: Very steep hills  (Read 3602 times)

sportse

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Re: Very steep hills
« Reply #15 on: May 23, 2022, 05:31:02 PM »
...I get excessive engine noise at 15mph on a slight incline, minimal throttle. As mentioned it feels as though the 'gearbox' wants to change up but just doesn't and can't make its mind up and decides not to.

It sounds like there could be an issue with your car.

I sometimes drive elderly people and can accelerate fairly briskly from 0-40mph with hardly any sound at all, even up slight hills.

By pressing the accelerator a bit and keeping it there, the car is very quiet and accelerates very well.

If I roll on the accelerator and keep increasing the pressure it will make a lot of noise.

Lord Voltermore

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Re: Very steep hills
« Reply #16 on: May 23, 2022, 09:19:53 PM »
Amazing coincidence, I drove over two alpine passes today. The fern pass and the Brenner.No problem up or down. I think I got some engine off braking on the fern pass. Not sure as it was only for few seconds and didn't concern me at all. A couple of times  when the battery only had two bars  at the start of a long climb the engine raced for a short time. But no big deal or particularly noisy,j just different from how quiet and refined it normally i  and coming down the fern pass,driving through the centre of Innsbruck  then over the Brenner pass to Verona  I got 3.2 litres per 100 km. Thats 88 mpg  :'(  That's avoiding motorways but going with traffic flow.
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IanG

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Re: Very steep hills
« Reply #17 on: May 23, 2022, 09:20:41 PM »
Drove Hardknott Pass about a month ago.
Car pulled like a train uphill and B mode downhill was great. Akin to engine braking and the battery recharged in no time. Engine didn’t appear excessively noisy uphill, possibly as battery had charge from the downhill. I do notice a noise change when the battery is fully charged and you continue decent in B mode. A pitched generator whirring  sound, as if it’s spinning freely, without any battery capacity left to store charge. Seemed like the engine braking was reduced whilst this occurred. I appreciated the cars narrower width on the narrow Lake District roads and the short length for finding tight parking places. 3 up and plenty of room for walking gear and large case with one back seat folded flat.
« Last Edit: May 23, 2022, 09:27:29 PM by IanG »

DERMOT

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Re: Very steep hills
« Reply #18 on: May 23, 2022, 09:56:56 PM »
I 've driven (2 up) in co Cork. Narrow steep, slow tarmac lanes. One was ~1:3 /4 going by block wall of yard wall. Painful to walk down, and a couple of switch backs. The torque means you don't need a run at the hill, and you can slow down to almost stopped to get around switch back. So at max 20 mph and overall not that much climb, I was very impressed.
At 15 20 mph there is an odd spot as Shufty says . On ev it is effortless, but on engine you press the acc pedal and a lot of revs for little change in speed. Almost like it in neutral. Accelerate past20 and it is ok.
For open moorland roads and long steep hills, I don't know. But I think you'll be impressed unless you're planning to race an mg..

The engine brakes once battery is full is not something I see. My daily commute is steep decline that just gets me full battery, gentle slope that keeps it full, and 1 mile flat that empties battery just at the work carpark. Speed rather than steepness for date of charging, so if you are not bombing downhill maybe ok.

Bristol_Crosstar

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Re: Very steep hills
« Reply #19 on: May 24, 2022, 08:53:43 AM »
Drove Hardknott Pass about a month ago.
Car pulled like a train uphill and B mode downhill was great. Akin to engine braking and the battery recharged in no time. Engine didn’t appear excessively noisy uphill, possibly as battery had charge from the downhill. I do notice a noise change when the battery is fully charged and you continue decent in B mode. A pitched generator whirring  sound, as if it’s spinning freely, without any battery capacity left to store charge. Seemed like the engine braking was reduced whilst this occurred. I appreciated the cars narrower width on the narrow Lake District roads and the short length for finding tight parking places. 3 up and plenty of room for walking gear and large case with one back seat folded flat.
If I get the battery to 100% going downhill in 'B' I change to 'D' and use the brake, I think the car's happier and there's no energy benefit in staying in 'B' when the battery's full.

Kenneve

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Re: Very steep hills
« Reply #20 on: May 24, 2022, 09:24:13 AM »
...I get excessive engine noise at 15mph on a slight incline, minimal throttle. As mentioned it feels as though the 'gearbox' wants to change up but just doesn't and can't make its mind up and decides not to.

It sounds like there could be an issue with your car.
I sometimes drive elderly people and can accelerate fairly briskly from 0-40mph with hardly any sound at all, even up slight hills.
By pressing the accelerator a bit and keeping it there, the car is very quiet and accelerates very well.
If I roll on the accelerator and keep increasing the pressure it will make a lot of noise.

I think I agree, there could be an issue with your car.
In normally motoring, I find it difficult to know whether the engine is running or not, as the vehicle is so quiet overall compared, with my previous Jazz cars. I do need to look for the EV logo, for confirmation. Certainly if I floor the gas pedal, then there is some engine noise, but in my view, no more that any manual gearbox Jazz and in the main, totally unnecessary.
Admittedly, I do have the radio on most of the time, but only around volume No7, which is not going to drown out any engine noise.

Kremmen

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Re: Very steep hills
« Reply #21 on: May 24, 2022, 10:04:02 AM »
Same here, I've never heard the engine except on initial startup before I get moving and the radio is on, volume level 12 for me.

I only know the engine is running by looking at the instant MPG bar.
Let's be careful out there !

Jazzik

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Re: Very steep hills
« Reply #22 on: May 24, 2022, 11:29:37 AM »
If I get the battery to 100% going downhill in 'B' I change to 'D' and use the brake, I think the car's happier and there's no energy benefit in staying in 'B' when the battery's full.

When going downhill I don't change "B" to "D" when the battery is full. Maybe no energy gain by staying in "B", but not (or much less) using the mechanical brakes.
I asked the Jazz if it (he?..she?) feels happy enough downhill in "B" with a full battery. It (he, she) did not answer and shrugged.
When I repeated the question, but specifically to the brakes, they nodded and the discs began to gleam with joy.

And now seriously: also in "D" the car wants to charge the full battery, only less than in "B". In addition, you need your mechanical brakes much more.
Nowhere I can find that on a descent in "B" you should switch to "D" when the battery is full...
I assume the Honda engineers are smart enough to avoid damaging the electric drive system and/or battery from a long descent in "B".
If nothing goes right, go left!

Bristol_Crosstar

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Re: Very steep hills
« Reply #23 on: May 24, 2022, 06:16:00 PM »
If I get the battery to 100% going downhill in 'B' I change to 'D' and use the brake, I think the car's happier and there's no energy benefit in staying in 'B' when the battery's full.


When going downhill I don't change "B" to "D" when the battery is full. Maybe no energy gain by staying in "B", but not (or much less) using the mechanical brakes.
I asked the Jazz if it (he?..she?) feels happy enough downhill in "B" with a full battery. It (he, she) did not answer and shrugged.
When I repeated the question, but specifically to the brakes, they nodded and the discs began to gleam with joy.

And now seriously: also in "D" the car wants to charge the full battery, only less than in "B". In addition, you need your mechanical brakes much more.
Nowhere I can find that on a descent in "B" you should switch to "D" when the battery is full...
I assume the Honda engineers are smart enough to avoid damaging the electric drive system and/or battery from a long descent in "B".
There are many steep hills where I live, when the battery is 100% going downhill in B the engine becomes quite noisy so I change to D, I didn't say it would damage the engine in B, also a chance to clean the disk brakes as I hardly use them ordinarily

Lord Voltermore

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Re: Very steep hills
« Reply #24 on: May 24, 2022, 06:47:31 PM »
Today went over the Raticota pass between Bologna and Florence. "Only" 968 metres but a proper pass with hairpins. Part of the Mille miglia route and unofficially a test route for Ducati. Much more challenging than anything in the UK. Jazz went over no trouble at all.With enough battery bars it will climb a 1 in 3 hill with ease. If it needs to climb without battery assistance the engine will run at higher revs than the road speed so is quite noisy and
it  guzzles fuel .as soon  as it can (maybe after only a few hundred meters)    it settles down again. During these brief manic periods it still climbs as well as most cars with this size I.c.e .It's not intolerable for me. I have just refueled at 800 kilometers,having been over 3 mountain passes. Genuine 82 mpg,not fibometer.with Aircon on. Engine off or barely audible 99 Per cent of the time.   I have sized engine braking.Coming down a very long and steep pass is no problem as long as you are not racing down.  D mode gave sufficient braking with an occasional jab on foot brake if it starts to build up speed. No where near enough to overheat the brakes. If I tried to use  B mode when battery full it very quickly used the engine for braking. And engine speed  did get very high and noisy. The  solution is simple. Don't use B mode. Use the brakes  infrequently and as gently as possible should you need to moderate your speed decent. I didn't need to to use brakes any more often than I did in a manual car in a lower gear on similar mountain passes,much longer than anything in the UK.
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Lord Voltermore

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Re: Very steep hills
« Reply #25 on: May 29, 2022, 08:15:00 PM »
Just done  8 km (5 miles)  without using any fuel at all.  :P    Easy.  Fill the tank at the top of a mountain pass.  When it levelled off a bit and used some fuel  I was still getting 285 mpg.  :-*  The downside   Going up there were times the engine was working hard and I was  only getting 15 mpg  :o . Same with a few , erm, enthusiastic' overtakes .    But 200 km later,  doing 90kph,occassionally more ,it still averaged out at over  80mpg. ;D

This is real world usage.  If a truck can get up  hill, so can  the jazz,with ease.   And make the descent without needing B mode for additional engine braking or stressing its brakes. Get real here. Even in the lake district, North wales ,scotland and other hilly places  (or indeed the alps)there are not many hills a truck cant climb.    A word of warning. ALL cars  can overheat their brakes on a long descent if you are not cautious.   You walk down a steep hill. If you try and run down  you will lose control and fall over. Controlled descent from the top, simples.   1 in 3 and 1  in 4 hills are a bit of a novelty, and rarely very long.  Model T fords from the 1910's and 1920's might need to go up in reverse ,which has lower gearing  ,but the Jazz will eat them for breakfast and go up no problem at all.  . If its a bit noisier than normal for a few minutes,or seconds, in very exceptional circumstances, thats no reason to miss out on is normally  exceptional quietness and fuel economy.
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Neil Ives

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Re: Very steep hills
« Reply #26 on: May 30, 2022, 10:29:01 AM »
For the first time, yesterday I experienced the engine racing while I was descending a long steep hill. I was probably using B mode. The battery charge indicator went right up to the top, then the engine started to race. What caused this?
Neil Ives

Pine

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Re: Very steep hills
« Reply #27 on: May 30, 2022, 12:04:09 PM »
For the first time, yesterday I experienced the engine racing while I was descending a long steep hill. I was probably using B mode. The battery charge indicator went right up to the top, then the engine started to race. What caused this?
I have experience of this in a Toyota hybrid.  When the hybrid battery is approaching full the battery powers up one of the motor generators to use some power and prevent overcharging.  This has the effect of spinning the engine, no petrol is being used.

Lord Voltermore

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Re: Very steep hills
« Reply #28 on: May 30, 2022, 04:59:40 PM »
Normally the Jazz uses the  drag  from the  powerful electromagnets in the generator  to slow the car, either on a descent  or  when slowing from speed.   This 'regenerative braking ' has the advantage that its also charging up the HV battery without needing to use the petrol  engine to drive the generator.   This effect may be powerful enough that driving gently  you may not need to use the footbrake as well  , but in reality  there will be times that you also need to brake.

On a long descent  the HV battery may get fully charged.  The electromagnets needs to be switched off to prevent the battery being overcharged and damaged.   So the car reverts to old school engine braking instead, literally using the compression of the petrol engine to slow the car.     If the hill is quite gentle  and you  use some prudent braking as well  you may not notice the engine is actually being used  - Its not powering the car, its trying to slow it down.
  With B mode especially  if the hill is quite steep and you are avoiding using brakes  the engine might,in an attempt to slow you down sufficiently    ,rotate at very high revs for the road speed. A bit like coming down a hill in second gear   with little use of the brakes. Noisy !  .  A useful safety feature in extreme circumstances  if you are worried the  footbrakes  may overheat and fade   , but I have driven over a lot of mountain passes   and have never needed to be this extreme.   
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Neil Ives

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Re: Very steep hills
« Reply #29 on: May 30, 2022, 05:44:32 PM »
... With B mode especially  if the hill is quite steep and you are avoiding using brakes  the engine might,in an attempt to slow you down sufficiently    ,rotate at very high revs for the road speed. A bit like coming down a hill in second gear   with little use of the brakes. Noisy !
That describes it exactly  :o
Neil Ives

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