Clubjazz - Honda Jazz & HR-V Forums
Honda Jazz Forums => Honda Jazz Mk4 2020 - => Topic started by: Jazzdriver on May 23, 2022, 09:48:11 AM
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I hope to visit the Lake district soon. I would love to drive the Wrynose and Hardknott pass again. I imagine the B mode would greatly help when descending and would generate plenty of battery power, but how is the Jazz/Crosstar at climbing steep (up to 1 in 3) inclines? (There would be three of us on board.)
No gears (other than D/B). No clutch. Just relying on the motor to pull you up.
Has anyone experienced steep inclines in the Mark 4 Jazz/Crosstar?
Thanks.
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I have been to Italy and Switzerland twice with the jazz. Although I don't think I have been up a 1in3 I have been up some very steep hills with no problems. The problem I had was coming down as once the battery is full charged which didn't take long then the engine started to try and slow the car. It made a lot of noise. No idea what reves it was at. Needed to use the brakes a lot.
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Yes,
I got the same type of problems, big noise and big vibrations, but it's the normal way of use of this tecnology (I raised the issue during the last service and the service guy told me that there is nothing wrong)
I don't know how other Hybrid cars handle the problem of the battery full during an descent from the top of an hill
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I've had other hybrids, they both did the same thing.
Once the battery is full the engine started up with no fuel and ran as an air brake to provide braking - like the brake on a truck, it makes lots of noise as it is just wasting energy to keep the speed down.
The Jazz battery does fill up very quickly though, so it's likely to happen more.
There are a few steep hills where I can fill the batter gauge on the Jazz whereas I only ever had the full gauge once on the Auris hybrid.
You can also fill the Jazz battery up quickly when braking on motorway slip roads too.
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...I've found that even on something not remotely hilly that if you accelerate from a slowish speed that the engine 'revs' soar, speed increases but not drastically and the engine sounds like its trying to 'change gear' but never does. Even if you ease off the engine sound doesn't quell even though you are not really going anywhere.
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Yes, in that situation the EV action is reversed, in that the EV motor becomes a generator, driven by the wheels to generate power, to rotate the engine, to thereby provide the required retardation.
Very much the same, as changing down to a low gear on a manual gearbox.
It would pointless to simply lock the dog clutch, to connect the engine to the wheels, since the overall gear ratio would be far too high (equivalent of 5th or 6th gear) to provide any significant retardation.
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Yes, in that situation the EV action is reversed, in that the EV motor becomes a generator, driven by the wheels to generate power, to rotate the engine, to thereby provide the required retardation.
Very much the same, as changing down to a low gear on a manual gearbox.
It would pointless to simply lock the dog clutch, to connect the engine to the wheels, since the overall gear ratio would be far too high (equivalent of 5th or 6th gear) to provide any significant retardation.
Yes, in the Auris/etc it runs the engine without fuel as it's directly connected through a type of gearbox.
In the Jazz, maybe the engine is generating electricity to power the motor backwards to try and provide braking?
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Yes,
I got the same type of problems, big noise and big vibrations, but it's the normal way of use of this tecnology (I raised the issue during the last service and the service guy told me that there is nothing wrong)
I don't know how other Hybrid cars handle the problem of the battery full during an descent from the top of an hill
Doesn’t that make for a stressful journey? It seems that a problem with the Honda (and other) hybrid systems are the excessive noise while climbing and descending steep hills; okay if you live and drive somewhere flattish (Easy Anglia) but less so in hillier parts of the Country. I am seriously considering a Crosstar or HR-V but don’t know whether I could live with the noise/vibration issues I keep reading about.
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The noise/vibration is only when going down hills with a full battery, so won't happen very often at all.
Going uphills is fine if you set the accelerator and keep the setting, I have had 5 people in my Jazz with luggage going up a motorway hill no problem maintaining 70 with not much engine noise at all.
I drove 150 miles on the motorway yesterday at 70mph and rarely had lots of noise from the engine.
I've found I only have one accelerator position now for accelerating - about 1/3 to 1/2 way down, just press it there and keep it. You get good acceleration (maybe 80% performance) with not much noise.
If you want absolutely 100% of the performance then you will get noise - the car will hold 6,000 revs the whole time and add some fake gear changes to break up the noise.
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Thanks. I was only thinking of challenges going uphill. I hadn't thought much about going downhill. Wrynose and Hardknott are often up and downhill, so often the battery would soon get used up again after getting fully charged. But there are some long downhill stretches too.
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Thanks. I was only thinking of challenges going uphill. I hadn't thought much about going downhill. Wrynose and Hardknott are often up and downhill, so often the battery would soon get used up again after getting fully charged. But there are some long downhill stretches too.
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Well, I appear to be in a minority if I relate my own experience of going up steep hills. The sort of gradients you get on A roads or motorways, absolutely no problem, plenty of torque. But on say a 20% uphill incline B road it seemed to struggle and it was the only occasion after a year's driving I have ever felt the car was underpowered. It did get up the hill ok, but glad I wasn't in a hurry!
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To give some context for those who have not driven Hardknott and Wrynose, here's a graph of my journey over there in my MGBGT in 2012, travelling eastwards. The average descent gradients in that direction are approximately -17% and -14%. Of course, the graph doesn't show the bends... the highest speed (shown by the blue line) was approx 31mph.
The other photo is the western descent from Hardknott.
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I just don’t understand the term ‘excessive engine noise’ when negotiating steep hills.
It is no different to a manual gearbox in such conditions.
You will be in a low gear and the engine will be revving to provide the power required for such hills. Or of course in a low gear to provide engine braking.
It is just something you live with in such situations.
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...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.
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The engine noise is worse going up a steep hill if your battery is low at the start as all the electricity has to be generated by the engine, if the battery is fairly full before you start the incline it helps reduce the engine revs when ascending.
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...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.
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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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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.
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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.
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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.
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...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.
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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.
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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".
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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
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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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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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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?
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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.
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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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... 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