[Cessna182]

Thanks for the explanation.
Does this system really save fuel? I know that the Ciaz returns good mileage, but is it considerably more in Indian traffic conditions, compared to other cars like the City?

[Leoshashi]

Originally Posted by Cessna182

Thanks for the explanation.
Does this system really save fuel? I know that the Ciaz returns good mileage, but is it considerably more in Indian traffic conditions, compared to other cars like the City?

I'd say yes. My friend recently got a Ciaz S. And he also has a 4th Gen City in extended family. Where the Ciaz easily touches 20kmpl on highways, City gives 15-16kmpl under similar conditions, on same road and driven by same driver.

In my XL6, I feel lesser need to press the accelerator, when system is getting mild boost. Lesser throttle input=lesser fuel consumption.

But, if you consider the cost of Pb batteries, and SHVS hardware (if in case it ever goes bad), the fuel saved won't even matter.

As an owner I like the torque assist which helps in driveability and Automatic Stop Start system which definitely is a nice to have feature at traffic signals.

Regards,
Shashi

[mayd85]

I believe the reasons for retaining starter motor are:
1. Of course as a fail safe mechanism, when the ISG goes kaput. Since it's belt driven, there are chances of belt becoming loose, wearing out, chewed by rats and what not.
2. In cold cranking, the torque required for cranking the engine is much higher compared to that for a hot engine. Since it is not designed for high torque application like a full hybrid, the small ISG machine cannot generate that kind of torque. Hence, it is used only during start stop. You may notice that, idle stop-start may not start operating immediately after vehicle starts. It starts working after some time when engine has reached certain temperature.

[RSR]

Many thanks for this highly detailed and informative post on Maruti Suzuki's SHVS system, Leoshashi!

It's good to see Maruti Suzuki introduce their genuine SHVS micro-hybrid system with a Li-ion battery on their petrol cars (as found on some international Suzukis). Earlier, they sold cars like the Ciaz DDiS without a Li-ion battery, that they labelled as SHVS.

Originally Posted by Leoshashi

But, if you consider the cost of Pb batteries, and SHVS hardware (if in case it ever goes bad), the fuel saved won't even matter.

How expensive are they?

I have another query. Suppose the Li-ion battery goes dead and/or the SHVS goes kaput, can the car be used as a regular car without the stop-start system & torque-assist function, and with obviously lowered fuel efficiency?

Once their cars get quite old, and the SHVS and/or Li-ion battery were to go kaput, I guess owners may prefer not to replace it/them if the expense turns out to be too much.

There is a lot of nonsense and misinformation circulated in the media.

Of course! Many "auto journalists" in India are shockingly clueless. I feel nothing but pity for those who believe whatever they say. I mean, there are people stupid enough to take the words of ignorant "auto journalists" to be the gospel truth, that when the myths created & spread around by those clueless jokers get busted, they find it extremely difficult to accept the actual facts! A really pitiful state of affairs.

[SS-Traveller]

Originally Posted by Leoshashi

Paid attention on this aspect today, in my case it was going well below 1500 rpm and the Li Ion battery was still being charged. Continued till approximately 1200 revs.

That happens when the lead acid battery is fully charged, such as when driving on the highway. The cutoff is then at ~1200 rpm as you rightly said.

[Reinhard]

Originally Posted by Leoshashi

As promised, here I am with a detailed description of the Smart Hybrid system. There is a lot of nonsense and misinformation circulated in the media. Have a look at this video:

Hope this eliminates many doubts.

Thanks Shashi for the brilliant informative post as always. Cleared my doubts & confirmed most things that I had guessed based on how it was behaving. Loved reading it. Rating it 5 stars.

Its good to see that the software controller logic is quite well thought out & evidently tested in a learning mode of technicians to add more and more safeguarding mechanism. Little things like checking brake booster pressure to decide whether to shut off engine or not - are vital. Goes to show how much R&D + testing actually goes into features and mechanicals of a car that people take for granted. The unsung engineering heroes of manufacturing & design worlds are always invisible to the outer world. People who's efforts actually contribute directly in life saving designs.

On the other hand - honestly do I feel the SHVS is worth the price it comes at (+ the replacement costs in case it develops problems post warranty) - no I don't. I'm not a fan of the mild/micro-hybrid technologies. Bring the real ones!

[extreme_torque]

Originally Posted by Leoshashi

I'd say yes. My friend recently got a Ciaz S. And he also has a 4th Gen City in extended family. Where the Ciaz easily touches 20kmpl on highways, City gives 15-16kmpl under similar conditions, on same road and driven by same driver.

In my XL6, I feel lesser need to press the accelerator, when system is getting mild boost. Lesser throttle input=lesser fuel consumption.

But, if you consider the cost of Pb batteries, and SHVS hardware (if in case it ever goes bad), the fuel saved won't even matter.

As an owner I like the torque assist which helps in driveability and Automatic Stop Start system which definitely is a nice to have feature at traffic signals.

Regards,
Shashi

I think its purely anecdotal as the engine's are quite different. The Honda engine makes more power and also has VTec. Also while it may have a marginal effect on fuel economy due to the start stop system and some level of torque assist, I dont think it will be that drastic. Also, SVHS should not make any difference at highway speeds. Is the assist even available at highway speeds?

[Leoshashi]

Originally Posted by RSR

How expensive are they?

For example 45Ah normal battery costs around 5-6k. Exide conservo which is EFB battery costs around Rs. 8500. Thankfully I have a friend who is a distributor of Exide batteries, and he too got Ertiga recently. So I am assured of slightly cheaper replacements.

I have another query. Suppose the Li-ion battery goes dead and/or the SHVS goes kaput, can the car be used as a regular car without the stop-start system & torque-assist function, and with obviously lowered fuel efficiency?

Yes. The car continues to work as any other car.

Once their cars get quite old, and the SHVS and/or Li-ion battery were to go kaput, I guess owners may prefer not to replace it/them if the expense turns out to be too much.

Indeed, at current prices, it won't be worth. But I am being told prices are being reduced as many components are being localised/economies of scale factor kicks in. At one point of time, the MGU(or ISG) used to cost north of 90k. It's now around 40k. I am expecting cost of Li Ion battery too to fall down considerably once local production resumes.

Of course! Many "auto journalists" in India are shockingly clueless. I feel nothing but pity for those who believe whatever they say. I mean, there are people stupid enough to take the words of ignorant "auto journalists" to be the gospel truth, that when the myths created & spread around by those clueless jokers get busted, they find it extremely difficult to accept the actual facts! A really pitiful state of affairs.

Reminds me of your recent struggle.

Originally Posted by Reinhard

On the other hand - honestly do I feel the SHVS is worth the price it comes at (+ the replacement costs in case it develops problems post warranty) - no I don't. I'm not a fan of the mild/micro-hybrid technologies. Bring the real ones!

True. But I wouldn't call this system entirely gimmicky. The torque assist alone makes it worth for me. You can tell the difference when Li Ion battery charge is low, and you need to accelerate. Feels much more sluggish.

Good for Fuel efficiency and other cost savings- definitely not in the long term!

Originally Posted by extreme_torque

I think its purely anecdotal as the engine's are quite different.

Of course, I was asked about comparison with other sedans, hence my reply.

Also, SVHS should not make any difference at highway speeds. Is the assist even available at highway speeds?

It does. Torque assist function is available from 1000-3900 rpm.

Regards,
Shashi

[TrackDay]

I was about to ask about the whole hybrid battery and SHVS system going dead question. Seems like it has already been asked and answered. One of the bigger question that was always there was whether the car would have any long term effect running with a damaged/non used SHVS + Hybrid battery.

Without the Hybrid what is the approximate real world mileage of the
new ciaz ? I also take it that this whole SHVS mechanism is same across the brezza, XL6 etc.

[Leoshashi]

Originally Posted by chiranjitp

How much do they cost? (the Li-ion battery, ISG & related parts)

Originally Posted by MadTiger

I have included the prices that Sashi has included in this thread.

Apologies for the error, the Primary battery Exide Conservo ISS N55 costs Rs. 6500. Rs. 8.5k is the approximate price of earlier DIN 70 Conservo which was used in Diesel engines.

Regards,
Shashi

[SS-Traveller]

Originally Posted by Leoshashi

Paid attention on this aspect today, in my case it was going well below 1500 rpm and the Li Ion battery was still being charged. Continued till approximately 1200 revs.

Managed to click this:

Attachment 2079272

Regards,
Shashi

If the Pb-acid battery is fully charged and voltmeter shows <13v, the Li-ion battery will receive charge on slowing down (throttle off) till as low as 1100-1200 rpm. Otherwise, when voltage shows ~13.2-14.2v, the Li-ion battery charge indicator stops at around 1500 rpm.

[SgtRepeat]

Originally Posted by Leoshashi

I'd say yes. My friend recently got a Ciaz S. And he also has a 4th Gen City in extended family. Where the Ciaz easily touches 20kmpl on highways, City gives 15-16kmpl under similar conditions, on same road and driven by same driver.

This is one area where my experience has been quite different. Even with a sedate driving style, my Ciaz Alpha AT doesn't produce a mileage of more than 11 kmpl in the city.

We recently went on a 1500 km round trip to Goa where I got a mileage figure of 14.5 kmpl, admittedly after lots of redlining and driving at speeds of 90-100 kmph.

Wonder if the gear ratios in the 4 speed AT is responsible for the increased fuel consumption as compared to the 5 speed MT.

[PearlJam]

In today's news, Maruti has been served a show cause notice for allegedly evading around 71 crores duty over 'dubious' hybrid technology:

https://timesofindia.indiatimes.com/...w/81881004.cms

[Ritz2010]

I had similar thoughts of having battery running the cars for short run-abouts like reverse and creeps in traffic signal - this was me as a fresh Engineering graduate and first time car owner (read mileage conscious) - but MSIL implementing a fraction of that claiming hybrid is just not acceptable.

Kudo's for fantastic explanation with wiring diagrams.

The system seems almost negligible and isn't a great achievement for a company like Maruti Suzuki I believe.

Pure hybrids are too costly for Indian and market and Indian players are dishing out college graduates projects as solutions. It could have been little more effective - around 75%. 27% improvement seems too low.

[RavyaLe]

Dear Leoshashi, Thank you for the detailed review of the SHVS system.

I drive 2018 1.3 DDiS VDI model. I am facing the following issues, I am curious to know the solutions.

1. During idle conditions/ traffic signals this system is not working. What may be an issue?
2. Can we bypass this Hybrid tech, by disconnecting that extra battery and drive the car.
3. For the diesel model, I think this SHVS is not useful, on the other hand, if any problem arises we have to pay hefty money to replace the extra batteries.

Awaiting feedback/response from the experts.