Understanding the 2012 Buick LaCrosse with eAssist System

[Z-06]

Understanding the 2012 Buick LaCrosse with eAssist System

V. V. Haldavnekar

2010/12/05

With the 2012 Buick LaCrosse General Motors (GM) introduced the second generation Belt Alternator Starter (BAS) system, officially known as the eAssist, at the 2010 Los Angeles Auto Show. GM claims that eAssist, which means "light electrification" helps the near 2 ton car achieve a 25 percent increase in the fuel economy compared to the fuel economy of the 2.4L, 4 cylinder/6-speed LaCrosse. GM expects the eAssist LaCrosse to deliver a class leading fuel economy of 25 mpg city and 37 mpg highway. The system will be standard on all 4-cylinder equipped LaCrosses.

The eAssist system in the 2012 Buick LaCrosse is coupled with a 180-hp 2.4L Ecotec direct-injection 4-cylinder engine and a 6-speed automatic transmission. An advanced 115V lithium-ion battery and latest-generation 15-kW motor-generator unit help increase fuel economy through regenerative braking that provides up to 15-hp of electric power assistance during acceleration, automatic engine shut-off when the vehicle is stopped, aggressive fuel cut-off during deceleration down to zero vehicle speed, and intelligent charge/discharge of the high-voltage battery.

The eAssist system will become the standard powertrain on the LaCrosse starting next summer, with prices to start around $30,000.

Belt Alternator Starter System

GM introduced the BAS system in a 2007 Saturn Vue Green Line. The technology later proliferated into Saturn Aura Green Line and Chevrolet Malibu Hybrid. The BAS system is also referred to as a mild hybrid.

A mild hybrid vehicle is essentially a conventional vehicle with oversized starter motor that also acts as a generator and an electric turbo. The electric generator/motor/starter not only permits the engine to be turned off whenever the car is coasting, braking, and stopped, but also aids it to restart quickly and cleanly. Accessories can continue to run on electrical power while the engine is off, and as in other hybrid designs, the motor is used for regenerative braking to recapture energy. The larger motor is used to spin up the engine to operating rpm speeds before injecting any fuel. The motor also kicks in anytime when sensors detect heavier load on the gas engine, such as operations during a hill accent or under acceleration. Although unable to operate in pure all-electric EV mode, the BAS system provides improvements to both city and highway fuel efficiency over similar non-hybrid versions.

Given the simplicity of the system, BAS equipped vehicles are relatively inexpensive compared to a full hybrid counterpart. Another perceived benefit of the BAS technology is that it fits in the same space as a conventional engine. No significant modifications are required to the vehicle chassis to accommodate the BAS system, with the battery pack housed in the trunk or spare tire well. This allows the BAS equipped vehicles to be produced on the same assembly line as the non-hybrid versions, resulting in substantial cost savings and allowing flexibility in production.

The downside of early mild hybrids was that the air conditioning suffered in performance when the gasoline engine shut down, but with the eAssist GM assures that the problem is essentially solved using electric air conditioning. Another disadvantage BAS was that the engine starting and stopping operations were easily noticeable. The control system for BAS initially was somewhat crude in comparison to the full hybrid engine startups and for some people it turned to be annoying. However with 2012 LaCrosse eAssist, GM claims the start-stop efforts will be seamless.

GM's Generation I BAS System

The Generation I BAS used a 36 volt electrical system (operating range between 42 and 45 volts), which was powered by a 10kW nickel-metal hydride battery pack. The battery pack consisted of three 12V NiMH battery cassettes in series, with each cassette having two 12V modules in parallel. The electrical system operated a permanent magnet motor/generator unit mounted to the engine in a similar manner as to a conventional alternator. Through a high-tension drive belt, the BAS system was capable of starting or assisting the 2.4L Ecotec engine used in the application. A conventional 12V starter motor was retained and used during cold start operations. The air conditioning compressor was operated through a belt-driven pulley, but for fuel economy improvement it could be disabled in auto-stop mode if the "ECO" A/C mode has been selected by the operator.

A conventional 4T45-E 4-speed automatic transmission was used in the vehicles equipped with the BAS system. The transmission had been modified to include a more efficient final-drive ratio and included an electrically-driven pump to provide pressure in auto-stop mode.

The instrument cluster of the BAS vehicles was modified to inform the driver on operations of the hybrid powertrain:

• AutoStop indicator in the tachometer notifying the driver when the engine is in AutoStop mode,
• ECO (Economy) indicator light notifying the driver when the vehicle is exceeding the EPA fuel economy estimates,
• Charge-Assist gauge that indicates whether the system is charging or providing assist power,
• The Driver Information Center (DIC) is programmed to provide messages specific to the Hybrid operation.

The Gen I BAS system resulted in modest to significant gains in fuel economy. For 2009, the Malibu Hybrid was rated at 26 city and 34 highway – resulting in a 4-mpg increase over the base-level Malibu. The conventional Malibu started at $20,745, while the Chevy Malibu Hybrid started at $24,695. The 2009 FWD Saturn Vue BAS hybrid was rated 25/32/28 mpg for city/highway/combined cycles, respectively with improvements of 32% /24%/ 27% for city/highway/combined cycles, respectively over the base 4cyl FWD version.

The BAS equipped vehicles received mild reviews from the publications citing the deficiencies stated above. Cobasys supplied the BAS system's nickel-metal hydride battery pack for Gen I system. The company had to conduct a recall in 2008 apparently due to leakage of the battery modules.

GM Gen II BAS System (eAssist)

The eAssist is mated to a 2.4L Ecotec direct injection four-cylinder engine and a next-generation six-speed automatic transmission. The engine is rated for 180 horsepower. A 115V lithium-ion battery and a latest-generation 15-kW motor-generator replace the original 36V NiMH battery pack and the older 10 kW motor. Following are the significant features of the eAssist system:

• Providing up to 15 kW of electricity to charge the battery from regenerative braking,
  
• Providing up to 11 kW (15 hp) of electric power assistance during acceleration,
• Shutting off engine automatically when the vehicle is stopped,
• Cutting off power down to zero during deceleration, enabled by the torque smoothing provided by the motor-generator unit,
• Charging and discharging of the high-voltage battery using intelligent systems.

The eAssist system"s 115V air-cooled lithium-ion battery bolsters the 2.4L Ecotec four-cylinder engine with approximately 11 kW (15 horsepower) of electric power assist during heavy acceleration and 15 kW of regenerative braking power. Those numbers are significantly better than the 2 kW of power assist and 5 kW of regenerative power on the previous BAS system. The greater power capability enables greater energy capture during regenerative braking for improved fuel economy.

While the eAssist system shares the same basic belt-alternator-starter configuration of previous BAS designs, it delivers more than three times the power and is more refined and capable than the Gen I BAS system. Its ability to integrate regenerative braking with the latest lithium-ion battery technology creates a system that delivers fuel-efficiency gains.

The eAssist system's electric motor-generator is mounted to the engine in place of the alternator to provide both motor assist and electric-generating functions through a new engine belt-drive system. The motor-generator is a high-performance, compact induction motor that is liquid-cooled for increased performance and efficiency.

The system also enables the Ecotec engine to shut down fuel delivery in certain deceleration conditions, which saves additional fuel. While in fuel shut-off mode, the motor-generator unit continues spinning along with the engine to provide immediate and smooth take-off power when the driver presses on the accelerator. Furthermore, as the vehicle comes to a stop, the motor-generator unit spins the engine, bringing it to a smooth stop and also properly positions the vehicle for a smooth restart.

GM's global chief engineer of the eAssist system, Steve Poulos says that the battery system is designed to provide power assistance to the internal combustion engine, rather than storing energy for all-electric propulsion. Mr. Poulus further states that the eAssist is an extension of the conventional internal combustion engine, but not its replacement.

The eAssist power pack contains the 115V lithium-ion battery pack, the integrated power inverter and 12V power supply. It is located in a compartment between the rear seat and trunk, and is compact and lightweight. GM states that the system weighs only about 65 pounds. Due to its compactness, rear access to the trunk is allowed via the split-folding rear seat, an attribute which GM claims is not shared with other hybrid competitors. The trunk space for the eAssist equipped LaCrosse is down to 10.9 cubic feet compared to 13 cubic feet for the conventional 4-cylinder model. An electric fan cools the power pack, drawing air from a vent located in the package tray, behind the rear seat. The fans are designed to be quiet from the cabin.

To further boost the fuel economy, Buick LaCrosse with eAssist technology also features improved underbody aerodynamics and tires optimized for performance and fuel economy, as well as active control of front-end airflow that improves aerodynamics and engine warm-up. Electronically controlled shutters in the lower grille close at higher speeds to push more air over the vehicle, thus increasing the aerodynamic efficiency to enhance fuel economy.

LaCrosse with eAssist includes an ECO gage on the instrument panel that continuously responds to driving behavior, enabling the driver to drive with maximum efficiency. It also features a hill-assist system that captures brake pressure to help the driver more comfortably accelerate from a stop on a moderate or steep grade. The operation is achieved by greatly reducing the tendency of the vehicle to roll backward with the engine in shut-down mode.

A Special Mention – New GM 6-Speed Transmission

GM will introduce the next-generation Hydra-Matic 6T40 in the 2012 LaCrosse eAssist. GM says the new transmission incorporates features specifically designed to enhance powertrain efficiency.

Significant internal transmission changes to clutch controls and hardware are incorporated in the new transmission to provide reduced spin losses while improving shift response and time. The added electric power provided by the eAssist system allows for higher gearing to improve steady state efficiency without impacting acceleration performance or drivability. The system's capability of providing some electric assistance at cruising speeds allows the driver to accelerate lightly or ascend mild grades without the transmission downshifting.

An auxiliary, electric-driven transmission oil pump has been added to the 6T40, which keeps the transmission primed and the fluid flowing when the engine shuts down at a stop. This auxiliary system keeps the transmission ready to perform when the driver accelerates, providing a seamless delivery and smooth driving experience.

Summing it up

GM has been one of the main proponents of BAS system and with eAssist has shown renewed commitment to the system. GM replaces the 4-cylinder Buick LaCrosse with the eAssist system as standard for the 2012 model. The price increase over the conventional 4-cylinder CX model is expected to be approximately $3,000, thus making the base MSRP of the LaCrosse in the range of $30,000. The price bump also aids in creating a gap between the Regal and the LaCrosse that are currently priced within few hundred dollars of each other. While the real world advantages of the system can only be judged by a road test, the 2012 Buick LaCrosse eAssist looks stronger on paper than any GM Gen I BAS vehicle had.

The infomercial from GM, portraying the eAssist technology can be found in the following video.

http://www.youtube.com/watch?v=BUnI6pMwqLA

[vonVeezelsnider]

All well and good... BUT:

1. What is with this nonsense about taking out the coolant gauge. It's good especially in colder climates like mine to judge just how quickly the damn heater is going to kick in! It's also valuable information that is better displayed as a relative gauge than a number... and I didn't like having to click through the DIC to access it on my Cobalt either. The whole gimmick of an ECO gauge just smacks of petty greenwashing anyway.

2. Sure, lets drop a giant battery in the trunk and make it even smaller than it already is (which is inexcusably, smaller than a Cobalt small). The trunk as it presently stands is almost already a dealbreaker for practical minded people like myself.

[CanadianBacon94]

where would you want the battery?

[loki]

so...they're not using the "normal" 2.4L now with DI so they'd have to use the 6L45? (to handle the more power) is this weird?

i was just skimming.. is the 2.4 just going to be Atkinson cycle?

Edited December 6, 2010 by loki

[Drew Dowdell]

The Lacrosse has automatic climate control. The heat will kick on automatically once the engine has started giving off heat.

[67impss]

Good job Z

This looks quite good and might allow us to keep our performance and large cars & trucks a bit longer

[vonVeezelsnider]

where would you want the battery?

My point is that this is a full size car with, now, a ten cubic foot trunk.

[CanadianBacon94]

My point is that this is a full size car with, now, a ten cubic foot trunk.

Yes, i saw that, but my question involves the fact that a car that wasn't a hybrid from the beginning doesn't really have a place to hide the battery without intruding somewhere

[dwightlooi]

so...they're not using the "normal" 2.4L now with DI so they'd have to use the 6L45? (to handle the more power) is this weird?

i was just skimming.. is the 2.4 just going to be Atkinson cycle?

(1) At 180hp (as opposed to 182) I am pretty sure it is NOT Atkinson. An Atkinson cycle engine loses between 20~30% of the compression stroke to regurgitation through the intake valves -- they have cams that are ground to keep the intake valves open for the first 20~30% in of the compression stroke. This causes a similar 20~30% decrease in power output compared to the same engine were it to be operating with a regular Otto cycle*. If the 2.4L were to be Atkinson cycle, one will expect the output to drop from 182hp to about 127~146hp.

(2) There is a way to get the best of both worlds. You can switch between Atkinson Cycle and Otto Cycle Cam lobes if you implement a cam switching system (ala VTEC). The engine can operate on Otto mode during hard acceleration and revert to Atkinson mode during idle, cruise and light throttle situations. It's not a free lunch of course. Using same pistons and heads, there is a dramatic difference between the compression ratio of the engine in Otto and Atkinson modes. For instance, if the engine is normally 11.2:1 (Eg. GM's "LAF" DI 2.4L), an ideal Atkinson cam will drop the effective compression to 7.8:1 -- that's pretty darn low. If you want to keep the effective compression at around the Prius' 9.5:1, the compression ratio under Otto mode will have to be a staggering 13~13.5:1. Even with premium fuel, that is a bit too high. Hence, some kind of compromise has to be struck. Either the Atkinson mode is not as deep as a dedicated Atkinson engine would use, or the Otto mode compression is higher than typical calling for premium fuel usage, or a combination of both. An engine that does Otto-Atkinson switching is the Honda Civic's SOHC R18A 1.8 Liter -- it makes 140hp and uses a rather "mild" Atkinson grind during low load situations.

(3) I do not believe the GM 2.4 is using a cam switching system. The current heads are not designed to accommodate it and if they switch the head architecture to a completely new one, I am sure they'll trumpet it.

* Eg. The Toyota Prius' 1.8 liter engine (2ZR-FXE) has a geometric compression ratio of 13.0:1. It keeps the intake valves open for the first ~27% of the compression stroke. This ejects about a similar percentage of the intake air before the valves close and compression begins, resulting in an effective compression of about 9.5:1 in Atkinson mode. The Prius's engine (2ZR-FXE) makes 98hp compared to 138hp the non-Atkinson version in the Corolla (2ZR-FE). A 29% output loss to (similar) 27% compression stroke reduction.

[regfootball]

My point is that this is a full size car with, now, a ten cubic foot trunk.

deal breaker. taurus trunk. 21 c.f.

[loki]

thanks dwight, but the tranny isn't rated for even 180hp, unless it actually is a different design, just the same "6L40". is that 180 with the 15hp motor added? ...could the engine be 1/2 atkinson 1/2 otto, so it'd loose ~10% power?

this is what's confusing me.

[dwightlooi]

thanks dwight, but the tranny isn't rated for even 180hp, unless it actually is a different design, just the same "6L40". is that 180 with the 15hp motor added? ...could the engine be 1/2 atkinson 1/2 otto, so it'd loose ~10% power?

this is what's confusing me.

(1) There is no such thing as a 6L40 to begin with and there is no way the Lacrosse will use a "6L" transmission. There is the 6L45, 6L50, 6L80 and 6L90 -- there is no 6L40 in existence. All the 6L transmissions are for Longitudinal, Rear Drive, applications. Hence, the "L".

(2) The 4-pot Lacrosse uses the 6T40 transmission -- 6 speed, Transverse, torque rating 40. This transmission is rated for 180hp / 177 lb-ft and is used in the Lacrosse, Equinox and Terrain. The V6 Lacrosse uses the 6T70 tranny with their 3.0 and 3.6 V6 engines.

(3) If you are interested, the ratings for all the aforementioned GM Hydramatic Transmissions are as follows:-

• 6L45 -- 6-speed, Longitudinal, Up to 278 hp / 258 lb-ft / 7000 rpm
  
• 6L50 -- 6-speed, Longitudinal, Up to 315 hp / 332 lb-ft / 7000 rpm
  
• 6L80 -- 6-speed, Longitudinal, Up to 469 hp / 439 lb-ft / 6500 rpm
  
• 6L90 -- 6-speed, Longitudinal, Up to 555 hp / 550 lb-ft / 6200 rpm
  
• 6T40 -- 6-speed, Transverse, Up to 180 hp / 177 lb-ft / 7000 rpm
  
• 6T70 -- 6-speed, Transverse, Up to 315 hp / 280 lb-ft / 7000 rpm
  
• 6T75 -- 6-speed, Transverse, Up to 315 hp / 300 lb-ft / 7000 rpm
  

Note: The 6L45, 6L50 and 6L80 are also sold to BMW for use in the 3-series and 5-series. BMW buys GM trannies because their traditional supplier (ZF) did not have a suitable transmission to support the "xi" AWD models. The 6T70 model is jointly developed with Ford and is also used in the Ford Fusion, Lincoln MKZ and other Ford vehicles.

(4) The ratings have pretty conservative built-in margins. Generally, you can exceed them by a bit with absolutely no ill effects. In fact, GM routinely does that. The Equinox and Terrain for instance puts 182hp through the 6T40 even though it is rated at 180hp. The CTS-V exceeds the 6L90's ratings by 1 hp and 1 lb-ft.

(5) Yes, an engine can be a "mild" Atkinson and lose only 10% of its original power rating. It all depends on how late you close the intake valves. A typical Atkinson engine closes them about 25~30% into the intake stroke, losing a similar percentage of power. You can close it a mere 10% into it and lose 10%. But, you'll also not reap as much efficiency benefits. I don't think this is the case here though... 182 hp --> 180 hp is so trivia that it is probably from small variations in the exhaust, air box or things of that nature.

Edited December 7, 2010 by dwightlooi

[loki]

thanks again.

i was thinking it didn't look right... the L and T.

[motorman]

i was stuck in a 28 mile long traffic jam and it took over 6 hours to get out of it. how many times can this system restart the car when you only move less than a car length each move? can it be shut off ?

[Drew Dowdell]

More than likely, putting the transmission into sport mode will override the engine shut off.

[Guest Lou]

OK, Every one sounds like they might be able to help me, or at least explain my problem,

I have 2012 Buick Lacrosse, 4cly eAssist, 6speed, 16,000 miles, I bought it used, 11,390 miles, everything seemed ok, Every once in awhile the check engine light came on, dealer asked if it was solid on, or blinking, it was on solid, brought car to dealer, found history in EVDR(event data recorder) It was cleared after checking with program scanner, Reprogramed various control modules, lets get back to the problem,

The "AutoStop" feature does not function at all, since the reprogramming was done, back to the Dealer. they can't find the problem/ it didn't repeat it self, (AHHHHH, it wasn't working) did anyone test drive the vehicle? Nope, I give up, called GM, there are sorry for my problems, BRING IT TO THE DEALER, well, if the dealer can't find the problem, who do I bring it to??

Here is my night mare......NO WARRANTY on vehicle, what so ever...when I bought the car, the title was "Rebuilt" yes, I knew and accepted that, for a better price, But, I DID HAVE A DEALER, GM, check it, and they gave it a OK, said it appears only to be body damage, Should I kick my self in the butt, or can some one guide me as what to do?? or what could be the problem.

ONE extra Note...since the reprogamming, the Idle seems higher, the gauge on dash used to be around 500 rpms to 550, in drive, now 750 to 800??

[Drew Dowdell]

1st, try a different dealer.

2nd, does the auto-stop work when the hvac system is powered off and the engine is at operating temp?

[dwightlooi]

The effectiveness of a Hybrid system is directly proportional to the amount of regenerative braking it can provide. That is the ONLY source of free energy in a Hybrid. Charging the battery by running the engine or running it harder costs more fuel have than the stored energy will help you save when converted back to mechanical energy. That is because there is generation and motor losses along the way, not to mention a small amount of battery self-discharge. Everything else is secondary to this...

The Prius is a more effective hybrid than the 2nd Gen Insight because it can slow the car with a 67 hp motor. And (more importantly) it has 295 lb-ft of torque working to slow the car in lieu of the brakes and capture that kinetic energy into battery charge, whereas the Insight only has 13hp flywheel integrated motor-generator with 58 lb-ft of twist. Slowing a 3500 lbs Buick with a 15hp belt attached device which is torque limited by its means of attachment isn't much slowing and hence doesn't capture a lot of "free" energy for reuse. It's that simple. If GM is serious about eAssist it cannot be a bolt on Belt-Alternator-Starter. Is should be a motor integrated into the transmission or flywheel.

For a 3500 lb car... a hypothetical "Electramatic 6E75" will be ideal. Basically, it is a 6T75 6-speed automatic transmission with a 300 lb-ft input torque rating fitted with a 70hp/300 lb-ft synchronous motor in lieu of the torque converter. The car always pull away from a stop using just the electric motor with 300 lb-ft @ 0 rpm. At above 1000 rpm the internal combustion engine may start if needed. If the ICE is used the electric motor torque is electronically limited such that the combined torque going into the transmission never exceeds 300 lb-ft. During deceleration or below 1000 rpm the engine always uses the 2-stage Variable Valve Life system to shut-off all the valves and simply freewheel. This hybrid setup cannot idle the internal combustion engine; at rest the engine is always stopped and initial motion is always electric.

Hypothetical Electramatic 2.5L performance = 268 hp @ 4,700~6,300 rpm / 300 lb-ft @ 0~4700 rpm

Edited April 24, 2014 by dwightlooi

[carguy10101010]

The effectiveness of a Hybrid system is directly proportional to the amount of regenerative braking it can provide. That is the ONLY source of free energy in a Hybrid. Charging the battery by running the engine or running it harder costs more fuel have than the stored energy will help you save when converted back to mechanical energy. That is because there is generation and motor losses along the way, not to mention a small amount of battery self-discharge. Everything else is secondary to this...

 

The Prius is a more effective hybrid than the 2nd Gen Insight because it can slow the car with a 67 hp motor. And (more importantly) it has 295 lb-ft of torque working to slow the car in lieu of the brakes and capture that kinetic energy into battery charge, whereas the Insight only has 13hp flywheel integrated motor-generator with 58 lb-ft of twist. Slowing a 3500 lbs Buick with a 15hp belt attached device which is torque limited by its means of attachment isn't much slowing and hence doesn't capture a lot of "free" energy for reuse. It's that simple. If GM is serious about eAssist it cannot be a bolt on Belt-Alternator-Starter. Is should be a motor integrated into the transmission or flywheel.

 

For a 3500 lb car... a hypothetical "Electramatic 6E75" will be ideal. Basically, it is a 6T75 6-speed automatic transmission with a 300 lb-ft input torque rating fitted with a 70hp/300 lb-ft synchronous motor in lieu of the torque converter. The car always pull away from a stop using just the electric motor with 300 lb-ft @ 0 rpm. At above 1000 rpm the internal combustion engine may start if needed. If the ICE is used the electric motor torque is electronically limited such that the combined torque going into the transmission never exceeds 300 lb-ft. During deceleration or below 1000 rpm the engine always uses the 2-stage Variable Valve Life system to shut-off all the valves and simply freewheel. This hybrid setup cannot idle the internal combustion engine; at rest the engine is always stopped and initial motion is always electric.

 

Hypothetical Electramatic 2.5L performance = 268 hp @ 4,700~6,300 rpm / 300 lb-ft @ 0~4700 rpm

 

This seems like a great idea, what kind of cost and weight is associated with a 300 lb ft electric motor?  With the fuel economy numbers being released for the mid size truck twins this week and the general underwhelming reaction by the internet at large I wonder what a system like this could do when plugged into trucks like that.  Big torque from the get go would work well, and with no torque converter losses and some regenerative braking I would have to think fuel economy would really out do what they're currently going for.  Has anyone made a commercial alternator or generator that can run off of the exhaust stream?  If possible to implement it would seem like a good fit if the industry is going to keep heading towards electrification of vehicles.

[carguy10101010]

Even more could you take the current Chevy Colorado scheduled to come out in a month or two and give its 3.6L LFX an atkinson cam grind, then do something a la Acura's RLX sport hybrid with a larger electric motor bolted to the transmission and two smaller electric motors at each rear wheel?

 

This would result in a truck with full AWD functionality that would produce 300 lb ft from 0-6000 rpm.  With an ICE running with an atkinson cycle and no more drivetrain losses through a rear diff and transfer case a vehicle like this would be able to do something like 28/28 on the EPA cycle with a very healthy ability to tow and haul.  Electric motors would complement truck and sports car applications better than any others, it seems odd that mild hybrid setups like this one have not been implemented in any of them yet.

[Drew Dowdell]

but where do you put the batteries?

[carguy10101010]

but where do you put the batteries?

That shouldn't be too difficult in a truck platform.  GM butchered the under seat storage for the back seat so badly in the new canyon/colorado that batteries could be mounted there.  Honda put a truck underneath the bed in the Ridgeline, there is no reason the similar void space in a colorado/canyon could not be converted to battery use, instead of empty space or a trunk like the ridgeline has.  I would be more concerned about the durability of the electric motors they use in automotive applications and what their duty cycles are.  I have never read one way or the other what these motors are capable of putting out before some sort of cooling would be needed. 

[dwightlooi]

This seems like a great idea, what kind of cost and weight is associated with a 300 lb ft electric motor?  With the fuel economy numbers being released for the mid size truck twins this week and the general underwhelming reaction by the internet at large I wonder what a system like this could do when plugged into trucks like that.  Big torque from the get go would work well, and with no torque converter losses and some regenerative braking I would have to think fuel economy would really out do what they're currently going for.  Has anyone made a commercial alternator or generator that can run off of the exhaust stream?  If possible to implement it would seem like a good fit if the industry is going to keep heading towards electrification of vehicles.

 

 

(1) The weight will be significant, but not so much from the motor as from the battery itself. A 70hp motor itself will be in the order of 70~80 lbs, a battery powerful enough and which stores enough charge to support a 70hp motor however will be on the order of 200~400 lbs. Still that is about what the Prius lugs around and it will not offset the gains from regenerative braking and subsequent motor assist.

 

(2) There isn't much "steam" in the exhaust. Certainly not enough to drive anything. However, there is plenty of heat and plenty of pressurized gas. Another source of "free" power is to use half a turbocharger -- just the turbine section without the compressor -- to drive a generator. This way, the normally wasted energy in the exhaust is converted (at least in part) to electricity. The problem with that is that it is much more of an engineering challenge. Turbos run at up to 100,000~150,000 rpm. Generators generally don't work well at such high frequencies, meaning you have to gear it down to maybe 1/10th or 1/20th of that rotation speed. It's a similar challenge as say Pratt & Whintey faces in commercializing the Geared Turbofan except it is actually worse because the reduction ratio is much greater. Alternatively you can simply work with a very high frequency AC source... that's another challenge by itself (efficiencies aside).

Edited October 17, 2014 by dwightlooi

[carguy10101010]

 

This seems like a great idea, what kind of cost and weight is associated with a 300 lb ft electric motor?  With the fuel economy numbers being released for the mid size truck twins this week and the general underwhelming reaction by the internet at large I wonder what a system like this could do when plugged into trucks like that.  Big torque from the get go would work well, and with no torque converter losses and some regenerative braking I would have to think fuel economy would really out do what they're currently going for.  Has anyone made a commercial alternator or generator that can run off of the exhaust stream?  If possible to implement it would seem like a good fit if the industry is going to keep heading towards electrification of vehicles.

 

 

(1) The weight will be significant, but not so much from the motor as from the battery itself. A 70hp motor itself will be in the order of 70~80 lbs, a battery powerful enough and which stores enough charge to support a 70hp motor however will be on the order of 200~400 lbs. Still that is about what the Prius lugs around and it will not offset the gains from regenerative braking and subsequent motor assist.

 

(2) There isn't much "steam" in the exhaust. Certainly not enough to drive anything. However, there is plenty of heat and plenty of pressurized gas. Another source of "free" power is to use half a turbocharger -- just the turbine section without the compressor -- to drive a generator. This way, the normally wasted energy in the exhaust is converted (at least in part) to electricity. The problem with that is that it is much more of an engineering challenge. Turbos run at up to 100,000~150,000 rpm. Generators generally don't work well at such high frequencies, meaning you have to gear it down to maybe 1/10th or 1/20th of that rotation speed. It's a similar challenge as say Pratt & Whintey faces in commercializing the Geared Turbofan except it is actually worse because the reduction ratio is much greater. Alternatively you can simply work with a very high frequency AC source... that's another challenge by itself (efficiencies aside).

 

 

What kind of duty cycle can these electric motors handle?  Would they be capable of putting out max torque output over and over in a short time, say while towing/hauling through a town with a stretch of lights, or would they begin to overheat?  Is there a need to liquid cool a large enough electric motor when integrated in with the transmission?  I still think a setup like this would seem (at least on paper) to have the biggest benefit in the new mid sized trucks.  The electric motor could give a huge boost to the low rpm area of the torque curve, and the mild hybrid setup could essentially use wasted brake energy to remove the parasitic drain of the power steering pump, alternator, water pump, and torque converter - since all of those things would be electrified.  Could make stop/start systems work better too I suppose.

[carguy10101010]

Also, if its technically too difficult to use exhaust gasses to generate electricity directly, would it be possible to setup some of these hybrids with a smaller engine and small turbo and run a miller cycle?  Are the small turbos still too slow to spin up to be of use for a miller cycle engine?

 

With every manufacturer so anxious to turbo everything (allegedly for CAFE reasons) I have wondered why they don't switch to miller cycle engines.  They're already spending the money on forced induction and they would get better fuel economy out of the system.

[Drew Dowdell]

What about the BMW Turbo-Steamer that boiled water off the exhaust heat to run.... something?

[carguy10101010]

What about the BMW Turbo-Steamer that boiled water off the exhaust heat to run.... something?

 

I wonder how much water a system like that would consume?  I guess in theory one could make a closed loop system where boiled water was then condensed and boiled again.  Heck, if a system like that was not used you could probably do away with the entire cooling system since you could just boil water directly from the engine heat as well as from the exhaust.  You would take all of that waste heat that gets dumped into the atmosphere and doing work with it.  I wonder if a water injection system, maybe with an extra couple of strokes could suck enough heat out of the engine to reduce or eliminate the cooling system. 

 

Shame its so expensive to develop new car tech.  Lots of interesting ideas out there.

[Drew Dowdell]

It's closed loop

[G. David Felt]

 

What about the BMW Turbo-Steamer that boiled water off the exhaust heat to run.... something?

 

I wonder how much water a system like that would consume?  I guess in theory one could make a closed loop system where boiled water was then condensed and boiled again.  Heck, if a system like that was not used you could probably do away with the entire cooling system since you could just boil water directly from the engine heat as well as from the exhaust.  You would take all of that waste heat that gets dumped into the atmosphere and doing work with it.  I wonder if a water injection system, maybe with an extra couple of strokes could suck enough heat out of the engine to reduce or eliminate the cooling system. 

 

Shame its so expensive to develop new car tech.  Lots of interesting ideas out there.

 

Water injections was a big deal in the late 70's I remember my dad and I trying a number of systems that came to market. But they never really panned out. Course we did not have the computers and the technology then to probably make it a reality. Something very well could work today.

[Drew Dowdell]

I think that is a different type of system than what BMW did with the Turbo Steamer.

[G. David Felt]

I remember most of them were in a plate you put under the carburetor and it misted or sprayed water very finely with the fuel so it got sucked down the engine to make the fuel more efficient. Yet it seemed to have issues around specific RPM if memory serves me correct.

[Drew Dowdell]

yeah, not at all the same as the BMW concept.

[carguy10101010]

Sounds like the turbo steamer (if it works financially to be mass produced) could net a substantial gain to all vehicles.  It could be one of those pieces of technology that everyone begins to use if it really can capture as much waste heat as BMW's claims would have us believe.  In conjunction with a mild hybrid system we could potentially see some pretty substantial gains in both city and highway mileage in the future.  Definitely good news!

 

The turbosteamer is designed to capture wasteheat from the exhaust and coolant and transform it into usable energy.  Water injection is designed to cool the intake charge to prevent detonation and allow for higher compression ratios in the engine.  I think someone has proposed an engine that has an extra "water cycle" where water is injected after the exhaust stroke to be turned to steam to convert waste heat into mechanical work, but that would require a decent sized water tank.  A lot of guys use water/methanol injection on their diesels to keep their EGTs down, but some of those systems really use an incredible amount of water/methanol.  I think some inject over 10% water/methanol mixture v/v with diesel into the air charge.  Since most guys use the windshield reservoir for this its a huge pain since it can get emptied pretty darn fast.  If diesels had gone the route of water/methanol injection instead of urea injection to control Nox diesels would be more efficient, have more power, and would have cleaner valves.  Bummer on that one.  If a good set of tuners comes along for Chrysler's ecodiesel that allows the SCR to be shut off and a kit created to use the urea tank for water/methanol injection I would buy one in a heartbeat.

[dwightlooi]

Sounds like the turbo steamer (if it works financially to be mass produced) could net a substantial gain to all vehicles.  It could be one of those pieces of technology that everyone begins to use if it really can capture as much waste heat as BMW's claims would have us believe.  In conjunction with a mild hybrid system we could potentially see some pretty substantial gains in both city and highway mileage in the future.  Definitely good news!

 

The turbosteamer is designed to capture wasteheat from the exhaust and coolant and transform it into usable energy.  Water injection is designed to cool the intake charge to prevent detonation and allow for higher compression ratios in the engine.  I think someone has proposed an engine that has an extra "water cycle" where water is injected after the exhaust stroke to be turned to steam to convert waste heat into mechanical work, but that would require a decent sized water tank.  A lot of guys use water/methanol injection on their diesels to keep their EGTs down, but some of those systems really use an incredible amount of water/methanol.  I think some inject over 10% water/methanol mixture v/v with diesel into the air charge.  Since most guys use the windshield reservoir for this its a huge pain since it can get emptied pretty darn fast.  If diesels had gone the route of water/methanol injection instead of urea injection to control Nox diesels would be more efficient, have more power, and would have cleaner valves.  Bummer on that one.  If a good set of tuners comes along for Chrysler's ecodiesel that allows the SCR to be shut off and a kit created to use the urea tank for water/methanol injection I would buy one in a heartbeat.

 

Water injection has a nasty habit of chewing up spark plug electrodes in short order. The problem is not so much corrosion, but that there is no spark plug which is of the proper heat range for when the misting is on and when the misting is off.