What modern technologies have made a significant advancement in fuel economy?

[V]

I have been thinking about the changes in internal combustion engine design over the decades that has increased the fuel economy of an engine of a specific capacity or specific power output. How many of these technologies can be retrofitted to a vehicle with an older engine design as an upgrade.

 

• Better fuel injection
• Multivalve cylinder heads, three or four valves per cylinder
• Flow improvements in port design - Cylinder head, inlet and exhaust manifolds
• Variable cam timing
• Overhead camshafts - lower mass valve trains
• Roller cam followers
• Improved spark ignition - fully electronic, coil on plug, distributor-less wasted spark
• Forced induction - turbocharging, supercharging
• Hybrid electric power - low speed, high torque movement on electric power
• Regenerative braking
• Electric powered ancillaries - power steering, coolant pumps
• Dry sump oil scavenged lubrication
• Lighter pistons, rods and crankshafts
• Transmissions with better gearing and less losses
• Skinny tyres
• Aerodynamic aids
• Multi-displacement - switching off cylinders

 

I would be interested in what could be done to achieve a 50% fuel economy improvement on the Jeep 4.0L without losing any power or torque.

[AlexK]

Mahle developed a pre-chamber ignition system, called Mahle Jet Ignition, to permit especially lean fuel mixtures. Originally it was intended for retrofit, although I’m only aware of Maserati deploying the system in their V6. It’s available in two forms, active and passive, the difference being the presence or absence of a small spark plug within the pre-chamber.  From memory, the Maserati implementation uses the system only in certain circumstances to save fuel. The retrofit intention was that the MJI module is technically small enough to replace the existing spark plug, negating the need for complex re-engineering of the head. I’m not aware of the existence of any retrofit kits though. Now, the system is being used to investigate hydrogen and ammonia fuel replacement systems. I’ve no idea how you would go about using it.

[V]

I have noticed that dry sumping has found it's way into the stock GM LS7 and is an option on some Mercedes V8 now. I don't know if the pistons and gudgeon pins in a 4.0L rely on splash lubrication from the crankshaft. If it does, a dry sump system for the 4.0L would need a piston oiling spray rail inside the crank case. I don't know if that would require a separate stage on a scavenge pump. Currently looking at really basic 2 and 3 stage old-skool scavenge pump implementations.

[V]

https://www.mahle-powertrain.com/en/experience/mahle-jet-ignition/

 

It looks like a very interesting idea.

 

Quote

In the Active MAHLE Jet Ignition® configuration, significant fuel savings are achieved by the higher, almost diesel-like efficiency.

 

Edited October 24, 2022 by V

[jeepstertim]

In real terms, I suspect not much short of making it more aerodynamic.  In cost terms, LPG, same (or slightly less) MPG but roughly half the cost.

[Ludders]

Direct injection, turbo charging, variable cam timing and duration.

 

Are the biggest aids in fuel economy.  All of these have given designers the ability to increase power with reduced cylinder size which in turn reduces fuel economy. 

 

You could fit an over-run pulley alternator which reduces drag on over-run, and continues charging the battery, thereby reducing the overall drag on the crankshaft.

Electric fan, maintains a higher engine temperature, and provides less drag on the engine of a viscous one.

 

Regenerative braking is a sales term and no such thing exists (pet hate incoming)..

The drag of the motor charging the high voltage battery slows the vehicle down. It should be called regenerative retardation.... Not so slick though is it...

This requires a motor/generator and batteries to be useful, and the additional weight may not make it any more efficient overall. 

However, the Lexus LS650H incorporates a high voltage motor in the auto gearbox. This is starting to be utilised by tuners to create Hybrid rwd cars..... just a thought. 

[V]

I have been using LPG for two decades and I am happy to continue using it. I think all of the Liquid Injection LPG systems have been taken off the market as a result of mergers and acquisitions. The Vialle system produced more BHP and fuel economy under LPG than the OEM petrol system on converted vehicles. I would not be surprised if the money behind most of the LPG manufacturers is also a dominant investor in BEV.

 

Aerodynamics on a car really isn't much of an issue on a Jeep until you get past 50mph. The vehicle needs a really low rolling resistance for there to be an improvement. You could put a replica fibreglass body of the most aerodynamic production car on a Wrangler's rolling chassis and I doubt there would be any difference in fuel economy if the vehicle was restricted to 40mph. If a vehicle is designed with a low rolling resistance from the beginning, 2wd or 4wd with wheel motors, low sprung mass, low rotational mass and skinny tyres then aerodynamics will make a difference at low speeds.

 

With the majority of speed limits in my locality have been dropped 10mph, so that 50mph is the maximum speed between market towns and 20mph when you get there, aerodynamic improvement is not at the top of my own list. However, a full length underbody skid plate that smooths out airflow underneath may be advantageous until you consider the two axles, two propshafts and all of the control arms, and steering linkages in the air stream that would be creating turbulence.

[V]

I had an idea back in the 1980's that I did some work on that may deserve crowd funding now. I think that it is possible now to fix the bits that I couldn't resolve back then. I thought complexity would be a barrier to adoption, but in the decades that have passed since then DPF AdBlue systems are just as if not more complex.

 

Approximately 80% of the energy put into an internal combustion engine is wasted. Frictional losses account for some, but the majority is wasted in heat through conduction and radiation through the cooling system and exhaust. I think it is possible to recover 30% of that heat or more as power in petrol, diesel and gas engines.

 

If an internal combustion engine was used like a nuclear reactor to create superheated steam to drive a turbine connected to an electricity generator, a large proportion of that wasted heat could be recovered. The engine's cooling jacket still gets coolant, but only after it condenses from steam back into a liquid. The steam circuit would be closed loop as it contains antifreeze. No steam would leak to atmosphere so it would not need topping up in normal use. Engine driven ancillaries like alternator, coolant pump, radiator fan, power steering, air-conditioning could all be powered by electric motors. It is Combined Heat and Power (CHP) for vehicles.

 

The downside is the exhaust temperature. A hot exhaust at the tailpipe only allows condensation to form in the exhaust system when the engine is switched off. The small amount of creosotes formed as a result are burned off during the next engine start. If an exhaust is running substantially cooler, condensation in the exhaust will occur continuously during use which may create an acidic tea like discharge from the exhaust.

 

Since, I dropped my idea, modern engines have become cleaner burning and now have catalytic converters which have to be run reasonably hot to work properly. A super heated steam generator would need to be downstream of the catalytic converter but it would have less soot in the exhaust than in the 1980's. A final exhaust driven turbine could be used to centrifuge condensed liquids where the captured liquid could be encouraged to separate from the solids, the latter being captured in a removable, disposable canister. When I initially had this idea, my lack of chemistry skills prevented it from going any further. Back then acid rain was a thing and my idea created acid car pee. Today, planet earth still acts as a condenser for exhaust particulates that mix with atmospheric water vapour, we just don't see it happening in real time.

[V]

I have just reread what I wrote. The engine's coolant jacket would not be pressurized beyond it's designed pressure when running at coolant temperature of 103 DegC. There would be a water-to-water heat exchanger between the steam system and the engine cooling jacket. The engine's cooling jacket is the steam circuit's pre-heater to raise condensed vapour back to boiling point 100 DegC. Both circuits will need antifreeze to withstand freezing when not running. An air-to-water radiator would still be required in the engine coolant system as an emergency heat sink.

[AlexK]

The irony is that, now OEMs are moving to BEVs, heat recovery is becoming a thing, ranging from relatively simple heat pumps that warm the cabin using excess heat from the motor and batteries, to more complex systems that attempt to recover that lost energy back into the batteries.

 

I always liked Mazda's i-eloop system. A supercapacitor is charged by the alternator during deceleration and overrun, with that energy used to power the vehicle's electrical systems. That reduces load on the alternator at other times, and extends the amount of time the start/stop system can keep the engine off for when stationary. A full capacitor charge takes only a few seconds and can run the car's electrical systems for around a minute at a time. Component count, cost and weight were minimal, and Mazda reckoned it led to fuel savings of around 10%.

[digger]

Hi V, I completely support that aerodynamics do very little until high speeds are achieved. I believe (possibly depending on the vehicle)  that in fact little happens until 70 +.

I remember, 20 odd years ago when  racing 250cc short circuit geabox karts that all the competitors had massive rear wings which they were using in long circuit racing (up to 150mph) too.  We thought they did little when short circuit top speed was only 115mph ish. We were told  ''you won't be able to stay on the track without it!   You will flip/take off!! I consulted  our sage . He said all it did was create drag in his view!!   We took it off!  ''Mad'' was the call! The laughter was loud until our lap times dropped. Interestingly it still took  a couple of years before they had vanished from short circuit!! 

 

When Porsche first brought out the 'whale tail' many years ago,   I thought it was a picnic table! 

 

[V]

48 minutes ago, AlexK said:

I always liked Mazda's i-eloop system. A supercapacitor is charged by the alternator during deceleration and overrun, with that energy used to power the vehicle's electrical systems. That reduces load on the alternator at other times, and extends the amount of time the start/stop system can keep the engine off for when stationary. A full capacitor charge takes only a few seconds and can run the car's electrical systems for around a minute at a time. Component count, cost and weight were minimal, and Mazda reckoned it led to fuel savings of around 10%.

10% is a massive benefit. This should be a mandatory retrofit on any vehicle that can show deceleration on a data bus and uses an alternator's field windings to control generation load. Perhaps it could be packaged as a modified alternator for simple swaps.

 

 

[V]

38 minutes ago, digger said:

When Porsche first brought out the 'whale tail' many years ago,   I thought it was a picnic table!

I guess it worked on the 911 because to cancel some of the natural aerodynamic lift that the body shape has. The increase in drag was compensated by the traction gains at higher speed. I don't think it was a case of downforce but more of lift mitigation. I think they also stuffed an intercooler or oil cooler in the whale tail so it was convenient for extra engine bay space.

[Ludders]

8 minutes ago, V said:

10% is a massive benefit. This should be a mandatory retrofit on any vehicle that can show deceleration on a data bus and uses an alternator's field windings to control generation load. Perhaps it could be packaged as a modified alternator for simple swaps.

 

 

It is, virtually every manufacturer uses this method to supplement the ICE, it's marketed as mhev (mild hybrid electric vehicle). The power for the stop/start system is recouped and utilised via the the starter/generator.

Some manufacturers use 48v, but with li-ion advancements, they're using 12v as they're easier to slip into a vehicle. Under the seats (for example Renault & Nissan 12v) rather than in the boot (like Kia & Ford 48v).

[V]

9 minutes ago, Ludders said:

It is, virtually every manufacturer uses this method to supplement the ICE, it's marketed as mhev (mild hybrid electric vehicle).

So why not make the technology available as retrofit for vehicles that are already in use? Surely, a 10% fuel economy improvement of the nation's existing vehicles is a 10% drop in CO2 without the CO2 of manufacturing a whole new vehicle.

Edited October 25, 2022 by V

[Gerald F]

Checking the fuel consumption on my WK2, whilst driving from Aberdeen to Falmouth and back, in stages, I found it quite feasible to get around 40mpg with speeds between 50 and 60 mph, even on country roads if there was little traffic (it did happen once or twice). motorway cruising at 63-64 mph gave around 36mpg, steady 70 mph about 32. I tend to use cruise control in the North, since traffic is usually light. The big difference comes when it is windy, and 10-20mph winds make a huge difference to 70mph consumption, easily 10%, either way. 

Below about 45mph, the fuel consumption tends to rise again, since it doesn't like to stay in 8th gear, and I don't like to force it with the manual controls. Optimal efficiency from the engine in normal road use seems to be at around 1,700 - 2,000 rpm, and even the 'eco' setting always changes up after a few seconds of 1,500.

I've usually been happy to burn the fuel on long journeys, as maintaining 70 on a 400 mile trip to see family in England saves us arriving in Birmingham at rush hour, and the consumption increase due to air resistance is acceptable. However, I was surprised at how much difference there was, in an unexpected direction, between 40 and 50 mph.

I don't know how the gearing compares with other Jeep models, but the GC is one of the least non-aerodynamic vehicles in the range. There is quite a difference between the FCA 3l diesel and the WK Mercedes 3l, and I don't think it is just about the better gearbox in the former. There's certainly more power in the WK2, especially when towing. I have tried a (petrol) JL towing a caravan, and the lack of grunt was quite off-putting!

 

[V]

I have just been reading some more about Mazda's i-ELOOP. I think this might be possible as an enhancement to a vehicle with an engine driven fan. The viscous fan coupling is replaced with a solenoid clutch so that engine driven fan rotation can be switched on and off by a controller. Primary cooling can be done by an electric fan driven by a separate battery, secondary cooling by the engine driven fan. A supercapacitor is charged every time the brake lights are illuminated and discharges to the electric cooling fan circuit as required by a controller monitoring the coolant temperature. The solenoid clutch should be a shuttle clutch to minimise power requirements to change of state only. Engine cooling would primarily be from recovered electrical energy produced by the engine during braking, with an automatic mechanical backup reverting to crankshaft driven if it fails. I suppose, getting rid of the viscous fan clutch is only required if there is a clearance issue. It doesn't hurt to keep it. The solenoid clutch housing would need to be bracketed to the water-pump fixings.

 

Going a step further, separating the engine driven fan from the water-pump altogether would allow the engine coolant circulation to also be powered by the capacitor when it has the energy to do so and by the alternator at all other times. Dual electric coolant pumps, one alternator circuit powered, one capacitor circuit powered would add redundancy and protection against a single pump failure while the engine was running. This could lead to other enhancements like a coolant manifold to equally distribute coolant at the same temperature to each cylinder simultaneously rather than the temperature gradient common in most engines on a first and last cylinder coolant flow circuit. The 4.0L i6 would benefit from this mod.

[AlexK]

2 hours ago, Ludders said:

It is, virtually every manufacturer uses this method to supplement the ICE, it's marketed as mhev (mild hybrid electric vehicle).

 

MHEVs are a different system, and use batteries to store recuperated energy which can then be used to drive a small electric motor on the accessory belt to provide assistance during acceleration. Suzuki's SHVS system was neat in that it had a particularly low component count and was easy to integrate on an existing vehicle, with just an ISG on the accessory belt and a battery pack under the front passenger seat.

 

i-ELOOP is unusual in its use of capacitors and doesn't provide any motor assistance. Batteries are relatively slow to accept a charge, whereas a capacitor can quickly store even small amounts of power very efficiently. That means that even if you lift off the gas for only a fraction of a second, it can still recharge the capacitor. Do that several times and you've accumulated a useful level of charge that a battery could never have achieved. i-ELOOP then uses that only to power items on the electrical system, perhaps lights, HVAC, etc. It's beauty is in not needing additional batteries or motors, and if I remember rightly it used a conventional alternator. Doesn't even need an ISG.

[AlexK]

Just to confuse the issue a little further, the Wrangler's 4xe system is technically both a mild-hybrid and a plug-in hybrid. It has a small motor on the front belt like the e-torq system, plus a larger motor inside the transmission bell housing along with two clutches.

[BLUE STAR]

Of coarse when all this new tech goes wrong (usually as it ages) any economic savings on fuel will be blown away by having to get it replaced or junking the vehicle 

 

V "So why not make the technology available as retrofit for vehicles that are already in use? Surely, a 10% fuel economy improvement of the nation's existing vehicles is a 10% drop in CO2 without the CO2 of manufacturing a whole new vehicle" 

 

Sounds sensible, but 'they' don't care, as CO2 isn't a 'real problem or pollutant'. 'They' need for you to replace your vehicle as often as possible like iPhones for Taxes & profit.

That's why 'they' keep gaslighting the population very successfully with all the unrelenting media 'controlled' climate propaganda. (Nothing really changed since Joseph Goebbels time, same methods deployed, but on a much grander scale)

Imagine having a million V's about in the UK, who can keep their straight 6 dependable engines running for 30 years +  "Nightmare scenario"  for Govt & manufactures 

[digger]

18 hours ago, V said:

I guess it worked on the 911 because to cancel some of the natural aerodynamic lift that the body shape has. The increase in drag was compensated by the traction gains at higher speed. I don't think it was a case of downforce but more of lift mitigation. I think they also stuffed an intercooler or oil cooler in the whale tail so it was convenient for extra engine bay space.

Yep, I agree. I was being facetious. at the end of the day the traditional 911 shape had and does have its shortcomings.  

[Vernon]

11 hours ago, BLUE STAR said:

Of coarse when all this new tech goes wrong (usually as it ages) any economic savings on fuel will be blown away by having to get it replaced or junking the vehicle 

 

V "So why not make the technology available as retrofit for vehicles that are already in use? Surely, a 10% fuel economy improvement of the nation's existing vehicles is a 10% drop in CO2 without the CO2 of manufacturing a whole new vehicle" 

 

Sounds sensible, but 'they' don't care, as CO2 isn't a 'real problem or pollutant'. 'They' need for you to replace your vehicle as often as possible like iPhones for Taxes & profit.

That's why 'they' keep gaslighting the population very successfully with all the unrelenting media 'controlled' climate propaganda. (Nothing really changed since Joseph Goebbels time, same methods deployed, but on a much grander scale)

Imagine having a million V's about in the UK, who can keep their straight 6 dependable engines running for 30 years +  "Nightmare scenario"  for Govt & manufactures 

Totally agree re CO2.

 

Anyone who studied biology knows that CO2 is plant food and a vital part of our respiration cycle as photosynthesis provides the Oxygen we breath.

 

6 CO2 + 6 H2O via sunlight = C6H12O6 (carbohydrates) + 6 O2

 

And something that always fascinated me is the fact that we have Haemoglobin in our blood that transports the O2 around our body.  It’s a four chain protein with an iron molecule at the centre of each.

 

Chlorophyll - the green pigment in plants that facilitates photosynthesis is virtually identical in structure to haemoglobin - the main difference being it has Magnesium rather that Iron.

 

So CO2 is not a poisonous nor the devils flatulence as some would have you believe.  I also think we are being conned in a buy buy buy falsehood.  Helped by useful idiots like the greens and those who glue themselves to roads and damage works of Art.

 

And the worst thing is these useful idiots are usually Art students with no technical, mechanical, scientific or intellectual ability whatsoever.

 

My personal experience of one Caroline Lucas of our Green Party was that at a talk she gave some years ago I realised that whilst she was introduced as “Dr” Caroline Lucas - she had no scientific knowledge whatsoever.  
 

So I checked her out.  She does have a PhD from Exeter and it is in Elizabethan Romantic Women’s Literature.

 

Apologies for hijacking a really interesting thread.

 

My two penneth on efficiency would be LPG/petrol dual fuel cars with LPG preferable in urban areas due to its lack of particulate emissions.

 

Also - having used solar panels to great effect in our caravans - I do wonder why these are not incorporated more into car design?  
 

And a final funny - About 6 to 8 years ago there was much talk of saving the planet by placing Solar Panels in road surfaces.  
 

All went well until traffic actually used the road and blocked out the sunlight.

 

 

[V]

6 hours ago, digger said:

Yep, I agree. I was being facetious.

That's just my neurodiversity getting in the way of spotting what's obvious to everyone else.

[Caroline12]

Aerodynamic efficiency starts at 15mph.

I did time trialling, aerodynamic advantage is key to going fast on a push bike and winning.
aerodynamics clothing etc also counts for top sprinters (lyrca or baggy shorts and tops) and wind advantage stops them getting world records.  Aerodynamics advantage start a lot lower than 40, 50 or 70mph, they start at 15mph. 
 

for fuel efficiency, how you drive is more important, boy racer vs mature person.
 

making your vehicle aerodynamic is also a key element of fuel efficiency, along with weight.

heavy, brick shaped vehicles take more fuel to get going, lose the weight.

Heavy vehicle = worse fuel efficiency.

Correct tyre pressure is also key for driving on the road.

 

I change my tyre pressure from 35psi and got 32-34mpg, tyre pressure to 39psi I got 39-40mpg. 
 

a clean waxed vehicle bodywork also helps. For time trialling, lots of small advantages or percentages add up to a big advantage at little cost.
 

basic things before engine mods can have a tremendous effect. 

 

 

[V]

19 minutes ago, Caroline12 said:

Aerodynamics advantage start a lot lower than 40, 50 or 70mph, they start at 15mph.

I agree, aerodynamics matter as soon as a vehicle starts moving. It's arguable that aerodynamic stability is just as important for a stationary vehicle in a strong wind as a moving vehicle with no wind. However, frictional drag caused by the tyres, the rolling resistance usually has to be overcome before aerodynamic improvements are noticeable. A bicycle with skinny tyres will have a lot lower rolling resistance than a Jeep on mud terrains. Therefore as the rolling resistance is low, aerodynamic gains are noticed comparatively earlier at a lower speed.

 

For a Jeep, the rolling resistance caused by a bump in the road surface would probably eclipse any aerodynamic gain the bodywork might achieve at 15mph. It's not a case that there are no aerodynamic gains below the level of rolling resistance, it is just that they are harder to notice and can be eliminated purely by a change in road surface.

 

This graph hopefully should illustrate why aerodynamic gains on a car are worthwhile after defeating rolling resistance.

 

The rolling resistance for a bicycle tyre is in the range 0.0022 to 0.005

A normal car tyre on a concrete road is 0.01 to 0.015, on sand it is 0.3

At a guess, a 35x12.50R15 BFG KM3 would be 0.04-0.06

 

Consider an impact from a Wrangler hitting another Wrangler at 5mph squarely on the bumpers.

A victim Wrangler on 37" mud terrains isn't going to move as far as one on stock street tyres. If the victim Wrangler was on an infinitely long magnetic levitation platform/track before the impact, it would be propelled a considerably longer distance down the track before aerodynamic drag brought it to a standstill.