Leerlaufverbrauch | Posts 16+

@Bertil: Yes, about 20 years ago, automatic throttle shut-off was introduced, and this coincided with the shift to port fuel injection in gasoline engines. A throttle cutoff can be implemented more easily in a throttle-body injection system with electronic engine control than in a carburetor system (in the latter, all nozzles would have to be closed during throttle cutoff, which would make the carburetor even more complicated).

However, there's significant potential for fuel savings that hasn't been utilized yet: in stop-and-go traffic. Unfortunately, this is a common occurrence for many of us. And in that situation, tons of fuel is wasted unnecessarily while the engine is idling. Turning off the engine isn't practical either, because the line of cars only moves a few meters every few seconds. That's why I'm always happy when we're going downhill in stop-and-go traffic, because then you can actually turn off the engine. You just roll downhill.

My idea: There are light-triggered auxiliary machines that sit directly on the crankshaft. (There were even devices like the Dynastart 40 years ago). Such auxiliary engines could easily move the car in stop-and-go traffic with the engine switched off in first gear. However, the diesel engine would have to be disconnected from the drivetrain via a separate clutch. Something like that probably already exists. I just don't understand why such methods are not widely used in Germany. In urban areas with a high proportion of stop-and-go traffic, something like this would be worthwhile. Because in stop-and-go traffic, a vehicle really has a very poor efficiency.

ideeAlist wrote:

@Bertil: Yes, 20 years ago, automatic throttle shut-off was introduced, and that was because, during that time, there was a shift towards port fuel injection in gasoline engines. A throttle cutoff can be implemented more easily in a throttle-body injection system with electronic engine control than in a carburetor (in the latter case, all nozzles would have to be closed during throttle cutoff, which would make the carburetor even more complicated).

"Throttle shut-off was also present in carbureted engines - it was regulated using vacuum - my JB Jetta (built in 1981) had something like that."

Quote:

However, there is significant potential for fuel savings that has not yet been utilized: in stop-and-go traffic. Unfortunately, this is a common occurrence for us and in Germany. And in that situation, tons of fuel are wasted unnecessarily while the engine is idling}. Turning off the engine is not practical either, because the line of cars moves forward a few meters every few seconds. That's why I'm always happy when we're going downhill in stop-and-go traffic. Then you can really turn off the engine. You just roll downhill.

Well, it's not exactly allowed, but you'll really save money doing it that way.

Quote:

My idea: There are light-triggered auxiliary machines that sit directly on the crankshaft. (There were even devices like Dynastart 40 years ago). Such auxiliary engines could easily move the car in stop-and-go traffic with the engine switched off in first gear. However, the diesel engine would have to be disconnected from the drivetrain via a separate clutch. Something like that probably already exists. I just don't understand why such methods are not widely used in Germany. In urban areas with a high proportion of stop-and-go traffic, something like this would be worthwhile. Because in stop-and-go traffic, the diesel engine really has a miserable efficiency.

The Ecomatic principle, which was already present in some Golf models 10 years ago, hasn't gained widespread acceptance. However, the potential for fuel savings is enormous. That's absolutely correct, but the engineering effort involved is also quite significant. Will the customer pay for that? Probably not.

The Golf ecomatic already had a starter motor directly on the crankshaft? Hmm, to my knowledge, it had a normal pinion starter that simply automatically restarted the engine?!? Okay, I'm happy to be proven wrong.

Regardless, the engineering effort involved is certainly higher, and a crankshaft starter will undoubtedly add a few kilograms to the vehicle's weight. To generate a reasonable amount of torque, it must have a diameter that is at least as large as the flywheel. In addition, there is a second clutch that disconnects the stationary diesel engine from the drivetrain.

However, there is a similar development in the context of city buses, which goes even further: There are now high-performance ultracapacitors, which are electrical energy storage devices based on a capacitor, that - unlike batteries - can store and release large amounts of electrical energy extremely quickly. This has made it possible to save 20% fuel by storing braking energy, as the electric motor acts as a generator during braking. MAN offers buses like that.

Please refer to http://www.ultracapbus.de.

Well, for me personally, an electric stop-and-go mode would be sufficient (driving with the electric motor in first gear).

ideeAlist wrote:

Did the Golf ecomatic have a starter motor directly on the crankshaft? Hmm, to my knowledge, it had a normal pinion starter that simply automatically restarted the engine?!? Okay, I'm happy to be proven wrong.

No. The Ecomatik always switched off the engine when it was not needed and restarted it using a rotating flywheel. The starter motor was only used to start the engine with the ignition key.
The principle is the same as what you're imagining. Only you want to switch the trigger to the KW (keyword) to use it for a start-stop automatic system - and the manufacturers are working on that.

Sure, here's the translation:

"Supplement:"
"12V won't do the trick - 24V (for buses/trucks) is already possible, and the 42V system will likely take some time to become a reality for safety reasons."

Ah, that was a clever idea. But the rotating flywheel was definitely heavier than the normal flywheel.

The advantage of having the starter motor mounted on the crankshaft is that I can not only start the engine with low wear, but also use it as an electric motor in stop-and-go operation (pure electric mode).

Actually, something like that already exists. I've read about 'starter motors mounted on the crankshaft' in various places. But the manufacturers are not budging.

How much would I have to pay for something like that? Let me think about it. With a new price of 12,000 euros, it might be worth 500 euros, and depending on the performance and features of the system, perhaps even 1000.

Oh, and one more thing: Such an electric motor on the crankshaft could also be used for 'kick-down.' If a short burst of extreme power is required, it can provide an additional 1 kW from the battery. Limited to 20 seconds.

Hello Bertil,

Quote:

No. The Ecomatik would always switch off the engine whenever it was not needed and restart it using a rotating flywheel.

Are you absolutely sure about that? Where exactly should this part be located?

Best regards,
Albrecht.

Actually, something like that already exists. I've read about 'starter motors mounted on the crankshaft' in various places. But the manufacturers are not budging.


Please visit www.sachs.de.

CU Gremlin.

Well, that's exactly what I had in mind .

'Quote from Sachs'
Functions

Generating electrical energy + Starting the internal combustion engine + Automated start/stop operation + Boost mode + Regenerative braking + Idle stabilization + Active vibration damping + Battery management.


The only function that's still missing is the stop-and-go mode (slow driving using only the electric motor in first gear, with the diesel engine turned off).

The question is, why is it taking so long to gain acceptance?

Albrecht wrote:

Hello Bertil, Quote: No. The Ecomatik would always switch off the engine whenever it was not needed and restart it using a rotating flywheel. Are you absolutely sure about that? Where exactly should this part be located? Best regards, Albrecht

Hi Albrecht,

Unfortunately, I only know about the prototype based on the Golf 2. However, that one still had a manual clutch. The Ecomatic no longer has a clutch pedal at all (despite having a manual transmission).
The design was simple and straightforward (in my opinion, also inexpensive to implement). The motor had two flywheels, one of which had a freewheel clutch on the other. When disengaged, the motor would shut off after 5 seconds. The motor flywheel would then stop, while the freewheel flywheel would continue to rotate (allegedly for up to 5 minutes). When engaged, the freewheel was first bypassed, thereby starting the motor, and then the transmission was normally engaged. The transmission was a standard 5-speed gearbox. Only the flywheel-clutch assembly was slightly different. This system was a simple mechanical system. I'm no longer sure whether there was a planetary gearbox between the flywheels. I think I remember something like that.
The Ecomatic received a servo coupling, but supposedly no other major changes were made to its design.

Hi,
The thing about electric drives isn't really new; there was a study in 1996: the Audi Duo (A4, 90 hp TDI, 21 kW synchronous motor).
Electric blowers are currently being developed as turbochargers with auxiliary power. Of course, a 1kW vacuum cleaner blower won't achieve much when a turbocharger typically converts 18 kW.

Well, a true hybrid powertrain is quite expensive, not least because of the expensive specialized battery. See Honda Insight.

I would be satisfied with a semi-hybrid system: A slightly larger, but standard and cheaper lead-acid battery, a starter-generator connected directly to the crankshaft via a second clutch, with a power output of 1 kW. See www.sachs.de

With 1 kW, you can even manage to ride up a slight incline in first gear.

Great, thanks for the data so far! Bertil probably overestimated or underestimated a bit with his 30%. 2.6L/100km is equivalent to 2.6L/h (wow, what a calculation on my part ), which is about 6 times 0.4L, so the fuel consumption at 100km/h is 500% higher than the idling consumption.

Could you handle the rollout for us? Of course, you'd need to be in a flat, mountainous area – basically, a completely flat landscape. And ideally, long, straight, and easily navigable country roads. Dead calm, as always.

The best way to mark the 100 km/h and 50 km/h speed zones is to use a paintball gun while driving. Perhaps even just looking at the daily counter is enough, but those are not very accurate.[/b]

Hi,

I drove a Golf today that was provided by the company (ATD).
Idling fuel consumption: 1.5 liters per hour, which translates to 1.5 liters per 100 km when traveling at a constant speed of 100 km/h.
Fuel consumption at 100 km/h: 3.1 liters per 100 km.

Look at that, the data looks completely different compared to the Lupo!

Unfortunately, I couldn't test the rest of the features because I didn't drive far enough and couldn't find a long enough, flat stretch of road.
I find it amusing that the MFA (Multi-Function Display) seems to be showing incorrect information, because it indicates a fuel consumption of 4.xx L/100km for the Golf at a speed of 90 km/h.

Idle fuel consumption: 1.5 liters per hour

I wouldn't be able to do it, even with the air conditioning on and the gear engaged.

Without both, it settles at a flow rate of 0.7 liters per hour when the machine is warm.

'On these 50 kilometers of country road, I've even managed to achieve 4.8 liters per 100 kilometers. The last third was done drafting behind a truck, and the city section had green light signals. That brings it down to a real 5 liters. In the first third of the route, there's a hilly section, allowing for a brisk pace. At 85 km/h behind a truck, the fuel consumption drops to 2.5 - 3 liters. Without drafting, it's about 3.5 - 4 liters at 80 km/h. Around 4.5 liters at 100 km/h, all using cruise control, of course.'

'By the way, I wouldn't necessarily use a 3L Lupo for these rolling tests. It's optimized for rolling resistance and aerodynamics. It's sure to produce great results, but those results wouldn't be useful for the average person...'

IMHO, this discussion is pointless because, when I drive my automatic station wagon 'normally' (i.e., not trying to show off or speed near speed limit signs, etc.), the fuel consumption settles at 5.5 liters. When I compare that to a 3-liter car, the Polo is essentially just a token effort.
Currently, my total fuel consumption (all inclusive) is 6.3 liters per 100 kilometers. However, this figure doesn't take into account the use of the auxiliary heater, which significantly increases my average fuel consumption during the winter months due to its frequent use and the short distances I typically drive.

CU Gremlin.

I'm adding 0.4 liters per hour to this discussion about a hot awx machine. It's a bit cold, around 0.9 degrees.

@ Gremlin,
I don't think the comparison to the Lupo 3L is ridiculous.
but that would only show what is technically feasible and affordable.
and that the 3L wasn't actually a failed project.
Of course, it would still be useful to...
to draw a comparison to what you might call an 'average person.'
But so far, only discussions have taken place, and no action has been taken.
greetings

5.5 liters per 100 kilometers in normal driving conditions with a Skoda Octavia Combi, automatic transmission, 66 kW engine.

I'm going to throw that in front of the Lupo 3L.

MY OPINION: When compared directly, the Lupo is more of a token effort. Just compare the size and weight of these vehicles...

CU Gremlin.