Engine segmentation: principle and usefulness

As you probably already know, internal combustion engines (or rather combustion ...) are made up of pistons that move back and forth in cylinders due to the force of combustion that pushes them backward. A little reminder with the diagram below:

What would be without segments?

You may notice that there is a small problem here ... Indeed, the chamber is not airtight as there is a gap between the piston and the cylinder! As a result, we lose power, or rather, when we squeeze, as if we were making a notch in a firecracker, the latter explodes much less strongly ... Therefore, something is needed that clogs this gap in order to use as much of the burning force as possible, so we invented the segments ... They are wrapped around the piston and act as a sealed wall. By grasping the piston by hand, you can press the segments down, demonstrating their flexibility and ability to adapt to the piston width (they move slightly like springs until they hit the wall).

Here is a part of the engine on display at the international exhibition. We notice, as in the top diagram, that there is no segmentation here. It seems that the directors of this exhibition failed to keep them on this cutting plane (the fact that the piston was cut must have complicated matters).

And with?

Now that you understand what the role of segments is, it's really easy to grasp when you see two diagrams. The cylinders can now be pressurized to improve engine efficiency. Also note that damaged valves (green and red "things" in the diagram that open and close) also cause leakage and therefore loss of compression ... The engine must be completely sealed.

They are present in the Ford Ecoboost engine, even if you have to pay attention to them.

To summarize, we can say that the role of segments is as follows:

• Do not allow exhaust gases to enter the crankcase (under the piston)
• Also, do not let the oil go up.
• Spread the oil evenly over the cylinder wall.
• Aim the piston stroke so that it runs straight (especially it should not tilt slightly during lifting ...)
• provides heat transfer between the piston and the cylinder (due to the contact that they establish between the cylinder wall and the piston contour).

Multiple segment types for multiple roles?

There are three types of segments:

• First, all the way up, there to protect the other two below : the goal is to keep the engine running for a long time!
• The second is by far the most important because it makes sure that the top of the cylinder is tight against the bottom... Hence, he must be able to undergo significant reductions.
• The one at the bottom is used to "sweep" the oil to knock it down, this is the scraper segment. Therefore, its purpose is not to leave oil on the walls, which could cause it to ignite when the piston is at the bottom. It often looks like wavy segments.

What are the symptoms of damaged segments?

Damaged rings result in loss of engine power (due to loss of compression), but also usually result in oil consumption. Indeed, the latter should generally remain behind the latter (at the bottom) in order to lubricate the segments that rub against the cylinder (to avoid very rapid engine wear) and never enter the combustion chamber. In this case, the oil rises and burns, causing the level to drop (logically...). A sign of burning oil is the famous blue smoke.

The worry is that the segmentation occurs in the middle of the engine ... As a result, repairs are so expensive that sometimes (for economic reasons) you have to abandon the engine and replace it.

Check the segments yourself

Thanks to François of Garage Bagnoles and Rock'n Roll, see how to test segmentation yourself. Still, let's say that we need to be sufficiently motivated, because we need to at least remove the stack ... A simpler test is to check the compression of each cylinder.

Engine Segmentation Testing 💥 Hyundai Accent 2002

Your feedback

Here are some reviews from reviews (on cards) posted by Internet users. The system highlights the parts in which you mentioned a segment of the word.

Volkswagen Tiguan (2007-2015)

1.4 TSI 150 ch bv6 milesime 2011 100 кмил км jantes 18 : Replaced 2 camshaft sensors .. More serious oil consumption (1 l / 5 mil km) from 60 mil km. With multiple clogging of the intake flap (changed 3 times for 20 thousand km), the WV did not eliminate, requiring the installation of an oil vapor sump from the crankcase. segmentation Petrol engines 1.4 tsi from 2008 to 2012

Peugeot 208 (2012-2019)

1.2 Puretech 82 ch Active Finish, BVM5, 120000 км, : Fragile gearbox (2nd synchronizer gets tired at 100 km / s despite gearbox oil change and cold power). Lack of engine and clutch approval (jerks, dips at medium speed, jumps at the slip point of a hot engine in urban conditions) And, above all, more than excessive oil consumption (000 liter for every 1 km from 800 km, occurred for no apparent reason) ... That is segmentation the engine starts to get tired, or the oil check valve is faulty, or both. The issue is known and acknowledged by Peugeot, but not supported.

BMW Series 7 (2009-2015)

750i 407 HP 6 m. 2009-speed automatic transmission, alloy wheels with exclusive custom trim. : segmentations pistons .. valve stem gaskets .. broken rail guide .. flow meter x2 HS. additional water pump heating HS…. breather + hoses x 2 HS .. nozzles x 8 piezoelectric HS .. front shock absorbers x2 HS… Ect… ect… Well, in case of resale, the new owner could stay calm for at least 140 km, usually… total maintenance invoice 000 23850 euros, including 19000 km.

Renault Kangoo (1997-2007)

1.5 dCi 85 hp 5,210000 km 2004 Sheet Metal Original 60 Amp : Problem 1 passenger airbag warning light Problem 2 Cylinder head gasket 200 km Problem 000 segmentation and a piston showing a serious damage problem found at 220 km

Ford Focus 2 (2004-2010)

1.8 Flexifuel 125 HP Gearbox 5, 185 km, titanium trim, 000 Flexifuel : Abnormal oil consumption, no leaks outside the engine, oil just eats up, suspicion of a valve stem seal or segment tired. Otherwise races

Citroen C3 III (2016)

1.2 PureTech 82 channels : The engine is tightened to 53000 km! 2 Possible Causes 1- Wet timing belt, dating to the wrong period and not recalled by PSA for correction, is falling apart, especially after a period of non-use such as restraint. It clogs the strainer, oil pump, and eventually squeezes the engine. When the oil warning light comes on, the PSA is instructed to replace this belt directly. 2- ECU configuration error causing too high idle pressure and oil leak at second level. segment in carburation. PSA has not recalled machines to reprogram computers. If the reprogramming is done too late, segment damaged and the engine consumes too much oil. The absence of a level or an increase in the malfunction leads to cranking of the engine due to lack of oil.

Peugeot 308 (2013-2021)

1.2 Puretech 130 channels : P0011, camshaft phase shifter. The timing belt has worn out by 170 km. Repairs to a known brand defect € 000, 3000% coverage. excessive oil consumption, 50 liters for 1.5 km. Verdict segmentation hs. No support from Peugeot - at best they are thieves, at worst they are scammers.

Audi A5 (2007-2016)

2.0 TFSI 180 hp Manual transmission, 120000 km : Abnormal oil consumption (found after buying a used one for 20000 km). After checking the consumption for Audi Toulouse, they offered to replace the pistons, segment and connecting rods. After tough negotiations with Audi France, the bill was paid by Audi 90% (400 euros from my pocket). Since then, the car does not consume oil at all. The electronic oil level sensor sometimes works by itself (from 90000 km), sometimes it reports a low level when the level is normal. (I bought a pressure gauge to check)

Peugeot 308 (2013-2021)

1.2 Puretech 130 2014 : Replacing the engine by 70 km segmentation the engine was backed by 75% of the cost of my pocket with a clutch and flywheel 2500 XNUMX. On my part, this engine is unreliable.

Audi A4 (2008-2015)

1.8 TFSI 120 ch 91000km 1.8T 120 ambition luxe 2009 : Oil consumption, wear segmentation

BMW Series 3 (2012-2018)

318d 143 h automatic transmission, 150000 km run at the time of the chain break, 2015. : So, in August 2018, the car was a little over 3 years old and had a mileage of 150300 118000 km, and the timing chain failed on the highway without warning. The only thing I had before was the oil warning light that came on at 136000 50 km and 1 1000 km. I was aware of the changes. A big fight with bmw for support, they got me things from space so as not to pay in the end only 1% support and a lot of lies, because from the moment of repair the car consumes not far from 1000 liters of oil per XNUMX kilometers ... But there is no concern for bmw before as long as we do not exceed XNUMX liter / XNUMX km ... And when I asked a real impartial mechanic, he told me that everything is of course a machine, no leaks, and the only remaining explanation is that segmentation worn out on the pistons, which explains the excessive oil consumption, as well as the particulate filter, which is highly charged and which I have to clean when the car goes to safety ... Here is bmw dishonesty and greed in all its glory, because he knew since the breakdown and repair - all this, but they also knew that this would lead them to malfunction, because it is the lack of oil that explains, in their opinion, the chain that breaks 😡

Vauxhall Zafira Tourer (2011-2019)

1.4 manual transmission 120 hp, 103 km, October 000 : Engine failure at 103 km, segment HS piston, HS cylinder that is regularly serviced, there is no warning on the dashboard.

Renault Megane 3 (2008-2015)

1.2 TCE 115 hp Manual 110000km 2012 : Break segment... Oil consumption worthy of the old days.

Toyota Avensis (2008-2018)

2.0 D4D 126 chassis : Head gasket that leaks or wears out every 100 km Hello; I bought my car Toyota avensis 000l d2d 4 hp in May 126. December 2014, after 2016 km of run, the cylinder head gasket exploded, it was necessary to change the resort to replace the entire engine segment, pistons,… including the cylinder head. At 220 km, or about 000 km using this new engine, rebelot, the engine heats up, I come into contact with oil mixed with the water circuit. Find Toyota still leaking cylinder head gasket !!. I'm waiting for a quote that should be salty ... because the whole engine needs to be redone !!. The gentleman from Toyota told me that we can go even further and have the engine block and cylinder head repaired !! All this is just to say that this type of engine is fragile and has a manufacturing defect. home of Toyota and has been located since 100. I urge if people like me faced similar problems in Algeria or elsewhere should come forward and join forces to protect Toyota should take responsibility for this manufacturing defect and therefore broken cars should be repaired or recovered by the parent company ... This is serious, the buyer pays, it was very expensive to pay for these cars, choosing and trusting a scale manufacturer and international renown such as Toyota to provide us with such cars with an engine that fires every 000 km of use.

Citroen C3 II (2009-2016)

1.0 VTi 68 channels : The engine must be replaced. segment hs motors at 6 years old

Renault Captur (2013-2019)

1.2 TCE 120 hp : segmentation HS. Engine malfunction at 60000 km. Hidden fault from Renault.

Alfa Romeo Juliet (2010)

1.8 TBI 240 HP TCT 40000 km 3 YEARS 7 MONTHS : segment BREAK REPLACE HS ENGINE (D AFTER ALFA DOESN'T LUCK, IT'S ARRIVED) MINIMUM PARTICIPATION BUTTON WHICH RELEASES SEAT, SEMI-SHAPED BALLET FLOOR MAT, UNSTABLE AFTER 3 MONTHS

Renault Captur (2013-2019)

1.2 TCE 120 HP EDC, 41375 km, 1st registration 11/2013, intensive finish with all options : Engine malfunction without warning after 5 years and 2 months. No warning sign, drive to airport parking lot. Two weeks later, 10 meters from the engine, operating on 2 supports, and shutdown, the engine failed, segmentation Pancake on 3 cylinders out of 4! Proposed a standard replacement, and after a little teardown with Renault 80% PEC, and 2 months ago, a lawsuit about a hidden defect. In this case, 100% PEC would be required, not to mention the overflow that I had for 2/3 years of the order of 0.2, 0.3 liters at 100A.

Nissan Juke (2010-2019)

1.2 hand excavator October 2016 21878 XNUMX km : segment on cylinder no. 4 HS, so the engine needs to be changed. Auto plus revealed a problem with a gasoline engine 1.2 DIG-T

Renault Megane 3 (2008-2015)

1.2 TCE 130 ch EDC - Bose - 2015 - 80 km A: Engine replaced at 37 km, very high oil consumption, low distribution noise. 000% supported by Renault and 90% by the dealer where I just bought it 10 months ago. The battery is discharged after driving 1 km on the motorway. It is necessary to check the electronic control of the generator. Air conditioning noise from gas circulation and condenser freezing after several hours of continuous operation. No solution... After replacing the engine, the front parking sensors often work for no reason. Solved after checking the beam. It must have been incorrectly assembled when the engine was replaced. Cracks on the left edge of the driver's seat are a common problem with this faux leather upholstery...

All comments and reactions

Dernier comment posted:

Eric (Date: 2021, 04:30:22)

Bsr to all? After the repair of our tdi amarok everything is nickel ... But from today the smoke in the gauge is good ... Jsui was confused. The engine has been rebuilt by professionals to its original dimensions. Are the segments inverted between the fire segment and the second segment? Segments misaligned? TO?? hand ... No suspicious noise, RAS ... Thank you

Il I. 3 reaction (s) to this comment:

• Taurus BEST PARTICIPANT (2021-05-01 09:53:45): Typically, the segments are not identical in shape and thickness. Drive by hand of course. Are the valves replaced or broken? it is possible to forget about the valve stem seals.
• Administrator SITE ADMINISTRATOR (2021-05-01 17:57:37): How little smoke in the sensor can be a problem? If the oil level is normal, then everything is in order.

  And in the worst case, this would mean misfiring leading to the sending of fuel to the crankcase (or DPF control: forced regeneration, which causes an additional injection).

  Thanks again to Taurus for sharing his knowledge ... Because he knows everything, boy!

• Eric (2021-06-03 12:36:39): hello everyone. Now we have engine oil consumption ...

  I will speak immediately with the professional who worked in the operating room ...

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