Technical analysis Toyota S20A engine, the new Highlander 2.0T has to increase the price?

Luca car 2022-05-19 03:51:57 阅读数:247

technicalanalysistoyotas20aengine

( Toyota 8AR-FTS 2.0T The engine )

Early domestic consumers' technical understanding of the engine , General inertia believes that turbocharging technology is better than naturally aspirated Technology . In addition, Japanese brands were more self-priming in the domestic market at that time , So for quite some time , This has become one of the product points that Japanese cars have been roast . Regardless of the path of engine technology , Just the field of turbocharging , The most powerful response of Japanese brands is Toyota, code named 8AR-FTS Of 2.0T The engine . In addition to the output and technology of the engine , And matching AT Together with the transmission , Including hannanda and crown 、 lexus NX Wait for medium and high-end models , Have left an excellent reputation .

at present , In the new Highlander series on sale , It's still there 8AR-FTS Of 2.0T Model sales . It's just , With TNGA The full spread of the architecture , In the past AR Series engines have bid farewell to our vision . The same is true for hannanda , A brand new code named S20A Of 2.0T The engine , About to be carried on it . From the vehicle tail mark on the declaration drawing , conversant D-4ST The logo appears again , So this engine is really just 8AR-FTS Magic change ?

Digital games , Who is the new engine more like ?

First ,D-4ST It's just a four stroke turbocharged engine with dual injection technology of in cylinder direct injection and manifold injection . If the turbocharging structure is not considered , This technology path has been widely used in Toyota TNGA Models under the framework , So this tail mark is not of much value .

indicating contrast S20A The code is more worth pondering , Refer to Toyota's naming rules ,“A” I'm afraid it means that this engine will still be imported ,“20” Of course, it refers to the displacement . however “S” Sequence , There are not many objects to refer to . If it extends to the current power trend of Toyota , Almost at the same time as , It will be equipped with overseas models such as Highlander T24A-FTS Connect the engine , It seems that everything suddenly opens up .

( Overseas Toyota T24A 2.4T The engine )

Whether from TNGA Architectural considerations , Or start with the law of engine technology iteration , Individuals are more inclined to put this S20A The engine , And overseas version T24A Connect . Although there is a big difference in displacement between the two (T24A by 2.4T The engine ), But in fact, it is very familiar with A25 Series engine ( Equipped on Camry and other models 2.5L Naturally aspirated engine ) It's quite original . Several code strings , Seems to be confused , Then let's disassemble and estimate in detail S20A Technical characteristics of .

Strengthen low torsion , Say goodbye ?

First , Whether it's an overseas version T24A, Or it has been used in China A25 series , Even M20 series , Toyota engines of this generation are characterized by long stroke . The corresponding is the old one 8AR-FTS, Its cylinder diameter and stroke are 86mm, It can be said that it tastes very old-fashioned , So in those years, it also swept away the argument that Toyota had no high output engine .220Ps Maximum horsepower , Even in the present , Can also be between BMW B48 Engine high power and standard power adjustment .

( Toyota A25 series 2.5L Naturally aspirated engine )

and 350N・m Maximum torque of , It is also the level of the first echelon . It's just the difference between the new engine , Right here .8AR-FTS Although the torque is great , But the speed at which the maximum torque is emitted is 1800-4000rpm. And the new long stroke design , It can strengthen the torque output at low speed . For example T24A The engine, for example ,430N・m Maximum torque of , It just needs 1700rpm Can achieve . The corresponding is , After the displacement increases ,T24A The cylinder bore is only expanded to 87.5mm, The stroke is as long as 99.5mm. And what we're familiar with A25 series , It's also 87.5mm Bore diameter , The stroke is more exaggerated 103.4mm.

Of course , It's not that the new power attaches importance to low torque , You give up the performance features . actually , In terms of power rise ,T24A Still slightly better than 8AR-FTS Of . After all, in terms of efficiency , There are already between the two generations of engines “ Generation difference ” There is .

coating 、 The crankshaft 、 Oil pump , The probability will follow up

As mentioned before , It has been used in China A25 Series and overseas edition T24A There are many very similar places . Sum up , In the application of new technology , The two engines are working together 、 Crankshaft and oil pump have many commonalities . First , Both engines have a double overhead camshaft structure , With Toyota's skilled dual variable valve timing system . Cylinder body , Coating technology is widely used . With T24A For example , On the piston, the compression ring and the edge of the oil ring adopt DLC Diamond like carbon coating and so on , This can reduce friction , Increase efficiency , And extend engine life .

( The overseas edition of 2.4T lexus NX Chassis diagram )

The second point is that the crankshaft , The longitudinal axis of the crankshaft and the cylinder axis of both engines have 10mm The migration , This reduces the wear of the piston on the cylinder wall . This technical feature is similar to the previous introduction of Subaru 1.8T The engine feels a little similar . Finally, the application of a new variable pressure oil pump , stay 8AR-FTS On the engine , Toyota has used variable oil pumps , The two engines of the new generation adopt ECM Electronically controlled variable pressure oil pump , It can provide lubrication more accurately , And the relationship between trade-off and power output . It is worth mentioning that , Maybe it's in 8AR-FTS At this stage, it has a good oil-gas separation design , TOYOTA in T24A There is no BMW in the B48 The improved version is integrated into a timing chain . But still keep the traditional 2 A chain , And two tensioner designs , This is also in line with Toyota's technical characteristics of seeking stability .

All in all , The above is a new idea compared with peers in the technical path of the new generation Toyota engine , Whatever is coming S20A In what form , There should be no lack of them . But the next point is more difficult to judge .

Central direct injection , You have to add... Whether you use it or not 95 Oil no

TOYOTA in T24A For the first time, the engine adopts the central direct injection design , And in the A25 In the series , The direct injection part of double injection still adopts the side position . Just take the civil category as an example , Central direct injection technology is before the emergence of high-pressure direct injection at this stage , A solution to the effect of fuel atomization “ Strange trick ”. Because in theory , Central direct injection can reduce the possibility of gasoline injection into the cylinder wall . At the same time, the piston ring is tested “ machining ”, It is easy to create a more efficient rolling flow of combustion gas . However, side direct injection is the absolute mainstream , Its advantage is that the working temperature of the fuel injection nozzle is lower , It is not easy to produce gasoline coking and so on , Theoretically, it can adapt to lower oil .

( Overseas Lexus NX)

Back to Toyota , For the coming S20A, Will it continue the side or adopt the new central direct injection design , At present, I dare not draw a conclusion . But it's worth mentioning , Toyota in addition to performance cars , Its effect on “ Ultra high pressure ” Direct spray ( for example 350bar High pressure direct injection ) The use of has been very cautious . Even in the T24A On the engine , The direct injection pressure under the maximum working condition is only 300bar level .

Of course , In whatever form ,S20A The engine is still expected to eat 95 Fuel oil No . After all, the old model 8AR-FTS All need to be filled 95 Fuel oil No , And it had... At that time 10 A compression ratio . If you refer to the new T24A The engine , Its compression ratio has been increased to 11 individual . Even with a mixed jet , And not exaggerated , And adjustable injection pressure , New Highlander with coarse grain , Or other Toyota and Lexus models equipped with this power in the domestic market in the future , Eating coarse grain is probably extravagant .

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