sohc vs dohc

5638hao

回复 19# WaRKinG


    个人认为···dohc在city驾驶····他的最佳扭力值···根本没有发挥出来···
没有理由在city驾波波都4000转以上吧～～

seizai

rotary 属于哪个？

雷Leong

我的车是1.1cc的sohc的，在红青灯开始跑是占上风，但是3度牙后就哈哈，吊车未了。sohc回省油咩？

rickyee

我有个朋友是做4man的···他说不要以为4g91doch就是很有力的···差 还是4g15有力···  ...
5638hao 发表于 2-3-2010 01:11 PM

4g91+222 manual gearbox+8寸半clutch set+ ecu6123和wirering？？？如何？？？

keenyuen

虽然现在我的4g18有点问题，idle不稳定，应该是TPS坏或该调整了，还是喜欢4g18 sohc.

WaRKinG

回复  WaRKinG


    个人认为···dohc在city驾驶····他的最佳扭力值···根本没有发挥出来·· ...
5638hao 发表于 2-3-2010 09:00 PM

我的vtec需要6000rpm以上才有感觉到最佳的扭力，也没有说rpm高就尾力的说法，通常性能引擎都可以一踏油直接升值到4000转以上，所以dohc的pick up也可以做到如sohc更好的效果。sohc通常是比较容易修理，零件简单，引擎轻量，省油等，大多数本田和benz注重发展的原因。（注：BMW虽然说引擎科技好，但省油量还是不如benz控制得好）

keenyuen

还有OHV没有说到，虽然没有很多车是OHV，也可以分享下。。。。
OHV engine design

4-cylinder 8 valves OHV engine OHV means OverHead Valve - an engine design where the camshaft is installed inside the engine block and valves are operated through lifters, pushrods and rocker arms (an OHV engine also known as "Pushrod" engine). Although an OHV design is a bit outdated, it has been successfully used for decades. An OHV engine is very simple, has more compact size and proven to be durable. Downside: it's difficult to precisely control the valve timing at high rpm due to higher inertia caused by larger amount of valve train components (lifter-pushrod-rocker arm). Also it's very difficult to install more than 2 valves per cylinder or implement some latest technologies such as Variable Valve Timing - something that could be easily done in a DOHC engine.

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OHC or SOHC engine

4-cylinder 8 valves SOHC engine OHC in general means OverHead Cam while SOHC means Single OverHead Cam. In the SOHC engine the camshaft is installed in the cylinder head and valves are operated either by the rocker arms or directly through the lifters (as in the picture). The advantage is that valves are operated almost directly by the camshaft - easy to achieve the perfect timing at high rpm. Also it's possible to install three or four valves per cylinder The disadvantage - an OHC engine requires a timing belt or chain with related components - more complex and more expensive design.

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DOHC or Twin cam engine

4-cylinder 16 valves DOHC engine DOHC or Double OverHead Cam - the setup used in many today's cars. Since it's possible to install multiple valves per cylinder and place intake valves on the opposite side from exhaust vales, DOHC engine can "breath" better meaning that it can produce more horsepowers with smaller engine volume. Compare: The 3.5-liter V6 DOHC engine of 2003 Nissan Pathfinder has 240 hp, similar to 245 hp of the 5.9-liter V8 OHV engine of 2003 Dodge Durango. Pros: High efficiency, possible to install multiple valves per cylinder and adopt variable timing. Cons: More complex and more expensive

love_sephine

回复 27# keenyuen


   這個解釋圖 真得很清楚也

5638hao

回复 27# keenyuen


    感谢大大的分享···

Tougewaja

rotary 属于哪个？
seizai 发表于 2-3-2010 21:25

Rotary 是 NSNDOHC 组的....

Tougewaja

虽然现在我的4g18有点问题，idle不稳定，应该是TPS坏或该调整了，还是喜欢4g18 sohc.
keenyuen 发表于 2-3-2010 22:13

因为那 2750 RPM 的关系..............低转有力， 高转出大力..不错的一课引擎..最重要 Gear Ratio 也陪的很对...配到 City 能， High Way 也能....

AhH00ng

Rotary 是 NSNDOHC 组的....
Tougewaja 发表于 3-3-2010 01:41 AM

NSN是....?

零123

回复 27# keenyuen
OHV可以说是很旧的引擎设计了。。
目前比较常见到的是在美国的muscle car。。。
GM的新款车辆有些还是用到它。。。
nissan c22 van也是用ＯＨＶengin。。。

cent

高速SOHC会比DOHC耗油吗？

夜雨ㄨ楓葉

不懂，4A-GE Black top 20 valve 是怎样的列。托海的86用着的

Tougewaja

NSN是....?
AhH00ng 发表于 3-3-2010 02:22

我搞乱水的.....
是 NO SINGLE N DOUBLE OVER HEAD CAM...........

WaRKinG

高速SOHC会比DOHC耗油吗？
cent 发表于 3-3-2010 11:03 AM

未必的。。。

terminatorzenon

理智来看。。1.5l 的车。。榨干了也没多少马力。。“一些车除外”。。所以应该以省油为主。。
所以我选soh ...
SXN 发表于 2-3-2010 01:44 PM

抱歉，是1300cc当300马力的跑车来驾.....

5638hao

因为那 2750 RPM 的关系..............低转有力， 高转出大力..不错的一课引擎..最重要 Gear Ratio 也陪 ...
Tougewaja 发表于 3-3-2010 01:43 AM

    过了2750rpm扭力走下坡了····
最重要引擎要耐用！

keenyuen

不懂，4A-GE Black top 20 valve 是怎样的列。托海的86用着的
夜雨ㄨ楓葉 发表于 3-3-2010 11:24 AM

   


Here's a scan of the 4A-GE powerband from a 1988 Toyota Corolla brochure.
Note: The following was taken directly from a Toyota Service Manual.

Here are some cutaways of the 4A-GE as illustrated in the Service Manual.

The 4A-GE engine is an inline 4-cylinder engine with the cylinders numbered 1-2-3-4 from the front. The crankshaft is supported by 5 bearings specified by the inside of the crankcase. These bearings are made of aluminum alloy.
The crankshaft is integrated with 8 weights which are cast along with it for balancing. Oil holes are built into the center of the chrankshaft for supplying oil to the connecting rods, pistons, and other components.
The engine's ignition order is 1-3-4-2. The cylinder head is made of aluminum alloy with a cross flow-type intake and exhaust layout and with pent roof-type combustion chambers. The spark plugs are located in the center of the combustion chambers.
The intake manifold has 8 independent long ports and utilizes the inertial supercharging effect to improve engine torque at low and medium speeds. Exhaust and intake valves are equipped with irregular pitch springs made of oil-tempered silicon chrome steel wire which are capable of following the valves even at high engine speeds.
Both the exhaust and intake cam shafts are driven by a single timing belt. The cam journal is supported at 5 places between the valve lifters of each cylinder and on the cylinder head of the front end. Lubrication of the cam journal and cam is accomplishe by oil being supplied through the oiler port in the center of the camshaft.
Adjustment of the valve clearance is done by means of an outer shim-type system in which valve adjusting shims are located above the valve lifters. This permits replacement of the shims without removal of the camshafts.
The resin timing belt cover is composed of 3 pieces. A service hole is provided in the #2 timing belt cover for adjusting the timing belt tension.
Pistons are made of hihgly temperature-resistant aluminum alloy and a depression is built into the piston head to prevent interference with valves.
Piston pins are of the full floating-type with the pins fastened to neither the piston boss nor the connecting rod. Instead, snap rings are fitted on both ends of the pins preventing the pins from falling out.
The #1 compression ring is made of steel. The #2 compression ring is made of cast iron. The oil ring is made of a combination of steel and stainless steel. The outer diameter of each piston ring is slightly larger than the diameter of the piston and the flexibility of the rings allows them to hug the cylinder walls when they are mounted on the piston. Compression rings #1 and #2 work to prevent the leakage of gas from the cylinder and the oil ring works to scrape oil off the cylinder walls to prevent it from entering the combustion chamber.
The cylinder block is made of cast iron. It has 4 cylinders which are approximately 2 times the length of the piston stroke. The top of the cylinders is closed off by the cylinder head and the lower end of the cylinders becomes the crankcase in which the crankshaft is installed. In addition, the cylinder block contains a water jacket through which coolant is pumped to cool the cylinders.
The oil pan is bolted onto the bottom of the cylinder block. The oil pan is an oil reservoir made of pressed steel sheet. A dividing plate is included inside the oil to keep sufficient oil in the bottom of the pan even when the vehicle is tilted. This dividing plate also prevents the oil from making waves when the vehicle is stopped suddenly and thus shifts the oil away from the oil pump suction pipe.


This is just a table that I threw together. I "tested" each engine in my Corolla GT-S and here's what came out:

	Hp	Torque (lb-ft)	0-60 (s)	1/4-mile	Top Speed (mph/kph)
My AE92 GT-S	120@6600	108@4800	8.0	16.4@86.5	128/206
20-valve 4A-GE	170@6600	128@4800	6.4	15.1@93.3	142/229
Formula Atlantic	240@8500	136@7600	7.2	15.2@102.2	157/253
Japan-spec 4A-GZE	170@6400	152@4400	6.7	17.9@94.9	137/221
Modded 4A-GZE	200@6400	185@4400	6.1	14.2@100.6	137/221