Whether it is NA, Force Induction, there are reasons for putting different types of engines in different cars. Performance or ride comfort and applications are biggest reason I guess.
Generally, you want to pick a car depend on driving habit (majority on city or highway, stop & go, etc) and needs.
Especially with the high gas price these days, there's absolutely no reason to buy a SUV when you are driving alone or carry only 1 pessenger most of the time.
To combat high gas price and keep the maintanance low, I have an Odyssey, Mazda3 and Versa in our family (we need some stuff to write off for my parents' business); for city driving, going to work, I use the Versa because it is light and very flexible, thus saving a lot of gas even in stop and go traffic. Mazda3 is my toy, that doesn't count. I only use the Odyssey when I have visitors and need to haul a lot of stuff. Out of the 3 cars, the Odyssey uses the most gas 15L/100KM. However, once on the highway, the Odyssey save a lot more gas caz the engine is powerful enough that it only requires little work to keep it at 100kph (higher RPM = more gas used). It deactivate 3 cylinders automatically at crusing speed and that keeps the consumption low. On the other hand, I have to push the pedel harder on the Versa to keep it up to 100kph. 3 different cars for various purposes. In no way I will drive my Odyssey in busy streets during peak hour.
Maybe my answer is irrevelent to the topic, I think cylinders are not so important when buying a car today.
It deactivate 3 cylinders automatically at crusing speed and that keeps the consumption low.
When its running 1500 cc probably is adequate.
I guess Honda is successful to do that, I heard Merc in Europe does that on V8 they run on 4 when cruisng on hwy. Yrs ago GM had 4-6-8 V8 they failed miserably. So as anythng they touched.
If Honda can overcome the parasitic loss from the non running cylinders then s a good thing. Probably de-activates the intake and exhaust valve.
Old diesel boat engine was like that too, there's lever to turn off valves, when you crank the engne to start it has no compresson, so the fly wheel able to spn at a much hgher speed, then you flip the lever and the flywheel has enough energy stored to compress the engine to start.
A turbo engine saves most fuel s when u not usng the turbo, means just cruising along and not stepping on the gas hard.
In 2004, Honda introduced an i-VTEC V6 (an update of the J-series), but in this case, i-VTEC had nothing to do with cam phasing. Instead, i-VTEC referred to Honda's cylinder deactivation technology which closes the valves on one bank of (3) cylinders during light load and low speed (below 80 mph) operation. The technology was originally introduced to the US on the Honda Odyssey minivan, and can now be found on the Honda Accord Hybrid and the 2006 Honda Pilot.
It was proven during the 60s' when Ford won the Le Mans , " Nothing beats the inches"
Now with high fuel price, unless you're the nephew of Sultan of Brunei, we all want something easy on fuel.
FI just don't give the same throttle response as NA.
closes the valves on one bank of (3) cylinders during light load and low speed
They may use solenoid opens the intake valves, dsabled the injectors. So there is no load in those cylinders. Closed the exhaust valves.
Maybe the GM failed because those engines were using carb, and cannot stop the gas going into those cylnders, mind as well be running it.
This is a complex question with no simple answer. But in my humble opinion, the biggest difference is in "smoothness". The more cylinders you have, generally the smoother will be your torque curve, meaning that you get more or less the same torque regardless of rpm.
For a typical 4 cylinder engine, torque is weak at low rpm. A 5 cylinder engine is significantly smoother than 4. A 6 cylinder shows additional improvement, but not as much an increase as you go from 4 to 5.
There are several configurations for 6 cyclinder, for example, inline or "straight". A straight 6 is a very long engine, and it can no longer be placed in the traverse orientation in the engine compartment. You will find such cars with a relatively long engine compartment, with the front wheels very close to the front bumper, and with some room between the front wheels and the firewall (e.g. Lexus IS250, BMW, Mercedes). This configuration is not good for front wheel drive - you will find almost all straight 6 to be rear wheel drive cars (or all wheel drive).
Volvo is one of the mainstream manufacturers with 5 cyclinder engines. The engine is now just short enough to be placed in the traverse orientation and therefore you find Volvos to be front-wheel drive cars (or all wheel drive). Having an odd number of cylinders, the engine is not naturally balanced and requires certain designs in the crankshaft, flywheel, engine mounts, etc. to compensate.
There are a lot of other configurations, such as H4, V6, H6, etc. Technology has been improving and if you drive for example a 4 cyclinder late model Camry you may notice that while it still drives like a 4-cylinder its smoothness has improved significantly.
V6, being shorter than straight 6, can be placed in the traverse orientation and suitable for front wheel drive. V6 is a lot more popular than straight 6 because front wheel drive is more popular than rear wheel drive.
Horsepower = torque x rpm. It is very common to find high horsepower 4-cylinder cars which revs up to 8,000rpm. Such cars are usually not smooth to drive. Depending on your style you may prefer a car with more cylinders than 4.
發表於 2008-6-1 12:33
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I only use the Odyssey when I have visitors and need to haul a lot of stuff. Out of the 3 cars, the Odyssey uses the most gas 15L/100KM. However, once on the highway, the Odyssey save a lot more gas caz the engine is powerful enough that it only requires little work to keep it at 100kph (higher RPM = more gas used). It deactivate 3 cylinders automatically at crusing speed and that keeps the consumption low. On the other hand, I have to push the pedel harder on the Versa to keep it up to 100kph. 3 different cars for various purposes. In no way I will drive my Odyssey in busy streets during peak hour.
