如何选择手动档汽车和自动档汽车

How to Choose Between a Car With Automatic or Manual Transmission

Buying a car but can't decide on whether to get a Manual or Automatic? Get the differences explained here!

[edit] Steps

1. Here's some basics. Just like that of a manual transmission, the automatic transmission’s primary job is to allow the engine to operate in its narrow range of speeds while providing a wide range of output speeds.
2. Without a transmission, cars would be limited to one gear ratio, and that ratio would have to be selected to allow the car to travel at the desired top speed. If you wanted a top speed of 80 mph (130 km/h elsewhere), then the gear ratio would be similar to fourth gear in most manual transmission cars.
3. You’ve probably never tried driving a manual transmission car using only fourth gear. If you did, you would quickly find out that you had almost no acceleration when starting out, and at high speeds, the engine would be screaming along near redline. A car like this would wear out very quickly and would not be drivable.
4. When choosing between manual and automatic, one of the considerations is power.
   • If you want the most power from your engine, going with a manual transmission versus an automatic is most likely going to be your best bet.
   • While some modern automatic transmissions, i.e. CVT transmissions, manumatics, and conventional 4 or 5-speed automatic transmissions allow for some excellent acceleration, there is still usually a substantial difference in 0-60 times between these types of automatics and a 5 or 6-speed manual transmission.
   • • For example, an automatic equipped Dodge Neon has a reported 0-60 MPH time of approximately 10.5 seconds.
     • The same Neon when equipped with a 5-speed manual has a reported 0-60 time of 8.1 seconds; a huge difference.
   • While most cars do not have this large of a 0-60 MPH gap between auto and manual transmissions, 99 percent of the time you will receive noticeably better performance from a manual gearbox.
5. The acceleration offered from a vehicle when equipped with a manual transmission is usually superior for a number of reasons; most predominantly due to gear ratios and the availability for more precise shifting. To explain, if you own a car that receives 200 horsepower @ 7,000 RPM, but your automatic transmission will up-shift under full throttle at only 6,000 RPM, you probably will never feel the full amount of power that your engine was made to offer. So, your engine may be stamped with a 200 horsepower rating, but because your car is equipped with an automatic that up-shifts too soon, you may be missing up to 20% of available power. On the other side, with most manual transmissions, you can usually take the engine revs to redline (or past). This enables you to get the most power possible to the front, rear, or all 4 wheels under full throttle take-offs.
6. So, is fuel economy a huge issue?
   • If you answered yes, then going with a manual transmission is probably going to be your best bet, although it is far from your only choice.
   • Many newer cars with automatics have an EPA rating of only 1 or 2 MPG less than the same model car equipped with the manual.
     • With everything in life, there are exceptions to this rule. Some vehicles get better mileage (5 mpg or more) as an automatic compared to the manual, most notably in Toyota's like RAV4, and the FJ Cruiser.
   • If this is the case, most people are not going to save a significant amount of money on fuel costs going with the 5-speed manual (especially if you do a lot of city driving).
   • Since the majority of drivers do not manually shift for economy (or know how to), the 1 or 2 MPG that is lost with the automatic can easily be gained.
7. Maintenance/Repair costs:
   • Even though the automotive world has come extremely far with refining automatic transmissions, most automatic transmissions still need to be serviced far more often than manual transmissions (some auto manufacturers state that their manual transmissions never have to be serviced with fluid changes, etc.
   • Manual transmissions are also usually slightly/much cheaper to fix when something mechanical goes haywire. This is not always the case, but on average, a manual transmission will cost you less to repair than an automatic in the same type of vehicle.
   • The clutch disc in manual transmissions does need to be replaced on occasion. There are many factors that determine how long a clutch will last such as driving style, the material the clutch disc is made of, and the amount of city vs. highway driving. Clutch replacement is often a labor intensive task and can cost several hundred dollars if performed at a repair shop.
8. You need to identify your Needs:
   • The engine that your car is equipped with makes a huge difference to which type of transmission should be chosen. To explain, if you are looking to buy a car with a 1.5 liter 4-cylinder that pumps out 62 horsepower, and 75 lb-ft of torque you will most likely want/need to go with a manual transmission. Since power in this case is extremely limited, you will need to make the most out of your engine for hill climbing, passing power, etc.
   • On the other hand, if you're looking to purchase a car with a V8 or V6 that offers plenty of power at both high and low revs, then going with a manual transmission is more of a preference than a necessity. While most drivers will still benefit in acceleration and fuel economy by going with a manual, it is not as detrimental as it would be with a car that was limited on power.
9. Some people obviously can't own a vehicle with a manual transmission for many reasons.
   • They might be unwilling to learn to use one.
   • They might have a physical handicap, etc.
   If this is the case then search for an automatic that combines both good shift patterns, and good fuel economy.
10. If you are willing to drive a manual transmission, there are a few features to look for.
    • Manual transmissions all have their own unique shifting characteristics.
    • Many are geared for fuel economy, others are geared for sport driving, and then there are many that offer the best of both worlds.
    • If you prefer to have your right hand available at all times to multitask then you will definitely prefer an automatic transmission.

 

[edit] Tips

• Manual Transmission vehicles are less expensive than automatics. Usually by $1000 or more.
• If you want the quickest possible acceleration go with a manual transmission.
• If a manual is out of the question, first check out the reported engine RPM where the car in question achieves its peak horsepower, such as an online website.
• Be aware of other transmission choice(s). Some manufacturers such as BMW or VW offer semi-auto (or semi-manual per se) transmission. Each manufacturer have a different name for this type of transmission (SMG for BMW, DSG for VW) but they all operate in a similar manner. They are essentially manual transmissions with special electronics/hydraulic system that engage and disengage the clutch for you. This let you drive a car like automatic. Or you can shift gears manually if you choose to do so. Since the clutch is controlled by the car itself, there's no clutch pedal and it still has all the performance advantages of manual transmission described above but may still not be as reliable, due to the complex operating mechanisms.
• An automobile with a competent automatic transmission should hold gears to suit your right foot, that includes holding gears till the car's engine hits peak horsepower (or at least close) if the driver is so inclined.
• Check the EPA ratings (city and highway) of the car in question with both transmissions. EPA ratings are not always accurate, but they do give you a good idea on what type of fuel economy you will receive.
• Test drive the car as many times as you need to make sure you are in the right vehicle.
• For a driver unfamiliar with a manual transmission, automatics are safer as they allow you to concentrate on hazards. A manual transmission requires significantly more attention to drive initially, but, with experience, operating the whole car, transmission included, will become as natural as walking.
• Automatics put less strain on engine and drivetrain components than an improperly-driven manual and maintenance costs over the life of the car may well be less.

 

[edit] Warnings

• If you are shopping for a new vehicle, some models that may have offered both transmissions in a previous edition may offer only the manual or only automatic.
• During the test drive, if the automatic transmission up-shifts with the pedal to the metal more than 1000 RPM before peak power is reached, it is suggestible to look for another car.
• Take extra care when driving a car with a transmission you are not familiar with.

 

[edit] Related wikiHows

• How to Buy a New Car
• How to Buy a Used Car from a Private Party
• How to Drive Manual
• How to Play Tire Wars

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