So now that you have read it this one is going to focus on the notation of how future engines will be getting more complex and what that has the potential to mean. Engines are getting more and more controlled by computers, running at higher compression ratios, direct injection. But lets not forgot our friend just aft the mill, the transmission. Automatics are replacing Manuals, gears are going as high as eight now and each has many different settings. So lets jump in shall we.
Now here is something you have probably never ever thought of...
A car going a 100km/h, lets say at 2000rpm is traveling 100km which would take, an hour.
This means that in an hour the car's motor will turn over (2,000rpm x 60minutes) 120,000 times. Now on that average rate if your car has a 100,000km it has potentially spun 1,200,000,000 times!
I don't know about you but that concept blows my mind. Here we have a consumer product that does so much and we just take it for granted. Not only that it will last for a considerably long time.
Now what turbocharging and supercharging an engine does is force more air into an engine. To make it more efficient you add more air for a more complete burn. This adds power more importantly by increasing the compression ratio in each cylinder. The more compressed it is in the piston the more power the combustion will give producing more power at the wheel. This is where things can get complicated. With cars you are producing controlled explosions. When you are making a stronger explosion, you need materials that can sustain the repetitious force without shattering, keeping seal etc. In modern automotive engineer you want to do this as light as possible to save weight. A delicate balancing act.
Modern turbo chargers are more and more becoming power for free. Past chargers can produce a lot of heat and lag. Newer and future chargers will essentially give added power for nothing by using bearings and set ups with less friction and better aerodynamics. Lag is reduced in some cars by the presence of multi-stage chargers, using a small charger to give a small amount of boost until the larger one has enough exhaust pressure to click in and produce a wave of torque. One of the reason that turbos could do this when they never could before is that there is a bit more computer tech, not so much controlling them but controlling the engine map based on the output of the charger. If the charger hasn't provided sufficient boost it will increase the fuel in the mix. And once the air starts flowing in, the mix will change to accommodate the increased presence of oxygen.
Transmission are becoming one of the biggest game changers in the industry for speed and application of power. Sequential shifters can now allow a person to change gear in 0.4seconds, way faster then one could on any stick. Sequential shifters makes the driver train easier to warranty as you don't have to worry about people misusing the clutch and hurting the motor on shifts. It also has cut ins that won't allow a person to stall the engine or over rev it. And newer automatic programming with the engine are starting to make automatics better on fuel then manuals. More control on the revs, and all the engine outputs make it easier to manage the overall.
Back in the 50s cars had 2 speeds, 3 speed transmission automatics which are essentially how many modern lawnmowers have. Newer transmissions are getting as high as 8 speeds. This boggles the mind and the computer. Lots of these systems can't decide what gear they want like a child waffles about flavour of ice cream. It does however make sense. More gears means the more dynamic situations the car can handle, in essence, not sure if it works yet. The reason for a transmission is to reduce the amount of torque from an engine to make it more usable. Reducing the speed of the engine, while using it's power band provides more power to the wheels to make it easier to get going. As you go faster you want less reduction to better use the frequency of the revs, meaning you get closer to using the actual speed of the engine. These newer trannies have a great abundance of overdrive gears which means the output shaft of the transmission is spinning faster then the input received by the engine. This means more speed for less rpm. and less rpm means better milage. It is something that is altogether complicated to do but it makes better use of the better engines.
When you put all these little changes and improvements together you will eventually get faster, more powerful cars. The issue is that they will rely on more programming and computer software, and more complicated components. Some of this is great, but it may be making things a bit too complicated. As a rule the more complicated something is, the more likely it is to fail and the harder it will be to fix.
transmissions - always gear changing, the logic behind more gears
Yikes, very interesting article.
ReplyDeleteIf you like that, look at my blog on turbine powered cars, and Death to Hybrid cars
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