Toyota's Direct Injection Four-Stroke Superior version (D-S4) engine combines direct injection (which injects fuel into the combustion chamber) with port injection (which injects fuel into the intake ports). It controls the two types of injectors in accordance with driving conditions. Under heavy load, direct injection is employed. Under medium or high load, both types are used. In the drawing on the left, the engine uses both types of injectors (port injection is marked as "1" at the top). On the right, the engine uses direct injection only. (Source: Toyota)
I have survived several motorcycle accidents. Apparently, I was "allowed" more than 1 accident. However, I get the point: cars (for most people/situations) are safer.
And, yes, more mass will increase your chances of survival in a crash.. but not because of a stronger cage around you. It has to do do with rate of change in velocity (think bug vs windshield for mass differences), crush zone size (de-accel time/distance) and occupant containment (seat belts). Race cars drivers have survived crashes in cars weighing less than 2,000 lbs - hitting brick walls (straight on) while traveling in excess of 150 mph. Numerous times. It had little to do with the additional mass of their "cage" (or even use exotic materials).
Regardless of this, it is not likely the payloads on 18 wheelers will be reduced to reduce risk to other motorists - there will never be the "political will" to do this. 100,000 lbs against 1,000 lbs or 3,000 lbs - the odds have not changed much with additional 2,000 lbs - the smaller vehicle is going to lose, big time. The only change: chances of hitting a car of equal or smaller mass. And if all cars are lighter, the odds have not changed. The reality is likely to be something between the two extreme examples - a slight increase in risks compared to the avg car on the today.
David: That's quite the claim. Ten years? No fossil fuels. I'd be happy if you were right, but . . .
. . . I remember Popular Science articles in the 70's touting the flying cars we all would be driving by the turn of the century. :-)
As for replacements, I'm good with #1. I think batteries will make incremental improvements over the next several decades.
As for #2, I must have had a Rip Van Winkle moment, and forgive me, I have never heard or read of an inert gas plasma motor. Any links to where the reader might learn more about this technology?
And #3, well, I'd be happy if they could sustain and control hot fusion for more than a femtosecond or so. I understand that if you set a cold fusion reaction cell outside during the day, it does get warmer. Commercializing that may have a few hurdles to overcome.
On a motorcycle you are only allowed 1 accident and you are dead. If all cars are lighter and trucks still weigh 100,000 lbs. the danger still exists. The weight is required to make a safety cage around the occupants so when the 100,000 lb. truck hits you and you bounce down the street the vehicle remains intact instead of crushed like an egg. If the cars are going to be weigh about 1000 lbs then trucks should be downsised to about 25,000 lbs. maximum also.
I have found that driving habits (or shall we say "technique") does make a significant difference.
My own commute is about 50 miles one way and I ran a simple experiment over the course of a couple weeks to see how far I could stretch my mileage. My drive is about 35 miles at highway speed ann 15 miles in heavier/slower traffic. Driving normal, I get about 32mpg over time. However, while driving with the intent to increase mileage, I was able to approach 39 to 40mpg. This was done by slowing down from 75-80 to 65-70mph, staying within "drafting" distance of other vehicles, avoiding hard accelerations, and popping the tranny out of gear to coast whenever possible.
It seems odd that simple old common knowledge is being ignored though. Such as we have known for decades that a simple air dam at the bottom of the front of the vehicle will greatly reduce air drag from the bottom of the vehicle. But no one builds in air dams on a regular basis, except for cars like Alfa Romeo, Porsche, etc.
While direct injection costs more because of the high pressures needed, it can be exrtremely efficient. That is because it eliminates pre-ignition, ping, and knock. That means compression ratios can be increased dramatically, getting much more HP out of the same fuel combustion. The need for premium gas is also eliminated.
It also brings back the potential for going back to 2-stroke engines, that can get twice the HP for the same engine weight. With direct injection there is no mixing oil and gas or chance for excape of unburned fuel.
Actually motorcycles are much safer than cars. They have far fewer accidents, mostly because they are so manuverable they can easily avoid them. Same is true of smaller cars. And in fact, if you are in a one car accident, small cars are safer, because it is the weight of the back end of the car that tries to crush the passenger compartment. Trying to make cars heavier so that you kill others instead of just making all car lighter and safer, makes no sense at all. If all cars are lighter, there will be far fewer deaths.
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