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)
An even "better" idea for lightweight wiring is Sodium. High conductivity, light weight. Amazingly, it is trying to make a comeback (www.sodiumwire.com). Just remember, don't let it get wet, and never, ever, feed it after midnight.
The military uses 28 volts on aircraft. I know because I spent most of my career designing automatic test tquipment for aircraft and missile electronics. I imagine the military uses 24 volts in vehicles. I have no experience with that.
A big problem with a high battery voltage like 36 or 42 volts is that the various incandescent lamps in the vehicle will have longer, thinner, more fragile filaments. This would greatly reduce their reliability. While everything is moving toward LEDs, switch-mode power converters will be needed to adapt LEDs to such a high voltage. This would cause weight, cost and reliability issues. Of course, even at 12 volts, higher powered LEDs would require switch-mode power converters to avoid energy loss. The size and cost of the components in a switch-mode power converter are affected by the wattage, not the battery voltage.
Referring to slide #7, aluminum wiring. That's a very bad idea. While aluminum may be lighter than copper, aluminum oxidizes far more easily than copper, causing faulty electrical connections. It was used in houses for a while, but caused many fires and has since been discontinued. Now add to that, the temperature and humidity of an automotive application, I predict that the reliability will be extremely low. Bad idea!
In reality a higher battery voltage will mean a larger alternator and a greater alternator load. The reason for the higher voltage is to provide enough electrical power for all of the loads. The higher voltage was never to reduce the weight of the wires. The first suggestion s for the 36 volt system, (42 volts) was to power the electrically heated catalytic converter. The concept was to delay the start while bringing the catalyst up to operating temperature using electrical heat. The power consumed was about the same as for cranking the engine for several minutes. The good news is that the idea was so very stupid that it was never released. What could be useful for the stop-start driving method would be a 24 volt alternator/starter unit, such as the Continental one pictured in the slideshow.
What stands in the way of the effective impplementation of the ultimate stop-start system is engine driven power steering, and air conditioning demands. Right now, I can shift my car into neutral and coast to a light, but it will not drop below 1500RPM until the vehicle is stopped. That is to assure power steering bost while still moving.
With most cars now being much lighter than when power steering first became popular, it seems that we should go back to the non-powered type of steering systems. They were not that hard to turn, and they were both less expensive and more reliable. And if we got rid of some drivers, so much the better. Fewer drivers, les crowded roads.
42V is dead and buried, 48V is the new future voltage.
The average car has ~1100 wires, ~¾ mile in length for now. With the increasing regulation & major reductions planned for CO2 things are going to get much worse as we lurch towards self-driving cars.
Extra sensors, cameras, computers & whatever else is needed to meet these new legal / techie requirements will result in pushing up the wire count & weight.
So we need the higher voltages & aluminium to reduce the wire weight given the much, much higher wire count otherwise we are back at square one. This will help by partially offsetting the weight increase caused by all the regulatory extras.
So for the average car 12/48 V systems with step down DC/DC converters will be the end result – 48V for high power & 12V for the legacy loads like car radios & sat-navs, etc.... Hybrids and electric cars already have a high voltage power source with step down DC/DC converters so there is less effort needed to up-tech them.
This doesn't count all the body changes towards a high strength steel bodyshell & lightweight alloys for the internal structure combined with plastics to replace glass windows.
Perhaps the future is a very high tech version of the old East German Trabant with modern materials replacing cheap steel & papier-mâché !!!
OK, VW group to off-set their car consumption bought Ducati, so now when A(nother) U(n) D(oubted) I(diot) driver hits a Ducati rider they get both repairs too.
All cynicism aside a lot of car makers also have a bike division, or in the case of BMW the other way round, so not everyone is trying so hard yet. That said we drove 690 miles over 6 days recently in a 2008 Suzuki (badged Vauxhaul Agila) Splash 1.3 CDTi. Thats the Fiat 1.3 common rail turbo intercooled diesel, without air-con it returned at ~65 mph 71 MPG, with air-con, and several hours of city centre crawling, overall 4 up with luggage it returned 65 MPG. And whilst we're Europeans, we're not small built people either!
The Splash/Agila is still being built, but Suzuki/GM stopped buying in the Fiat engine in 2010, that was a mistake, neither of the petrol engines can return such good fuel economy with useable power, perhaps thats where the real future lies, more collaboration, less competition?
I like a lot of these ideas, but I agree that using aluminum wire is scary! Millions of homes were wired with aluminum wire in the 1960's and early 70's, until electrical fires became epidemic in those houses, resulting in millions of dollars in lawsuits due to the property damage, injury and deaths those fires caused. The problem was when connectors and devices made for copper wire were connected to the aluminum wire or when copper and aluminum wire were spliced together, causing galvanic corrosion at the connections. As the joints began to corrode, the resistance of the connections increased, raising the temperature of the connection until the insulation failed, resulting in a short circuit and fire.
This wouldn't be as much of a problem for the OEM, as he could prevent the use of mixed-mode wiring, but for mechanics in the field, it would be a disaster, trying to determine what kind of wire was in the car before making electrical repairs. It would be even worse if they used copper wire in place of aluminum to make the repair, only to have the car catch fire a few months later!
The government needs to set targets because a free market will progress very slowly on its own. These new technologies are expensive to engineer / design / and implement, and cause reliability / repair cost issues. Consumers gravitate to low cost which is why electric vehicles with extended ranges are not popular....they cost too much. This is a lot of very little improvements, without a mandate, it would be hard to get excited about any one of them. Even with all of these, the automakers will likely need to hope / push people move to smaller cars. I would have bought a hybrid Toyota Higlander 7 years ago but the $10K premium did not seem like a good payback at the time. If the price of new vehicles skyrockets with this new mandatory technology, I will vote to keep my older cars longer and longer.
A recently released government report has raised the hopes of automakers looking for a break on future fuel economy regulations, despite the warnings of an Environmental Protection Agency official who said the agency is unlikely to back down on its goal of 54.5 mpg by 2025.
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