Drive it Forever
Q. It is good that we can blend renewable fuel, such as ethanol, with nonrenewable, petroleum-based fuel. But a big problem with ethanol as fuel is that it in the United States it is made of corn. Corn is a food source for many parts of the world. The food-or-fuel trade-off has caused food prices to rise in parts of the world that can ill afford the rising cost of food.
Methanol is derived from wood sources. If methanol can be blended with petroleum-based fuel to form gasoline, then we will be able to have a renewable-fuel source without causing undue hardship on the parts of the world that rely on corn for food.
Do you know if methanol can be blended with petroleum-based gasoline?
A. Yes, it can.
There were a number of M85 cars - 85-percent methanol, 15-percent gasoline, similar to the E85, ethanol-burning vehicles you can buy today - on the market back in the 1980s.
M85 never caught on, although the cars ran pretty well. The mileage wasn't very good, and methanol was -and is - more expensive than gasoline, especially per mile driven.
More to your point, most methanol isn't made from renewable sources, but is derived from nonrenewable resources - petroleum or natural gas.
Q. I changed out my brakes, and now my ABS and parking-brake lights won't go out and the brake pedal is soft on my 2001 Dodge Ram 1500 Quad Cab.
I checked the brake lines, and there is no air in the lines - and yet my brakes are still giving me problems. What could the problem be?
A. I'll bet that you didn't bench-bleed the master cylinder. There's air trapped inside the master cylinder that's almost impossible to remove with normal manual-bleeding procedures.
It's called bench bleeding because new master cylinders, which have no brake fluid whatsoever, can be bled before they're installed. You also can perform this procedure with the master cylinder already installed on the car, however.
Q. Just read the article about gas-saving devices, all of which made sense except for the last one.
The hydrogen generator should have worked if the O2 sensor had been modified to compensate for the added oxygen in the exhaust.
The ECM senses more O2 in the exhaust - a lean condition - and dumps more fuel into the mix. In reality the fuel is almost completely burned, but still has excess O2 in the exhaust. Fourteen-point-seven-to-1 should not be a set-in-stone rule. Vehicles can run on leaner mixtures when HHO gas is introduced into the combustion equation. I myself am working on my own HOD (Hydrogen on Demand) system - and, yes, I am up against the O2 sensor as well.
A. You're wrong.
When you electrolyze water to make HHO, also known as Brown's gas, you get not only oxygen but also hydrogen, both of which are introduced into the intake. When the plug fires, the extra oxygen will simply recombine with the extra hydrogen and produce water vapor, not excess oxygen.
You are right about one thing: If the O2 sensor sees an extra proportion of oxygen in the exhaust, it will richen the mixture and decrease fuel economy. Besides which, you'll get only about 20 to 30 percent of the energy in the Brown's gas back by burning it in the engine, because most of the energy from the heat in the combustion chamber is lost before it gets to the rear wheels.
The output of these hydrogen generators is far too small to provide any significant amount of hydrogen or oxygen, anyway.
And one more thing: I never tested a hydrogen generator for that article, so you must have me confused with someone else.
Mike Allen is a senior editor for Popular Mechanics magazine. Questions should be sent via e-mail to driveit@nytimes.com.
