Monthly Archives: February 2011

What To Do If Your Steering Fails

While total steering failure is very rare, it can still happen. Recently, a friend recounted to me what is perhaps the most dramatic steering failure story I’ve ever heard. Visiting South Africa during the World Cup, she took one of the country’s notorious “minibus taxis,” essentially a large van that picks up and drops of passengers along predetermined routes. These taxis are known for their powerful sound systems, aggressive marketing strategies, and lack of regularly scheduled maintenance (aside from upgrades of said sound system.)

One day, she chanced to flag down a very old and rickety taxi with a particularly aggressive driver. After a harrowing five minutes hurtling down a busy road, the taxi driver turned sharply into a side street to drop off a passenger and, as he did so, the steering wheel came off in his hands. Luckily, the side street was empty and he was able to bring the vehicle to a safe, albeit abrupt, stop. My friend quickly decided to walk to her destination.

Hopefully, you will never let your car’s condition deteriorate to this point! However, steering failure can occur for other reasons and, in the spirit of being prepared, it’s good to know what to do in such a situation.

First off, there are two kinds of steering failure: total failure and a loss of power steering. I’ll begin with the latter, as this is more likely. In cars that have power steering, failure can occur for a number of reasons. The most likely is a leak in the hydraulics, which enable the system to function. If it’s a slow leak, you’ll start to notice a whining sound in your steering column and/or a gradual stiffening of the steering. If this is the case, you’ll hopefully have time to get your car checked out by a mechanic before steering functions are seriously compromised.

In the case of a fast leak, however, you could lose function fairly quickly. If this happens, the first thing that you, as the driver, will notice is that the steering becomes stiffer or “heavier,” i.e. the wheel is more difficult to turn. Hang on tight to maintain control of the car! You will still have steering control over the car, but it will be more difficult. Avoid the impulse to brake suddenly and bring your car to a very slow speed or stop, as manual steering will be more difficult at lower speeds. Instead, slow down gradually and, if possible, turn on your emergency flashers (or have a passenger do so.) Then, carefully make your way to a location where you can bring your car safely to a stop and call for assistance. Note that a failure in the hydraulic system may also compromise your brake system, so be prepared for brakes that feel stiffer or don’t function properly. You may need to respond to brake failure as well as steering failure.

Mechanical failures (like your steering wheel falling off) can also occur, although these are even more rare. In this case, you will lose all steering capability. In such a situation, you don’t have too many options. As with all emergencies, the key thing is to make sure that you remain calm. Think clearly, respond appropriately, and avoid panic.

If your steering fails, you will need to stop as soon as it is safe to do so. If you are in an area without much traffic and conditions are dry, brake as quickly as possible. If it is wet or icy, try to pump your brakes and downshift to avoid skidding, since you won’t be able to steer to correct a skid.

If you are in a heavily trafficked area, such as on a highway, first try to alert other drivers by flashing your lights, honking, and gesturing with your hands. At night time, flick your high beams on and off. Once you’ve done this, begin to slow down gradually (if possible) so that other drivers have time to respond. Try to use a combination of downshifting and braking to gradually bring your car to rest on a shoulder or near a divider—anywhere you can stop in relative safety. Then, move away from your car and call for help.

To read more on a broad range of subjects from “How To Change A Tire” to “How To Jumpstart Your Car”, visit DefensiveDriving.com’s Safe Driver Resources website!

Check out these sites for more information about online defensive driving in Texas, online defensive driving in Florida, and business driver safety.

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What To Do If You Are Trapped In A Blizzard (In Your Car!)

Record snowfalls have been wreaking havoc across the country this winter—and it looks there’s still lots more to come. As mounting snow banks turn city sidewalks into tunnels, it’s a good time to review some tips for dealing with snow emergencies, particularly what to do if you find yourself stuck in your car during a blizzard. Seventy percent of blizzard-related deaths occur among those who are travelling during the storm. While travelling in inclement weather is never ideal, it can be necessary, and so it’s always best to be prepared.

If you find yourself driving in snow that is so heavy you can no longer see adequately, it’s time to pull over and wait for the storm to subside somewhat. Of course, the danger in doing so is that your car will be snowed in. Be prepared for this situation, even if it seems unlikely. Recently, drivers in Chicago found themselves trapped on Lake Shore overnight. Being prepared for such a situation can help to keep you safe and more comfortable in the case of disaster.

First, don’t get out of your car unless you can see a building of some sort from your car. Blizzards, like fog, can be extremely disorienting; you don’t want to end up walking towards what you think is shelter only to discover yourself further from your goal and unable to get back to your car.

While it’s important to keep running your heater at regular intervals, you don’t want to run the heater constantly. Aim to keep the heater on for about fifteen minutes each hour. First, you want to conserve gas, as you can never be sure how long you may be stuck. You also don’t want to risk carbon monoxide poisoning. For this reason, you should check to make sure that the tailpipe isn’t blocked. You should also crack one of the windows slightly to allow air to circulate. Symptoms of carbon monoxide poisoning include drowsiness, dizziness, and headaches; if you or any passengers notice these symptoms, exit the car and open the windows to ventilate. Since carbon monoxide is odorless and colorless, these symptoms are the only warning signs you will have.

Next, make sure that you travel prepared in winter. During the colder months, it’s a good idea to keep your car stocked with an emergency kit that includes:

  • High calorie, non-perishable food items such as granola bars, trail mix, packets of sugar, chocolate, etc.
  • One or two heavy blankets
  • Flashlight and batteries
  • Extra hats and gloves
  • A brightly colored cloth or flag
  • Matches in a waterproof container
  • Jumper cables
  • Two empty coffee cans
  • One or two rolls of toilet paper
  • Bottles of rubbing alcohol
  • Bottles of water, provided the bottles are not completely full. Remember that water expands when it freezes
  • A Swiss army knife

Some of these items are self-explanatory: small amounts of food can radically increase your chances of survival, while the blankets and extra hats and gloves will keep you and your passengers warm. It’s important that you keep moving in order to stay warm; in particular, make sure to keep your extremities warm and dry. You can also huddle together with other passengers for warmth. Put on as many layers as possible; garbage bags or other plastic bags can be used as an extra layer. You can also cut material out of the seats for insulation. You can make holes in the seats and curl up inside, placing the cut out material over your body for warmth.

Make your car more visible in order to alert rescuers. Attach the bright cloth to the highest point on the outside of the car, such as an antenna or roof rack. At night, turn on the headlights and the dome light within the car to increase visibility.

Take stock of your food and ration it appropriately. Plan so that your food will last at least four days. Also make sure to keep hydrated by drinking small amounts of water throughout the day. If you don’t have water available, you can melt snow using the matches and one of the coffee cans. If you don’t have this equipment, then you can suck on small amounts of snow. Make sure to find snow that is clean and away from road salt and chemicals and don’t eat too much at once. Small amounts of food and water can go a long way. In December 2000, a man in Oregon survived inside his car for sixteen days on M&Ms, orange juice, and a quart of water.

In order to conserve gas (or if you run out), you can make a can heater using rubbing alcohol and toilet paper. Remove the cardboard center from the toilet roll, place the paper inside a coffee can, and soak in rubbing alcohol. Set the paper alight. The flame will keep burning for a fairly long time, provided you continue to replenish the rubbing alcohol.

While in the car, keep your seat belt buckled as much as possible, in case traffic begins to move again, snow shifts, or another similar disruption occurs.

If help doesn’t arrive for a long time and you’re unsure when you’ll be able to escape, you can light a tire (starting with the spare tire) in order to stay warm. Do so at least fifteen feet away from the car. Cover the tire in gasoline and light with a match; don’t approach the tire to light it. Instead, toss the match from a distance. The tire will burn for 10-12 hours, producing heat and a thick black smoke that will help to attract attention. Be careful not to inhale the smoke, however.

As a last resort, you can try to walk to safety. This can be very dangerous. First, make sure to bundle up and cover all exposed skin using clothes or cloth from the car seats. If your car is heavily submerged, try to assess the depth before digging out. If you think you’re more than three feet under, tunneling won’t be safe. Even if there is less snow, be very careful, as you don’t want the snow to collapse on you as you dig.

 To read more on a broad range of subjects from “How To Change A Tire” to “How To Jumpstart Your Car”, visit DefensiveDriving.com’s Safe Driver Resources website!

Check out these sites for more information about defensive driving and business driver safety.

How A Car’s Steering Works – PART TWO

Power Steering

When a car is said to have power steering, it means that the steering system contains a hydraulic component that amplifies the force exerted by the driver. This makes it much easier to steer the car. While it’s possible to drive cars without power steering, it can be very difficult to turn the wheels when the car is stationary or moving slowly; this can make maneuvers like parallel parking extremely difficult. Patents for power steering systems date back to the 1930s, but the first vehicle with power steering, the Chrysler Imperial, didn’t appear until 1951.

A power steering system requires a modified design for the rack and pinion gear. In this system, the rack contains a cylinder with a piston inside of it. Hoses pass from the pinion gear to both sides of the piston. When the driver turns the wheel, fluid moves to one side of the piston or the other, forcing the track rod right or left.

There are two other key components to this system: the rotary-vane pump, which provides the hydraulic pressure, and the rotary valve, which senses how much pressure to exert on the rack and in which direction.

Let’s start by talking about the pump, which is the simpler of the two components. The pump is connected to the engine by a pulley. As the engine spins, the pump turns and forces low pressure fluid from a reservoir into the power steering system at high pressure (See figure six).

 

Figure 6: Rotary-vane pump

 

As the engine turns the rotor, the vanes, which can slide in and out, pull the fluid from the return (input) hose and force it into the pressure (output) hose at a higher pressure. Since it’s important that the pump be able to provide force even when the engine is idling, the pressure is magnified a great deal by the pump. For this reason, the pump has a built in release valve, which can siphon off some of the pressure should it become too much. This valve is connected to the pressure hose on one side; when open, it allows fluid from the output hose back to the return hose.

All the pump does, however, is supply the brute force needed to amplify the driver’s input. The amount of power provided and the direction in which force is exerted is determined by the rotary valve. The rotary valve has two components: the torsion bar and the spool-valve assembly.

The torsion bar is a thin metal bar that twists when torque (rotational force) is applied to it. The top end of the torsion bar is connected to the input shaft from the steering wheel while the bottom end is connected to the pinion gear. Thus, the more force the driver exerts in turning, the greater the twist in the torsion bar.

The torsion bar is also connected to the spool valve assembly (see figure 7).

 

Figure 7: spool valve assembly

As you can see, the inner valve is connected to the input shaft (and the top end of the torsion bar), while the outer valve is connected to the bottom end of the torsion bar. As you turn the wheel, the inner valve and outer valve rotate in relation to one another. The amount of rotation (and direction) depends on the force exerted on the steering wheel and the direction in which the steering wheel is turned. As the valves rotate, the channels (orange, yellow, and green components) are brought into alignment with one another, so that pressurized fluid flows from the rotary vane pump to the cylinder inside the rack. Notice that the yellow channels send force to the right side of the rack, while the green channels send force to the left side of the rack. Depending on which way the valves rotate, force is thus directed to one side or the other of the rack.

Looking to the future: electric steering systems

Unfortunately, this power steering system isn’t very efficient, and a lot of energy is lost in the transfer of hydraulic power. Many carmakers are now investigating alternatives, such as the steer-by-wire system. This is an entirely electronic system in which the steering wheel functions more like a Wii controller, sensing motion and force and transmitting power to the wheels accordingly. This kind of system would reduce vibrations within the car, improve efficiency, and allow individual drivers to tailor the responsiveness of the car’s steering to their individual preferences. It would also provide a roughly 1 MPG advantage in fuel efficiency over traditional hydraulic systems.

Another system under development is the electro-hydraulic system, which is a compromise between a fully electric and fully hydraulic system. In this system, turning power is still supplied by a hydraulic system, but this is powered by a fully independent electric pump, rather than the engine itself. In this system, the power supplied by the hydraulics is no longer linked to engine RPM, so that the power steering can provide greater assist at lower speeds and become more efficient at higher speeds.

Read Part One of this two-part series.

To read more on a broad range of subjects from “How To Change A Tire” to “How To Jumpstart Your Car”, visit DefensiveDriving.com’s Safe Driver Resources website!

Check out these sites for more information about defensive driving and business driver safety.