Lots of things about cars have evolved over the years: styles, configurations, manufacturing origins, even power sources. But relatively speaking, instrument panels have stayed about the same.
They still are dominated by gauges and dials that relay information about the extremely vital functions and status of the automobile. But as computer and sensor technology continues to generate more information, designers are trying to work new data into the most logical place: a spot on the car's instrument panel. Tire-pressure data is making a strong play these days, for example, as is information about the functioning of hybrid powertrains. It's like grocery store items fighting for shelf space.
And because instrument-panel space is so limited, automakers are always looking for different ways to package it. The new Subaru Tribeca crossover, for instance, moves the fuel-level and engine-temperature gauges into separate little pods on the far lower right and lower left of the car's instrument cluster, requiring a more concerted glance from the driver than usual to see how much gasoline remains in the tank.
On the other hand, BMW aims for instrument-panel minimalism: The entire panel consists of a large speedometer, with a fuel-gauge inset, next to a large tachometer, inside of which is a small fuel-economy gauge. The only other display is a small digital-data readout between the two big analog dials.
The space squeeze also is prompting automakers to consider giving up some of the traditional information on the instrument panel. For example, the new BMW 3 Series doesn't have a coolant temperature gauge.
"You're seeing designers really play around with different concepts about how to treat the instrument cluster [compared to] the traditional package," said Jeff Greenberg, senior technical leader for human-machine interface for Ford.
A Map to Your Instrument Panel
Here are the basic gauges and dials on your car's instrument panel and what they do:
Charging system gauge: This gauge monitors the health of the electrical-charging system in the vehicle so you have a warning of a problem before it disables the vehicle. If the monitor indicates a charging problem, you can still drive a short distance to find help. The most common problem is a broken alternator belt.
Engine temperature gauge: This instrument reads out the temperature of the engine coolant in degrees. It lets you know when the engine is warm enough to turn the heater on and get warm air. It also will tell you if your engine temperature is in an acceptable operating range. If the gauge moves all the way to hot or the temperature warning light comes on, you need to safely pull off the road, turn off the engine and let it cool.
Fuel gauge: Tells you how much gas is left in your tank. In most vehicles, it remains on "full" while it uses a gallon or two, before it begins gradually dropping. For a similar design reason, you also usually have a reserve of a gallon or two of gasoline in the tank even after the gauge reads flat "empty."
Odometer: Odometers keep track of how much the vehicle has traveled, using a toothed wheel mounted to the output of the transmission and a magnetic sensor that counts the pulses as each tooth of the wheel goes by. If someone tries to "roll back" the odometer, the value stored in the engine control unit — which can be read at any car dealership — will disagree. A trip odometer tracks mileage until it is reset by the driver to begin counting miles again.
Oil pressure gauge: This measures engine oil pressure in pounds per square inch, monitoring a vital function. An integrated oil lamp usually lights when oil pressure is dangerously low, an indicator that demands that the driver stop the vehicle as soon as is safely possible and shut off the engine.
Speedometer: This is the most used gauge, telling you how fast you're going in miles and kilometers per hour. Today's cars generally employ an electronic sensor that measures wheel speed and sends the signal to an electronically driven speedometer.
Tachometer: This gauge measures how fast the engine is turning in revolutions per minute. It mainly helps knowledgeable drivers obtain optimum performance or fuel economy — although it is notably much more useful with manual than with automatic gearboxes because drivers directly control the transmission.
As Vehicles Evolve, so Does Information
In nearly all new vehicles, the instrument panel also provides flexible space for communicating digital information from the increasing use of advanced electronics, such as traction control and cruise control systems — and in some high-end vehicles, an instrument-panel representation of your iPod menu.
Readouts for tire-pressure monitoring have also become common and will be standard equipment on all model-year 2008 and later vehicles, in compliance with federal safety requirements. High-end models specify which tire may be a problem.
And in hybrid vehicles, a tachometer would be useless, so instrument-panel designers substitute a diagram or gauge that tracks the flow of energy to and from the various components of the powertrain. On the 2008 Chrysler Aspen and Dodge Durango hybrids, for example, this gauge relays information about whether the vehicle is relying on the gasoline engine, the battery pack or both. It tells the driver whether he is driving fuel-efficiently or not and it shows when the vehicle is charging the battery through the regenerative-braking system.
In fact, the spread of hybrid powertrains may provide one of the last nails in the coffin of the tachometer, except on manual-transmission vehicles. "Basically, a tachometer today means nothing unless you're playing around in the car," said Daniel Johnston, a marketing communications manager for Volvo, which is moving to deemphasize tachometers on future models.
But don't count on tachometers going the way of bench seats. "For the person that is driving-oriented, there is still some romance around having and seeing a tachometer," said Ken Kcomt, a product-planning director for Nissan and Infiniti. "So that's something we'll continue to have as we move forward."
Dale Buss is a journalist based near Detroit.
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