Friday, February 25, 2011

Honda Power

Here is the battery from our 2003 Honda Civic Hybrid. It's rated at 144 volts, so let's take a look at how we come up with that number. As you can see, there are 20 tubes of D-cell sized nickel metal hydride batteries. Each cell is rated at 1.2 volts, so 6 cells per sleeve equals 7.2 volts. Twenty sleeves times 7.2 volts equals 144 volts. Pretty simple. Unlike Toyota hybrid cars, the Civic is a parallel hybrid, meaning that the power from the internal combustion engine (ICE) must travel through the electric motor to power the car. Since the rotor of the electric motor is bolted directly to the ICE crankshaft, it cannot power the car unless the ICE is running. Series hybrids are configures to allow the ICE and electric motors to run independent from each other. Honda employs idle stop strategy on this car, which means that whenever the car stops rolling the engine shuts off. It feels just like the engine has stalled, but when you release the brake and step on the accelerator the engine starts back up.  The transition is almost seamless, as the electric drive motor is used to restart the engine. If you have the radio turned up loud you won't even notice the transition. In the lower part of the picture you can see a pair of linesman's gloves. They are rated for exposure to 1,000 volts. Don't get anywhere near any orange colored parts or cables on your hybrid vehicle without them. And don't lick the end of the battery to test it. 

Thursday, February 10, 2011

The Work Goes On - And On - And On.......

Work on the Hybrid Trainer Vehicle is pretty much on schedule. The "drive by wire" accelerator pedal has been mounted. Four of the eight computers have been installed; only the hybrid battery computer has been wired up so far. The wire mesh floor has been fitted and the hybrid battery cooling system is finished. The coolant pump for the inverter/converter is up and running; after the system was filled, we ran the pump for a few minutes to purge any air from the system. The brake system will be finished next week, as will the console. Then the real work starts: wiring everything together. All of the computers communicate through a network, so everything must be perfect. 
  I've been working anywhere from 12 to 14 hours per day at school lately in an effort to keep the work on the trainer on schedule while teaching my classes. It's starting to take it's toll. This weekend I'm driving down to Grand Rapids for a day of seminars at the Auto Value Tech Expo. It will be a welcome diversion for me. The morning class will be covering oscilloscope waveforms, followed by an afternoon class on Green Technologies as they apply to automotive applications. 

Accelerator pedal (no cable - just wires!)

Transmission controller
Console - lots of instruments to install here...