DETROIT - Cars today use about 1.8 kilowatts of power, a huge step from cars of the 1920s, which used only about 100 watts of power.
But mild hybrid cars of the near future will demand 40 kilowatts of power - and true hybrids more - electricity that must be generated by the vehicle without boosting fuel use or compromising operating systems.
Finding that power will be a challenge, one which may require hybrid cars using integrated starter-alternator devices, said Harry Husted, senior systems engineer at Delphi Automotive Systems.
His remarks came in an address to a technical session during Convergence 2000, held in Detroit Oct. 16-18.
`ELECTRONIC TURBO BOOST'
Delphi calls its integrated starter-alternator device 'Energen 10,' a system that couples a powerful electric motor/generator in the driveline between engine and transmission.
The motor can be used for what Husted referred to as an 'electric turbo boost' for acceleration, using stored electric power for bursts of speed, then replacing that energy while the gasoline engine operates in an ultra-efficient cruise mode.
The Energen system can also offer start-stop engine use while driving, cutting the engine off during coasting or brief stops. But another system, using a highly engineered version of today's alternator, may be able to do the same thing, Husted said.
'So far, we've pretty much been using a bigger alternator,' for increased electrical output, he said.
A 42-volt alternator-generator may serve not only as the bigger power maker, but also double as its own starting motor. Such an alternator would use a modification of the current power-take-off serpentine belt drive to be able to also power an engine to life.
That may be an interim system during the early phase of higher-voltage systems than today's 14-volt electrical system on cars. But the maximum benefit for reducing fuel use while increasing available electrical power may need to come from a true hybrid, perhaps an eventual high-voltage system which uses more electrical than gasoline direct propulsion, according to Husted's examples.
'The value of a hybrid powertrain has to be greater than the cost. That's very simple, but also very profound,' he said.
Delphi is working to decrease the size and manage the heat created by power distribution electronics.
Husted showed a series of high-voltage switching equipment, beginning with a large, single-switch assembly that first appeared in 1995 on GM's EV1 electric vehicle.
The final, computer-controlled switch could do more at a far smaller size, he said.
'There's a reason we call it `the domino,' ' Husted said.
As batteries improve and power management systems advance, engineers will be able to improve the efficiency for electrical generation at higher voltages. Husted said the key is to implement those changes in ways that drivers never notice, though.
He likened it to automotive air conditioning today. Few drivers realize that most cars cut off the air conditioner when the driver momentarily floors the accelerator pedal.
The cutoff feature reduces the load on the engine, increasing the available drive power by four to five horsepower. Such events are usually so short that drivers never notice the missing cool air, Husted said.
'The goal is really to energy manage the vehicle in such a way that he customer never notices,' he said.
When start-stop alternator/generators are introduced, it will be in ways that are transparent to most people - except in offering more convenience and better economy, Husted said.