Drive

How the Honda Accord Hybrid’s electric brakes save you power, gas, and money

When you take your foot off the gas pedal, your car starts to slow down. Savvy drivers take advantage of it, letting off the throttle before they need to brake, which can help them save fuel.

Automakers also capitalize on it, including Honda, which has designed an electric servo brake pedal system for its new Accord Hybrid.

“This is mainly for electric and hybrid cars,” says Hayato Mori, manager of product planning for Honda Canada. “Anything with a large storage battery.”

Hybrid vehicles recharge their batteries through regenerative braking, capturing the kinetic energy when coasting and converting it into electricity. When more energy is captured, the car doesn’t use its gasoline engine as much, which saves fuel.

The Accord Hybrid’s brake system is essentially the same as with any other car. When you press the brake pedal, it sends hydraulic fluid to each of the car’s four wheels, squeezing the brake pads against the brake discs to stop the car.

The difference is that when you put your foot on the pedal, it sends a signal to an electronic control unit, which determines how hard you’re pressing it. If you’re only touching it lightly, such as when you’re slowing down for a red light up ahead, you may not need full braking power yet. If that’s the case, the system uses regenerative braking, which slows the car down and also feeds energy into the battery.

When the car’s speed drops sufficiently, the system then sends hydraulic pressure to the brakes. It will also go straight to the hydraulic system any time you press the brake pedal firmly, or slam your foot on it during a panic stop, to activate the brakes immediately. The system reacts instantly, and the driver is never in any danger of not having full brakes when they’re needed.

Honda estimates that the new system provides eight per cent better regeneration than with its Integrated Motor Assist, used in vehicles such as the Civic Hybrid, and has improved brake control.

Because it’s electronic, the brake pedal doesn’t feel the way most drivers would expect, so Honda added a spring to it. “It’s called a pedal feel simulator,” Mori says. “The first few centimetres you’re just turning on a switch for the regenerative braking, so this simulates the force as if you’re pressing on a normal brake. Most people can’t tell the difference.”

Brake out the facts

  • Cars generate a lot of wasted energy when braking, and automakers are looking at new ways to harness it, both in hybrids and in conventional models.

  • When driving a hybrid vehicle, you should try to coast as much as possible, which keeps the battery topped up and saves fuel.

  • The regular Honda Accord uses a vacuum actuator for its power brakes, while the Accord Hybrid uses an electric actuator.

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