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The ins, outs of electric power assisted steering |

The ins, outs of electric power assisted steering

Question: I’m getting ready to buy a new car and am trying to sort out a few things that are new to me. One of them is electric steering. Can you explain what it is and if it’s something I’d want?

Answer: For a number of reasons, electric power assisted steering, or EPS, has really caught on. Its main advantage over tried-and-true hydraulic steering systems is probably fuel economy, which is generally about 1 mpg better in models with electric steering.

With such a system, instead of the car’s engine continuously driving a hydraulic pump, an electric motor is used to reduce steering effort. Energy for this motor does come from the engine via the charging system, but the motor is only active a portion of the time the vehicle is driven. Ditching the power steering pump and hydraulic hoses can save weight and bulk and reduce the chances of fluid leakage.

Depending on design, an EPS motor may be attached to the steering column or the steering rack. A torque sensor relays driver rotational grunt to an electronic control module that also looks at a host of other sensors, resulting in a series of calculations that then drive the motor and provide steering assistance with the best response and feedback possible. Some early EPS systems were criticized for being numb and unresponsive, but more recent designs can better a hydraulic system in driver satisfaction. I get a chance to drive a handful of new cars each year and would be hard-pressed to say which had EPS and which didn’t without peeking under the hood.

EPS makes a lot of sense as it also allows for features like lane-keeping, self-parking and autonomous driving. I’d have no concerns owning a car equipped with it.

Q: My son just bought a nice used car. Everything about it is great except its noisy belt. He’s tried using a belt lubricant and even replaced the belt, but the noise keeps coming back. How can he fix it?

A: There are two differing types of belt noise: chirping and squealing.

Chirping is a repetitive sound usually caused by pulley misalignment or fluid contamination. Misalignment can be the result of a replacement alternator, power steering pump or idler pulley sitting slightly forward or rearward due to improper installation or wear. Contamination can be due to engine oil or power steering seal leakage, a coolant leak or the use of belt dressings, which aren’t a good idea at all.

Squeal is an occasional or continuous noise caused by belt slippage. High belt load due to air conditioner operation, sharp wheel turning or rapid acceleration can cause a belt that is generally quiet to briefly sound off. Improper belt adjustment or a worn tensioner are likely causes, as is fluid contamination. A new belt may bring temporary relief until its softer fiber coating begins to wear away during break-in.

A check of pulley alignment and proper belt tension should provide the key to solving this. Hopefully your son didn’t apply a belt dressing to the new belt and it’s still good to go.

Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers may send him email at [email protected]; he cannot make personal replies.

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