[msharma_79]

Hi guys,

i thought this thread might help us all to understand steering system of our cars. usually when people go to buy new car they basically just ask, does the car have a power steering?
and the sales man says ,"Yes "and people merrily buy the car and come back home.

But we are not laymen here, we are bhpians.


so let's discuss power steering system.

what is power steering:-

The advantages of power steering hardly need to be elaborated. For the user, in addition to better control and stability at various speeds compared to the ordinary manual-type steering, the power steering will also reduce driver fatigue. In congested city traffic conditions, manoeuvring the car will be easier with assistance from the power steering. In the long run, driver comfort and safety will get a boost. The only compromise being a marginal fall in fuel efficiency and engine power.

Types of Power steering available in India:-

• Hydraulic Power steering
• Hybrid power steering
• Electric power steering

Hydraulic Power steering

Most power steering systems work by using a belt-driven pump to provide hydraulic pressure to the system. This hydraulic pressure is generated by a rotary-vane pump which is driven by the vehicle's engine. As the speed of the engine increases, the pressure in the hydraulic fluid also increases, hence a relief valve is incorporated into the system to allow excess pressure to be bled away.
While the power steering is not being used, i.e. driving in a straight line, twin hydraulic lines provide equal pressure to both sides of the steering wheel gear. When Torque is applied to the steering wheel, the hydraulic lines provide unequal pressures and hence assist in turning the wheels in the intended direction.

Tata cars and logan have this type of steering system in India.even toyota in india comes with hydraulic only.
http://www.toyotabharat.com/inen/cars/camry/specs.asp
if they have hydraulic system in camry then i thought they would have the same system all across the product line. correct me if i am wrong.

Hybrid power steering

Electro-hydraulic power steering systems, sometimes abbreviated EHPS, and also sometimes called "hybrid" systems, use the same hydraulic assist technology as standard systems, but the hydraulic pressure is provided by a pump driven by an instead of being belt-driven by the engine. These systems can be found in some cars by Skoda and you guys can add more names.

although I could not find any data on skoda's site to back that.

TechnicalData

Electric Power Steering

Electric power steering (EPS or EPAS) is designed to use an electric motor to reduce effort by providing assist to the driver of a vehicle. Most EPS systems have variable assist, which allows for more assistance as the speed of a vehicle decreases and less assistance from the system during high-speed situations. This functionality requires a delicate balance of power and control that has only been available to manufacturers in recent years. The EPS system is replacing the hydraulic steering system (HPS or HPAS) and is destined to soon become mainstream among automotive manufacturers.

EPS systems do not require engine power to operate. Thus, a vehicle equipped with EPS may achieve an estimated improvement in fuel economy of 3% compared to the same vehicle with conventional HPS. As an added benefit, more of the engine's power is transmitted to its intended location — the wheels.
Some cars mentioned below with EPS System.
Honda City: Performance : Specifications
:: MARUTI SUZUKI SX4 ::#

No doubt the fight between Honda City and Sx4 is so fierce.

benefits from EPS are:-

Low maintenance cost.
No Oil leakages
Lowers the load on engine
Increases safty on higher speed
reducing the chance of over reaction(must have seen it so many times on highway)

Maruti Introduced this system in small car segment with Zen Lxi and WagonR i, later on followed by Sx4 and all others.

So next time whenever you go for the new car always ask what type of power steering the company is offering you. most of the company don't disclose it on their catalogues for simple mere reason that hydraulic systems are cheaper option for them to install. The cost of technology for EPS is high so lot of companies are not interested in investing.

• Any corrections or pointing a mistake in the post are most welcome.
• Adding more name of the cars with the specific steering system will help people make their decision fast.
• source of information are wikipidia, honda, skoda, maruti and how stuff works websites.

Take Care
God Bless

Manu

[akash_m]

Wow Sharmaji, your reviews are always knowledge based and enligthning. Just simple queries though:

1. Are all buses and trucks (especially Indian) fitted with power steering? I mean the driver would otherwise have tough time manuvering these vehicles!
2. Just as the hydraulic power sterring would effect the F.E marginally, does the E.P.S put extra load on the car battery? I mean is the battery life shortened...

thanx

[V-16]

Very informative Msharma_79 as usual. This will in a nutshell (big nutshell) give a basic understanding of the various power steerings and the principles behind them. A pointed out by Gr8guzzler, this topic is covered but who doesn't need an extra bit of useful information huh?

[lambuhere1]

Originally Posted by msharma_79

ok, but how come when i search for these never find any?

there goes my first half of the day

Mods please do the necessary, i see lot of different stuff up there but what the heck... . see if it can survive or merge it, whatever

Nothing to worry about. I believe you need to have used tha advanced feature option.

But you know what, You can become a great writer. Wonder how many are there in here.

Chill out

[mithun]

Nice work !

Very informative !

[diabloo]

All about EPS & HPS on TBHP:
site:team-bhp.com EPS HPS

[sbasak]

Good article!

Just like to add a few bits. If the car has EPS, when you switch on the ignition, the word EPS should appear in instrument panel. It should go out as soon as you switch on the engine (just like engine oil/battery light). Also, EPS makes steering a bit stiffer at higher speeds - so that you don't deviate too much from your path at high speed while steering.

Nowadays, worldwide even small cars (eg. Mitsubishi Colt, Suzuki Ignis etc.) are being fitted with EPS.

I'm not sure how EPS is more expensive than HPS. Ideally, it should be cheaper as it requires less no. of components.

[msharma_79]

Originally Posted by diabloo

All about EPS & HPS on TBHP:
site:team-bhp.com EPS HPS

good job done, congratulations.

[DCEite]

Originally Posted by sbasak

Good article!

Just like to add a few bits. If the car has EPS, when you switch on the ignition, the word EPS should appear in instrument panel.

Does this happen in Maruti cars also? Actually never noticed!

[msharma_79]

Originally Posted by DCEite

Does this happen in Maruti cars also? Actually never noticed!

i think he is suggesting that if this happens then it can be helpfull, because with eps the steering gets stiffer on higher speed. basically actual status of stiffness ( don't read too much into it ) should be measured and reflected on the meter.

[msharma_79]

Originally Posted by lambuhere1

Nothing to worry about. I believe you need to have used tha advanced feature option.

But you know what, You can become a great writer. Wonder how many are there in here.

Chill out

Originally Posted by mithun

Nice work !

Very informative !

thanks guys, not sure about writer but may be an editor .
@mithun, great attitude bro, usually the people who have similar thread are the first one to come with suggestion to close the new thread.
but you had actually posted in the new thread.

my thread really got merged with right one here.

regards

[lohithrao]

Wow neat info. great thread!

btw what kind of power steering does OHC has? EPS or Hydraulic???

[vnabhi]

Originally Posted by msharma_79

Hi guys,

TechnicalData


EPS systems do not require engine power to operate. Thus, a vehicle equipped with EPS may achieve an estimated improvement in fuel economy of 3% compared to the same vehicle with conventional HPS. As an added benefit, more of the engine's power is transmitted to its intended location — the wheels.

Manu

Theoretically, this is correct. I have a WagonR lxi for the past 6 years. But when I drove a WagonR without power steering (LX model), I found it had a fantastic pick-up compared to mine. If EPS is not the culprit, then what is to blame?
As regards driving, my WagonR is very easy to drive in the city, but on highways, it does not inspire confidence, though the steering becomes tauter at speeds above 50. On the contrary, my Fiesta, which has HPS, feels very stable at high speeds, though in city driving, it requires a tad more effort to steer.

[Pankaj401]

Originally Posted by lohithrao

Wow neat info. great thread!

btw what kind of power steering does OHC has? EPS or Hydraulic???

Speed sensitive HPS.

[Torqy]

I have a Bolero 2007 with Power Steering. It's really scary to operate the steering at high speeds as it is NOT speed sensitive.

-- Torqy