Wednesday, December 26, 2007

Driving lessons on my Swift VDi

During our family holiday at Lonavla, I gave some driving lessons to my wife and younger daughter at a deserted spot near the Sunset Point at INS Shivaji. We found something very interesting about the car, which I must share.

The deserted spot near Sunset Point at INS Shivaji. Duke's Nose visible.

For a beginner, the co-ordination between clutch and accelerator is most tricky while trying to set the car in motion. The reason is that when one releases the clutch, load comes on the engine and its RPM falls, tending to stall it. To prevent stalling, one has to gradually rev the engine by gently pressing the accelerator while releasing the clutch. To our pleasant surprise, we found that one can set a diesel Swift in motion by simply releasing the clutch (without even touching the accelerator). The technical reasons for this, as I figure, are :

a) Due to high torque of the Swift diesel engine at low RPM, even at idling RPM (about 800) the engine is able to pull the car at low speed.
b) The accelerator of the Swift diesel is completely electronic (‘drive-by-wire’ technology) and does not involve any mechanical linkages or cables. As you press the gas pedal you are merely turning a potentiometer (or something of that sort) and sending an electronic signal to the on-board computer. At idling (when the pedal is at zero position) the computer controls the idling RPM, and it is probable that even when some load is put on the engine the computer tries to maintain the set engine RPM by increasing the fuel input.

Whatever be the technical reasons, the bottomline is that even for a child it is as easy as apple pie to set a diesel Swift in motion. The fact that the clutch is very very smooth and effortless also helps.

Sunset as seen from the Sunset Point, INS Shivaji


Sriram V Iyer said...

You are quite brave to start driving in a diesel - And, any decent car would move once you put it in first gear and slowly remove your leg from the clutch - It is not speciality of Swift DDiS :-)

Anonymous said...

I have a Swift (Petrol) & have the same observation as you - there is no need to release the clutch slowly & raise the accelerator when you start moving.

Stalin said...

Mr. DM, I have been driving the Tata Sierra since a teenager and recently bought the swift. Your discovery regarding the vehicle moving without applying acceleration is quite common in diesel engines...I used to do the same thing on the Sierra in Mumbai's traffic and am currently doin the same with the swift VDI..

anyways it was nice reading your blog and keep the posts coming..