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Why Diesel engines are costlier?

Discussion in 'Engine Compartment' started by pv_krish, Sep 8, 2014.

  1. pv_krish

    pv_krish Regolare

    Grande Punto 1.3 90 HP
    Hi TFIANS,

    Even after being in the run for so long and with the technical advancements, why are Diesel engines still costing higher than petrol engines?

    The injection and turbo charging for diesel had started much before petrol. Gone are the days where having a diesel engine was a nightmare. It is as good, if not better than petrol engine.

    With such a lot of volumes and being readily available, why are they still costly compared to petrol engines?
  2. asimpleson

    asimpleson Esperto

    Linea 1.3
    It is not just the engine. There is the higher tax component due to emissions and extra subsidies of fuel itself. The use of heavy alloys/cast iron block (mostly in engine blocks/heads) and other components, the fuel rail, high pressure pump/fuel pump, water pump, injectors, Diesel Particulate Filters, EGR system, the turbo, extra plumbings and fittings, larger radiators, intercooler, also needed is a better clutch and braking to handle all that torque inherent in diesels even at lower rpms.

    It might be argued that some higher quality/capacity systems are used commonly in petrol variants also these days including clutches, brakes and emission systems etc., but a total combination of all these items is a reason for the generally higher costs of diesel vehicles.

    It is also a belief that majority diesel engines with proper maintenance can go for a few lac kms perhaps 3-4 lac easily, before a rework or overhaul is necessary. However, common passenger car owners (& not tourist vehicles and fleets) get rid of cars before such a stage is really needed to fix the compression and oil leaks within the engine cylinders/pistons and a head/s replacement or valve rework. (it does not stop there..) The point being that the extra cost is justified in a way due to extra strenuous workhorse nature of work the diesel engine is supposed to undertake. However, IMO not everyone exploits or gets to exploit the diesel engine benefits over a life time of the car as is the intended use of such engines. In real world many cars change hands before that time, but thats besides the main point.
  3. GP_Freak

    GP_Freak Regolare

    Linea 1.3
    On a technical front, the Diesels needs to be built more robust(nearly twice) which is required based on their operating principle and anything which are build more robust are obviously going to cost more. This is the most simplest reason which can be put forward. The reason for robust built in diesel is because the compression ratio is typically high for having maximum volumetric efficiency when compared to NA pertols.

    fyi, Forced induction petrols run with less compression ratio than a NA petrol. Its a very vast subject if we get in to technicalities of Diesel Vs Petrol Vs forced induction petrols.

    The previous reply from Simpleson covers most of the reasons due parts cost and tax part.

    Btw, even the injectors are different in petrol and diesels owing to the atomization requirement and the rail pressure. The pump and their operating pressure is different in petrol and diesel. we could keep going on and on in this, but I will limit to less technical aspect for now unless you have very specific technical query.
    bharath likes this.
  4. Italia-Linea

    Italia-Linea Staff Member Janitor

    1. Injectors - They cost more than double than the petrol ones.
    2. High pressure fuel pump - Costs in the range of 45k - nothing required on the petrol engines
    3. Common rail - costlier in case of diesel
    4. Block and head - costlier in case of diesel and stronger too
    5. Turbo - if VGT then it costs 45k whereas FGT costs just 17k

    With the above itself the cost difference shoots above 1 lac. Miscellaneous costs added this will shoot more than 1.4 lacs
    bharath and mchanna like this.

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