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[TheBoy]

The answer is already above....highlighted!

So I guess so!

Ah, I think we posted at same time!

[Marks DTM Calib]

The answer is its the petrol engine setup that gives it the efficiency!

The Prius does not have an Otto cycle engine, it has something closer to the Atkinson cycle with valve timing etc skewed towards max efficiency as per the highlighted fields above.

Trouble is that such an engine is rather horrible to drive so they have to bolt an electric motor setup on it to make it useable and over come its poor standard operating conditions.

The choice of cycle also explains why its shite on a track for economy as your now operating in the upper revs where it has no go!

[tunnie]

plus the engine is hidden under all the electrical gubbins, no independant garage will touch them, dealers only.

Spark plug replacments (every 60k) the engine has to be removed to do this..... from underneath!

It means you have to drive to a main dealer, my closest would be Oxford, whats environmentally friendly about driving 30 miles to a dealer, when there is a local garage 1/2 mile away?

[TheBoy]

The answer is its the petrol engine setup that gives it the efficiency!

The Prius does not have an Otto cycle engine, it has something closer to the Atkinson cycle with valve timing etc skewed towards max efficiency as per the highlighted fields above.

Trouble is that such an engine is rather horrible to drive so they have to bolt an electric motor setup on it to make it useable and over come its poor standard operating conditions.

The choice of cycle also explains why its shite on a track for economy as your now operating in the upper revs where it has no go!

Added to that, surely all the battery charging is seriously going to hurt economy anyway, thus raising emissions in reality (even though not raising on the standard tests)?

[Marks DTM Calib]

The answer is its the petrol engine setup that gives it the efficiency!

The Prius does not have an Otto cycle engine, it has something closer to the Atkinson cycle with valve timing etc skewed towards max efficiency as per the highlighted fields above.

Trouble is that such an engine is rather horrible to drive so they have to bolt an electric motor setup on it to make it useable and over come its poor standard operating conditions.

The choice of cycle also explains why its shite on a track for economy as your now operating in the upper revs where it has no go!

Added to that, surely all the battery charging is seriously going to hurt economy anyway, thus raising emissions in reality (even though not raising on the standard tests)?

Battery charges at 'opportune' moments...i.e. when cruising and to a lesser extent, under braking (regenerative). Clearly that spent enegry for charging is recovere when the motor is running (round town and accelerating).

But, as stated, we are discussing the reason behind the efficiency here.....rather hoped somebody might pick straight up on it following the engine threads but, it still highlights the theory and consequences of operating at one extreme of valve timing!  

[TheBoy]

The answer is its the petrol engine setup that gives it the efficiency!

The Prius does not have an Otto cycle engine, it has something closer to the Atkinson cycle with valve timing etc skewed towards max efficiency as per the highlighted fields above.

Trouble is that such an engine is rather horrible to drive so they have to bolt an electric motor setup on it to make it useable and over come its poor standard operating conditions.

The choice of cycle also explains why its shite on a track for economy as your now operating in the upper revs where it has no go!

Added to that, surely all the battery charging is seriously going to hurt economy anyway, thus raising emissions in reality (even though not raising on the standard tests)?

Battery charges at 'opportune' moments...i.e. when cruising and to a lesser extent, under braking (regenerative). Clearly that spent enegry for charging is recovere when the motor is running (round town and accelerating).

But, as stated, we are discussing the reason behind the efficiency here.....rather hoped somebody might pick straight up on it following the engine threads but, it still highlights the theory and consequences of operating at one extreme of valve timing!  

I real world, is it that much more efficient (purely on day to day mpg) than a similar sized car (Focus/Astra)?

[Marks DTM Calib]

The answer is its the petrol engine setup that gives it the efficiency!

The Prius does not have an Otto cycle engine, it has something closer to the Atkinson cycle with valve timing etc skewed towards max efficiency as per the highlighted fields above.

Trouble is that such an engine is rather horrible to drive so they have to bolt an electric motor setup on it to make it useable and over come its poor standard operating conditions.

The choice of cycle also explains why its shite on a track for economy as your now operating in the upper revs where it has no go!

Added to that, surely all the battery charging is seriously going to hurt economy anyway, thus raising emissions in reality (even though not raising on the standard tests)?

Battery charges at 'opportune' moments...i.e. when cruising and to a lesser extent, under braking (regenerative). Clearly that spent enegry for charging is recovere when the motor is running (round town and accelerating).

But, as stated, we are discussing the reason behind the efficiency here.....rather hoped somebody might pick straight up on it following the engine threads but, it still highlights the theory and consequences of operating at one extreme of valve timing!  

I real world, is it that much more efficient (purely on day to day mpg) than a similar sized car (Focus/Astra)?

Yes because the engine can be optimised for efficiency!

[TheBoy]

The answer is its the petrol engine setup that gives it the efficiency!

The Prius does not have an Otto cycle engine, it has something closer to the Atkinson cycle with valve timing etc skewed towards max efficiency as per the highlighted fields above.

Trouble is that such an engine is rather horrible to drive so they have to bolt an electric motor setup on it to make it useable and over come its poor standard operating conditions.

The choice of cycle also explains why its shite on a track for economy as your now operating in the upper revs where it has no go!

Added to that, surely all the battery charging is seriously going to hurt economy anyway, thus raising emissions in reality (even though not raising on the standard tests)?

Battery charges at 'opportune' moments...i.e. when cruising and to a lesser extent, under braking (regenerative). Clearly that spent enegry for charging is recovere when the motor is running (round town and accelerating).

But, as stated, we are discussing the reason behind the efficiency here.....rather hoped somebody might pick straight up on it following the engine threads but, it still highlights the theory and consequences of operating at one extreme of valve timing!  

I did, but only because you prompted me, so I went and looked over the timings  

[TheBoy]

Yes because the engine can be optimised for efficiency!

Real world, Prius is around mid 40s.  I would have thought that a 1.4 Focus/Astra should be achieving near that anyway without lugging all that heavy metal about?

I know our loan Rover 414 we had for ages a while ago managed high 30s day to day.

[cem_devecioglu]

Yes because the engine can be optimised for efficiency!

Real world, Prius is around mid 40s.  I would have thought that a 1.4 Focus/Astra should be achieving near that anyway without lugging all that heavy metal about?
I know our loan Rover 414 we had for ages a while ago managed high 30s day to day.

Agreed..and you dont need to pay for 2 engines initially and maintenance for 2 engines..  Means 2X trouble in my dictionary

[cem_devecioglu]

Use 2 cars instead and pay 2x tx and insurance

[Martin_1962]

I knew it had a different cycle - ie it actually pumps the inlet air back out to raise efficiency.

Horrid engine though.

Rather have an M3 - more economical when driven normally

[Kevin Wood]

Real world, Prius is around mid 40s.  I would have thought that a 1.4 Focus/Astra should be achieving near that anyway without lugging all that heavy metal about?

I had a ride in a Prius last week. An Italian Taxi driven by an Italian Taxi driver in an Italian city (Milan). That scenario gets me thinking sub-20 MPG whatever the car. From what I could tell from the horrendously complex MID equivalent and the metric fuel consumption display it was averaging 60MPG. He wasn't hanging about with us on board and the average wasn't dropping. This was urban driving in its extreme. TLGP followed by heavy breaking for the next set of lights for 15 miles or more.

I guess in addition to the tune of the engine, when the engine is running, it doesn't need to run lightly loaded because unwanted power can be belted back into the battery, meaning the engine never runs in an inefficient, heavily-throttled-back state. It's either heavily loaded (by the car and / or the battery) or stopped.

I'd like to see what happens on a long motorway cruise. In a city, it'll always have the ability to pump energy into the battery, and use it again, because of the nature of the driving. On a motorway cruise that's fast enough that the electric motor can't sustain it, I can't see any option but for the engine to run lightly-loaded once the battery can accept no more charge. Maybe the more efficient tune of the engine will still give a significant gain over a normal petrol car. Maybe not. :-/

It's an interesting idea, but I'd want to know what a liability they are when they reach middle-age before buying one.

Kevin