Why are there no diesel Hybrids for Maximum economy.?

Question

Instead of the Petrol Hybrids aimed at minimum pollution in pre 2005 terms excluding CO2

Answer 1

Diesel engines are not as good at the constant start-stop that the current hybrid designs employ (primarily a gasoline engine, with some electric assist and perhaps electric-only propulsion).

Also, the currently-available hybrids are designed more for lower emissions, than for high fuel economy.  Diesel engines will put out more emissions than a gasoline engine, even at the same fuel economy.  Diesel engines will usually have better fuel economy than a gasoline engine (so lower CO2 emissions), but they will usually put out more NOx and particulate matter.

Perhaps some future hybrids may employ a diesel engine used solely as a generator for an electric propulsion system, but none currently exist.

Answer 2

There are a number of reasons.

The main one is cost-benefit. A hybrid system adds about £1000 to the component cost to the manufacturer. A diesel engine in place of a petrol engine adds about the same. Therefore a diesel hybrid will cost even more.

Given that a diesel engine is already about 30% more efficient than a petrol engine, the improvement in consumption by adding a hybrid is less, so the extra expense gives less benefit. Add in that the hybrid's key benefit is in stop-start conditions, where a diesel is already far more efficient than a petrol, and the cost-benefit balance doesn't make economic sense.

There is also the issue of driving styles, driving conditions and fuel-types favoured in different parts of the world.

If you assume that there are two methods of improving efficiency - diesel or hybrid - then the diesel is well-accepted in Europe, and its performance suits European driving, but it is not well-accepted in the USA or Japan, so another solution is required there. The hybrid is best suited to large urban areas, with limited high-speed driving (think LA or Tokyo).

From an engineering point-of-view, there have been problems integrating the hybrid system with a diesel engine. Because of its high compression ratio, starting a diesel engine is not smooth. This means that achieving the smooth transition from electric to combustion-engine power that petrol hybrid manage is very difficult with a diesel engine - the whole car would jolt as the diesel engine starts.

Demand for ever-lower CO2 emissions, tax breaks for low-CO2 emission vehicles and higher fuel prices are now beginning to make the cost-benefit equation balance more in favour of the diesel hybrid, and the technology to make the transition smoother is being developed, so expect to see a few diesel-hybrid cars appearing in the next few years.

Answer 3

Hybrid cars arent about economy, they are about less emissions. Diesel cars create more emissions than , so they would be very environmentally friendly.

Answer 4

i'm sorry. i have no idea about diesel motorbikes.

Answer 5

There are some in the pipeline from Peugeot, in their 307 model. However they are likely to be expensive because the technology is new, they difficult to sell in the states. The emissions that are measured, in the us, are NO2 (nitrous oxide), diesels produce larger amounts of these than petrols, that coupled with the culture and image of diesels mean that sales would be probably be low.

No company would market a very expensive to design car and have it effectively shut out from the us market, the largest in the world. There are also engineering problems in matching the two power plants together, both a diesel and an electric power plant produce torque low down.

Currently I know of no other manufacturers that have any on the drawing board.