Electric motors vs internal combustion engines

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Discussion Overview

The discussion centers on comparing the power to weight ratio of electric motors versus internal combustion engines (ICE), particularly in the context of vehicles. Participants explore various aspects such as energy density, performance in racing scenarios, and the implications of weight from fuel versus battery systems.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • Some participants assert that electric motors generally have a higher power to weight ratio compared to internal combustion engines.
  • Others argue that while electric motors may have a higher power to weight ratio, internal combustion engines combined with fuel have a significantly higher energy to weight ratio.
  • A participant provides a personal example, noting that their battery pack is heavier than the fuel for an ICE, but the fuel allows for much greater distance traveled.
  • Concerns are raised about the additional weight of components required for ICEs, such as fuel pumps and exhaust systems, which may affect the overall comparison.
  • Participants reference a Tesla outperforming a Lamborghini in a drag race, suggesting that electric vehicles can compete effectively in performance scenarios.
  • There is speculation about the context of the original question, with some participants suggesting it pertains specifically to vehicles.

Areas of Agreement / Disagreement

Participants do not reach a consensus, as there are competing views regarding the power to weight and energy to weight ratios of electric motors versus internal combustion engines. The discussion remains unresolved with multiple perspectives presented.

Contextual Notes

Participants note the lack of context in the original question, which may influence the interpretations and comparisons being made.

Tabaristiio
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On average, which has higher power to weight ratio between the two? So on average, if both weighed the same, which one is going to have more power?
 
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An electric motor has more power to weight
 
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But an internal combustion engine plus a tank of fuel usually has more energy to weight ratio than an electric motor plus battery.
 
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anorlunda said:
But an internal combustion engine plus a tank of fuel usually has more energy to weight ratio than an electric motor plus battery.

By a huge factor. My battery pack weighs 275 pounds, but my fuel weighs 60 - and will take the car 20x farther. Indeed, the battery pack and the engine weigh about the same, and the motor and the gas weigh about the same.
 
Vanadium 50 said:
By a huge factor. My battery pack weighs 275 pounds, but my fuel weighs 60 - and will take the car 20x farther. Indeed, the battery pack and the engine weigh about the same, and the motor and the gas weigh about the same.
True, though the 'fuel' portion gets on the scale with quite a bit of a necessary baggage that the EV portion does not need: fuel n water pumps, fuel and oil and air filters, carburation or fuel injection, exhaust system, high power heat rejection, starter system, multi gear transmission, differential. Last, the ICE itself is perhaps double or triple the mass of the E motor (4x in your case?).
 
The OP gave no clues as to context. We speculate when we think he means vehicles.
 
cosmik debris said:
But can it beat it in two races?

Cheers
It did. It was a best of three runs. 2:1 to the Tesla.
 
  • #10
CWatters said:
It did. It was a best of three runs. 2:1 to the Tesla.

If it was done without recharging then it is a better result. You see incredible times for some electric vehicles but they can only do one run.

Cheers
 

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