# Automotive Temperature and mass flow rate of ICE exhaust gas

1. Mar 9, 2016

### y2j

Hi everyone
I searched about the mass flow rates and temperatures of exhaust gases of light gasoline internal combustion engine at different condition but I don't fond anything yet .
Anyone can guide me?
.

2. Mar 10, 2016

### MexChemE

Most engineering thermodynamics textbooks include chapters on internal combustion engines, you can get an idea on the values you need by looking at the examples provided in the books.

Check out Çengel's Engineering Thermodynamics.

3. Mar 10, 2016

### y2j

I need to actual values of mass flow rates and temperatures of exhaust gases of light gasoline internal combustion engine for analysis and studying effect of waste heat recovery

4. Mar 17, 2016

### J Mc

Modern road car engines can manage around 30% thermal efficiency, meaning that 70% of the heat energy generated by the engine is lost to the atmosphere. This heat energy is dissipated through the exhaust AND cooling system. While i cant give you figures on mass flow rates, exhaust gas is approximately 2/3 less dense than the intake. Exhaust temps can reach above 800C during peak operation, but can range from 250-500C during normal operation.

As a side note, the latest F1 engines(1.6L Turbo) manage a thermal efficiency of 45-50%

Hope this info helps
J Mc

5. Mar 17, 2016

### y2j

Thank you so much

6. Mar 17, 2016

### Staff: Mentor

Generally, the rule of thumb is a third of the heat is dissipated at the radiator and a third goes out the tailpipe.

How good are you at chemistry? It isn't all that hard to use the equation of combustion to calculate the mass flow rate.

7. Mar 17, 2016

### y2j

that required the temperature of gases also and mole fraction of component

8. Mar 17, 2016

### Rx7man

Wouldn't the mass flow rate going out be the same as the mass air flow rate going in plus the weight of the fuel? If you know the volumetric efficiency (VE) of the engine at a given RPM and the air/fuel ratio you should be able to get the mass flow rate from that. I think most stock engines operate in the 70-85% VE, while highly tuned engines (F1, Nascar, etc) can get significantly over 100% where the engine makes peak torque. And that's without a turbocharger.. Turbocharged engines (especially race diesels) can reach over 1000% VE.. Compounded turbos can provide boost pressures of 200PSI.

9. Mar 17, 2016

### Staff: Mentor

Right, it doesn't depend on temperature: what goes in must come out. If you know the fuel flow rate and the chemistry (or there is some back-way of doing a fuel/air mixture), that's all you need.

10. Mar 17, 2016

### Rx7man

I think the trickiest thing is to get the specific heat of the exhaust gas.. at high temperatures and pressures it may be significantly different from STP, and that is going to be a key part of the equation of how much heat you can extract.