We have borrowed a digital laser temperature gauge from UNITEC workshop to measure the exhaust temperature using a digital laser temperature gauge.
Car tested: BMW 520 6 cylinder engine year 2000
Test condition: after warming up the engine we drove the car on the motor way for 15 minutes at an engine speed of 3000rpm
The temperature gauge has been mounted securely in the engine bay so it can measure the exhaust manifold temperature with a webcam also mounted to read the gauge reading but was not accurate as the spot that the gauge is reading cannot be controlled from inside the car while driving.
After driving the car on the motor way we stopped on a safe place on the side way of the motor way and immediately started to change the spot that the gauge is measuring and the gauge recorded a temperature of 488 ºc .
Using the measured temperature the wasted heat energy can be calculated.
CV for air fuel mixture =0.73 kj/kg
= 488ºc
=15ºc
Using the measured temperature the wasted heat energy can be calculated
CV for air fuel mixture =0.73 kj/kg
This is the heat out on one exhaust pipe and as this car is 6 cylinder engine the result needs to be multiplied by 6
At engine speed of 3000RPM there is 1500 exhaust stroke multiplied by number of cylinders
1500 6 = 9000 Exhaust stroke per minute
By knowing the water heat capacity we can calculate the raise in temperature per kg of water this energy can make
Water heat capacity = 4.2 kj/kg. k
Temp raise per kg =
If assumed that the system will run on 5liter of water we can calculate the temperature of the steam using the heat energy from the exhaust .
The temperature in the water tank is affected by the engine compartment temperature and the steam temperature as it is a close circuit, therefore it can be assumed that the water temperature in the water tank will be around 100ºC.
Water Temp = 95ºC
Water heat capacity = 4.2 kj/kg. k
latent heat of evaporation of water = 2256kj/kg
Water vapour heat capacity=1.95kj/kg.k
Q = mL(∆T)
(Q) Energy in form of heat
(L) Latent heat
(m) Unit of mass
An experiment has been carried out to see how much fuel is injected to the engine per minute
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