UWE Bristol Engineering showcase 2015

Matt Thomas
Motorsport Engineering BEng
Project Supervisor:
Changho Yang
The Effect of Internal Water Spray On Turbocharged 4 Stroke Internal
Combustion Engines
Ricardo WAVE Modelling
To more accurately understand the inner workings of the internal
combustion engine when subjected to water spray, a system was created in
Ricardo WAVE. This software will be used to give an overview of the running
temperatures and pressures at specific points in the engine, giving a
multitude of parameters to analyse.
Two models were created initially, one petrol 4 cylinder turbo, and a diesel
V6 turbo. Both were created with high levels of forced induction, in order to
fully vaporise the water injected to the charge later in the investigation.
Turbo control was left to the pre-determined turbo map for the 4 cylinder
engine, a Garrett GT45 turbo fitted- a turbo that would usually be considered
too large for the mass air flow of this application – the lag shown on the
results later on would outline whether the turbo could be spooled faster
with the expansion of the superheated steam.
Water Injection Simulation
Even with careful planning and advice, it transpired that WAVE could not
complete the task of injecting water into the combustion process, meaning
all of the project objectives could not be fully met.
Despite this problem, the data collected from the ‘dry air’ simulation runs
proved invaluable when empirically calculating the increase in volume and
pressure of the steam due to the combustion process. The results correlated
with the array of previous studies, indicating an increase in thermal and
turbocharger spool efficiency. Further to this, simulation runs after the
software update due 1 st May could validate the work as a viable method for
torque, reliability and efficiency increases, whilst additionally reducing NOx
emissions.
Project summary
This project set out to further previous investigations
into the effect of increasing the performance of a 4
stroke piston IC by injecting water, or specifically
water vapour, into the engine. The simulation
Project Objectives
The direct aim of this report is to quantify and
evaluate the effect this practice has on both
the efficiency and performance of an IC
engine.
Project Conclusion
It is difficult to profess any concrete
conclusions from this project- the initially
planned role of the software was not fully
undertaken – the multitude of results
parameters offered by the simulation not
available, leaving only the dry, un sprayed
initial results from Ricardo, and simplified
empirical calculations to evaluate the effect of
a very complex process.
Nevertheless, conclusions can be drawn from
this, and the extensive correlation of previous
results from past reports does gel with the
empirical calculations performed – the steam
tables indicating that the water vapour within
the charge would be converted to
superheated steam during the combustion
process, soaking up excess heat, and
powering the turbocharger as it expands after
the exhaust stroke, therefore reducing turbo
lag.