Modelling and Control of Linear Combustion Engine (LCE)
Pavel Němeček, Ondřej Vysoký, Michal Šindelka
Czech Technical University in Prague
Faculty of Electrical Engineering
Department of Control Engineering
Internal Combustion Engines
inline V
flat (boxer) Crank shaft turns the piston's up and down motion into circular motion
Series Hybrid Car
Gasoline engine turns a generator Generator can either charge the batteries or
power an electric motor that drives the transmission
Thus, the gasoline engine never directly powers the vehicle
and no rotation needed ?!
Linear Combustion Engines
single hit – easy industrial staplers
how to achieve repetitive (periodic) motion??? by proper configuration and control
LCE – animation
Two-stroke, Two opposite cylinders (2x50 ccm) Pistons directly connected by rod (no crankshaft) Direct air assisted fuel injection Contains linear electric motor-generator
- enable starting of LCE- provide conversion to electric energy- enable intervention when misfire occurs
No mechanical output, application for serial hybrid vehicles Control, control, control !
Schematic diagram of LCE
Advantages of the LCE
Elimination of friction losses- associated with the crankshaft and it’s accessories- piston friction reduction (no angular loading)
=> higher efficiency High power density Compact shape (allow non-standard inbuilt) Reduced amount of moving parts
- increase durability- simplify mechanical construction - simplify lubrication
Compression ration is not fixed => theoretically multi-fuel operation is enabled
Designing of the simple model, which allow study of the basic LCE behavior
Building up of an experimental prototype of the LCE and validation of the model
Control algorithm design for achieving a steady operation Controller’s optimization with respect some criteria of
quality (efficiency, emission, power etc.) Design of a power management strategy of a serial
hybrid vehicle with the LCE as the main power unit
Phases of LCE research
Model of the LCE
nonlinear scavenging, non homogenous mixture3 order
Model of Electric motor-generator
Model of Combustion Engine
Block diagram of the control system
PC with dSpace DSP board
Interface board
IGBT bridge
Injection control
unit
Ignition unit
Ignition coil
Throttle regulator
MAF
Position senzor
Power supply
3-phase network
On system variable
measurement
Power switch
Load resistor
Linear-motorgenerator
Requirements for the control system of the linear electric motor-generator
Collision avoiding between the piston and the cylinder head
Maximization of drained electric power in each cycle Prevention of the LCE from stopping
when a misfire occurs Starting of the LCE (with respect to a actual LCE state)
Experimental results
Time [s]
Po
sit
ion
[m
]
Long term steady operation was achieved
Max. drained electric power: 400 W at 1200 rpm
Experimental results
Position [m]
Vel
ocity
[m
]
Experimental results
0.5 1 1.5 2 2.5 3 3.5 4 4.5
x 10-5
0
0.5
1
1.5
2
2.5
3x 10
6
V [m3]
p [P
a]p-V diagram comparison
SimulatedExperimental (filtered)
Video – LCE prototype in operation
Conclusion and further work
Conclusion Long term steady operation was achieved Efficiency of the present experimental prototype is low,
but it allow study of the system behavior
Further work Optimization of the thermodynamical cycle Design and construction of a new prototype in
cooperation with mechanical engineers to increase efficiency and durability of the LCE