Application and Simulation
of Atkinson C
y
cle En
g
ine for the Ran
g
e Extender
Limian Wang
1
, Zhenghe Song and Shumao Wang
College of Engineering,China Agricultural University, Qinghua East Road, Haidian District Beijing,China
1
Faculty Secretary Office, Beijing Automotive Technician College, Caiyu Town, Daxing Beijng, China
Keywords: Atkinson cycle engine, Range extender, Simulation.
Abstract: The range extender can effectively improve the driving mileage of the electric vehicle, which is equipped
with an engine and a generator. The characteristics of the Atkinson engine are evaluated in this paper.
Additionally, Cruise software is used to simulate the performance of the range extender which is composed
of an Atkinson cycle engine and a generator. The study has illustrated that the Atkinson cycle engine if used
in the range extender can greatly reduce fuel consumption.
1 INTRODUCTION
The range extender is composed of a generator and
an engine. It is arranged in a straight line with the
battery pack and the transmission system. The
traction device of the range extended electric vehicle
is made up of three parts: the engine device, the
generator device and the motor device. When the
vehicle is running, the engine drives the generator to
produce electricity, then the controller transfers the
generated electricity to the battery or traction motor,
and finally drives the vehicle through the
transmission system (Zhu Longfei, 2012).
Though the electric vehicle is evolved from the
traditional vehicle, the operation mode of the range
extended electric vehicle is different from the
traditional vehicle. It operates mainly in all-electric
mode, with the extended range mode only serving as
a supplement. The driving mileage is effectively
improved by this mechanism. As the core of the
range extended electric vehicle, the range extender
works only when the power battery is insufficient. In
this way, it always works in the high efficiency zone
when activated. The system configuration of the
current range extender is similar, but the power
source of the generator varies. It is essential to
choose an engine which is stable, efficient and
environment-friendly.
2 CHARACTERISTIC ANALYSIS
OF THE ATKINSON CYCLE
ENGINE
Atkinson cycle is the working cycle of the internal
combustion engine with high compression ratio and
long expansion strokes. It is designed with only one
flywheel to drive the crank connecting rod
mechanism to achieve 4 strokes (Mehedad Ehsani,
2010).
The implementation of Atkinson cycle
technology can greatly improve the fuel economy of
the engine. The oil consumption of the gasoline
Atkinson cycle engine can reach as low as
200g/kWh, as shown in figure 1. The thermal
efficiency of the conventional engine is
approximately 30% (250g/kWh) while the thermal
efficiency of the Atkinson cycle engine is as high as
36% (200g/kWh), saving about 25% of the oil. The
saving credit attributed to compression ratio increase
from 10 to 13 is about 15%, while the remaining
saving credit attributed to reduction of oil pumping
loss is about 10%. If it is used as a utility model
engine, the objective of ultra low fuel consumption
and low emission can be realized effectively.
584
Wang, L., Song, Z. and Wang, S.
Application and Simulation of Atkinson Cycle Engine for the Range Extender.
In 3rd International Conference on Electromechanical Control Technology and Transportation (ICECTT 2018) , pages 584-587
ISBN: 978-989-758-312-4
Copyright © 2018 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved

Figure1: Map of the typical Atkinson cycle engine
3 APPLICATION AND
SIMULATION OF THE
ATKINSON CYCLE ENGINE
FOR THE RANGE EXTENDER
In this paper, a small Atkinson gasoline engine and a
generator are used as the range extender. The engine
performance data is obtained from the bench test.
The engine model and the generator model are
established in the Cruise, which ensures the high
precision of the simulation.
3.1 Engine Model
Figure 2: Input interface of basic parameters of the engine
module
The parameters that need to be set under the engine
module mainly are: engine type, displacement,
normal working temperature, cylinder number, idle
speed, maximum speed, moment of inertia and fuel
parameters (type, calorific value, density) (Dong
Xinyang,2012). The input interface of basic
parameters of the engine module is shown in figure
2. The engine characteristics are specified by
following parameters: engine external characteristic
data, engine universal characteristic data, anti-drag
characteristics, fuel consumption and emission
performance, as shown in figure 3 through figure 5.
Figure 3: Efficiency diagram of the engine
Figure 4: External characteristics of the engine
Figure 5: Anti-drag characteristics of the engine
After torque calibration by bench test and
emission test, the map of the internal combustion
engine of the range extender is generated, in addition
to three-dimensional table containing engine load,
Application and Simulation of Atkinson Cycle Engine for the Range Extender
585

speed and fuel consumption rate, as shown in figure
6. The function model of the engine is formulated by
putting it into the corresponding module of the
Cruise.
Figure 6: Map of the engine
3.2 Generator Model
The built-in motor module in the Cruise is used as
the generator (Zhao Jinlong, 2014), and the input
interface of the generator parameters is shown in
figure 7 through figure 10 below.
Figure 7: Input interface of the generator parameters
Figure 8: External characteristics of the motor
Figure 9: Universal characteristics of the motor
Figure 10: Efficiency map of the generator
ICECTT 2018 - 3rd International Conference on Electromechanical Control Technology and Transportation
586

4 SIMULATION ANALYSIS
After the simulation test, the fuel consumption curve
of the Atkinson engine is obtained as shown in
figure 11. It can be seen that the minimum fuel
consumption can reach 230g/kWh.
Figure11: Fuel consumption curve of the engine
The external characteristic curve is generated as
shown in figure 12 by taking data from the best
efficiency working points of the engine (the low fuel
consumption point) and setting up the engine
working conditions.
Figure 12: External characteristic curve of the engine
The comprehensive fuel consumption per
hundred kilometres (L) (GB/T 19753-2005) is less
than 1.9, which is obtained by operating the range
extender according to the Atkinson cycle optimal
curve.
5 CONCLUSIONS
The study shows that applying the Atkinson engine
to the range extender can reduce the fuel
consumption, so that the comprehensive fuel
consumption per 100 km can reach 1.9 or less by
running the engine at the optimal efficiency points.
REFERENCES
Zhu Longfei. Parameters design and performance
optimization of the power system of the range
extended electric vehicle [D], Hefei, Hefei University
of Technology, 2012.
Dong Xinyang. A study of control strategy design and
optimization for the powertrain of the range extended
electric vehicle [D], Hefei, Hefei University of
Technology, 2012.
Zhao Jinlong. Parameter matching and control strategy
research of powertrain system for Range-extended
electric vehicle [D],ChongQing University, 2014.
Mehedad Ehsani, Yimin Gao, Ali Emadi. Modern electric
vehicles, hybrid electric vehicles and fuel cell vehicles
-- basic principles, theories and designs (second
edition of the original book) Translated by Ni
Guangzheng, Ni Peihong and Xiong
Suming[M].Beijing, Machine Press, 2010.
Wang Da, Wang Bo. Research on Driving Force Optimal
Distribution and Fuzzy Decision Control System for a
Dual-motor Electric Vehicle [A]. Chinese Control
Conference[C]. Hangzhou: Institute of Electrical and
Electronics Engineers, 2015.
Zhang Xiaoling. Simulation and analysis for the power
system of the extended range electric vehicle[J],
Journal of Chinese Agricultural Mechanization, 2017,
37(6).
Wang Peng. A Study on powertrain matching and
optimizing for Ｒange -extended electric vehicle[J],
Computer Simulation, 2016,33(8).
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