The purpose of this study is to create a new
combustion concept that offers a high thermal efficiency
and very low NOx and soot emissions. To this end,
we performed 3D-CFD simulations to identify problems
with an actual PCCI that is characterized by in-cylinder
mixture non-homogeneity that arises through the direct
injection of diesel fuel. We compared the combustion
characteristics with an ideal 'HCCI' with homogeneous
mixture conditions. Then, to overcome PCCI problems
such as difficulties in combustion controllability
and the limited operating range, we identified the
key parameters impacting the HCCI/PCCI process through
experiments with a variety of paraffinic hydrocarbon
fuels. Finally, based on the knowledge gained through
these steps, we developed a new concept for dual-fuel
PCCI combustion using high- and low-RON fuels to achieve
extremely low NOx and smoke emissions. In this system,
gasoline was supplied from the intake air port and
diesel fuel was injected directly into the engine
cylinder to act as an ignition trigger at a timing
before TDC. It was found that the ignition phasing
of this PCCI combustion can be controlled by changing
the ratios of the two injected fuels, such that combustion
proceeds very mildly, even without EGR, thanks to
the spatial stratification of ignitability in the
cylinder, which prevents the entire mixture from igniting
instantaneously. The operable load range, where the
NOx and smoke emissions were less than 10 ppm and
0.1 FSN, respectively, was extended up to an IMEP
of 12 bar using an intake air boosting system together
with dual fueling.
�@�{�����́C�����M�����Ɣ��ɏ��Ȃ�NOx��X�[�g�G�~�b�V�����𗼗�����V�R�ăR�� �Z�v�g��n�o���邱�Ƃ�ړI�Ƃ���B�����B�����邽�߁C�ŏ���3D-CFD�V�~�����[�V������p���ė��z�I��HCCI�R�Ă̓����Ɣ�r���邱�Ƃɂ���āC�G���W�������ɔR
���ڕ��˂��邱�ƂŎ��������C�s�ώ��ȍ����C���z�����݂���ꍇ��PCCI�̖��_�𒊏o�����B
�@���ɁC�R�Đ��䐫�̍����^�]�̈�̋����ɑ�\�����PCCI�̖��_���������邽�߂ɁC��X�̃p���t�B���n�R����p������b�����ɂ���āCHCCI/PCCI�̔R�ĉߒ��ɉe����^����d�v�ȃp�����[�^����肵���B�Ō�ɁC�����̒m�������ɂ��āC��RON�R���ƒ�RON�R����2�R���ɂ���ĔR�Ă𐧌䂳�ꂽDual-fuel
PCCI�̃R���Z�v�g���J�� ���CNOx��X���[�N�̑啝�Ȓጸ���\�ɂ����B���̃V�X�e���ł́C�K�\�������z�C��
�ɕ��˂��C���Ό��Ƃ���TDC�O�̑����Ɍy���ڃG���W�������ɕ��˂���B����2�R���̕��˗ʔ�ɂ����PCCI�̒��Ύ����𐧌䂷�邱�Ƃ��\�ŁC������EGR��p���Ȃ��Ă��C�����ɒ��ΐ��̋�ԕ��z���`�����������_����}�����邱�ƂŁC���₩�ȔR�Ă��������邱�Ƃ��ł����B�܂��C�ߋ���p���邱�Ƃɂ���āCNOx��10ppm�ȉ��C
Smoke��0.1FSN�ȉ��̃N���[���ȉ^�]�̈��IMEP = 12bar�܂Ŋg��ł����B
�@
�@
