Mechanism; General (Introduction); Feature Of Combustion (E-Cdis); Structure Of Combustion (Center Direct Injection System (E-Cdis)) - wsm 03-CR-E4 Workshop Manual

MECHANISM

1. General (Introduction)
MECHANISM

1. General (Introduction)

1.1 Feature of combustion (E-CDIS)

This model utilizes a structure called E-CDIS where
injectors are arranged on the centerline of pistons. (E-
CDIS: Center Direct Injection System)
With this system fuel is injected directly to the center of
the top of the piston.
The combustion chamber at the top of the piston is a
reentrant type so fuel and intake air form a swirl and
mix uniformly.
This effect enables a stable and high efficiency
combustion.
1.2 Structure of combustion (Center
direct injection system (E-CDIS))
The combustion system is made up of the injectors and
pistons and the like.
(1) Injector
(2) Exhaust valve
03-CR-E4,03-CR-TE4BG
(3) Piston
(4) Intake valve

1.3 Flow of combustion (E-CDIS)

Combustion flow is separated into 4 processes.
(1) Pressure
(2) Crank angle (degree)
(3) Temperature (℃)
(a) Spontaneous combustion
temperature of fuel
(b) Air temperature
(c) Injection
(d) Combustion
(A) Point A
1. Ignition delay period
The ignition delay period is the period from when
fuel is injected into the cylinder as a mist until start
of combustion is attempted.
Fuel that injected into the cylinder at the high
temperature high pressure compressed air through
several degrees before compression top dead
center is vaporized by heat of air.
Thereafter, the fuel mixes with air nearing ignition
point (B point) and ignites.
2. Flame propagation period
The gas mixture accumulated in the ignition delay
period ignites at B point and rapidly combusts
instantly raising the pressure and temperature in
the cylinder.
3. Direct combustion period
Fuel continues to be injected even after passing
point C but the fuel combusts immediately due to
the ignition that took place between B and C.
This continues through the point (point D) where
injection stops and here pressure rise is relatively
slow.
4. Late combustion period
After fuel injection stops, combustion continues for
a short period burning the remaining fuel.
This period is called late combustion period and this
period should be as short as possible.
4. ENGINE
(B) Point B
(C) Point C
(D) Point D
(E) Point E
1 Ignition delay period
2 Flame propagation period
3 Direct combustion period
4 Late combustion period
4-1
KiSC issued 02, 2021 A