Joint International Conference on Long-term Experiments ...

It was marked with AI the area of the leaking section near the needle top of injector with
conic top.
Ai = f(sa, β, d) = ct;
Ai = π(dp - 0,5 sa sinβ)sa sin β/2;
sa = 0,15 mm; dp = 1…1,2 mm; β = 60 0 .
Figure 2: The calculation scheme of electromagnetic injector
Discharge of gasoline which passes the injector leaking section is calculated by the
relation:
2(
pb
− pga
)
Q = μ ⋅ A
; (4)
b i i
ρb
where μI coefficient of discharge in the section offered by the needle; μi = 0,8 - 0,93 ;
Taking in consideration relation (2):
Q
2K
= μ ⋅ A
(5)
r
b i i
ρb
where: Ai is the leaking section at the injector; pb – gasoline pressure at the entrance of
injector; pga – air pressure from the manifold; ρb – gasoline density; Kr - constant
regulator pressure; Qb- discharge of the gasoline.
In the other hands it is lanown from the relation of the discharge definition, that is
the leaking fuel volume during a time unit.
We obtain
Q
b
V
=
t
b
i
mcb
=
ρ ⋅t
b
i
From the equality of relation (5) and (6) results un duration of the injection, ti:
mcb
1
ti
= ⋅
ρb
μ ⋅ A ⋅
2K
r
mcb
=
;
μi
⋅ Ai
⋅ 2K
r ⋅ ρb
1
d =
λ ⋅ Lo
m
=
m
i
i
ρ
b
429
(6)
cb
aer
;