Steve Wilson <no@spam.com> wrote:> Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:>> onsdag den 6. juni 2018 kl. 21.38.54 UTC+2 skrev Steve Wilson: >>> Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:>>> > at idle and low loads there isn't much pressure>>> Q: Why should there be any difference? The compression ratio doesn't >>> change. When you measure the cylinder compression, it is a static >>> measurement at low rpm. The engine is cranked over by the starter. >>> Variations between cylinders indicates leakage from intake or exhaust >>> valves or worn rings, or a blown head gasket.>> because the throttle is closed so the manifold is at vacuum. When doing >> compression test you need the throttle wide open> The throttle is not completely closed. It is at idle. Plenty of air > enters the cylinder to measure the compression.>>> High loads means more fuel and air enters the cylinders. If the >>> cylinder pressure increased, it would start acting as a diesel. This >>> is called knock and can be very destructive. Most cars have a knock >>> sensor to prevent damage.>>> Also, diesel engines idle fine. This means the cylinder pressure is >>> adequate to ignite the fuel. Why should it change at operating rpm?>> diesel engines don't throttle the air they just meter the fuel> Yes. You havn't explained why the cylinder pressure is low at idle.Throttle. Throttle. Throttle. It doesn't matter if the compression ratio is constant. If you don't have much air to being with, you won't get much pressure at the end. Smarter every day. Anything I can do to keep my car away from Candian Tire is good. Good discussion. Thanks.
SPICE model for a spark plug?
Started by ●June 5, 2018
Reply by ●June 6, 20182018-06-06
Reply by ●June 6, 20182018-06-06
On Wednesday, 6 June 2018 20:50:48 UTC+1, Jim Thompson wrote:> On Wed, 6 Jun 2018 11:29:26 -0700 (PDT), tabbypurr wrote: > >On Wednesday, 6 June 2018 19:19:17 UTC+1, Jim Thompson wrote: > >> On Wed, 6 Jun 2018 11:08:36 -0700 (PDT), tabbypurr wrote:> >> >One car I had with points & coil produced around 6kV for sparkplugs IIRC, nothing like 20kV> >> What brand? In air, or under compression? > >> > >> ...Jim Thompson > > > >Lada, late 1960s design. 6-7kV at idle. AIUI figures like 20kV are more associated with electronic ignition, but it's not an area of expertise for me. Measured by an adjustable spark gap in open air, that was measuring the max V_out the coil could produce. So it can't have delivered more to the compressed cylinder content - must have dlivered less in fact. > > > > > >NT > > That voltage is _after_ the HV finally breaks-over. > > ...Jim ThompsonIt was incapable of jumping the gap at all at any wider spacing, so around 6kV was the _peak_ output. NT
Reply by ●June 6, 20182018-06-06
On Wed, 06 Jun 2018 09:40:06 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:>On Wed, 06 Jun 2018 08:52:05 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>On Wed, 6 Jun 2018 02:41:47 -0700 (PDT), Klaus Kragelund >><klauskvik@hotmail.com> wrote: >> >>>On Wednesday, June 6, 2018 at 1:09:35 AM UTC+2, Joerg wrote: >>>> Looking for a SPICE model that mimics a spark plug, ideally with and >>>> without fuel. Does anyone know where to find one? >>>> >>>> So far I found: >>>> >>>> >>>> .subckt spark_gap 1 4 >>>> R_off 1 2 1e7 ; dark resistance (affects breakdown voltage) >>>> R_ion 1 2 R=10/V(ion)**.75 ; dynamic ionization resistance >>>> Dfall 2 3 10V ; bidirectional cathode fall voltage >>>> Cdfall 2 3 50p Rser=100 ; for convergence >>>> V_ion 3 4 0 ; current sense for behavioral sources >>>> B_ion 0 ion I=I(V_ion)**2 ; measure of channel ionization >>>> C_ion ion 0 5u Rpar=1 ; ionization time constant >>>> .model 10V d(Vfwd=10 Vrev=10 Ron=1) >>>> .ends spark_gap >>>> >>>> >>>> However, the spark occurs at a few hundred volts and changing parameters >>>> doesn't do much. >>>> >>>> -- >>>Wouldn't be better to "just" run a test, and feed the voltage/current waveform into spice? >>> >>>Cheers >>> >>>Klaus >> >>Break-over depends on risetime as well as voltage. I may have a >>model. Cross fingers. >> >> ...Jim Thompson > >Untested by JET. It has the odor of an LTspice model, so behavior and >convergence are automatically suspect >:-) > >.SUBCKT SPARK_GAP2 1 2 PARAMS: V_GLOW=1500 V_ARC=150 I_SUS=.002 >V_BREAKDN=12000 I_ARC=.2 > >* SINCE THE STRIKING IS VERY FAST, IT IS STRONGLY ADVISED >* TO SET TRTOL TO 1 VIA: .OPTIONS TRTOL=1 and ITL4=1000. THIS WILL >FORCE >* PSpice TO BE MORE VIGILANT IN THE VICINITY OF TRANSITIONS >* >* Documentation on the Sparkgap model can obtained from AEi Systems, >www.AENG.com, 310-216-1144, Info@AENG.com >* >D_D3 10 11 DZ_ARC >X_SARC 9 0 3 10 SPARK_GAP2_SARC >R_RT1 7 0 50 >D_DT2 8 9 D1N4148 >E_EBREAKDN_CONTROL 6 0 VALUE = {IF(ABS(V(1,2))>{V_BREAKDN} , 12 , >+ IF( ABS(I(V_VSENSE)) > {I_SUS} , 12 , 0 ))} >D_D4 5 11 DZ_ARC >E_EARC_CONTROL 8 0 VALUE = { IF( ABS(I(V_VSENSE)) > {I_ARC} , 12 , 0 >)} >D_D2 5 4 DZ_GLOW >V_VSENSE 5 2 DC 0 >C_CT2 9 0 0.1U >R_RT2 9 0 50 >C_CT1 7 0 0.25U >X_SBREAKDN 7 0 1 3 SPARK_GAP2_SBREAKDN >D_D1 3 4 DZ_GLOW >D_DT1 6 7 D1N4148 >.MODEL DZ_GLOW D (BV={V_GLOW} IS=1U RS=5 IBV=10U) >.MODEL DZ_ARC D (BV={V_ARC} IS=1U RS=5 IBV=10U) >.MODEL D1N4148 D (RS=.8 CJO=4PF IS=7E-09 N=2 VJ=.6V >+ TT=6E-09 M=.45 BV=100V) >.ENDS >.subckt SPARK_GAP2_SARC 1 2 3 4 >XS_SBREAKDN 3 4 1 2 SWhyste Params: Ron=5 Roff=50MEG VT=10 VH=0 >RS_SARC 1 2 1G >.ends >.subckt SPARK_GAP2_SBREAKDN 1 2 3 4 >XS_SBREAKDN 3 4 1 2 SWhyste Params: Ron=5 Roff=50MEG VT=10 VH=0 >RS_SBREAKDN 1 2 1G >.ends > > > ...Jim ThompsonPhil, This is from LTspice Digest #9378: "Spark Gap Sun Jun 3, 2018 4:54 am (PDT) . Posted by: bordodynov Hello. I developed the arrester models based on the model from analogspiceman. I added inertia, i.e. depending on the speed of the voltage supply, the breakdown voltage changes. I developed (based on the datasheet) the EM90X, EM230X, EM300X, EM350X, EM400XG, EM550X and EM3000XB models. I would like to expand this list with other arresters. Please indicate the types of surge arresters that models are desirable to have. Bordodynov. " Check out the "files" section to get the model (I'd guess). ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Thinking outside the box... producing elegant solutions, by understanding what nature is hiding. "It is not in doing what you like, but in liking what you do that is the secret of happiness." -James Barrie
Reply by ●June 6, 20182018-06-06
On Wednesday, 6 June 2018 21:00:00 UTC+1, Phil Hobbs wrote:> On 06/06/2018 03:54 PM, Joerg wrote: > > On 2018-06-06 12:50, Jim Thompson wrote: > >> On Wed, 6 Jun 2018 11:29:26 -0700 (PDT), tabbypurr wrote: > >>> On Wednesday, 6 June 2018 19:19:17 UTC+1, Jim Thompson wrote: > >>>> On Wed, 6 Jun 2018 11:08:36 -0700 (PDT), tabbypurr wrote:> >>>>> One car I had with points & coil produced around 6kV for > >>>>> sparkplugs IIRC, nothing like 20kV > >>>>> > >>>>> > >>>>> NT > >>>> > >>>> What brand? In air, or under compression? ...Jim Thompson > >>> > >>> Lada, late 1960s design. 6-7kV at idle. AIUI figures like 20kV are > >>> more associated with electronic ignition, but it's not an area of > >>> expertise for me. Measured by an adjustable spark gap in open air, > >>> that was measuring the max V_out the coil could produce. So it > >>> can't have delivered more to the compressed cylinder content - must > >>> have dlivered less in fact. > >>> > >>> > >>> NT > >> > >> That voltage is _after_ the HV finally breaks-over. ...Jim Thompson > >> > > > > On Russian-made cars you never know. I remember one journalist who was > > transferred to Russia who reported about his experience when buying a > > car there. They had exactly three cars at the dealership, all the same > > type Lada (essentially a copy of an older Fiat model), in three > > different colors. Two wouldn't start and the third had a flat tire (in > > the show room!). So they bought the one with the flat tire. > > > > It was a copy of a Fiat 124 sedan, including the reliability. LADA is a > Russian acronym for "Fix it again, Ivan". ;) > > Cheers > > Phil HobbsNo, it wasn't. The body was a reinforced Fiat 124, the rest was mostly Russian. The Lada is unusual in having a lot of misinformation about it out there. NT
Reply by ●June 6, 20182018-06-06
On Wednesday, 6 June 2018 21:19:54 UTC+1, Lasse Langwadt Christensen wrote:> onsdag den 6. juni 2018 kl. 21.54.48 UTC+2 skrev Joerg:> > On Russian-made cars you never know. I remember one journalist who was > > transferred to Russia who reported about his experience when buying a > > car there. They had exactly three cars at the dealership, all the same > > type Lada (essentially a copy of an older Fiat model), in three > > different colors. Two wouldn't start and the third had a flat tire (in > > the show room!). So they bought the one with the flat tire. > > > > https://youtu.be/mIAYxWCXF8A East Germany but close enough ;)The Trabi was a 1950s economy car, a very different animal. Plastic body, 2 stroke engine with 5 moving parts, no fuel gauge etc. The Lada was a good car when it came out. But it kept being manufactured about 40 years. NT
Reply by ●June 6, 20182018-06-06
On Wednesday, 6 June 2018 21:53:26 UTC+1, Joerg wrote:> On 2018-06-06 12:59, Phil Hobbs wrote: > > On 06/06/2018 03:54 PM, Joerg wrote:> >> On Russian-made cars you never know. I remember one journalist who was > >> transferred to Russia who reported about his experience when buying a > >> car there. They had exactly three cars at the dealership, all the same > >> type Lada (essentially a copy of an older Fiat model), in three > >> different colors. Two wouldn't start and the third had a flat tire (in > >> the show room!). So they bought the one with the flat tire. > >> > > > > It was a copy of a Fiat 124 sedan, including the reliability. LADA is a > > Russian acronym for "Fix it again, Ivan". ;) > > > > A friend's brother had the station wagon from Lada. It came standard > with a crowbar included. IIIRC the car gave him a lot of grief. > > https://en.wikipedia.org/wiki/VAZ-2101#/media/File:Lada_Riva_estate_Cambridge.jpgI've never seen one come with a crowbar. Do you mean a starting handle? They had those, being designed to operate in Siberian temperatures & offroad in the Russian climate, where inability to start the car was sometimes life-threatening. NT
Reply by ●June 6, 20182018-06-06
On 2018-06-06 16:05, tabbypurr@gmail.com wrote:> On Wednesday, 6 June 2018 21:53:26 UTC+1, Joerg wrote: >> On 2018-06-06 12:59, Phil Hobbs wrote: >>> On 06/06/2018 03:54 PM, Joerg wrote: > >>>> On Russian-made cars you never know. I remember one journalist >>>> who was transferred to Russia who reported about his experience >>>> when buying a car there. They had exactly three cars at the >>>> dealership, all the same type Lada (essentially a copy of an >>>> older Fiat model), in three different colors. Two wouldn't >>>> start and the third had a flat tire (in the show room!). So >>>> they bought the one with the flat tire. >>>> >>> >>> It was a copy of a Fiat 124 sedan, including the reliability. >>> LADA is a Russian acronym for "Fix it again, Ivan". ;) >>> >> >> A friend's brother had the station wagon from Lada. It came >> standard with a crowbar included. IIIRC the car gave him a lot of >> grief. >> >> https://en.wikipedia.org/wiki/VAZ-2101#/media/File:Lada_Riva_estate_Cambridge.jpg > >> > I've never seen one come with a crowbar. Do you mean a starting > handle? They had those, being designed to operate in Siberian > temperatures & offroad in the Russian climate, where inability to > start the car was sometimes life-threatening. >Not a crank like my Citroen 2CV had. It looked like a giant tire iron which was easily suitable to break down a locked front door. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●June 6, 20182018-06-06
On 2018-06-06 16:02, tabbypurr@gmail.com wrote:> On Wednesday, 6 June 2018 21:19:54 UTC+1, Lasse Langwadt Christensen > wrote: >> onsdag den 6. juni 2018 kl. 21.54.48 UTC+2 skrev Joerg: > >>> On Russian-made cars you never know. I remember one journalist >>> who was transferred to Russia who reported about his experience >>> when buying a car there. They had exactly three cars at the >>> dealership, all the same type Lada (essentially a copy of an >>> older Fiat model), in three different colors. Two wouldn't start >>> and the third had a flat tire (in the show room!). So they bought >>> the one with the flat tire. >>> >> >> https://youtu.be/mIAYxWCXF8A East Germany but close enough ;) > > The Trabi was a 1950s economy car, a very different animal. Plastic > body, 2 stroke engine with 5 moving parts, no fuel gauge etc. > > The Lada was a good car when it came out. But it kept being > manufactured about 40 years. >Are they still building them in Egypt? -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●June 6, 20182018-06-06
Steve Wilson <no@spam.com> wrote:> Throttle. Throttle. Throttle. It doesn't matter if the compression ratio > is constant. If you don't have much air to being with, you won't get much > pressure at the end.being with -> Begin with
Reply by ●June 6, 20182018-06-06
On Thursday, 7 June 2018 00:22:44 UTC+1, Joerg wrote:> On 2018-06-06 16:02, tabbypurr wrote: > > On Wednesday, 6 June 2018 21:19:54 UTC+1, Lasse Langwadt Christensen > > wrote: > >> onsdag den 6. juni 2018 kl. 21.54.48 UTC+2 skrev Joerg: > > > >>> On Russian-made cars you never know. I remember one journalist > >>> who was transferred to Russia who reported about his experience > >>> when buying a car there. They had exactly three cars at the > >>> dealership, all the same type Lada (essentially a copy of an > >>> older Fiat model), in three different colors. Two wouldn't start > >>> and the third had a flat tire (in the show room!). So they bought > >>> the one with the flat tire. > >>> > >> > >> https://youtu.be/mIAYxWCXF8A East Germany but close enough ;) > > > > The Trabi was a 1950s economy car, a very different animal. Plastic > > body, 2 stroke engine with 5 moving parts, no fuel gauge etc. > > > > The Lada was a good car when it came out. But it kept being > > manufactured about 40 years. > > > > Are they still building them in Egypt?I can't remember. The relevant company is Bogdan IIRC. ISTR they put weird door handles on them. NT
