Electronic Unit Pump Diesel Engine Control Unit Design for Integrated Powertrain System.pdf

electronic unit pump diesel engine control unit design for integrated powertrain system liu bo-ian （刘波澜） ， zhao chang-iu （赵长禄） ， zhang fu- un （张付军） ， huang ying（黄 英） （schooi of mechanicai and vehicuiar engineering，bei ing institute of technoiogy，bei ing 100081，china） abstract：the performance of the eiectronic unit pump（eup）diesei engine is studied，it wiii be used in the integrated powertrain and its muiti parameters are controiiabie. both the theoreticai anaiysis and experiment research are taken. a controi unit for the fuei guantity and timing in crankshaft domain is designed on this ba- sis and the engine experiment test has been done. for the constant speed camshaft driving eup system，the fuei guantity wiii increase as the suppiy angie goes up and in ection timing has no effect. the controi precision can reach 1 ca. the fuii in ection timing map and engine peak performance curves are made successfuiiy. key words：eiectronic unit pump（eup）diesei engine；integrated powertrain；eiectronic controi unit clc number：u 464.172document code：aarticle id：1004-0579 （2005） 01-0071-04 received2004-04-26 sponsored by the ministeriai levei advanced research foundation（104010302） biographyliu bo-ian （1974 - ） ，iecturer，ph.d.，iiuboian. an integrated powertrain system means that the engine and the transmission shouid be treated as a whoie. both design method and controi system devei- opment shouid be organized together 1. generaiiy， the best engine working points are chosen as the gearshift moment for either vehicie fuei economy or power performance. on the other hand，some re- searches have focused on active engine controi during gear shifting 2. in this paper a powertrain composed of an eiectronic unit pump（eup）diesei engine and an eiectronic automatic transmission（eat）is stud- ied. the controiier of both the power unit and the transmission wiii be deveioped and caiibrated to make the engine and the transmission work rightiy. to impiement the operation mentioned above，as a power unit the eup diesei engine is suitabie because its in ection guantity and timing are freeiy controi- iabie. based on these，some properties of the engine can be user-defined，such as the peak power curve， speed reguiate mode，torgue reserve coefficient etc.， which is guite usefui for the integrated controi. 1eup control method the fuei in ection guantity and timing controi are the most important aspects to engine controi unit. whiie the controi precision is guaranteed，the re- source of the system shouidn t be expended much. the sensor mounted on the camshaft is used for stroke udgement. the signai from crankshaft is the measure reference mark of both fuei guantity and tim- ing. configurabie timer moduie（ctm）and time processor unit（ tpu）of the micro-controiier unit （mcu）are utiiized. when a ctm interrupt is trig- gered by the camshaft，it means that the compress stroke wiii come and the controi unit shouid prepare for fuei suppiy. the crankshaft signai is connected to a channei of tpu that uses the pmm function. the pmm function detects a missing transition and marks the teeth number. if there exists z teeth，the span is obviousiy 360/ z . the controi puise is generated by psp function combining with pmm. the psp has two operating modes：angie-angie and angie-time. in angie-angie mode，the rising and faiiing edges of the output puise are determined independentiy of each other. in angie- time mode，the faiiing edge of the output puise is de- termined in reference to the rising edge. the controi 17 journal of bei ing institute of technology，2005，voi.14，no.1 fig.lcontroi iogic of in ection guantity and timing parameters are anglel（start angie） ，ratiol （muitipie ratiol） ，angle2（end angie）and ra- tio2（muitipie ratio2） . the in ection timing of eup is controiied by the first two parameters. the in ec- tion duration is decided by the iast two parameters combined with the former part. we use angie-angie mode that is simiiar to the engine working process. the aigorithm of in ection guantity and timing is the best technigue to guarantee the controi accuracy. the angie number is an integer and the ratio is the proportion of 0 x 80 （hexadecimai） . for exampie，if the span is l0 ca，the resoiution wiii be 0.l ca， which is good enough for fuei in ection system. the detaiied deduction couid be expressed as t = 360/ z， nl= （td -!i） / （t - l） ， rl= （td -!lt） / （l28t） ， n2= （td -!i+!d） / （t - l） ， r2= （td -!i+!d- n2t） / （l28t） ， where t is the span between two teeth；!iis the in- ection timing；!dis the in ection duration； nlis eguai to anglel and n2is eguai to angle2；rlis eguai to ratiol；r2is eguai to ratio2；d is the teeth number of tdc. 2eup properties research 2.1injection time delay there exists a time deiay of fuei in ection. at the point of start of in ection（soi） ，a drive signai is imposed on the eup. the fuei wiii be in ected after a short period tdthat is caiied deiay. as the eup is a compound system，which is composed of eiectric，hy- drauiic and mechanicai components，so that the deiay aiso has those three eiements 3. this is guite mean- ingfui for controi system design for the drive puise minus the deiay part is effective for fuei guantity con- troi. we get the deiay by means of a piezocrystai sen- sor，which is mounted on the high-pressure fuei pipe near the in ector. as shown in fig. 2，in the wave- form of pipe vibration there is a saitation point，at that time the fuei has been deiivered to the in ector. we test the deiay at different engine speeds，which has cieariy shown the reiationship of deiay angie vs. engine speed. it is a noniinear curve that the siope is big at iower engine speed and is getting smaii as the engine goes to a higher speed. fig.2in ection time deiay 2.2fuel 0uantity and engine speed in a definiteiy period of time，the fuei guantity deiivered to the cyiinder is decided by both the pres- sure change rate and the backward fuei mass rate. for the iatter the fuei return is treated assembiy as a pressure reiief vaive and we have 4 m l= cda0 2 （p 0- pc! ） ，（ l ） where cdis the fiow coefficient of the return orifice； a0is its section area；p0is the pressure before the orifice or we caii it upstream pressure；pcis the fuei return controi pressure by which the backward fuei fiow rate through a spring is controiiabie. when the engine speed goes higher the pressure before orifice increases whiie the return controi pres- sure is stiii changeiess. this wiii make the backward fuei mass rate higher. the other important thing is that the phenomenon of pressure hysteresis which is the pressure drop in the pipe costs time. the time span even wiii go ionger as the engine speed goes up， which aiso makes the return fuei increase. here we meter the fuei by the crank angie，so we have the test resuits in fig.3. in fig.3 the fuei guantity increases 27 journal of seijing institute of technology，2005，voi.l4，no.l iineariy with the fuei suppiy angie and the high speed one in the iow position means for the same fuei in ec- tion duration the fuei mass under iower speed is more than that under higher speed. mfcrefers to the fuei guantities per cycie. fig.3engine speed vs. fuei suppiy guantity 2.3injection timing in ection timing is criticai for engine controi con- sidering that it affects both the fuei economy and emission performance. we aiso investigate the effect of in ection timing on the fuei guantity under the same suppiy angie. the pressure change rate of the unit piunge pump is expressed as 5 p =!t v l dm dt + dh dt a p ，（ 2 ） fig.4in ection timing vs. guantity where!tis the isothermai eiastic moduius of the fuei； h is the iift of the piunge whiie v and apare their voiume and cross section area. from the eguation we can teii that if the mass change rate is invariabie oniy the piunge iift speed wiii affect the pressure change rate. here we use a con- stant siope profiied camshaft as the drive. so as the fuei suppiy angie increases the fuei guantity wiii change iineariy and fuei in ection timing wiii have no effect on the fuei guantity for no matter where in ec- tion starts. we got this in fig. 4 from which it is cieariy shown that the fuei guantity is iineariy in- creased and different in ection time curves cannot change this trend.as a resuit， such a kind of camshaft wiii make the controi unit design easier. meanwhiie to meet the more stringent emission regu- iations，the cam profiie maybe need some change for good in ection rate shaping. this is stiii in researching. 3experiment research experiment research has been done on a four- cyiinder turbocharged diesei engine. fig.5in ection timing map it is known that the super high pressure in ection systemeup has a potentiai to satisfy euro! emission standard and even to meet euro 6. the caiibration work of the system is important. so at first，an in ection timing map is made point by point considering both fuei economy and emission property. a certain working state（l 400 r/ min，320 nm）is seiected to sampie this. the angie of start in ection is added step by step and it is found that nooemits more whiie fuei economy and exhaust temperature change iess. that wiii decrease the emission to the opposite trend，but the angie couid not be too smaii that wiii make the fuei burning after the tdc. if this happened both the fuei economy and exhaust temper- ature wiii be worse. according to this ruie we make a fuei in ection timing map. fig.5 shows that the start in ection an- gie wiii increase when the engine speed goes up；this is ust because the mixture preparation and burning time wiii be iong. the ioads have iess effect compared with the speed and we oniy suspend the angie in mid- die ioad area and l 400 - l 800 rmin- lengine speed. this is so caiied common use area of heavy 37 liu bo-lan （刘波澜）et al. / electronic unit pump diesel engine control unit design for integrated powertrain system diesei engine in euro!test procedure. first we work some part ioad curves out. we find that the in ection puise is iinear with the suppiy angie and the power eguabiy whiie the in ection tim- ing angie can be operated freeiy. finaiiy we make the fuii ioad or the peak power curves in fig.6. for the speed stabiiization consideration we invaiidate the fan siiicon ciutch，which wiii make the fuei economy 10 g/ （kw h）more than the actuai vaiue. the high pressure makes the in ection duration iess，we can see the maximum angie is 30 ca of the rated point inciuding in ection deiay that property is beneficiai to future high speed and heavy duty diesei engine. by the oniine caiibration tooicucas（common used caiibration system） we have deveioped，the rated power curve，the siop of speed reguiate，the torgue reserve coefficient can be defined freeiy for different purposes of use. for the fuei in ection timing can be controiied，as you want at any points，aii this make the integrated controi meaningfui. in other words， the active controi of engine during transmission period promotes the guaiity of gearshift itseif. fig.6maximum break power curves of eup engine 4conclusions based on aii the research work mentioned above， we have the foiiowing conciusions： mounting the eup on the diesei engine wouid make the engine s fuei guantity and timing controi- iabie. as it is used as the power unit of the integrated powertrain，more parameters can be operated. #eup is a compound system composed of eiec- tric，hydrauiic and mechanicai components. it has the distinct time deiay and to the constant speed camshaft the suppiy angie is iineariy with the fuei guantity. in ection timing has no effect on it. $the fuei in ection timing map and engine p