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In order to correspond to the exhaust emissions regulations that become severe every year, more advanced engine control becomes necessary. Engine engineers are concerned about the Hydrocarbons (HCs) that flow through the air-intake ports and that are difficult to precisely control. The main sources of the HCs are, the canister purge, PCV, back-flow gas through the intake valves, and Air / Fuel ratio (A/F) may be aggravated when they flow into the combustion chambers. The influences HCs give on the A/F may also grow even greater, which is due to the increasingly stringent EVAP emission regulations, by more effective ventilation in the crankcase, and also by the growth of the VVT-operated angle and timing, respectively. In order to control the A/F more correctly, it is important to estimate the amount of HCs that are difficult to manage, and seek for suitable controls over fuel injection and so on.

A new 4.5 liter in-line 6 cylinder engine,1 FZ-FE has been developed for the Toyota Land Cruiser. To obtain high power, fuel efficient engine, we adopted the most advanced Toyota technologies, such as Toyota original 4 Valve DOHC system with scissors gear between camshafts, compact combustion chamber with smooth inlet and outlet system, KCS and so on. The engine produces 212 HP at 4600 rpm and 275 ft-lbs at 3200 rpm. Aluminum cylinder head,short skirt cylinder block stiffened with aluminum oil pan give the engine light weight and make it rigid enough to have low vibration and quietness. And we also designed every engine part appropriately so as to make the engine durable enough in severe operating condition of off-road vehicle.

To avoid knocking phenomena, a special crank mechanism for gasoline engine that allowed the piston to move rapidly near TDC (Top Dead Center) was developed and experimentally demonstrated in the previous study. As a result, knocking was successfully mitigated and indicated thermal efficiency was improved [1],[2],[3],[4]. However, performance of the proposed system was evaluated at only limited operating conditions. In the present study, to investigate the effect of piston movement near TDC on combustion characteristics and indicated thermal efficiency and to clarify the knock mitigation mechanism of the proposed method, experimental studies were carried out using a single cylinder engine with a compression ratio of 13.7 at various engine speeds and loads. The special crank mechanism, which allows piston to move rapidly near TDC developed in the previous study, was applied to the test engine with some modification of tooling accuracy.

In internal combustion engine, it is well-known that oil infiltrates the combustion chamber through the clearance between the piston ring and the cylinder bore with vertical reciprocating motion of the piston, leading to an increase in oil consumption. The deformation of the cylinder bore is inevitable to some extent in the actual engine because of the tightening of cylinder head bolt and heat load._As to the function of the piston ring, it is desirable that it conforms to such bore deformation. The author et al. made a glass cylinder engine in which closed piston ring gap could be visualized, based on the idea that piston ring conformability to the sliding surface of bore could be evaluated from minute changes of the piston ring gap. This newly-devised visualized engine was an in-line 4-cylinder engine, capable of running up to 6,000 rpm, in which the closed gap of piston ring could be observed minutely during engine operation.

The reduction of engine oil consumption rate is one of the important concerns for automotive engineers. However, it has been difficult to solve this subject, since the oil consumption mechanism has not yet been elucidated. In this study, to clarify the oil loss mechanism via the piston rings, a transparent glass cylinder engine was used to observe oil behavior between cylinder wall and piston surface. For photographic observation, a high speed camera, a still camera. and a TV camera were used. Since the new photographic system by using TV camera with a synchro - flash and a synchro-memory was applied, it was also possible to observe the oil behavior in detail. Moreover, a new visual method by which colored oil was injected from the various points on the piston surface and traced was developed for easy analysis of oil movement around the piston ring.

Fifty percent distillation temperature (T50) can be used as a warm-up driveability indicator for a hydrocarbon-type gasoline. MTBE-blended gasoline, however, provides poorer driveability than a hydrocarbon-type gasoline with the same T50. The purposes of this paper are to examine the reason for poor engine driveability caused by MTBE-blended gasolines, and to propose a new driveability indicator for gasolines including MTBE-blended gasolines. The static and dynamic evaporation characteristics of MTBE-blended gasolines such as the evaporation rate and the behavior of each component during evaporation were analyzed mainly by using Gas Chromatography/Mass Spectrometry. The results of the analysis show that the MTBE concentration in the vapor, evaporated at ambient temperature (e.g. 24°C), is higher than that in the original gasoline. Accordingly, the fuel vapor with enriched MTBE flows into the combustion chamber of an engine just after the throttle valve is opened.

In this paper, the authors have developed a new measuring method of the liquid fuel film thickness on walls, such as intake ports, the combustion chamber and cylinder liner of a Port Fuel Injection (PFI) engine, and clarified the fuel film behavior under various running conditions when Fiber-based Laser-Induced Fluorescence (Fiber-based LIF) was applied to the newly developed method. The thickness of the fuel film is measured by detecting the intensity of fluorescence from the film that is irradiated by a He-Cd laser. A single optical fiber is used to simultaneously transmit the laser beam and the fluorescence from the film. In addition, the S/N ratio of the fluorescence is improved by using a He-Cd laser of which the wavelength (λ=442nm) is able to efficiently irradiate test fuel doped 2-3-butandione. Using this method, the fuel film thickness on the wall of the PFI engine was analyzed in two case studies.

Toyota participated in Formula One1 (F1) Racing from 2002 to 2009. As a result of the downturn in the world economy, various engine developments within F1 were restricted in order to reduce the cost of competing in F1. The limit on the maximum number of engines allowed has decreased year by year. Toyota focused on the engine performance deterioration due to the combustion chamber deposits. In 2009, Toyota was successful in reducing around 40% of the deterioration by making combustion chamber cleaner in cooperation with ExxonMobil. This contributed to good result of 2009 F1 season for Toyota, including two second place finishes.

This report describes the implementation of the spark channel short circuit and blow-out submodels, which were described in the previous report, into a spark ignition model. The spark channel which is modeled by a particle series is elongated by moving individual spark particles along local gas flows. The equation of the spark channel resistance developed by Kim et al. is modified in order to describe the behavior of the current and the voltage in high flow velocity conditions and implemented into the electrical circuit model of the electrical inductive system of the spark plug. Input parameters of the circuit model are the following: initial discharge energy, inductance, internal resistance and capacitance of the spark plug, and the spark channel length obtained by the spark channel model. The instantaneous discharge current and the voltage are obtained as outputs of the circuit model.

A direct injection (DI) gasoline engine having a new stratified charge combustion system has been developed. This new combustion process (NCP) was achieved by a fan-shaped fuel spray and a combustion chamber with a shell-shaped cavity in the piston. Compared with the current Toyota D-4 engine, wider engine operating area with stratified combustion and higher output performance were obtained without a swirl control valve (SCV) and a helical port. This report presents the results of combustion analyses to optimize fuel spray characteristics and piston cavity shapes. Two factors were found to be important for achieving stable stratified combustion. The first is to create a ball-shaped uniform mixture cloud in the vicinity of the spark plug. The optimum ball-shaped mixture cloud is produced with a fuel spray having early breakup characteristics and uniform distribution, and a suitable side wall shape in the piston cavity to avoid the dispersion of the mixture.

The authors have developed an instrument that measures the CO2 concentration in engine combustion chambers using the infrared absorption method. The characteristics of this technology are as follows: 1 Measuring can be carried out while the engine is running at 600r/min to more than 3000r/min, full load operation. (Applicable to all EGR conditions) 2 Quick response; 2ms 3 High linearity; ±1% Full Scale and under (FS: 10%) 4 No aggravation is caused to the intake/exhaust performance of engines This technology contributes to the improvement of the in-cylinder EGR system using, for instance, a variable valve-timing mechanism that is now expanding in number of applications, and also the conventional EGR system.

This research aimed to identify how combustion characteristics are affected by the addition of hydrogen to methane, which is the main components of natural gas, and to study a combustion method that takes advantage of the properties of the blended fuel. It was found that adding hydrogen did not achieve a thermal efficiency improvement effect under stoichiometric conditions because cooling loss increased. The same result was obtained under EGR stoichiometric conditions. In contrast, under lean burn conditions, higher thermal efficiency and lower NOx than with methane combustion was achieved by utilizing the wide flammability range of hydrogen to expand the lean limit. Although NOx can be decreased easily by the addition of large quantities of hydrogen, the substantially lower energy density of the fuel causes a substantial reduction in cruising range. Consequently, this research improved the combustion of a CNG engine by increasing the tumble ratio to 1.8.

In order to realize higher response and lower emissions for 4-valve engines, TOYOTA has researched ways to homogenize the air-fuel mixture in the combustion chamber as well as to reduce intake port wall-wetting. To achieve these items we have developed an air-assisted type two-hole injector (air-assisted injector) system which has improved both fuel atomization and spray directions. This system has been introduced to a 3Liter V-6 passenger car engine and mass produced. The air-assisted injector atomizes the fuel by causing the air to collide and mix with the fuel. In order to obtain the air needed for atomization under all driving conditions, including idling, a new type idling speed control valve (ISCV) which has two air outlet passages has been developed. By means of this new ISCV, the new air-assisted injector system improves both fuel atomization and engine idling speed control during cold and hot engine conditions.

A new technologies for manufacturing of engine valve seats have been developed. This process, different from the conventional method that valve seats made of sintered alloy were press-fit into the cylinder head, is directly formed valve seats onto cylinder head by using the laser cladding technique. In order to develope the cylinder head with laser cladding valve seats, the laser cladding technology by which copper based alloy is deposited onto aluminum alloy with little dilution and stable bead has been established. And the unique cladding alloy, which is two phases in the liquid stage and in which iron or molybdenum rich hard particles are dispersed in the solid state, has been developed. Based on this technique, the practical process has been successfully completed.

The second generation methanol lean burn system has been developed. The power unit is a new, 4 valve 1.6L in-line four with compact combustion chambers. Lean misfire limit was extended by using a swirl control valve in the intake port which improves combustion under partial load. Lean mixture control is made by using a signal from lean mixture sensor provided in the exhaust manifold. An EGR system has been newly adopted to reduce NOx emissions and a under-floor type catalyst is also used to reduce formaldehyde emission in the cold transient mode in addition to the manifold type catalyst. Permissible excess air ratio range (PEXARR) was defined and used to indicate the potential for reducing vehicle NOx emissions in engine dynamometer tests to optimize compression ratio, valve timing and swirl ratio and to evaluate the effect of the EGR.

The use of ceramic insulation to reduce engine heat loss and thus improve fuel economy was examined but found to be detrimental rather than advantageous. This paper analyzes the reasons and presents an alternative approach, namely minimizing the heat transfer area. Experiments were conducted to determine the effects of surface smoothness on BSFC, output torque, heat release rate and piston temperature. It was found that with a mirror-finished combustion chamber, heat loss is decreased and consequently engine output is raised, while fuel consumption is lowered. The percentage reduction in heat loss was ascertained by numerically simulating combustion and was confirmed by FEM analysis of piston thermal distribution.

Engine dynamometer tests were conducted to evaluate the effect of detergent additives and gasoline components on Combustion Chamber Deposits (CCD). Additives with polyether amine (PEA) and with polyolefin amine (POA) chemicals were used. Three kinds of POA additives were used. Our results show that some kinds of additives and aromatics in gasoline increase CCD formation. Different polyolefin detergents show different tendency of CCD formation. The amount of CCD showed good relationship with the unwashed gum level of the gasoline. In general, smaller dosages produce less CCD. This means that detergents which have good IVD and PFID effectiveness at smaller dosage are better with regard to CCD. We analyzed the CCD by C13-NMR, GPC and IR method. The detergent contributes to CCD. Vehicle emissions tests were carried out to evaluate the effects of CCD on exhaust emissions.

A helical port with a swirl control valve (SCV) has been developed to satisfy two inconsistent requirements of achieving sufficient swirl generation to improve the combustion and still maintaining high volumetric efficiency. Their effects on combustion were confirmed in a single cylinder engine using high speed flame photography and cylinder pressure diagram analysis which has demonstrated faster combustion. As a result of a hot wire anemometer study, the differences in gas motion were clarified between two helical ports, one with and one without a SCV. A more active movement of the center of swirl was measured in the case of helical port with SCV which suggests the generation of higher turbulence in the cylinder.

The effects of high boiling point fuel additives on deposits were investigated in a commercial turbocharged direct injection gasoline engine. It is known that high boiling point substances have a negative effect on deposits. The distillation end points of blended fuels containing these additives may be approximately 15°C higher than the base fuel (end point: 175°C). Three additives with boiling points between 190 and 196°C were examined: 4-tert-Butyltoluene (TBT), N-Methyl Aniline (NMA), and 2-Methyl-1,5-pentanediamine (MPD). Aromatics and anilines, which may be added to gasoline to increase its octane number, might have a negative effect on deposits. TBT has a benzene ring. NMA has a benzene ring and an amino group. MPD, which has no benzene ring and two amino groups, was selected for comparison with the former two additives.

Squish flow control is well known as a key technology for improving knock limit in spark ignition engines. However, to acquire a sufficient squish area in a four-valve engine is difficult. In order to achieve a maximum effect of knock suppression with a minimum squish area, we have developed, what we call, a Slant Squish Combustion Chamber for new engines. A slant squish compared with a conventional squish produces an effective reverse squish flow in the early expansion stroke, resulting in higher flow velocity and turbulence. Furthermore, flame propagation to squish area and end gas is accelerated. These improvements are considered to suppress the knock phenomenon. Consequently, with a slant squish, a high compression ratio, to achieve low fuel consumption and high engine performance is realized.