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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.

Over the last few decades, in-cylinder visualization using optically accessible engines has been an important tool in the detailed analysis of the in-cylinder phenomena of internal combustion engines. However, most current optically accessible engines are recognized as being limited in terms of their speed and load, because of the fragility of certain components such as the elongated pistons and transparent windows. To overcome these speed and load limits, we developed a new generation of optically accessible engines which extends the operating range up to speeds of 6000 rpm for the SI engine version, and up to in-cylinder pressures of 20 MPa for the CI engine version. The main reason for the speed limitation is the vibration caused by the inertia force arising from the heavy elongated piston, which increases with the square of the engine speed.

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.

The characteristics of exhausted smoke of a methanol DI diesel engine which is ignited by diesel fuel are investigated to clarify the soot formation process. At this engine, very little smoke is exhausted when diesel fuel is kept below a certain amount, so soot and smoke emitting characteristics are studied under the various diesel fuel amounts. By analyzing microstructure of soot, it is found that the soot emitted from the methanol diesel engine is composed of inner core and outer shell, similar to that of the conventional diesel engines. From more detailed qualitative analysis, the calcium percentage from the lubricating oil in outer shell is much higher than that of the conventional diesel engines. In consideration of soot characteristics, spray structure and combustion characteristics, the soot formation process of the methanol diesel engine was clarified.

The effects of multiple-injection on exhaust emissions and performance in a small HSDI (High Speed Direct Injection) Diesel engine were examined. The causes for the improvement were investigated using both in-cylinder observation and three-dimensional numerical analysis methods. It is possible to increase the maximum torque, which is limited by the exhaust smoke number, while decreasing the combustion noise under low speed and full load conditions by advancing the timing of the pilot injection. Dividing this early-timed pilot injection into two with a small fuel amount is effective for further decreasing the noise while suppressing the increase in HC emission and fuel consumption. This is realized by the reduced amount of adhered fuel to the cylinder wall. At light loads, the amount of pilot injection fuel must be reduced, and the injection must be timed just prior to the main injection in order to suppress a possible increase in smoke and HC.

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.

The cause of the exhaust smoke and its reduction methods in a small DI Diesel engine with a small-orifice-diameter nozzle and common rail F.I.E. were investigated under high-speed and high-load condition, using both in-cylinder observations and Three-dimensional numerical analyses. The following points were clarified during this study. At these conditions, fuel sprays are easily pushed away by a strong swirl, and immediately flow out to the squish area by a strong reverse squish. Therefore, the air in the cavity is not effectively used. Suppressing the airflow in a piston cavity, using such ideas as enlarging the piston cavity diameter or reducing the port swirl ratio, decreases the excessive outflow of the fuel-air mixture into the squish area, and allows the full use of air in the whole cavity. Hence, exhaust smoke is reduced.

Means for reducing the particulate matter (PM) from swirl chamber type diesel engines were searched out, and the reducing mechanisms were examined using an optically accessible engine. The following points were clarified in this study. 1. At light load, the suppression of the initial injection rate reduces PM, because SOF is reduced by the change in ignition point and smoke is reduced by the retarded flowout of the dense soot from the swirl chamber 2. Under medium and high load conditions, the main cause of the exhaust smoke is fierce spray-wall impingement which leads to fuel adhesion on the wall and the stagnation of a rich fuel-air mixture. 3. Enlarging swirl chamber volume ratio suppresses the formation of dense soot in the swirl chamber. In the main chamber, however, the soot oxidization becomes insufficient due to the mixing effect reduced by the essentially decreased chamber depth. 4.

When fuel is vaporized and mixed well with air in the cylinder of premixed diesel engines, the mixture auto-ignites in one burst resulting in strong combustion noise, and combustion noise reduction is necessary to achieve high load premixed diesel engine operation. In this paper, an engine noise analysis was conducted by engine tests and simulations. The engine employed in the experiments was a supercharged single cylinder DI diesel engine with a high pressure common rail fuel injection system. The engine noise was sampled by two microphones and the sampled engine noise was averaged and analyzed by an FFT sound analyzer. The engine was equipped with a pressure transducer and the combustion noise was calculated from the power spectrum of the FFT analysis of the in-cylinder pressure wave data from the cross power spectrum of the sound pressure of the engine noise.

Piston ring moving zone in the cylinder is one of the most critical lubrication regimes in diesel engines. This area is susceptible to combustion substances. In particular, abnormal wear is occasionally detected due to Exhaust Gas Recirculation (EGR) system equipment. In Japan, NOx emission requirements for passenger car diesels have become more stringent effective October 1, 1986. OEMs tend to apply EGR systems to reduce NOx in exhaust gas. In order to identify the phenomenon of abnormal cylinder wear of EGR equipped engine, engine bench tests were conducted under varied conditions in EGR equipment, cooling water temperature and fuel sulfur content. The test results suggest that wear caused at low temperature is mainly corrosive wear attributable to sulfuric acid formed by reaction with fuel sulfur and condensed water.

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.

Diesel engines with relatively good fuel economy are known as an effective means of reducing CO₂ emissions. It is expected that diesel engines will continue to expand as efforts to slow global warming are intensified. Diesel particulate and NOx reduction system (DPNR), which was first developed in 2003 for introduction in the Japanese and European markets, shows high purification performance which can meet more stringent regulations in the future. However, it is poisoned by sulfur components in exhaust gas derived from fuel and lubricant. We then developed the sulfur trap DPNR with a sulfur trap catalyst that traps sulfur components in the exhaust gas. High purification performance could be achieved with a small amount of platinum group metal (PGM) due to prevention of sulfur poisoning and thermal deterioration.