[YesAuto Engine Technology] A few days ago, domestic media reported that GAC Toyota will launch a Ralink model equipped with a 1.2T turbocharged direct injection engine (hereinafter referred to as “Toyota 1.2T engine”). The new car is expected to be officially launched in April 2016. The 1.2T engine on it is likely to be the small-displacement turbocharged engine code-named “8NR-FTS” that FAW Toyota plans to introduce. What are the characteristics of this new engine? Now let's learn this together.
The important design goal of Toyota 1.2T is to improve the thermal efficiency of the engine. According to the data provided by the manufacturer, the thermal efficiency of the engine reaches 36.2%, which is close to the 38% thermal efficiency achieved on Toyota’s own 2NR-FKE 1.5L/1NR-FKE 1.3L naturally aspirated engine; but through the combination of Atkinson Circulation and turbocharging technology, this 1.2T engine has achieved a balance between torque output performance and fuel economy.
|Comparison of mainstream 1.2T turbocharged engine parameters|
|Number of cylinders||4||3||4||4|
|Maximum power||116Ps/5200-5600rpm||136Ps/5500rpm||110Ps/5000rpm|| 117Ps/5200rpm
|Peak torque||185N·m/1500-4000rpm||230N·m/1750-3500rpm||200N·m/2000-3500rpm|| 165N·m/1750-4500rpm
|Application model||Toyota Auris (Overseas)||308S||Seventh generation golf||Qashqai|
From the above comparison table, this Toyota 1.2T engine has no obvious advantage over competing products in terms of power output parameters. The fuel consumption data published by the Toyota Auris (overseas) 120T model is 19.4km/L (Japanese JC08 test cycle), which is 5.15L/100km when converted into the familiar fuel consumption per 100km. This is similar to the fuel consumption of the Volkswagen Golf 1.2T model 5.1L/100km (the comprehensive fuel consumption test cycle of the Ministry of Industry and Information Technology of China).
● VVT-iW variable valve timing technology with expanded adjustment range
Toyota 1.2T engine uses VVT-iW (Variable Valve Timing-intelligent Wide) variable valve timing technology. The same technology also appears on Toyota 2.0T engine code-named “8AR-FTS” (carried on Lexus NX, FAW Toyota Crown, GAC Toyota Highlander and other models). The VVT-iW variable valve timing technology on the engine does not use a common solenoid valve to switch the hydraulic oil circuit of the timing regulator to control the timing of the intake and exhaust valves. Instead, it uses a motor to switch the hydraulic oil. Way to obtain a higher adjustment speed and a wider adjustment range.
● Low inertia single scroll turbocharger
Toyota's 1.2T engine uses a low-inertia turbocharger with a single-scroll tube structure. Toyota uses Computer Aided Engineering (CAE) to optimize the shape of turbine blades and shells so that as much exhaust gas energy as possible can be used to pressurize fresh air, thereby contributing to the improvement of engine thermal efficiency.
● Water-cooled intercooler
Like many small displacement engines that we have disassembled (such as Volkswagen 1.4T, Ford 1.5T, etc.), Toyota's 1.2T engine also uses water-cooled intercooler technology. This technology can efficiently cool the charge air and has the characteristics of compact size. Compared with the external air-cooled intercooler, the water-cooled intercooler uses shorter pipelines, which can reduce the use of materials and reduce the manufacturing cost.
● Integrated exhaust manifold
Like mainstream gasoline engines worldwide, Toyota's 1.2T engine also uses integrated exhaust manifold technology. The integrated exhaust manifold can make the engine coolant heat up faster, which is conducive to the quick warm-up of the engine and the air-conditioning system to heat up faster. At the same time, when the engine is under high-speed and high-load conditions, the integrated exhaust manifold can effectively reduce the exhaust temperature and keep the turbocharger at a suitable operating temperature. In the past, the engine management system would increase the amount of fuel injected to reduce the exhaust temperature; with the integrated exhaust manifold, due to the increased heat exchange efficiency between the exhaust gas and the coolant, the additional fuel injection or no fuel injection can be reduced. Reduce the fuel consumption of the engine. In addition, the use of integrated exhaust manifold technology eliminates the external exhaust manifold, making the engine smaller and more compact, and can reduce the overall weight of the engine to a certain extent, thereby contributing to the reduction of vehicle fuel consumption. .
● Increase the intake tumble flow to increase the combustion speed
In order to increase the combustion speed of the mixture, increase engine torque output, reduce fuel consumption and emission levels, Toyota 1.2T engine adopts a unique intake port and piston crown design to increase the intensity of the tumble flow formed after the intake airflow enters the cylinder. The pit shape design on the piston crown promotes the flow of intake air flow. With precise fuel injection technology, even if the engine has less intake air at low load, it can form a strong enough mixed air tumble flow to improve combustion speed and efficiency. .
● New spacers for controlling the flow of coolant
Like the Toyota 2NR-FKE 1.5L engine we have analyzed before, the 1.2T engine also uses a new type of spacer located inside the cylinder water jacket. This spacer is made of foamed rubber and stainless steel sheet. This kind of spacer expands after absorbing the heat of the coolant, which can block the flow path in the middle of the cylinder. When the engine is under high load, this spacer can reduce the temperature of the upper part of the cylinder to reduce the probability of knocking; it can increase the temperature in the middle of the cylinder, reduce the viscosity of the lubricating oil between the piston and the cylinder wall, and reduce friction loss.
Like the small-displacement engines launched by European and American manufacturers, Toyota 1.2T also uses mainstream configurations such as integrated exhaust manifolds and water-cooled intercoolers. The difference is that the 1.2T engine uses VVT-iW technology to dynamically switch the Atkinson cycle and Alto cycle under different load conditions to achieve the goal of balancing fuel economy and torque output. In some technical details, it also reflects the excellence of Japanese manufacturers in technological research and development, such as a new type of partition to control the flow of coolant, and the design of a combustion chamber to increase the combustion speed. This 1.2T engine with a combustion efficiency of 36.2% may be the first to be equipped with Ralink. We will announce the actual performance of its power and fuel consumption as soon as we get the test drive. Please continue to pay attention to the relevant reports of our car home. (Picture/Partly from the network article/Car home Chang Qinglin)