Paladin06

Direct Injection

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Overview

Conventional gasoline engines are designed to use an electronic fuel injection system, replacing the traditional mechanical carburetion system. Multi-point injection (MPI), where the fuel is injected through each intake port, is currently one of the most widely used systems. Although MPI provides a drastic improvement in response and combustion quality, it is still limited due to fuel and air mixing prior to entering the cylinder.

To further increase response time and combustion efficiency, while lowering fuel consumption and increasing output, systems may use direct injection. Gasoline direct injection engines are engineered to inject the gasoline directly into the cylinder in a manner similar to diesel direct injection engines.

Direct injection is designed to allow greater control and precision, resulting in better fuel economy. This is accomplished by enabling combustion of an ultra-lean mixture under many operating conditions. Direct injection is also designed to allow higher compression ratios, delivering higher performance with lower fuel consumption. Currently, direct injection gasoline engines are being deployed throughout Europe in passenger cars.

Key Benefits
Simplifies development procedures for powertrain control system suppliers
Provides additional computing strength for complex applications
Supports vehicle networking with three TouCAN modules
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Design Challenges

Many of the design challenges in a direct injection system involve operation within harsh environments. Designing reliable, cost-effective injectors capable of withstanding the in-cylinder heat has proven to be a complex challenge. Due to the very short time for injection, high-pressure injectors are required. From an electronics standpoint, direct injection engines have a small window for injection. In direct injection engines, injection typically occurs during the intake stroke, allowing only 90° on an eight-cylinder (1.875ms) for total fuel delivery. During higher output modes, fuel can be injected during the intake stroke giving an additional 90° of injection time, a very short time compared to the 720° (15ms) an MPI engine typically has for fuel delivery.



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Solution

Any of the Freescale Semiconductor MPC500 Family members can be used for direct injection. The MPC500 Family of microcontrollers is designed to respond to direct injection implementation challenges based on its operation in a wide temperature range, from approximately -40°C to 125°C, and its high performance. The central processing unit (CPU) runs at speeds of up to 66 MHz. The MPC500 Family supports a wide range of on-board peripherals.

With three timer processor units (TPU3), the MPC565 provides additional computing muscle for complex applications. Each of these units has a 32-bit MicroRISC engine capable of processing up to 28 million instructions per second. Off-chip serial communications are handled by QSMCM modules for universal asynchronous receiver and transmitter (UART) and serial peripheral interface (SPI) functionality. Vehicle networking is supported with three TouCAN (CAN version 2.0B) modules and one J1850 interface. The package option is a 388-pin PBGA.

The MPC565 is the first embedded processor in the automotive market with 1MB of embedded Flash EEPROM memory. It has a comprehensive suite of low-level drivers software, enabling engine control and timing systems. It is designed to simplify development processes for powertrain control system suppliers